biodiversity

FOCUS
BIODIVERSITY
CNRS IN BRIEF
The Centre National de la Recherche Scientifique (National Center for Scientific Research)
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of France’s Ministry of Research.
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© CNRS Photothèque / Nicolas Cegalerba. An adult homopteran (Membracidae), French Guiana.
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FOCUS
BIODIVERSITY
page 04
EDITORIAL
page 06
DEBATE
page 12
UNDERSTANDING
BIODIVERSITY
page 18
ECOSYSTEM
DYNAMICS
page 24
THE IMPACT ON HEALTH
page 30
BIODIVERSITY
IN DANGER
page 36
SUSTAINABLE MANAGEMENT
page 43
BIODIVERSITY:
A FEW STATISTICS
SOMMAIRE
RESEARCH ON BIODIVERSITY
The huge variety of life on Earth is one of the great puzzles of modern science.
Why do so many species coexist? Is such diversity inevitable given the laws of evolution? What is the history of life? How did species diverge and succeed one another over the course of evolutionary history? What impact have dominant species had
on the formation of today’s environment? What role do they currently play in the
modification of environmental processes? These questions have fascinated biologists for many decades and are at the heart of one of the greatest intellectual adventures of our time. Since the Rio de Janeiro conference in 1992 biodiversity has also
become a social issue and its maintenance one of the major challenges for sustainable development. Biodiversity needs to be protected and managed, but why? The
simple answer to this question is that life on our planet depends on biodiversity.
Humans draw upon it for the food and the raw materials necessary for their survival.
Biodiversity is a source both of concern and of hope. It is a source of concern due
to the incredibly fast rate at which species are vanishing today, which leads the general public, understandably, to ask about the seriousness of the situation. In scientific terms, this issue is fueling a huge debate about the functional value of
biodiversity. For instance, we need to define the role that species play in the biophysicochemical organizations of which they are a part, or put another away, their
position in ecosystem structure and function. We also need to determine whether a
minimum number of species is required for ecosystem survival and whether or not
genetic diversity plays the same role as species diversity with respect to ecosystem
performance.
These problems are not only of theoretical interest to ecologists. They also have
a direct bearing on the quality of our environment. One only has to consider the key
role played by biodiversity in what are called ecosystem services, i.e. the ecological
functions listed in the Millennium Ecosystem Assessment, which affect the chemical composition of water and the atmosphere, the spread of disease, etc. Or the
response of ecosystems to climate change, which will depend above all on the number of species present in a given ecosystem, the nature of the interactions and relationships among the species, their ability to disperse and the impact of such
changes on genetic variability. For instance, the amazing plasticity of genomes such
as microbial genomes represents an evolutionary response to the spatially and temporally variable environment in which humans live. The future of our planet will thus
depend on our capacity to manage this biodiversity.
Biodiversity is also a source of hope. Firstly, there is nothing inevitable about the
loss of species. It can be slowed down or even halted by using innovative methods
of land management and species reintroduction based on the most recent research
findings. Secondly, living organisms are an almost inexhaustible source of molecules of interest to the pharmaceutical and chemical industries, which every day
enable us to fight disease or produce a number of substances which are essential
to industry. Knowledge of natural substances, their variability and how they change
in space and time is also an investment for the future. Finally, manipulating populations of plants, animals or micro-organisms in situ makes it possible to rehabilitate degraded environments or maximize certain of their characteristics or
functions, depending on the environmental problems, as well as issues related to
the exploitation of natural resources, which arise.
THE ACTIVITY OF CNRS
CNRS, in partnership with universities, the Muséum national d’histoire naturelle
(French National Museum of Natural History, MNHN), Inra (National Institute for
Agricultural Research), IRD (Institute for Research into Development), Cirad (French
Agricultural Research Center for International Development), Ifremer (French
Research Institute for Marine Resources), and others, is totally committed to research
into biodiversity. Aware of its responsibilities with regard to giving sustainable development a scientific basis, CNRS has made this issue one of its top priorities. In concrete terms, CNRS encourages theoretical and empirical innovation in four broad
fields: the analysis and management of biodiversity, mechanisms for the emergence
and maintenance of biodiversity, interactions between biodiversity and the environment, and the cultural, social and economic aspects of biodiversity. CNRS develops
this activity on the basis of studies carried out in collaboration with researchers from
various regions of the world, especially French Guiana and the French overseas
departments and territories, southern Africa (South Africa and Madagascar), Asia,
etc. To this end, CNRS relies on ca. 2,300 people, of whom about a thousand are CNRS
staff members, both in its own laboratories and in laboratories associated with universities and various partner organizations (MNHN, Inra, IRD, Cirad, Ifremer). All the
research departments of CNRS are concerned by the issue of biodiversity because of
its multidisciplinary nature. The recently created Department of Environmental
Sciences and Sustainable Development directly manages the laboratories which are
the most involved, looks after training and promotion of scientific activities in biodiversity, and organizes research and equipment development programs.
CNRS defines its policies in partnership with the other national bodies and institutions. A body which has traditionally adopted an integrated approach is the Institut
national des sciences de l’Univers (National Institute of Earth Sciences and
Astronomy), which plays a major role in financing research into the diversity of marine
organisms, interactions between the biosphere, the atmosphere and the hydrosphere,
and paleobiodiversity. CNRS is also a member of two scientific consortiums, the
Institut français de la biodiversité (French Institute for Biodiversity) and the Bureau
des ressources génétiques (Genetic Resources Institute), which regularly issue calls
for research proposals, represent France in a number of European and international
bodies and propose national programs on different themes. CNRS contributes to various bodies of the Agence nationale de la recherche (French National Research
Agency), the main funding agency in France. It also supports European organizations
such as the European Science Foundation via Eurocore Eurodiversity, as well as networks of excellence such as Marine Genomics.
Some of the major challenges currently facing researchers are the long-term
study of model populations, communities and ecosystems; the continuous monitoring
of variations in the environment (including its biological aspects); modeling evolution
and ecosystem functioning; and experimenting on biological assemblages of varying
complexity. However, an ever increasing number of results published throughout the
world on the dynamics of biodiversity are based on technical facilities especially dedicated to such approaches. There is therefore a strategic dimension to the development of such tools in France. CNRS gives financial support and provides staff for
diverse environmental research projects in specific areas where long term research
is being undertaken, an example being the experimental station at Nouragues in
French Guiana. CNRS has also initiated an ambitious Ecotron program (one in
Montpellier and one near Fontainebleau) whose objective is to conduct experimental
research on natural and artificial ecosystems within a confined environment.
René Bally and Luc Abbadie, Deputy Scientific Directors of the Department
of Environmental Sciences and Sustainable Development
Bernard Delay, Scientific Director of the Department
of Environmental Sciences and Sustainable Development
04-05
EDITORIAL
06
DEBATE
DESPITE ITS POPULARITY, THE CONCEPT OF BIODIVERSITY IS COMPLEX. TO DEMONSTRATE THE WIDE RANGE OF QUESTIONS IT RAISES,
FIVE RESEARCHERS IN ECOLOGY, TAXONOMY, GENETICS, ETC GOT
TOGETHER WITH RENÉ BALLY, DEPUTY SCIENTIFIC DIRECTOR OF THE
ENVIRONMENT AND SUSTAINABLE DEVELOPMENT DEPARTMENT AT
THE CNRS. IN WHAT FOLLOWS WE REPORT THEIR DISCUSSION, WHICH
ALTHOUGH CONTROVERSIAL AT TIMES, IS INSTRUCTIVE THROUGHOUT.
ROUND TABLE WITH LUC ABBADIE, ROBERT BARBAULT, PIERREHENRI GOUYON, HERVÉ LE GUYADER AND MICHEL VEUILLE.
WHAT IS BIODIVERSITY?
PIERRE-HENRI
GOUYON :
Humans
became aware of biodiversity very early
on. The idea of classifying the untidy,
messy thing called Nature was bound to
catch on. Living things are classified in
every known culture. The way they’re
classified, however, varies from one culture to another.
the Book of Genesis when Noah saves
each species by only keeping a single
couple of individuals. Darwin revolutionized the way we view this classification.
He introduced the idea that diversity within species and diversity between species
are of a similar nature. In other words,
that diversity between species is simply a
development of diversity within species.
Our initial view of biodiversity was exclusively based on classification by species.
Linnaeus stated that all species were created by the hand of an all-powerful
Creator, and that when these species
reproduced they remained confined to
their own type. He gave no credit to the
importance of within-species variability.
That was the Western view of the world in
the 18th century. You find the same view in
HERVÉ LE GUYADER : Biodiversity can be
defined at three levels: biodiversity of
genes, biodiversity of organisms and
biodiversity of ecosystems. What PierreHenri Gouyon has just said shows that
biodiversity between species and biodiversity between genes are totally connected. We should also remember that
all this takes place over time and in
space. We know little about species bio-
Pierre-Henri Gouyon is a professor at the Muséum
national d’histoire naturelle (French National
Museum of Natural History), at INA-PG and at the
École polytechnique. He is a researcher at the
Laboratory for Functioning and Evolution of
Ecological Systems.
Hervé Le Guyader is a professor at the University
of Paris 6, and Director of the Research Unit for
Taxonomy, Adaptation and Evolution.
diversity; we haven’t described everything, and I believe that we know even
less about the biodiversity of genes and
of ecosystems. We may thus have to
protect organisms that we don’t know
much about.
MICHEL VEUILLE : The word "biodiversity"
is recent. Our generation of taxonomists,
geneticists and ecologists has seen a
change in attitudes (in parallel with the
emergence of an interdisciplinary
approach to the study of biodiversity), both
with regard to cultural and social awareness of biodiversity, as well as in the need
for increasing cooperation in research, as
is shown by the creation of an interdisciplinary department dedicated to the environment and sustainable development
within the CNRS.
Michel Veuille is Directeur d’études at the École
pratique des hautes études, Director of the Taxonomy
and Evolution Department at the Muséum national
d’histoire naturelle and Director of the Research
Network for Population Genomics.
ROBERT BARBAULT : I believe that the
word "biodiversity" first emerged within
the context of the Rio Conference,
although the word was actually used several years earlier in scientific circles
where the talks were being organized.
From 1992 onwards, the entire scientific
community has adopted the word "biodiversity".
LUC ABBADIE : It could go further and
integrate the functional aspects which
regulate the interactions between the
organization of life and the flow of matter and energy and, more generally, the
environment. There has been a lot of
work done on the functional value of
biodiversity, practically all of it at
species level. Very little notice has been
taken of the functional consequences of
genetic diversity. However, life varies
along a continuum from the gene,
through the species, to the community
of organisms.
PIERRE-HENRI GOUYON : Can we create a
concept of biodiversity which integrates
both diversity within species and diversity between species? We don’t know how
to do that today. But this is a good time to
start working on it. To construct phylogenies—to understand the evolutionary
relationships among species—we can
now use gene coalescence. In this way
we can take into account genetic diversity in the study of diversity between
species. 150 years after Darwin, wouldn’t
it be possible to create an authentic concept of biodiversity which combines
genetics and taxonomy?
Robert Barbault is a professor at the University of
Paris 6, Director of the Institute for Ecology,
Biodiversity, Evolution and Environment and Director
of the Department of Ecology and Biodiversity
Management at the Muséum national d’histoire
naturelle.
PIERRE-HENRI GOUYON : Although we
have a conceptual framework, we would
only really get a handle on the problem if
we were capable of saying what processes determine the number of genotypes
and species. We know what the processes are, but we don’t know how to organize them in order to explain what’s going
on at the level of the planet.
ROBERT BARBAULT : By looking at biodi-
MICHEL VEUILLE : The word biodiversity is
an extremely valuable portmanteau
word. It reflects our ignorance. Linnaeus
knew of about forty thousand species.
Today, more than a century after Darwin,
about 1.8 million species have been
described. We know that there exist five
to ten times as many organisms traditionally described as animals and plants,
in other words between 10 and 15 million. We are only acquainted with a tiny
part of the biodiversity of bacteria and
fungi. It is currently thought that we only
know about 5 to 10% of fungi. We don’t
really have the research capability needed to discover all these species. When
researchers from the National Museum
of Natural History explore an area in the
Pacific they find that 20% of the mollusks
they bring up from the sea floor are new
species.
nonetheless a conceptual framework:
the theory of evolution. Darwin showed
that when there is selection, diversity
increases.
There exists a positive connection
between biodiversity and the productivity
or stability of an ecosystem. And yet
some very old and very productive
ecosystems are lacking in species. In
such systems enhanced genetic diversity
may "substitute" for low species diversity. Any such functional equivalence
between intraspecific (genetic) and interspecific diversity remains to be explored.
PIERRE-HENRI GOUYON : Theories determine our descriptions. Linnaeus and
Darwin had different views of biodiversity
because they had different mechanisms
in mind. We should give up the idea that
we can describe nature without having
any theories about the way biodiversity
has evolved.
MICHEL VEUILLE : It’s obvious that if we
had a theory which explained why there
are so many species, it would also be a
theory that would better explain ecosystem functioning and how we can preserve third order biodiversity, i.e. that of
populations and ecosystems. This order
determines many things.
versity from an ecological angle we can
attempt to answer these questions.
Besides kinship relations and genetic
variability, there are selective pressures.
The ecological context produces these
and enables us to understand why there
is a build-up of diversity, and why, after
each extinction crisis, biodiversity reestablishes itself. We live in a world that
is constantly changing on all scales. So
there are no species which are adapted
to all the conditions on the planet. On
that basis, just as for genetic approaches, we can gradually improve our understanding. That’s why, when I talk about
the diversity of life, I tend to start off at a
global level. What is the diversity of life?
It’s the living fabric of the planet, of which
we are part, which is made up of species
possessing enormous genetic variability.
It’s a fabric of countless interactions
which evolve in a changing world. The
reason diversity exists is the need to
adapt to unceasing changes in space and
time.
HERVÉ LE GUYADER : We can look at biodiversity from three different levels.
Pierre-Henri Gouyon started off by talking about species. Robert Barbault sees
it at a planetary level, as a fabric of interactions. If we had a hard-line molecular
biologist here, they would probably begin
with the genome and end up with the
diversity of genes. All biologists, whatever their starting point, eventually end up
at this concept of biodiversity.
HERVÉ LE GUYADER : Let’s be clear about
this. We don’t have a theory, but there is
Luc Abbadie is a professor at the University of
Paris 6 and Director of the Research Unit for
Biogeochemistry and Ecology of Terrestrial
Environments (Bioemco).
06-07
DEBATE
DO WE NEED TO PRESERVE
BIODIVERSITY?
MICHEL VEUILLE : People are becoming
© Pierre Lozouet, Marina Poddubetskaia et Stefano Schiaparelli - Panglao Marine Biodiversity Project
ever more aware of the fragility of nature.
Until recently, many biologists thought
in terms of equilibrium when they
constructed a model of population
genetics.
Many people say that the image of the
Earth seen from the Moon played a key
role. Today, the notion of the blue planet
is meaningful for everyone.
MICHEL VEUILLE : Aside from the moral
question posed regarding the conservation of the whole living world in existence
today, some people are wondering if so
many species are necessary for functional groups, or whether coral reefs really
need all those butterfly fish (pantodon
buchholzi), etc. Granted, there are 15
million species, but we have never been
aware of the existence of most of them.
Do we need to keep them all? Are they all
useful for the preservation of ecosystems?
PIERRE-HENRI GOUYON : For me, the
question is above all a moral one. I’m in
favor of the preservation of biodiversity.
We’re making a moral problem dependent on a scientific result. It’s the same
thing as saying that you shouldn’t be
racist because there are no genetic dif-
LUC ABBADIE : I agree with you, there are
first of all moral grounds for preserving
biodiversity. But there are also more
objective reasons. If I go back to what
we’ve just been saying, current biodiversity is basically the result of a piling up of
past events, of a series of reactions of
each species to pre-existing environments and to the presence of other
species. Certain organisms were abundant at one time. They are less so today,
but they might make a massive comeback, depending on changes in the environment.
The time scale is important. Some scientific results can be, and are, wrongly
interpreted. You hear conclusions such
as ‘There are many species which serve
no purpose Ecosystems could function
with fewer species.’ The trouble is that
we only see a snapshot of biodiversity. A
species which today appears redundant,
not essential, might become vital to the
ecosystem in some future phase because
the environment will have changed,
Photograph of the Earth as seen from
space (1968). For many people, seeing the
Earth as it looks from space made them
question the idea that nature is all-powerfull,
and to assimilate the ntion that nature is fragile
and that species can disappear.
PIERRE-HENRI GOUYON : I am one of
those who think that there is actually no
ecological need to have a huge amount of
biodiversity. I believe that there are
enough species, and enough genotypes
for species, to keep things ticking over
nicely. But that’s a personal impression. I
can’t prove it. Nor can those who think
otherwise.
ROBERT BARBAULT : There’s no proof, but
there is nonetheless some evidence for it.
Only a tiny proportion of the world’s species
are known. 1,600 marine species are
discovered and described every year. Tropical
regions, and especially coral reefs, are
exceptional reserves of unknown species.
During six weeks of intensive fieldwork, the
Panglao Marine Biodiversity Project (Muséum
national d’histoire naturelle/Universiy of San
Carlo/National University of Singapore)
discovered several hundred new species of
shellfish, and nearly a thousand new species
of mollusk.
ferences between ethnic groups. But if
we did find a genetic difference, would
that mean that we could be racist? The
problem is to know what role the human
species sees itself playing in the management of the Earth. This question
should be kept separate from that of
knowing whether we need lots of species
on the grounds of ecology or sustainability. Yes, I’m in favor of preserving biodiversity, first of all on moral grounds, and
then, if there are practical, concrete reasons as well, so much the better.
© NASA / Science Photo Library
For these biologists, before humans
made their considerable impact, and
with the exception of a few post-glacial
fluctuations, nature was in balance. It
was invulnerable. Nowadays we know
that this does not apply to the recent history of biodiversity. We know that even
before the Neolithic, when humans first
started to have a significant influence on
nature, there had been extinctions.
PIERRE-HENRI GOUYON : The idea that
species can become extinct is a new one.
It was Cuvier’s idea and is only 200 years
old. It took us a long time to assimilate it.
© CNRS Photothèque / J. Lecomte © Alexis Rosenfeld / Science Photo Library
species, each with little genetic variability, or should we keep few species, each
with a great deal of genetic variability, so
that they have the most chances of evolving? We don’t yet have the conceptual
tools to answer this kind of question.
PIERRE-HENRI GOUYON : We all agree that
Mediterranean and Pacific sea floors. Tropical
ecosystems have undergone little disturbance,
which is why biodiversity is greater there than in
the Mediterranean.
because it will have rained a little bit
more or less, for instance.
Biodiversity is a storeroom of responses
of living things to changes in the environment, which have been tested in the past
over thousands and millions of years. If
we reduce the content of this storeroom,
there will be a gap between the variations in the environment and the range of
possible responses. Every species has
probably had, at one moment or another,
a major impact on the environment. The
notion of key species is a dangerous one,
since a given species is only critical
("key") at a particular moment in time.
HERVÉ LE GUYADER : The Earth has
extraordinary stability. At the end of the
Permian, 80% of species vanished, and
yet this disturbance was absorbed. We’ve
always wondered why biodiversity, in the
western Pacific for instance, is far greater
than in the Mediterranean. Yet again it’s a
question of stability. Tropical ecosystems
have been very stable from an environmental point of view, whereas in the
Mediterranean, whether we’re talking
about glacials or about the evaporation of
the sea during the Neocene, there were
major fluctuations. Biodiversity frequently declined suddenly and never returned
to the level found in tropical ecosystems.
That’s one possible interpretation.
PIERRE-HENRI GOUYON : Events such as
these dry periods were widespread. If you
compare the diversity of plants in Africa
and South America you find the opposite
result. The high degree of disturbance in
South America formed refugia, and that
was certainly the reason why biodiversity
increased. Disturbances can have completely opposite effects depending on
their type.
HOW CAN WE MANAGE
BIODIVERSITY?
this conceptual work needs to
be done. That said, once we
have the answer, the question
will no longer be stated in the
same terms. You don’t manage
biodiversity in the same way as
you pack a suitcase. Oddly
enough, it’s the most deterministic sciences from which
we can learn. Today, physicists
and chemists who are working
in nanotechnology get objects
to self-assemble in order to
make systems, rather than trying to make each element in
the system one after another. In evolutionary biology and in the ecology of biodiversity, where everything is interaction and
where we work with very complex systems, we’re still wondering whether we
should keep species X or species Y. We all
work with this concept of self-organization even if we don’t always realize it. We
can try to manage the whole self-organized system, but certainly not each
species one by one.
MICHEL VEUILLE : I’d like to come back to
the little blue globe on which humans,
together with biodiversity, are traveling
through space. Since humans take up a
lot of room, there’s less room for biodiversity. The spread of invasive species is
another factor which is eroding biodiversity. Those which are human-commensal
species displace native or endemic
ecosystems by installing a kind of
McDonald’s ecosystem, which we’re soon
going to be finding in every corner of the
planet.
In a certain way, humans are now managing biodiversity like a garden. Until now,
biodiversity
was
self-sufficient.
Henceforth it will only exist insofar as we
leave it the room to do so. With regard to
biodiversity, humans are a bit like someone who’s packing a suitcase and who
has to decide what to take. Should you
take a wide variety of different types of
clothes, or a large number of clothes of
similar type? Should we keep many
ROBERT BARBAULT : The expression
"managing biodiversity" is totally excessive when you look at what we are capable of. On the other hand, we can
establish rules for preserving the diversity of large ecosystems without having to
intervene within those ecosystems.
In nature, there are parasites and
pathogens as well as food resources and
medicines. So it’s a struggle. But it’s a
judo-style struggle, which relies on
forces that already exist. In this way,
there can be an adjustment of the relationship between the development of
human societies and the preservation of
a biosphere in good working order.
However, to imagine that we’re going to
be running things as if we were some
kind of planetary super gardeners is not
on the cards.
There’s a difference between what we
have to do and what we decide to do. We
have to decide what kind of society we
08-09
DEBATE
want. We could single out showcase
areas of biodiversity such as coral reefs,
and focus all our efforts on preserving
them. As if the diversity of the tundra or
of Europe’s cold regions, which get less
media coverage, were of no interest to
the people who live there! We should try
not to confuse scientific analysis with
social or political choices.
overall logic of the ecosystem. This logic
is difficult to detect: natural systems,
which are sustainable, diversified and
productive, provide an ideal situation to
define the proper logic.
Although we now more or less understand the principles of evolutionary
mechanisms, the subsequent interactions that they generate are hugely complex. Throughout the history of the
planet, a vast number of "biodiversityenvironment" scenarios have been tested and live on in the way biodiversity is
currently organized. I think we should
try to preserve this potential, even
though I’m also a keen supporter
of ecological engineering. There
are natural models which we
would do well to think about.
HERVÉ LE GUYADER : Here are
Gold medal struck in India the elephant
moving to the right, eastwards, is a direct
reference to the conquest of India and to the
victory over the elephants of Porus in 326 BC.
LUC ABBADIE : Management basically
involves setting up a partially artificial
system which we think we can control.
However, we don’t have the intellectual
means for this control. Let me take a
specific example, that of farming systems. They often perform poorly despite
being supplied with huge quantities of
energy and nutrients. The reason for this
is that we have changed some of the
players and some of the processes without verifying that these alterations fit the
three current examples of
action being taken for biodiversity conservation. First, the
‘Apple-eaters’ Association’.
What are they doing? Well,
they’re in the process of "saving" all the varieties of apple
which are disappearing. Here
we’re talking about intraspecific
variability, i.e. within one
species.
Some people fight to save dolphins
and whales. They focus on one
species, usually a charismatic one,
because it’s big, it’s beautiful and it’s
pretty exceptional.
Let’s take a third example: the Australians and the Great Barrier Reef. Now
imagine that the fish in the coral reefs
weren’t as brightly colored. I’m not sure
that we’d hear about them as much.
I chose these three examples because
they represent the three levels of biodiversity. It’s obvious we could never "manage" all the species in the way the
Apple-eaters do. Actually, coral reefs
really are showcase ecosystems, but that
doesn’t mean that the tundra ecosystem
is any the less extraordinary.
BIODIVERSITY: ETHICAL VALUE
OR ECONOMIC VALUE?
PIERRE-HENRI GOUYON : I compare the
ethical issue of biodiversity with the
issue of the death penalty. You can find a
lot of rational arguments in favor of the
death penalty. But a society which gives
itself the right to kill people is simply a
society which devalues itself. As far as
I’m concerned, a society which gave
itself the right to destroy all the living
species which were of no use to it would
be in the same category. We can talk
about the usefulness of biodiversity to
humans —and I think that it’s a good
thing to talk about it— but that’s not the
main issue. The most important thing is
how we see ourselves in our relationship
with nature, from which we came, and to
which we belong. Today, we live in a
social, economic and political system
which has trouble taking this kind of
dimension into consideration. Unless we
succeed in giving ethical values an economic value, I fear that the attitude
which consists in systematically giving
everything, including biodiversity, an
economic value won’t let us take into
account the most fundamental dimension of this question.
MICHEL VEUILLE : Since 1992, the Rio
Convention on Biological Diversity has
given us a framework for thinking about
biodiversity which is different from an
absolute or, if you like, philosophical one.
The interesting thing about the Convention
was that it brought together nations which
see biodiversity in different ways: as an
esthetic resource, as a material resource
or even as a potentially economic
resource. The Rio Conference made it possible to think about these issues collectively, to escape from the sterile
discussion about the value of biodiversity
per se, and in so doing confront us with
our responsibilities.
ROBERT BARBAULT : I think that the first
thing that should be said when someone
asks what biodiversity is for —an irritating and poorly formulated question,
because they don’t say what biodiversity
should be for— is that the diversity of the
living world is the result of four billion
years of evolution. Species have invented
quite a few things. Over several millions
of years, they have been solving problems in order to survive, to reproduce
and so on. That should earn our respect.
Any wanton destruction of them is an
attack on our own status as the human
species. Once you’ve said that, you’ve
made the fundamental point. Then you
can say that we depend on the diversity of
THE CONVENTION ON BIOLOGICAL DIVERSITY
living things and on all the interactions
that it entails. We depend on it not only
for the esthetic and spiritual values that
are associated with it, but also for food,
for health and so on. It isn’t necessary to
give everything an economic value. Some
people are worried about the disappearance of species. First of all, it isn’t totally irreversible. In fact, the biodiversity
crisis is an opportunity for the human
species to react and to reconsider its
goals regarding development. This
brings us back to the need for lasting,
sustainable development, except that for
the moment it’s more a case of "let’s
hope it lasts" development.
large water companies are well aware
that it is cheaper to preserve the quality
of ecosystems, and therefore biodiversity, than to build and maintain huge water
treatment plants.
PIERRE-HENRI GOUYON : You often hear
people say, ‘Scientists will find a solution.’ Here I think it’s important to say
that we’re not going to find the solution
that people are expecting. We have a theoretical solution to the problem, but this
solution isn’t the one that people are
hoping for. It’s more about regulating
consumption, expenditure and so on.
MICHEL VEUILLE : Like Socrates would
LUC ABBADIE : Biodiversity is a symbol of
sustainability and adaptability. Our mode
of development is not sustainable
because it is not adapted to the finite
nature of resources and because it
ignores the role that other species play
in the regulation of our environment.
Civilization has reached a real crisis
point. We have to re-think the world; in
this respect, the history of life could provide some good ideas.
ROBERT BARBAULT : The ecological service concept, irritating though it is,
nonetheless has the merit of making
people understand that certain things
which are important for our well-being
may not be subject to market forces, and
that they can deteriorate to the point that
it becomes essential to take technical
measures to replace them. This can be
an extremely expensive business. The
© CNRS Photothèque / Jérôme Orivel
The Convention on Biological Diversity is a historic commitment. It is the first treaty concluded at world
level which tackles all aspects of biological diversity. It concerns not only the protection of species but
also of ecosystems and the gene pool, as well as the sustainable use of natural resources. It is the first
treaty to recognize that the conservation of biological diversity is a ‘common concern of humankind’
and that it is an integral part of any sustainable socio-economic development.
Open for signature at the Earth Summit, at Rio de Janeiro, 5 June 1992.
Came into force on 29 December 1993, 90 days after the 30th ratification.
Ratified by 188 countries.
say, the first act of reason is to be aware
of one’s own ignorance. Science can’t do
everything, and in particular it can’t
accurately predict the future, even
though one of its roles is to enlighten the
public about future changes. The other
area of society where predictions are
made is in politics. You can always go on
about unkept promises, and about the
actual consequences of what politicians
do. Nevertheless, when you put all those
political acts end to end the result is
called History. Somehow or other, it
marches on. That’s more or less the
image of what we can modestly hope to
have during the 21st century to preserve
biodiversity. However, whatever we do or
don’t do, consciously or not, whether it
be interventionist or laissez-faire, will be
decisive for the preservation of biodiversity. Science still underpins our thinking,
even though we need to oppose absolute
A caterpillar, Vettius tertianus, at the final
stage of development. This caterpillar is a
parasite in gardens inhabited by the ant
Pachycondyla goeldii.
faith in science.
PIERRE-HENRI GOUYON : That applies to
technology more than science!
HERVÉ LE GUYADER : I’d like to come
back to the problem of the notion of time.
In the 18th century, foresters managed
the forest for future generations. They
grew oaks to make ships. They knew they
would never see the oaks that were
planted used during their own lifetime.
Today, politicians only think in terms of
the next few years, i.e. until the next election.
MICHEL VEUILLE : Biodiversity is characterized by its cross-disciplinary nature,
which is now also true at CNRS. But
obviously, for it to be cross-disciplinary
there has to be something there for it to
cross! In fact, there are scientific foundations to this cross-disciplinary field. The
interesting thing about an institution like
CNRS is precisely that it combines fundamental research with a cross-disciplinary approach which brings everything
together.
10-11
DEBATE
12
UNDERSTANDING BIODIVERSITY
FROM GENETIC VARIABILITY TO THE WEALTH OF FAUNA AND FLORA,
FROM THE DIVERSITY OF SPECIES TO THE DIVERSITY OF ECOSYSTEMS
AND LANDSCAPES: UNDERSTANDING BIODIVERSITY MEANS FIRST OF
ALL IDENTIFYING, LISTING AND CLASSIFYING THE BIOLOGICAL ENTITIES THAT MAKE IT UP. IN ADDITION IT ALSO MEANS ANALYZING THE
GENETIC STRUCTURE OF THEIR POPULATIONS, RECREATING THE
HISTORY OF EVOLUTIONARY LINEAGES AND UNDERSTANDING THE
EFFECTS AND SCOPE OF PHENOTYPIC PLASTICITY. FINALLY, IT
MEANS INVESTIGATING THE WEALTH OF INTERACTIONS AMONG
SPECIES, WHICH MAKE UP THE ECOLOGICAL FABRIC OF WHAT IS
PROPERLY CALLED BIODIVERSITY DYNAMICS.
© Ifremer / A. Fifis
HOW MANY SPECIES ARE THERE ON EARTH?
Kiwa hirsuta was discovered by a
researcher at Ifremer in March 2005. During
the first weeks of March 2006 the media
quite unexpectedly took the story up. Within
a few days, the number of pages about this
animal on the Goggle search engine jumped
from a mere handful to 200,000.
From time to time, the announcement of the discovery of a plant or an animal
becomes widely reported in the media, rather than remaining confined to specialist
circles. For instance, the discovery of both the world’s smallest vertebrate,
Paedocypris progenetica, a fish from the mangrove swamps of Sumatra less than eight
millimeters long, and a species which represents a new family of crustaceans from
the Eastern Pacific, Kiwa hirsuta, have received a great deal of media coverage.
Away from the spotlight of the media, the inventory of our planet continues, with
16,000 new species described every year. Even in Europe, new species continue to be
discovered, with 600 descriptions of animal species being added per year, a rate that
hasn’t slowed down since the beginning of the 20th century. In fact, the only thing that
we’ve become sure of in the last twenty years is that the total number of living species
is one, or even two, orders of magnitude greater than the 1.8 million species already
described. Tropical forests, coral reefs, the large ocean basins and parasites as a
whole make up the main reserves of unknown species. For unicellular eukaryotes,
new types of organization (new classes and orders) doubtless remain to be discovered.
Completing the inventory of vertebrates, phanerogams and a few rare groups of invertebrates (butterflies and odonates) is no doubt by and large within our reach with the
human resources at our disposal. For most groups, however, the human and methodological means needed to describe species diversity is woefully inadequate, and will
also need to be upgraded by one or two orders of magnitude.
At the current rate at which new species are being listed, most of them will have
become extinct before they can be described and named. Viewed in this light, although
the molecular revolution drastically altered the taxonomy of prokaryotes as early as
the 1970s, its contribution to the taxonomy of eukaryotes currently remains marginal.
The impact of international initiatives such as the Bar code of Life, which consists in
sequencing the gene that codes for Cytochrome oxidase 1 in order to recognize and
separate species, is still a subject of debate among the scientific community.
248
Penn.
286
Eureptilia
Parareptilia
Sauropsida
Amniota
Reptiliomorpha
Mississi.
Amphibia
Tetrapoda
Devonian
408
Phylogeny of tetrapods.
Given the huge number of living species, biodiversity can only be made sense of by
using concepts. The role of classifications is to create these concepts as well as words
with generally accepted meanings. Classifications are arbitrary. Their function is to
meet pre-established specifications. Objects are grouped together in order to account
for certain specific properties: for example, our culinary needs (seafood, game, etc.).
In the field of biological sciences, the aim of a classification can also be to create
groups which reproduce the unity of species as regards their functional relationships
in environments (e.g. phytoplankton, zooplankton). A good classification accounts for
properties which have been agreed on.
Over the last 150 years, within the framework of the theory of evolution, the goal
of taxonomy (the science of classifying species) has been to create concepts known as
taxa which reproduce the relative degrees to which species are related to each other.
For a century, phylogeny has been the "tree of life" which depicts these relationships.
The role of taxonomy is not just to identify species and give them names. It pieces
together kinship relationships on the basis of comparative anatomy and by comparing
homologous genes. On a phylogenetic tree, each branch of the tree is given the name
of a particular taxon, and contains all the subsequent branches. A phylogenetic classification is a system of taxa nested within one another. We have only been able to create such phylogenies for about fifty years.
This way of classifying living things represents the culmination of a truly
Copernican revolution, the seeds of which were already to be found in Darwin’s ideas.
Rather than reflecting the central place in the Universe that humans liked to think
they had, it revealed the degree to which all living beings are related.
STRATEGIC DATA BASES
Just as with meteorology, modeling and predicting biodiversity is possible as long as large sets of
spatial zed data on species are available. By superimposing the geographical coordinates of the
occurrence of species on maps of climate, geology, ecology, etc., it is possible to calculate the
potential distribution of species on the basis of their observed distribution. For instance, by varying
the climatic parameters according to the various existing models, it is possible to predict the possible
evolution of local biodiversity under the influence of climate change. Experimental data of this kind
has accumulated in museum collections over the last two centuries —such as the specimens in the
herbariums at the Muséum national d’histoire naturelle (the French National Museum of
Natural History, www.mnhn.fr) and, much more recently, in data bases of environmental
observations (inpn.mnhn.fr). In order to build the infrastructure which will make it
possible to utilize all this data which is scattered among countless institutions, the
technological and scientific challenge is to make existing data bases interoperable. In
this way, any user will be able to utilize the data as if it were stored in a single database.
Computer software for this will be made available to potential users. To achieve this
goal, several international groups are working within an international network known as
GBIF (Global Biodiversity Information Facility, www.gbif.org), with a view to clarifying ideas
and creating software that will enable all this disparate data to be used.
A DIVERSITY FIRMLY ROOTED IN GENETICS
© GBIF
© Michel Laurin
320
360
Archosauromorpha
Synapsida
Mesosauria
Pareiasauria
Procolophonia
Chelonia
Younginiformes
Lepidosauromorpha
Aistopoda
Nectridea
Microbrachis
Rhynchonkos
Lysorophia
213
Pemnian
Triassic
Jurassic
144
Diadectomorpha
Apoda
Urodela
Anura
HOW CAN SPECIES BE CLASSIFIED?
Most of the mechanisms which can be used to explain diversity with regard to species
—chance, natural selection and migration— also operate at the level of populations.
Mutations, which take place randomly in the genome of individual organisms, provide the
basic variation on which the other evolutionary forces can work.
12-13
UNDERSTANDING
BIODIVERSITY
Expanding
population
THE MOLECULAR MARKERS OF THE HISTORY OF SPECIES
Time
Population
of constant size
Figure 1. Molecular signature of past
demographic events. In a population, the
sequences of the same gene (here, six
sequences represented by squares) have
common ancestors (represented by circles).
In a population of constant size, many of
these ancestors are recent, while a small
number are distant. In contrast, in an
expanding population, most of the common
ancestors date from the beginning of the
population’s history, and are comparatively
distant. The phylogeny of genes within
species thus gives us information about the
history of populations.
Time
Ancestral
species
Isolation
Speciation
Daughter
species A
Daughter
species B
Figure 2. The molecular signature in
taxonomy, or bar-code, is a simple system
for characterizing species. When populations
of the same species divide, giving rise to
different species, some polymorphisms of
the ancestral species are fixed, by chance or
by selection, in one or other of the daughter
species (mutations are represented by
circles). The diagnostic mutation is shown in
blue. This mutation appeared in the common
ancestor of all the sequences of daughter
species B. They are the basis of the
molecular "bar-code". However, not every
mutation leads to a new species.
Collaboration between geneticists and
taxonomists is vital if we are to define a
universal bar-code system.
A species’ history leaves traces in its genes. In the last few years, researchers have
made a spectacular leap forward in interpreting this molecular information.
Population geneticists are now able to enumerate the genes which bear the "signature" of natural selection or of demographic events (see Figure 1). For cultivated
plants, for instance, it is possible to detect the genes which bear a ‘domestication syndrome’, a record of the artificial selection carried out by early farmers.
Over the course of generations, mutations appear in a gene. The same gene can
thus be found in the genome of individuals from the same species in different forms.
Over the past twenty years there has been enormous progress in interpreting this
polymorphism of DNA sequences. "Coalescence theory", together with the development of new bioinformatic tools for data analysis has made it possible to interpret the
phylogeny of genes in a single species. Population geneticists have used these techniques to model the colonization of Europe by modern humans. Their model incorporates the geography of Europe and the growth of populations.
Inra’s laboratories have studied the recent spread through Europe of an invasive
species of corn pest. They have discovered the origin of the invasion. It is the result of
three different introductions of individuals from North America. The next challenge for
population genomics (see Figure 2) is to develop a molecular signature for each
species. This taxonomic information will then be of benefit to the whole scientific
community.
GENETIC DIVERSITY AND STRUCTURE OF POPULATIONS
In order to characterize genetic variability, certain biochemical or molecular
markers are used. Markers with a single genetic determinism, whose variation is discontinuous, are mainly used to "identify" gene flow between individuals (reproductive
systems on a local scale) and populations (reproductive systems on a regional scale).
They frequently consist of fragments of DNA of unknown function, whose variability is
apparently neutral with respect to natural selection. Phenotypic features —the visible
characteristics— can also be used to characterize genetic diversity. They are often
nonneutral with respect to natural selection.
We therefore use certain phenotypic characters which show continuous variation,
for whom the genetic determinism of the variation is frequently complex, and whose
expression is heavily influenced by the environment in which it is observed. The evolutionary success of different phenotypes depends on the environment, so much so
that it is possible to observe phenomena of local adaptation. Migration and mutation
have opposing effects on this local adaptation. These two evolutionary forces introduce variation, on which natural selection can then act. When populations are small
in size, natural selection becomes less effective. By chance, harmful mutations may
become more frequent and lead to populations becoming less viable. This is what is
called genetic load or inbreeding depression.
Consider the example of the island cabbage, Brassica insularis, a protected species
endemic to the islands of Sardinia and Corsica. This species has a self-incompatible
reproductive system. Two cabbage plants having the same allele at the self-incompatibility locus cannot breed. Besides the monitoring of populations carried out since
1999, molecular diversity, the diversity of quantitative characters and diversity at the
self-incompatibility locus have also been studied. All the results show that the populations are small in size, and have low genetic diversity and that there is a quasiabsence of gene flow among populations. What’s more, one of the populations shows
particularly reduced diversity at the self-incompatibility locus. Hence, little crossbreeding is possible among individuals in this population. The question here is as follows: is it better to reinforce this population, at risk of making it lose its genetic
identity, or to let things be and hope for the appearance of mutations at the selfincompatibility locus? The answer has yet to be found…
© CNRS Photothèque / Isabelle Olivieri
DIVERSITY: BEYOND GENETICS
Although genetic diversity is the chief source of diversity among individuals of a
given species, some types of phenotypic diversity are not necessarily associated with
genetic differences. For instance, plasticity enables two individuals with the same
genotype to have a different phenotype depending on their habitat, and thus be better
adapted to their environment. The amount of such plasticity depends on the individual
and on the species.
Other mechanisms, such as developmental instability, can lead to greater phenotypic variance. This random variability may be adaptive in an unsettled, unpredictable
environment. This, for instance, is the case for the flowering period of gorse, Ulex
europaeus.
Lastly, a gene can undergo different kinds of regulation during transcription (transformation of a DNA sequence into RNA). The same genotype can therefore give different phenotypes. It can undergo epigenetic variation, in other words hereditary changes
which are not coded for by DNA. These may be the chief source of diversity, as was
shown by a team from the Ecobio Laboratory for the invasive clonal grass Spartina
anglica. Understanding biodiversity thus makes it necessary to take into account the
whole of diversity, whether it be deterministic or random, hereditary or not, that can be
generated by the same genotype.
The genetic variability and genetic evolution of a population are very complex. There
are a large number of phenomena at work, of which we know but a few. The genetic
biodiversity which they give rise to is indeed considerable. We now need to incorporate
these phenomena at the ecosystem level. Their relationships with the environment, the
interactions among species and the evolution of these relationships over time are all
dimensions that need to be taken into account if we are to understand ecological
dynamics.
© Anne Atlan/Ecobio 2006
Population of the cabbage Brassica insularis
called Conaca. Not only does the reduced
genetic diversity at the self-incompatibility
locus result in a reduction of the proportion of
compatible crosses, but moreover, selective
pressure for resistance to flower parasites is
undoubtedly weakened, precisely because of
the low rate of reproduction in this population.
This is why attacks by parasites are more
pronounced in this population (in this case by
aphids) than in the other populations on the
island.
These two individuals of Ulex europaeus, of
identical age and grown under the same
experimental conditions, do not flower at the
same time. This experiment demonstrates
intraspecific variation in flowering.
14-15
UNDERSTANDING
BIODIVERSITY
Interactions among species are both numerous and complex. They play one of the
most important roles on the biodiversity stage.
Parasites, for instance, and more generally symbionts, are an integral part of biodiversity. It has even been shown that groups which have adopted a parasitic way of
life have become more diverse than free groups. This is a demonstration of the
extremely dynamic nature of durable interactions. Parasites are often dominant on
the "selective stage". They alter population dynamics and the evolution of free
species. They can play a predominant role in the success or failure of a biological invasion.
The success of an invasion of a new area by a free species can depend on the presence of its parasites. They may not follow the free species, or alternatively they may
become more virulent when on native hosts, acting as a sort of biological weapon.
This reasoning can be turned on its head in order to explain the failure of an invasion. There is any number of scenarios, the plot can become just about as complex as
you wish, and the outcome will to a large extent be linked to the factors on which the
local adaptation of hosts and parasites depends. Among these factors, the most
important are the characteristics which make up the genetic systems of species,
migrations, mutations and the reproductive mode, interacting with the abiotic environment. Parasites are involved in a large number of interactions. An increase in their
transmission may, directly or indirectly, increase their pathogenic effects and alter
characteristics connected to the reproduction, survival or even behavior of their hosts.
The hosts counter-attack. They initiate mechanisms help avoid parasites, stop infection before it starts, or limit its effects.
© CNRS Photothèque / Lerouge
BIODIVERSITY SHAPED BY A NETWORK OF INTERACTIONS AMONG SPECIES
The aquatic mollusk Biomphalaria glabrata
is the obligatory intermediate host of the
parasite Schistosoma mansoni.
© Roger Le Guen
COLORATION, A SIGNAL AT THE HEART
OF COMPLEX INTERACTIONS.
Using color is one of the ways in which animals communicate. It is a
compromise between attracting conspecifics, avoiding predators and
hiding from prey. The crab spider imitates the precise color of the
flower which it is on so as to camouflage itself. It imitates the color
within the range to which its predators and prey are sensitive: birds
have four types of cone (UV, blue, green and red) while insects have
three (UV, blue and green). These visual systems differ considerably,
not only in their range of sensitivity but also in the number of photoreceptors. It is thus unlikely
that the spider imitates the color of the flower accurately.
A team from the Ecotrop laboratory used spectroradiometry to measure the colors of a spider
placed on peppermint flowers and then at the center of a tansy ragwort flower. Results from
modeling show that color mimicry can operate simultaneously in the visual systems of predators
and prey. For birds, the spiders take on the pink color of mint flowers when seen with their four
cone system. Similarly, on the ragwort, each spider has the individual color of the center of the
yellow flower on which it hunts its prey. However, against the background of the outer petals of
the ragwort, where they don’t hunt, the spiders produce a strong color contrast which is easily
detected by birds. To hymenoptera the spiders appear to have the same blue-green color as the
mint flowers when seen with their three-cone system. To hymenoptera, they accurately mimic
the blue-green color of the center of the ragwort flowers, but stand out against the outer petals.
These results show that the crab spider’s color mimicry works well for the visual systems of
both predators and prey.
A PROCESS WHICH UNFOLDS THROUGH TIME
© MNHM, Paléontologie, D. Serrette
The number of plant or animal species in any particular place not only depends on
the ecological conditions prevailing today but is also the result of history, back to the
distant geological past. Evolution has shaped the structure and functioning of living
communities. For example, the extraordinary evolutionary process which during the
Devonian, 370 million years ago, led to the appearance of the tetrapods and to vertebrates leaving the water for the first time, had momentous consequences for the history of terrestrial biodiversity. At the other end of the geological time scale, the
adaptive radiation —i.e. rapid diversification and adaptation— of rodents during the
Pliocene and Quaternary (2 million to 50 000 years ago) enriched terrestrial ecosystems with thousands of new species of small size, thus presenting a large number of
carnivores with renewed biomass.
Tetrapod fossils from the Devonian. Skulls
of Ichtyostega and Acanthostega, and a leg of
Tulerpeton compsognathus.
© CNRS Photothèque / F. d’Errico, M. Vanhaeren
HUMANS AND BIODIVERSITY
These small pierced shells, Nassarius
kraussianus, dating from 75 000 years ago,
were discovered in the Blombos caves in
South Africa. They were used as ornaments.
They are the oldest jewellery ever discovered.
UNDERSTANDING BIODIVERSITY
Coordinator: Robert Barbault
Institut fédératif d’écologie fondamentale et
appliquée,(Federal Institut of Fundamental and
Applied Ecology) CNRS/université Paris
6,7,12/ENS Cachan/Muséum national d’histoire
naturelle (MNHN)/Institut de recherche pour le
développement (IRD)
With contributions from:
Philippe Bouchet
Taxonomy/Collections Unit, CNRS/MNHN
Guillaume Lecointre
Taxonomy, Adaptation and Evolution Unit,
CNRS/Université Paris 6/MNHN/IRD/ENS Paris
The latest episodes in the history of biodiversity are closely connected to the history of humans. Remains from archaeological sites, of both plants (charcoal, charred
seeds, and fruit) and animals (shells and bones), contain a wealth of information
which throws light on interactions between human groups and biodiversity. They tell
us about both the ways in which humans exploited these raw materials that were necessary for their survival and the impact of this exploitation on vegetation cover, the
structure of forests, the composition of animal communities, and the extinction of
large predators. Seen this way, the archaeological record gives us a unique opportunity to observe the long-term effects of a wide range of human activities, whether it
be hunting, fishing or the gathering of shells by small prehistoric groups, the organized management of the countryside by ancient or medieval cities, and animal husbandry and farming in the first village societies. Understanding this interaction on the
scale of centuries or millennia represents a major contribution to the understanding
of biodiversity dynamics, which is of key importance to the management of our current resources with a view to sustainable development.
Simon Tillier
Taxonomy, Adaptation and Evolution Unit,
CNRS/Université Paris 6/MNHN/IRD/ENS Paris
Isabelle Olivieri
Institut des sciences de l’évolution (Institute of
Evolutionary Sciences), CNRS/Université
Montpellier 2
Michel Veuille
Population Genomics Unit, CNRS/École
pratique des hautes études (EPHE)
Anne-Gile Atlan
Ecosystems, Biodiversity and Evolution (Ecobio)
Unit, CNRS/Université Rennes 1
Ioannis Michalakis
Genetics and Evolution of Infectious Diseases
Unit, CNRS/IRD
Jean-Denis Vigne
Archeozoology and History of Societies Unit,
CNRS/MNHN
Marc Théry
Functioning, Evolution and Regulatory
Mechanisms of Tropical Forest Ecosystems Unit
(Ecotrop), CNRS/MNHN
16-17
UNDERSTANDING
BIODIVERSITY
18
ECOSYSTEM DYNAMICS
AN ECOSYSTEM IS ONE OF THE MOST COMPLEX ENTITIES
RESEARCHERS CAN STUDY. ECOSYSTEMS ARE MORE THAN JUST THE
TOTALITY OF SPECIES PRESENT IN A GIVEN PLACE. THEY ARE ALSO
MADE UP OF ALL THE INTERACTIONS WHICH EXIST BETWEEN THE
SPECIES AS WELL AS BETWEEN THEM AND THEIR PHYSICAL ENVIRONMENT. THIS PARTICULARLY DENSE NETWORK OF INTERCONNECTED RELATIONSHIPS MAKES IT VERY DIFFICULT TO FORECAST
ECOSYSTEM DYNAMICS.
ECOSYSTEMS AND THEIR DYNAMICS
© CNRS Photothèque / Hervé Thery
Ecosystems are both physical and biological systems. They are capable of selfregulation and are dependent just as much on the laws of thermodynamics as on the
laws of Darwinian evolution. An ecosystem may be analyzed in terms of its structure.
In this case, researchers study the type of species present, the spatial distribution
of its species and physical components, and the organization of food webs between
species. However, the description of these systems can also focus on their functioning. In this case, stress is placed on variation in structure over time, the
movement of matter and energy within
the ecosystem, and exchanges of matter
and energy with the atmosphere, hydrosphere and geosphere.
Today, ecosystems are subject to
considerable pressure. They are being
subjected to rapid climate change, the
spread of built-up areas and farmland,
and reduction in biodiversity. And yet
they are essential sources of energy,
materials and food for humans. They
play a key role in regulating biogeochemical cycles. Because of this, more
and more research work is being carried
out on them, especially at CNRS.
Development of satellite towns in Brazil.
Nothing remains of the original savannah
vegetation: only the gallery forests have been
partly preserved.
BIODIVERSITY PRESERVES ECOSYSTEMS
The rapid fall in the number of species present on the planet leads many people to
wonder about the importance of the role that biodiversity plays in ecosystem dynamics.
What effect will reduced biodiversity have on the performance of ecosystems with
respect to resource utilization? Subject to disturbances of various kinds, e.g. storms,
fires and pollution, can ecosystems persist? Under what conditions do they maintain
their capacity for resilience? There is a positive connection between the performance of
an ecosystem and the number of species which inhabit it —its species diversity—
© CNRS Photothèque / Xavier Leroux
Annual brush fires are a major factor in the
dynamics of the West African savannah.
especially in plant communities. For instance, this is the case for European grassland,
where, for a given density, plant productivity increases in line with the number of species
present. A certain number of observations also hint at genetic diversity having a major
positive effect on the productivity and stability of ecosystems.
BIOLOGICAL INSURANCE
© CNRS Photothèque / Alain Dejean
Biodiversity provides the ecosystem with buffering capacity against fluctuations in
the physical and biological environment. The mechanisms of this effect, known as biological insurance, are still being debated, and are the subject of a great deal of experimental and theoretical work within the CNRS. The aim of this research is to
determine to what extent the haphazard selection of particular species, the complementarity between species and the establishment of mutualistic relationships
between species can explain the positive effects of biodiversity on the performance
and resilience of ecosystems. A major research effort is also being carried out on the
functional significance of the biodiversity of micro-organisms, especially with respect
to the regulation of certain key phases in the nitrogen cycle (nitrification and denitrification), and more generally on interactions between soil biodiversity and soil’s physical and chemical characteristics.
PREDICTING THE FUTURE OF ECOSYSTEMS
Diminishing biodiversity leads not only to a reduction in the number of species, but
also to a modification in the structure and dynamics of animal, plant and microbial
communities. The mechanisms which regulate the size of populations as well as the
nature and intensity of interactions between species are thus altered. Predicting the
effects of these changes on the functioning of ecosystems is still not easy to do and
gives rise to a great deal of modeling and experimental work. For instance, we are trying to understand the role evolutionary mechanisms play in the response of ecosystems to climatic variation, predict to what extent the flow of matter and energy can vary
within the ecosystem and between the ecosystem and atmosphere or hydrosphere, and
determine the conditions that make an organism become an invasive species, and the
effects of invasions on ecosystems. Invasive species themselves are a cause of reduced
biodiversity. For example, there is the famous case of Cape ivy (South Africa), which has
invaded the whole of Europe and is causing a drastic reduction in the number of plant
species found in grassland. Climate change and fragmentation of environments also
disturb communities, and their effects are added to those of species loss. One of the
big challenges for research today is to define the future geographical ranges of species
by analyzing the characteristics of their life histories, and use them to infer the new
(emergent) communities and ecosystems that will form. For instance, depending on
Grasshopper trapped by ants. These
Allomerus decemarticulatus ants, which live
exclusively in the plant Hirtella physophora,
construct a trap to capture insects which are
then consumed. The association between this
ant and the plant is a mutualism: the plant
provides the ants with a home in the form of
pockets located at the base of the leaves,
while in return the ants protect their host
plant against herbivorous insects. Thanks to
this trap, the ants manage to catch insects
over 1,500 times their own weight.
18-19
ECOSYSTEM
DYNAMICS
which assumptions are made, by 2100, the beech tree may either completely disappear
from France or remain just in the western part of the country.
CRU TS 2,0
1901-2000
Favorable area not reached
Colonized area
Increased likelihood of occurrence
Decreased likelihood of occurrence
Current distribution
Extinction
© Équipe de Génomique Intégrée des Interactions Microbiennes
The changing distribution of a species of
North American tree, Fraxinus americana, over
the 21st century, according to simulations
using the Phenofit model.
Left: simulation of the current range of the
species using data from the Climatic
Research Unit (CRU), (University of East
Anglia, UK).
Right: simulation of the range of the species
in 2100 using data from the HadCM3 model
(Hadley Center, UK), according to the A2 model
(defined by the IPCC).
The simulation shows that the species’
dispersion ability will not enable it to occupy all
the areas which are climatically favorable in
2100, and that populations located at the
southern most fringe of the range are likely to
become extinct by 2100.
IDENTIFYING THE BIODIVERSITY OF SOILS
The characterization of biodiversity is a difficult stage in any study of the biological
functioning of ecosystems. Indeed, it is practically impossible at species level for
the micro-organisms in soils, fresh water and oceans. New tools are being
developed at CNRS for the rapid characterization of genetic diversity in such
environments and to enable comparative approaches to be made. High throughput
genomic techniques as well as DNA chips open up interesting new possibilities for
understanding how soil biodiversity varies under the influence of environmental
change, including pollution.
DNA chips make it possible to identify micro-organisms present in complex
environments (soils, aquatic environments, etc.). DNA sequences from different micro-organisms are
obtained from international data bases. Thanks to the development of new algorithms, researchers at
the Protist Biology Laboratory can then determine the oligonucleotides which are specific to each
species of micro-organism, and fix them on a glass slide. The RNA of the micro-organisms from soils
or aquatic environments are then marked with a fluorescent label and hybridized with the specific
sequences fixed on the slide. Each dot of light thus reveals the presence in these complex
environments of one species of micro-organism, and in this way makes it possible to get a better
understanding of the mechanisms which govern how these ecosystems work.
© http//davesgarden.com
1
© Xavier Morin, CEFE
0
Simulated probability of occurrence
Scenario A2 HadCM 3
2001-2100
RESEARCH ON A LARGE SCALE
© CNRS Photothèque / Richard Lamoureux
In order to understand the consequences of global change —in climate or land use— on populations
and communities of vertebrates, it is necessary to do research on a large scale. The CNRS Center for
Biological Studies at Chizé is carrying out interdisciplinary research on environmental constraints,
adaptation of individuals and the implications for managing populations. The goal of this research is to
identify the mechanisms involved, through long-term research on populations of predators and
herbivores, both in marine and terrestrial environments. An evolutionary ecophysiological approach
makes it possible to study the mechanistic connections between variation in the environment and
phenotypes. Some research has shown the importance of variation in resources over space and time
for the structure of communities. Other studies endeavor to describe the relationships between global
change and biodiversity conservation. This work mainly concerns threatened species, such as bustards
and albatross, or invasive species such as roe deer, whose dynamics depend very strongly on global
change. These three areas of research are improving our knowledge of population
dynamics and animal communities in a changing environment, and are making it
possible to draw up new principles for the sustainable management of biological
resources.
THE ECOSYSTEM: A SET OF TROPHIC INTERACTIONS…
The concept of biodiversity has revitalized research on ecosystems by focusing
attention on interactions between organisms and geochemical cycles. In particular,
the aquatic environment has been the subject of a great deal of study in this area, due
to the ease of experimental work within it. CNRS is carrying out a great deal of
research in this field. Scientists are attempting to understand the role of the organization of food webs, which are groups of species linked together by predator-prey
relationships. For instance, they determine the trophic connections between species
and the role of their functional diversity on energy flows and on the movement of the
main elements (nitrogen, phosphorus, carbon, etc.) within ecosystems. In addition the
coupling together of classic (plant-animal) food webs and decomposers via the microbial loop is more fully integrated. The movement of matter within food webs, or the
trophic level of organisms can be measured more accurately by using markers for
organic matter such as fatty acids or stable isotopes.
...AND NON-TROPHIC INTERACTIONS
Increasing attention is now being paid to allelopathic interactions, in other words
to the inhibiting or stimulating effects of one species on another via chemical compounds. Similarly, the effects of anthropogenic chemical substances cannot be fully
understood without taking into consideration the structure of the food webs into which
they are released. Theoretical and experimental approaches are being developed in
order to better assess the relative proportion of direct or indirect effects of such
chemical substances on the working of ecosystems in connection with the structure
© CNRS Photothèque / Alain Pasquet
© CNRS Photothèque / Nathalie Mansion
Left: Nitrogen-fixing nodule (symbiosis
between Medicago truncatula (alfalfa) and
Sinorhizobium meliloti).
Right: The spider Arycope bruennichi. A large
species found locally. The blue patches are
marks made by the experimenter in order to
monitor the movement of individual spiders.
This makes it possible to test in the field the
influence of factors such as the density of
prey or of conspecifics on the way in which an
individual changes the place where it makes
its web.
20-21
ECOSYSTEM
DYNAMICS
© CNRS Photothèque / Alain R. Devez
of food webs. All these different aspects show how diverse the networks of interactions within ecosystems are. A detailed understanding of the role biodiversity plays in
functional processes within ecosystems is no longer conceivable today without taking
into account coupling between networks of trophic and non-trophic interactions (parasitism, competition, allelopathy and mutualism).
URBAN ECOSYSTEMS
Long considered to be of minor interest, biodiversity in urban environments is
today the subject of several research programs at CNRS. Contrary to popular belief,
urban areas are home to a substantial number of species, and some taxa are actually better represented in cities than in the surrounding countryside. Urban biodiversity
forms an ideal model for study of many current issues in ecology. This is because the
colonization of these new environments, which on the face of it are not very favorable
to living organisms, provides researchers with novel assemblages of species, i.e. with
new models for the analysis of the factors influencing the structure of communities.
The extreme fragmentation of urban environments leads to the formation of a network
of habitats that are isolated from each other, and that can also be used in order to
identify processes of colonization and extinction of small populations functioning as a
network (the metapopulation concept). In addition, cities provide a new type of habitat
for species, which are obliged to adapt to it. It thus forms an authentic evolutionary
laboratory, where we can expect to observe alterations in biological traits (dispersion,
reproduction, behavior, etc.) in response to natural selection. Finally, since cities are
artificial spaces, they make it possible to study the role of humans in the functioning
of ecological systems and to improve the scientific foundations of biodiversity conservation in anthropentric environments.
The long-tailed nightjar, Caprimulgus
climacurus, is a tropical African migrant and a
regular winter visitor. It lives in human
environments, such as trails, villages and
slash-and-burn cultivation, in the Makokou
region of Gabon.
© CNRS Photothèque / Jean-Georges Harmelin
AN OCEANOGRAPHIC LABORATORY FOR THE STUDY OF BIODIVERSITY IN THE MEDITERRANEAN
Oceanographic laboratories have long practiced the interdisciplinary research required for an
integrated approach to ecology and marine biodiversity. They provide facilities for experimental work
both in situ and in the laboratory using naturally circulating seawater, which makes it easier to allow
for interactions between the physical factors of the medium and biological complexity. These
laboratories have now been established for over a century and a half, and possess series of highquality long-term observations which not only make it possible to estimate environmental change but
also to validate models. Oceanographic laboratories also play an active role in disseminating
knowledge to decision-makers, schools, clubs and associations, and the general public, thus making a
contribution to good governance of the environment. The Diversity, Evolution and Marine Functional
Ecology Unit (Dimar), based at the Endoume oceanographic laboratory, in Marseille, is part of the
Centre d’océanologie de Marseille (Marseille Oceanology Center). It brings together the skills needed
for research into the connections between biological diversity (genetic,
phenotypic, specific and functional) and the dynamics and functioning of
marine ecosystems. Special importance is given to the study of the
impact of large rivers such as the Rhône on benthic communities and
on fishing, as well as to biological invasions, since the Mediterranean
Sea is severely affected by this phenomenon. The results are helping us
to understand and predict the impact of disturbances (whether natural
or anthropogenic) and of climate change on coastal environments. Many
researchers at Dimar are involved as experts in a large number of
protection and conservation programs, not only locally, but also at
regional, national and European levels.
Reef slope in the Cassis area, with
Parazoanthus (orange sea anemone) and
Corallium rubrum (red coral).
ECOTRONS: ECOSYSTEMS UNDER OBSERVATION
© Mandataire : P. Albaret - BET Technique Auvertech - Architecte : Agence Matte/Devaux/Rousseau
As a result of an article by Michel Loreau published at the end of 1998 in "Bio", the journal of the
Department of Life Sciences, CNRS decided to equip itself with Ecotrons on a national scale. In these
experimental stations, natural or artificial ecosystems, as well as animal, plant or microbial
communities, can be subjected to predetermined environmental conditions. The aim is to understand
and predict their responses to pressure such as global climate change.
The first Ecotron saw the day in the UK, at the Centre for Population Biology (Imperial College) near
London. Its goal is to quantify the relationship between the organization of biodiversity and ecosystem
functioning. Currently there are two projects under development in France, while a third one is
planned.
The first French project is the Montpellier Ecotron, to be located on the CNRS and Baillarguet
campuses. It is planned to contain an experimental plot and an array of twelve macrocosms, which will
be enclosed chambers in daylight, within which the climate can be controlled. The chambers will be
equipped with instruments which continuously measure temperature, humidity, the atmospheric CO2
concentration, etc. One of their original features is that the chambers will be able to accommodate
intact soil monoliths measuring 5 m3 complete with their natural vegetation. An array of mesocosms
and microcosms will used for short-term studies, i.e. less than two years in length. This setup, which
is used to study terrestrial ecosystems, will be completed by the Medimeer station (Sète), where it is
already possible to confine pelagic communities.
The Foljuif Ecotron, located near Fontainebleau, is run by the École normale supérieure. One plot is
used to carry out long-term experiments under natural conditions. The core of the project is an array
of 24 climate chambers designed to subject artificial, terrestrial or aquatic communities and
ecosystems to a range of environments. Ponds will be used for long-term monitoring of interactions
between the structure of food webs, the
dynamics of plankton communities and the
physical chemistry of water. Population cages
are used to test the effect of climate change
and fragmentation of the environment on the
dispersion of animals.
Finally, sophisticated greenhouses are used to
analyze the functioning of plant communities
under semi-controlled conditions.
A third Ecotron, given over to Alpine
biodiversity, is under study. It will be set up on
the site of the Lautaret Alpine garden, located
at 2,100 meters altitude. It will
in particular include cold
greenhouses which allow
accurate control of soil
parameters.
© Foljuif
Architect’s drawing of the Ecotron in Montpellier.
ECOSYSTEM DYNAMICS
Coordinator: Luc Abbadie
Unit for Biogeochemistry and Ecology of
Continental Environments,
CNRS/Inra/université Paris 6/Institut national
agronomique Paris-Grignon (INA-PG)/ ENS
Paris/École nationale supérieure de chimie de
Paris (ENSCP)
With contributions from:
Gilles Boeuf
Evolutionary and Cell Biology Models Unit,
CNRS/université Paris 6
Patrick Duncan
Centre d’études biologiques de Chizé (Chizé
Center for Biological Studies), CNRS
Pierre-Olivier Cheptou
Centre d’écologie fonctionnelle et évolutive
(Center for Evolutionary and Functional
Ecology), CNRS/universités Montpellier 1, 2,
3/École nationale supérieure agronomique de
Montpellier/Centre de coopération
internationale en recherche agronomique pour
le développement (Cirad)
Jean-Pierre Féral
Diversity, Evolution and Marine Functional
Ecology Unit, CNRS/Université Aix-Marseille 2
Gérard Lacroix
Biogeochemistry and Ecology of Terrestrial
Environments Unit, CNRS/Inra/Université Paris
6/INA-PG/ENS Paris/ENSCP
These experimental plots run by CNRS
at Foljuif enable researchers to carry out
a long-term study of the impact of
climate warming on the functioning of
populations.
22-23
ECOSYSTEM
DYNAMICS
24
THE IMPACT ON HEALTH
2.5 BILLION IN 1955, OVER 6.5 BILLION TODAY, AND NEARLY 10 BILLION
IN 50 YEARS TIME. THAT’S THE RATE HOMO SAPIENS SAPIENS IS
EXPANDING WITHIN THE BIOSPHERE. HUMANS ARE CHANGING THE
EARTH AND ALL ITS ECOSYSTEMS BY UPSETTING THE BALANCE OF
INTERACTIONS, COMPETITION AND COOPERATION AMONG SPECIES.
WHAT WILL BE THE CONSEQUENCES OF REDUCED BIODIVERSITY FOR
THE EVOLUTION OF MICROBES, WHICH, LIKE US, ARE PART OF THE
LIVING WORLD? OUR HEALTH DEPENDS ON THE ANSWER TO THIS
QUESTION.
© CNRS Photothèque / D. Cot, G. Nabias
MICRO-ORGANISMS: A CENTRAL ROLE
IN THE DEVELOPMENT OF HUMAN POPULATIONS
5 μm
© CNRS Photothèque
Bacteria and red blood cells in a mouse
intestine.
Staphylococcus aureus growing on a
vascular prosthesis.
Micro-organisms are one of the essential biological components of our planet, and
one that cannot be ignored. The emergence of higher organisms, including the first
humans, and their impact on the environment encouraged selection for new types of
activity by micro-organisms. These new possibilities gave rise to a large number of
associations which have proved beneficial to humans. Such microbial diversity has a
great impact on human health and on the development of human populations.
EVER SINCE THE BEGINNING OF HUMAN EXISTENCE…
Certain micro-organisms colonize humans and live in close interaction with them.
They are found on the skin, and in all the human body’s entry and elimination routes:
the nasal cavity, the oral cavity, the alimentary tract, etc. These micro-organisms use
the products of the human body or ingested and digested food in order to grow. The
colonization of these routes by the micro-organisms has been going on, generation
after generation, for at least several thousand years, and possibly for the last 195 000
years on the basis of the most recent dating of the oldest skulls of Homo sapiens.
However, it has only been in the last fifty years or so that the benefits for human health
of colonization by some of these micro-organisms have been recorded and recognized. Some micro-organisms break down food which has not been digested by
humans. They improve digestion, stimulate the immune system, and prevent colonization by pathogens. These observations have given rise to the term "probiotic", which
denotes a micro-organism which benefits the health of its host. However, despite the
benefits they bring, it shouldn’t be forgotten that some micro-organisms in the human
body can turn into opportunistic infectious agents if the body is weakened or immunodeficient.
© CNRS Photothèque / C. Delhaye, G. Nabias
RECYCLING ORGANIC MATTER AND WASTE TREATMENT
Micro-organisms lie at the heart of food chains and the major biogeochemical
cycles. Without their help and their great diversity, there would be a breakdown in the
recycling of organic matter, the bioavailability of many elements essential to life and,
more generally, ecosystem functioning. We would be submerged by vast quantities of
waste that can only be broken down and made accessible by micro-organisms, by a
process known as "regeneration". A significant example of how regeneration can be
put to work is given by the very concrete case of waste water treatment. Sewage has
often caused major epidemics (plague, cholera, typhoid, etc.) and produces foulsmelling odors. In 1914, British scientists used microbial diversity and Pasteur’s
research on fermentation to develop a system whereby sewage was aerated and broken down by micro-organisms in a tank. This method has since been modernized but
still uses the same principles. In the past few years, molecular analyses of microbial
diversity have demonstrated the great diversity and complexity of interactions in waste
water treatment plants. Intensive research is now being carried out, in particular at
CNRS, in order to characterize the micro-organisms involved, understand how they
work and study how they complement each other. This new knowledge should make
it possible to further reduce the biological and chemical risks associated with waste
water.
Thiobacillus ferroxidans sp. in a bacterial
mat in a pond for the treatment of acid water
polluted by arsenic, seen through a scanning
electron microscope.
Bird populations are reservoirs for viruses
such as West Nile fever or bird flu. Depending
on the diversity of bird species in a
community, the same infectious agent may be
transmitted in very different ways.
© Eye of Science/ Cosmos
It is biodiversity in general, and not only the biodiversity of micro-organisms, which
plays a key role in regulating the environment. The arrival of bird flu in Europe and the
outbreak of Chikungunya on the island of Reunion are there to remind us of the major
role played by reservoirs and host vectors in the development and spread of infectious
diseases. The problems related to the emergence or resurgence of diseases cannot
be understood from an anthropocentric, reductionist viewpoint. Their complexity
appears inextricable to us, since thousands of vector and reservoir species are connected by ecological interactions which are subjected to, and react to, environmental
conditions. The question of how to control diseases which have a major environmental component is not an easy one to answer. New epidemics are highly likely to occur.
What can be done to prevent them from spreading?
For a large number of diseases of environmental origin, an ecological approach
appears to be the most appropriate one, because the focus is on the interaction of living organisms with a microbial agent, and on the way in which this interaction reacts
to environmental conditions. The most productive studies using this approach are
unquestionably those which have revealed fundamental phenomena that explain the
movement of pathogens within ecosystems. Reservoir and vector animal species
show very varying abilities to pass on micro parasites. This natural diversity plays a
key role in the transmission of infectious agents in their environment.
In the US, Lyme’s disease illustrates this remarkably well. The bacterium which
causes this disease is transmitted by ticks to a number of animal species. In the
United States, the small rodent Peromyscus leucopus is far and away the most competent species when it comes to transmitting the microbe to ticks which bite them.
Environmental conditions, especially the fragmentation of forest ecosystems, have
encouraged the proliferation of this species to the detriment of others, thus leading to
increased transmission of the microbe to the vectors and therefore to human populations frequenting high-risk areas. This situation doesn’t occur in other more forested
areas of the US since the preservation of greater biodiversity in these ecosystems
leads to regulation of the population of Peromyscus leucopus. Thus, according to this
study, high local biological diversity tends to dilute the infectious agent in reservoir
hosts which are not or only slightly competent, and therefore to decrease the risk of it
being passed on to humans. This phenomenon has been named "dilution effect".
Since then, mathematical modeling has made it possible to show that these
results can be generalized to so-called "frequency-dependent" diseases, for which
contact with an infected individual does not depend on the density of individuals present. Nonetheless, the ecological mechanism in question seems more difficult to
© Gilles Balança (Cirad)
BIODIVERSITY CAN PROTECT US FROM DISEASE
If not treated, Lyme’s disease causes skin,
arthritic, heart, neurological and sometimes
eye disorders. The agent which causes the
disease, Borrelia burgdorferi, is a highly
mobile bacterium, spiral in shape and
between 5 and 25 micrometers long. It is
transmitted by ticks.
24-25
THE IMPACT ON HEALTH
© David Aubrey / Science Photo Library
explain for "density-dependent" diseases. To what extent can these results be extrapolated to other zoonotic diseases and to other environmental conditions? Today,
research is being carried out at CNRS with the aim of formalizing the effects of biodiversity and its evolution for other diseases such as West Nile fever and bird flu, diseases for which it is suspected that a great diversity of reservoir birds are involved.
The outbreak of bird flu is a phenomenon which is likely to recur. Natural bird sanctuaries and wetlands are stopping off places where migrating birds, carrying numerous pathogens, come into contact with resident species. These areas are highly
favorable to the movement of pathogens, even at a low level. To what extent did the
proximity of intensive poultry production and wetlands in the Ain Department, where
the H5N1 virus was detected, facilitate the triggering of a chain reaction, in which
humans may also have played a role, and which led to over a thousand turkeys being
slaughtered?
In the United States, Peromyscus leucopus
is a reservoir for Borrelia burgdorferi. These
rodents transmit the bacterium to ticks, which
transmit it to humans. It is therefore
necessary to study the dynamics of the rodent
population in order to understand the
frequency of Lyme’s disease.
BIODIVERSITY VERSUS EPIDEMICS
Depending on the diversity of bird species in a community, the same infectious agent may be transmitted
in very different ways.
1. In the presence of a diversity of reservoir species (each species can transmit the virus) the pathogen
can find many different ways of being transmitted, the overall result being a dilution of its effects.
The greater the proportion of reservoir species that have only a low capacity to transmit the virus,
the greater this dilution effect becomes.
2. In communities where reservoir species are less abundant, where one or several species which have
a high capacity to transmit the virus have taken advantage of the environmental conditions to breed,
the transmission of the infectious agent becomes easier and its effects are more easily seen.
This is a situation that can be encountered when migrating birds with a high capacity for virus
transmission settle in a local community where that virus is absent.
3. An extreme situation occurs where individuals of a single species of bird, with a high capacity for
virus transmission or which suffer its consequences, are concentrated in large numbers, as in poultry
farms.
1
2
3
THE EXAMPLE OF AGRICULTURE
Agriculture is another example of the role biodiversity plays in controlling epidemics. In the past few years, the risk inherent in cultivating a limited number of varieties of a given crop plant and the benefits of genetic diversity have been recognized.
In plant pathology there have been many cases of disease developing following the
cultivation of a particular variety or a group of related varieties. This observation has
led to the concept of "genetic vulnerability". The cultivation of vulnerable varieties is a
key factor in epidemics. It disturbs the balance between pathogens and their hosts
and encourages their propagation.
In contrast, intraspecific diversity may have beneficial effects. The progression and
DR
© CNRS Photothèque / D. Mc Key
A field of healthy cassava, and
a leaf affected by cassava
mosaic.
A field in Uganda destroyed
by cassava mosaic.
© J. M. Thresh
subsequent control of outbreaks of cassava mosaic in Uganda in the 1990s provides a
spectacular example of the beneficial role of genetic diversity.
The first time cassava mosaic was observed was in 1894 in Tanzania. This disease
of viral origin is transmitted by cuttings and
insects. Some varieties are more affected by
the disease than others. By selecting varieties
which were relatively unaffected farmers
avoided major crop losses. These early findings have since been corroborated by observations in a large number of African countries,
particularly during the outbreaks in Uganda in
the 1990s, which have been studied by
researchers at IRD. The most affected regions
in the country were those where the local
Ebwanateraka variety was almost exclusively
cultivated. The only crops to be spared were
those which contained a large number of
other varieties. Ebwanateraka had been
selected for its early maturity and high yield,
and grown by farmers several years earlier, at
a time when cassava mosaic was insignificant.
Ebwanateraka was grown in many regions of
Uganda, but the variety turned out to be very sensitive to outbreaks of cassava mosaic. There were thus considerable crop losses. The growth of the plants was so reduced
that they produced neither tubers for consumption nor cuttings for future planting. An
extensive survey carried out between 1990 and 2003 showed that there have been
major changes in the range of cultivars grown. Nearly twenty five varieties are now
grown in the areas where Ebwanateraka was predominant. Some were selected for
their resistance as a result of programs to improve cassava. Others are local varieties
chosen by farmers because of their resistance and tolerance. In this way production
recovered and the crisis was overcome.
In a number of areas in west and southwest Uganda, the situation was completely
different. A large number of varieties of cassava are grown there, and farmers are far
less dependent on it. When the first outbreaks of cassava mosaic occurred, the farmers eliminated the most seriously affected varieties and planted far more of those
which were least affected. They thus adapted rapidly to the disease, without any knowledge of mosaic, and without any technical assistance. This epidemic is one of the most
striking examples of the contribution genetic diversity makes to the control of plant
diseases.
EPIDEMIC IN UGANDA
As a result of the epidemic of cassava mosaic in Uganda in the 1990s, a large number of village
populations suffered a total loss of their income. Food shortages made their appearance, and
government boards of enquiry were informed of deaths due to famine. Since cassava was no
longer able to play its role as a stop-gap crop in the event of shortages, the situation became
especially difficult after the drought of 1993-1994. Given the almost total absence of cassava, the
farmers had no choice but to turn to other crops such as sweet potato. This led to prices
rocketing. Given the seriousness of the situation, emergency food aid was established, and
various governmental and nongovernmental organizations supplied cuttings of mosaic-resistant
cassava.
26-27
THE IMPACT ON HEALTH
PARASITES: ORGANISMS NOT TO BE OVERLOOKED
Unlike free organisms, parasites and pathogens have rarely been considered to
play a role in the working of ecosystems. Nonetheless, research carried out over the
past few years at CNRS have brought to light an unsuspected number of consequences of the influence they have on ecology and the evolution of the host populations. As often happens in ecology, these effects can be spectacularly amplified by
cascade processes. Parasites and pathogens can in this way totally disrupt food
chains, competitive relationships between species, or even the invasive potential of
some species. Upsetting these "balances" may or may not favor the preservation of
biodiversity.
Current scientific research into the consequences of parasitism in ecosystems,
range all the way from purely fundamental questions about the roles of parasitism in
ecosystems to more applied topics, such as clarifying the influence of land management methods (farming, hunting, deforestation, nature reserves, etc.) on the dynamics of parasite communities. Knowing that practically all the ecosystems on the planet
suffer the consequences of human activities to varying degrees, it would appear to be
of crucial importance to improve our understanding of the interactions between
human activities, parasitism and biodiversity. This research thus contributes not only
new information enabling more account to be taken of parasites in conservation programs, but is also laying the foundations of the rapidly growing discipline of health
ecology.
With regard to fundamental research, one of the top priorities for CNRS is the
identification of the mechanisms whereby parasites can locally favor biodiversity. The
processes involved are as astonishing as they are diverse. For instance, by altering the
appetite of their herbivore hosts, nematodes in the alimentary tract can indirectly
affect the structure of plant communities. Some parasites in lagoon ecosystems prevent shellfish from burrowing under the sediment and thus help to diversify the nature
of the possible substrates to which limpets, sea anemones, chitons and tube worms
fix themselves. This diversification of the habitat leads to a lessening of competition
between benthic invertebrates, which in return favors their coexistence.
© CNRS Photothèque
This cockle, Austrovenus stutchburyi, is
parasitized by the trematode Curtuteria
australis which prevents it from burrowing
into the sediment. This alteration in behavior
enables two species of invertebrate, the
limpet Notoacmea helmsi and the sea
anemone Anthopleura aureoradiata to coexist
in this environment.
© CNRS Photothèque / Laurence Médard
The leek moth, Acrolepiopsis assectella, a
plant-eating lepidopteran of the superfamily
Yponomeutoidea, attacks plants of the genus
Allium, and especially the leek, Allium porrum.
Found all over Europe, this species causes
huge damage to crops. In the center of the
picture, the hole made by a newly born larva
and the beginning of a mine can be seen.
Taking parasites into account is becoming increasingly important in conservation
biology, especially within areas which enjoy protected status. This is because parks
and reserves are hot spots when it comes to population density and species diversity.
These differences in the density of the animal population (and therefore of hosts) compared to adjoining areas have direct repercussions
not only on the dynamics of pathogen communities and on their virulence, but also indirectly on the populations of invertebrate prey.
Quantifying these phenomena is important for several reasons. For
instance, nature reserves may in some cases be areas where there is
a high parasite risk for the very species that they are supposed to protect, or where the prey available there is not as valuable to predators
because of parasitism. It is also conceivable that the concentrated
population of animals in these areas encourages the transmission
and proliferation of pathogens which are a potential risk to human health. This clearly illustrates the connection between conservation biology and health ecology.
For CNRS, it is essential over the next few years to provide the knowledge which
will enable ecosystems to be managed in a way that allows for the transmission of
pathogens to human and animal populations. However, so that they can be managed
in a way that also favors the preservation of biodiversity, it is essential that this
research be carried out in close collaboration between biologists, veterinarians and
managers of protected sites. Despite a great deal of progress regarding theory in this
field, the setting up of long-term studies and monitoring of the interactions between
human activity, biodiversity management and parasitism are more than ever of
utmost importance for the understanding and prevention of public and veterinary
health problems.
THE IMPACT ON HEALTH
Coordinator: François Renaud
Genetics and Evolution of Infectious Diseases
Unit, CNRS/Institut de recherche pour le
développement (IRD)
With contributions from:
Benoît Cournoyer
Microbial Ecology Unit, CNRS
Jean-François Guégan and Benjamin Roche
Genetics and Evolution of Infectious Diseases
Unit, CNRS/IRD
Denis Fargette
Crop Diversity and Genomes Unit, IRD
Frédéric Thomas and Camille Lebarbenchon
Genetics and Evolution of Infectious Diseases
Unit and la Tour du Valat Biological Station,
CNRS/IRD
A larva at the 5th larval stage on its host
plant. This is a male, which can be identified
by its orange testes. This larva mines the leek
leaf on hatching, where it will then take
refuge.
© CNRS Photothèque / S. Morin, J.-P. Pointier
BIODIVERSITY, PARASITISM AND HUMAN HEALTH: A FRAGILE BALANCE
For over twenty years, Guadeloupe’s
freshwater mangrove swamp has been used
as a natural laboratory by teams from CNRS
who are studying the evolutionary ecology of
host-parasite systems. In this swampy forest
in an island environment, a combination of
ecological, behavioral and demographic
factors has led to a human parasite (the
schistosome) crossing over to the
overabundant populations of roof rats.
Although this is a recent phenomenon, it has
already led to remarkable adaptations of the
parasite to its new hosts. Analysis of the
genetic co-structures of the populations
concerned (parasites, rodents and mollusks)
also makes it possible to understand the
dynamic processes at work in these complex
systems of interactions, and to envisage the
most appropriate ways of combating the
parasite.
28-29
THE IMPACT ON HEALTH
30
BIODIVERSITY IN DANGER
HUMANS ARE THE MAIN THREAT TO DIVERSITY. IN THE LAST FIFTY
YEARS THEIR POPULATION HAS MORE THAN DOUBLED AND THEIR
CONSUMPTION OF NATURAL RESOURCES HAS INCREASED SIXFOLD.
THE DEVELOPMENT OF HUMAN SOCIETIES HAS LED TO THE OVER
EXPLOITATION OF ANIMAL AND PLANT SPECIES TO THE POLLUTION OF
NATURAL ENVIRONMENTS AND IS NOW CONTRIBUTING TO CLIMATE
CHANGE. OVER AND ABOVE THE CHANGES THAT HUMANS HAVE
BROUGHT ABOUT BY THEIR NUMBERS AND THEIR ACTIVITY, THEY HAVE
ALSO DIRECTLY ACTED UPON SOME ECOSYSTEMS IN ORDER TO SATISFY THEIR NEEDS. ALL THESE FACTORS IMPACT ON BIODIVERSITY AND
ARE LIKELY TO CAUSE A MASS EXTINCTION OF SPECIES.
THE HUMAN IMPACT ON BIODIVERSITY
Biodiversity is an essential part of human activity, nutrition and health. Applied
research in the field of biodiversity may have a major impact on our development and
its sustainability. In the short term, the interest of such research is not always immediately clear, and it may be tempting to prefer research that leads to a rapid improvement in production or health. However, because of the major effect human activity has
on living species, as well as the importance of sustainability for medicine and farming, in the medium term, research on biodiversity is potentially of huge importance for
the future of our species.
© CNRS Photothèque / Yann Rantier
THE IMPACT OF AGRICULTURE
The sea floor off Frioul (Bay of Marseille) in
1970. Oceans and seas are used as garbage
dumps for the waste left over from human
activity.
Algal bloom in Lannion Bay. Every summer,
a large number of estuaries and bays in
Brittany are invaded by the alga Ulva lactuca.
The proliferation of these algae is due to high
concentrations of nitrates and phosphates in
coastal waters, and is directly caused by
human activity (farm waste, leaching from
farmland, and sewage).
Agronomists have always been aware of the need to make use of existing biodiversity. However, over the course of the last century, we have witnessed the emergence
of an agronomy which is less and less sustainable. Research into the origin of crop
plants, the basis of all human food, has shown that they are the result of a process of
domestication carried out in constant interaction between wild and cultivated forms.
The wild relatives of cultivated varieties provide the diversity which is essential for the
adaptation of cultivated forms to environmental changes (especially to pests and
pathogens). It is clear that the increasingly intensive nature of agriculture has been
detrimental to these processes.
Plant geneticists continue to
draw on wild forms for the
genetic resources which make it
possible to adapt cultivated
forms, but the preservation of
this diversity is becoming
increasingly problematic. The
only solution currently implemented on a large scale consists
in freezing existing diversity in
gene banks. Research aimed at
a more practical and active
management of genetic diversity, based on the agricultural
© CNRS Photothèque / Jean-Yves Pontailler
environment itself and treating the agro ecosystem as a whole, is currently under way.
It aims to transform an attitude based on productivity into one which encourages sustainable management practices. With this research, carried out in partnership by
CNRS, Inra, IRD and Cirad we treat questions of agronomy, as one leading member of
Inra put it, "as an applied branch of ecology".
PATENTING LIFE
Research has shown that plant pollen spreads much further than once thought. Naturally, in the
immediate vicinity of a crop, the quantity of pollen originating from this crop falls off rapidly the further
away you are. However, this is only true for pollen which has fallen straight onto the ground.
Other pollen, caught up by atmospheric turbulence, are spread almost uniformly throughout the turbulent
layer (from 0 to around 1,000 meters altitude), and the distance they disperse then only depends on how
long they survive. Apart from the many agricultural and economic consequences this phenomenon can
have, it takes on particular importance if you take into account the practice of patenting plant genes,
which is recognized all over the world except in Europe.
A Canadian farmer was recently convicted for sowing rape seed, collected from his own fields, which
contained genes patented by an agrochemical company. The genes, in the form of seeds or pollen, had
been blown into the farmer’s field. He hadn’t stolen them, but they were
patented. The farmer was therefore banned from continuing to use his
own seed. After a lengthy court battle, the Supreme Court of Canada
finally came down in favor of the firm. It’s easy to see that wind-blown
pollen and seed, together with American patent legislation, can enable
biotechnology companies to take over the genetic resources of the entire
planet. All they have to do is to patent the genes, grow the plants that
contain them, and then let the wind do the rest. This prospect opens up
the possibility of a massive loss of genetic diversity among
the organisms which are most valuable to humans: the plants
on which all their food is based.
© Eye of Science/ Cosmos
This grain of pine pollen has a
shape which favors its dispersion by
wind.
The need for diversity in cultivated forms has led to an innovative technical solution, which is to look for the genes which can be used to improve a domestic species
not just in closely-related species, but rather in any living organism. Research in the
field of biotechnology has been extremely active, and rapidly led to the production of
GMOs able to bring about a number of improvements to farming. Unfortunately, this
approach did not include a wider analysis of the diversity of crop plants and their wild
relations. Adding a gene taken from a bacterium to a plant in order to kill the insects
that attack it can certainly be useful to agriculture, by making it possible to fight
against pests without harming other species. Similarly, making a species resistant to
a herbicide makes it possible to be sparing with toxic chemicals when eliminating
weeds from crops. However, research into the impact of such practices jointly carried
out by CNRS and Inra, have shown that a certain number of precautions need to be
taken. Firstly, it would be irresponsible to make all plant species resistant to all herbicides. That would lead to an inextricable situation when it comes to dealing with
self-sowing plants of one crop within another. Secondly, it is necessary to make sure
© CNRS Photothèque / Nathalie Mansion
GMOS: A PRECAUTIONARY APPROACH
A genetically modified tomato plant.
30-31
BIODIVERSITY
IN DANGER
that crossbreeding between crop plants and wild plants doesn’t end up producing
resistant super-weeds. And finally, it would be foolish to insert the same resistance to
insects into all plants. Just as bacteria have become resistant to antibiotics, such an
approach would inevitably lead to widespread resistance by insects.
© CNRS Photothèque / Christophe Lebendinsky
CHEMICAL DIVERSITY: A COMPLEX PUZZLE
Catalytic ozonization device for breaking
down pollutants in aqueous solution in a
laboratory reactor. The goal of this research is
to study the reaction mechanisms of catalytic
ozonization on model molecules and to
develop processes for depolluting water.
Chemical pollution contaminates all food chains. Over 100,000 different chemicals are produced in Europe. Not much is known about their
individual effects, and even less about their synergistic or antagonistic
effects. Most of these substances or their breakdown products are
found in the environment. That makes thousands of different chemicals which have to be tracked and monitored. The development of new
analytical methods means that it is now possible to detect chemical
elements at very low concentrations, and identify new molecules liable
to have biological effects and which are as yet unregulated. It was in
the 1970s that people first became aware of the dangers of industrial
pollution, while the 1980s saw increased awareness of the problems
caused by agricultural pollution due to the use of fertilizers and pesticides. Now, in the
first decade of the new century, there is increased interest in the problems caused by
new substances which are present in the environment mainly because of use by individuals. These new classes of chemicals include plasticizers, detergents, pharmaceutical
and body care products, natural or synthetic estrogen compounds (contraceptive pills),
and pesticides with recent formulations. A number of carcinogenic, mutagenic, immunosuppressive and neurotoxic effects are associated with such chemical compounds.
The Reach directive is a major step forward with regard to the security and safety
of chemistry for health and for the environment. In future, chemicals will be authorized only if they have no toxic effects, or under special conditions if they are dangerous but essential. The industry will have to produce toxicological evidence that their
products are harmless. Over 30,000 chemicals produced or imported into the
European Union will be analyzed and recorded over a period of eleven years.
The eventual goal of Reach is to promote the withdrawal of those chemicals that give
most cause for concern and their replacement by alternative substances that are
more suitable and safer. These regulations will make the European
chemical industry more competitive by encouraging innovation (e.g.
green chemistry and toxicity tests) rather than restricting it as happened with previous legislation. What is more, this legislation establishes rules which will set an example to the World with regards
sustainable chemical production.
© W. Thuiller
BIODIVERSITY AND CLIMATE CHANGE
Pessimistic (left) and optimistic (right)
forecasts for the shift in the geographical
range of the chestnut by 2080 (in red, areas
where it will have disappeared; in blue, areas
which it will have colonized).
Besides direct human impact on certain ecosystems, the burning of
hydrocarbons and coal due to human activity has led, since 1950, to
a massive increase in greenhouse gas concentrations. Since then,
the global mean surface temperature has risen by 0.6°C. Models
predict that by the end of the 21st century this average global temperature will have
increased by between 1.5°C and 5.8°C.
Global warming has already to begun to manifest its impact on biodiversity. For
instance, of the 95 most common species of passerine birds, those in northern regions
are declining the fastest. This trend was confirmed during and after the heatwave of
2003. The most pessimistic projections predict that by 2050, 35% of living species will
probably have disappeared, with global warming coming on top of the other three major
causes of extinction: environmental deterioration, biological invasions and overexploitation by humans.
In return, biodiversity
makes a big contribution to the absorption of
anthropogenic emissions of carbon, and is
thus slowing down
ongoing
climate
change. The greater
the biodiversity, the greater the biomass. Biodiversity and climate change are therefore connected. The way in which biodiversity evolves will lead to either an acceleration or a slowing down of climate change in the future.
© CNRS Photothèque / Jérôme Fournier
Plants which make up the restinga, a plant
association which is typical of coastal dunes
in Brazil (Ilha do Mel, Brazil). The bay of
Paranaguá is located at a very pronounced
biogeographic boundary on South America’s
Atlantic coast, since it separates the tropical
and subtropical areas, and is home to plant
species and associations from both areas.
Climate change on a major scale would lead
to the expansion or decline of vegetation
belonging to one of the two areas
IT’S NOT ALWAYS EASY TO MOVE
© CNRS Photothèque / Xavier Arnaud de Sartre
© CNRS Photothèque / Alain Pavé
Besides the reorganization of communities, the impact of global warming on the
diversity of species could be made worse by the reduction in size of their ranges. The
number of species liable to disappear could double if individuals are not able to
migrate to their new ranges. Biodiversity monitoring stations are pointing to the existence of real difficulties for migrating species. Specialist species (dependent on one
particular type of habitat) are the most likely to decline in abundance and go extinct…
These movements of species are seriously disrupted by human land-use management. Human pressure is fragmenting natural habitats. A species whose demographic potential diminishes due to the deterioration of its environment caused by human
activities (urban growth, building of roads and freeways, barriers which prevent movement of migratory animals, etc.) is even more likely to become extinct if climatic conditions are no longer conducive to its survival.
View of a landslide caused by runoff in
southern India. Unprotected ground left bare
by the destruction of forest cover is especially
affected by this phenomenon.
Aerial view of the Trans Amazon Highway.
The road is absolutely straight, except where it
crosses a stream (middle of photo). Its route
was drawn in the offices of the military
authorities with the aim of occupying the
Amazon basin in a rational way. Only a few short
sections are paved. Running parallel to the
highway, a high voltage power line (visible due
to the clearing of trees beneath the line) serves
the main towns and exports the hydroelectricity
produced in the region.
32-33
BIODIVERSITY
IN DANGER
Adaptation to new climatic conditions will be an alternative response of species to
the reduction in their range or to problems in migrating. In this case, intraspecific
diversity represents is of major importance since it determines the persistence of
adaptive processes within a context of rapid climate change.
© CNRS Photothèque / Alain R. Devez
THE BIOLOGY OF EXTINCTION, A VICIOUS CIRCLE
Namibian desert. This succulent,
euphorbia, grows in cracks in the
rocks of Swartzbank. Sea mists from
the ocean, located 20 kilometers away,
condense on this granite inselberg and
provide water for the plants, which are
adapted to extreme drought stress.
Humans are the main threat to biodiversity. The deterioration of habitats is reducing the possible range of those species which, confined to the limits of their range,
experience a fall in numbers and become caught up in a spiral, leading to their extinction.
Besides outside pressure, once a population’s numbers have started to decline, random
processes may come into play and push the
species over the brink into extinction. The
smallest populations of the species are affected
by demographic, genetic and environmental
factors. The survival rate of a population is
directly connected to its size in terms of the
number of individuals present. Small populations are the most likely to disappear. Intuitively,
it is not difficult to imagine that a population
composed of only two individuals has far more
chances of disappearing than a population with
fifty individuals. The likelihood of the two individuals in the small population dying are greater
than the likelihood of the fifty individuals in the
larger population disappearing.
Over and above this demographic effect, a
small-sized population is faced with harmful
genetic effects which threaten its survival. At
the level of a population, the number of different
copies of a gene, i.e. the number of alleles, constantly diminishes, apart from the odd mutation.
Some alleles (alternate forms of gene) are not
transmitted to offspring. This phenomenon is
called genetic drift. Genetic drift impoverishes the evolutionary potential of the population. In the event of an allele which is less favorable to an individual’s survival or
fecundity being transmitted, it can also diminish the average fitness of the population.
If this allele becomes permanently established in the population, and its effects are
too weak for it to be rapidly eliminated by natural selection, inbreeding depression can
be observed.
EVOLVING TOWARDS EXTINCTION
Habitat degradation is the cause of the extinction of a large number of populations,
but a species can adapt to its new environment, even if it is degraded or partially
destroyed if it has sufficient evolutionary potential. It can colonize new sites, acquire
tolerance to pollution or new behavior, and so on. However, there are cases where a
species can not adapt to a new environment. For instance, it may be highly specialized
to its environment and thus not contain the genetic variability necessary for adaptation to new conditions. The range of a species can be restricted not only by the
absence of favorable environments but also by its limited ability to disperse. Moreover,
the absence of a favorable environment is in itself connected to the environmental
requirements of the species, and therefore to its degree of specialization. When there
are few favorable environments, genes that confer a decreased aptitude for dispersion
Centaurea corymbosa is a protected
monocarpic plant and is only found on a single
massif in the south of France near Narbonne.
© CNRS Photothèque / Bruno Colas
are selected. This phenomenon can be
illustrated by the distribution of
Centaurea corymbosa, an endemic plant
in the La Clape massif in the Hérault
department. The species is made up of
six populations, and its range is restricted to ten square kilometers.
THE AMAZON BASIN
© CNRS Photothèque / P. Charles-Dominique et Nicolas Cegalerba (grenouille)
Biological diversity in the Amazon basin is principally threatened by human activity for all the reasons we
have already mentioned, and especially by deforestation
to provide new land for agriculture and livestock farming. This is a worldwide, long-term process. Due to the
growth of human populations and therefore the increase
in food needs, as well as the need to promote new agricultural methods which are less harmful to the environment and human health, and will lead to more land
being farmed. Within fifty years, 30 to 50% of the Amazon
forest will have disappeared or been considerably
altered by humans. There is no doubt that this transformation will cause a decline in biodiversity.
BIODIVERSITY IN DANGER
Coordinator: Pierre-Henri Gouyon
With contributions from:
Denis Couvet
Species Conservation, Restoration and
Monitoring of Populations Unit, CNRS/Muséum
national d’histoire naturelle/Université Paris 6
Isabelle Olivieri
Institut des sciences de l’évolution (Institute for
Evolutionary Sciences),
CNRS/Université Montpellier 2
Alain Pavé
CNRS French Guiana Unit, CNRS.
Philippe Garrigues
Laboratoire de physico-toxicochimie des
systèmes naturels (Laboratory of PhysicoToxico-Chemistry of Natural Systems) (LPTC),
CNRS/Université Bordeaux 1
© CNRS Photothèque / Hervé Thery
The Central coast stubfoot toad of French
Guiana, Atelopus franciscus; fungi; the fruiteating bat Artibeus gnomus; the rainbow boa.
The Amazon basin, together with the other
tropical rain forests, covers 7% of the Earth’s
surface, and may contain over half of all living
species.
Controlled burning in order to clear grazing
land near Redenção, Brazil.
34-35
BIODIVERSITY
IN DANGER
36
SUSTAINABLE MANAGEMENT
THE STATES WHICH SIGNED THE RIO CONVENTION ON BIOLOGICAL DIVERSITY
AGREED ON THE NEED TO HALT THE REDUCTION IN BIODIVERSITY BY 2010. WE
NOW KNOW THAT THIS WILL BE FAR FROM BEING THE CASE, AND THAT MUCH
PROGRESS NEEDS TO BE MADE WITH REGARD TO MANAGING BIODIVERSITY.
MANAGING NATURE MEANS UNDERSTANDING AND ADAPTING HUMAN RELATIONS WITH RESPECT TO NON-HUMANS, WHETHER DOMESTICATED OR WILD. IT
IS THEREFORE NECESSARY TO OBSERVE, MODEL, DEVELOP ECOLOGICAL TECHNOLOGIES AND ENGINEERING, AND IMPLEMENT NUMEROUS TOOLS, FROM
LOCAL TO GLOBAL LEVELS.
© CNRS Photothèque / Colin Fontaine
and Depending on the culture they come
from, humans see nature in very different
ways. Left: View from the administration
building of the Jussieu campus in Paris: a
small patch of nature can be seen, consisting
of a few embankments covered with wild
composite plants. Right: Aka Pygmy children
washing their clothes in a creek. Central
African Republic.
Bombus terrestris on Mimulus guttatus. The
pollination of crops, which is essential to their
survival, is one of the services that
ecosystems provide and on which humans
depend.
© CNRS Photothèque / Alain Epelboin
© CNRS Photothèque
HUMAN RELATIONS WITH RESPECT TO NON-HUMANS.
Although the word ‘biodiversity’ had been coined some time before, this new word
only really came of age at the Rio de Janeiro conference in 1992. Even in the remotest
villages in the world, farmers were asked to change the way they viewed the world.
They were invited to do so by civil servants or by NGOs who very often didn’t
themselves really understand what the
word meant, but nevertheless talked
about the need to safeguard "nature".
Every society has its own view of nature,
and a Pygmy certainly doesn’t see it in
the same way as a French farmer, let
alone a Parisian! Nonetheless, the need
to preserve the diversity of the living
world is becoming a worldwide concern,
and reflects the idea that a watered down
version of life wouldn’t really be life at
all. People’s perception of nature underpins any management of biodiversity.
Managing biodiversity means managing human relations with respect to nature. How
can these different interests and activities be reconciled? It is up to scientists to clarify the choices and help the decision-making process.
Simply listing all the different life-forms implies a considerable long-term effort by all
of the world’s groups of taxonomists. This is nonetheless essential if we are to understand the interactions between these life-forms over space and time. It’s a huge task,
and it is already raising a number of problems with regard to managing, analyzing and
making the data available. Several international scientific programs are involved in
this, especially the GBIF (Global Biodiversity Information Facility) and the GTI (Global
Taxonomy Initiative), as well as others at European level.
The interactions between organisms and environments give rise to the services that
ecosystems provide, on which humans depend and from which they draw benefit, such
as recycling the atmosphere, filtering water, soil fertility, pollination, etc. Biodiversity
management is essential for the preservation of these ecosystem services.
The importance of these services in the economic and social spheres is poorly understood and considerably underestimated. Biodiversity is a source of raw materials,
technology and products: its profits represent somewhere between 20 and 90% of the
turnover of companies, depending on the industry. We need to invent a kind of "life
Variation in the abundance of birds in
France, according to their specific habitat
(statistics established on the basis of
observations of over 300 000 birds). The
‘common birds’ indicator appears to show an
especially steep decline in biodiversity in
farmland.
1,3
1,1
0,9
0,7
0,5
1989 1991 1993 1995 1997 1999 2001 2003 2005
Generalists + 7 %
Urban + 9 %
Forest - 17 %
Farmland - 29 %
MONITORING STATIONS AND INDICATORS
Biodiversity monitoring stations: rationale and first results
There is a lack of biodiversity monitoring stations whose job is collect quantitative information, as is
done in Earth and Astronomical Sciences, about the general state of biodiversity.
The most successful experiment concerns observatories for common birds, which have been operating
in the US for the last fifty years and in France over the last fifteen years. They show that there has been
a fall of around 1% per year in the bird population, i.e. a fall of over a million birds per year in France.
This major decline, which covers the whole range of ecosystems in the northern hemisphere, can only
be proved irrefutably by increasing the number of observation points (10,000 points per year in France),
given its low annual intensity.
Butterfly monitoring stations, which have been operating in Northern Europe for twenty five years have
observed not only a steep drop in numbers, but also a reorganization of communities, favoring
generalist and southern species (the same thing has been observed in birds).
As for plants, monitoring over the past sixty years in the State of Wisconsin, USA, has shown a steep
drop in plant diversity among protected species (-50% in species diversity as opposed to -10% for
ordinary species), which may be due to the proliferation of herbivores.
From monitoring stations to indicators
The findings from biodiversity monitoring stations provide information for the development of
indicators. Indispensable tools for biodiversity management, indicators can promote dialogue between
scientists, politicians, the general public and where relevant, farmers, hunters, industrialists, etc. This
is because indicators, besides providing a succinct description of the state of biodiversity, make it
possible to rank the different types of pressure affecting biodiversity and the effectiveness of measures
taken for its conservation. Indicators are only effective if they facilitate dialogue among the different
groups mentioned above.
WHAT GOVERNANCE AND WHAT TOOLS FOR MANAGEMENT?
Laws and regulations are the first tools that spring to mind. They are of great
importance, provided it is remembered that they are expensive and complex to implement and administer. For society, they are indispensable when their role is to define
the global rules of the game, but much less so when they attempt to go into the finer
details of management at the local level.
Protected areas play a major role in biodiversity management, by making them
safe from being plundered. They cover around 10% of land and less than 0.5% of the
36-37
SUSTAINABLE
MANAGEMENT
© Denis Couvet
accounting", which would place business activity within the context of living processes. Some scientists hold a completely different view, and believe that we could
improve management by giving nature a price. Simply evaluating the cost of replacing
these natural services by technical solutions is usually enough to demonstrate the
importance of preserving them. One oft-quoted example is New York’s drinking water
supply, where it was shown that the natural water treatment afforded by the hills was
more efficient and far less expensive than using a water treatment plant. It is cheaper to preserve the quality of water in the ecosystem than to treat used water.
Biodiversity management will have to be based on long-term observation systems
which enable indicators to be established. Indicators are tools which enable dialogue
between decision makers, the general public and scientists, in order to decide on the
goals and means for biodiversity management. For instance, monitoring bird populations provides information about changes in land use and in human habitats.
Modeling, which is developing very rapidly, has turned out to be crucial to understanding the living world on the basis of partial information, and also to uncovering the
dynamic systems of interactions between organisms and environments, as well as
between environments and societies.
© CNRS Photothèque / François Sarrazin
ocean. They make up one of the tools for the
management of biodiversity, and are themselves
diverse, ranging from strict nature reserves to
biosphere reserves, a Unesco concept aimed at
reconciling conservation and development. The
recent French National Parks Act (14 April 2006)
attempts to bring the management of the parks
into line with our current state of knowledge
about biodiversity dynamics. In particular, it
attempts to ensure that the surface areas are
appropriate given conservation constraints and
that there are ecological corridors. Regional
parks (Parcs naturels régionaux, PNR) are run
by the elected authorities, and are similar in concept to Unesco’s biosphere reserves.
Contracts play an important role in regulating relations between private and public stakeholders, especially with regard to bioprospecting. They are supposed to regulate access to resources and the sharing of benefits. Such contracts rapidly come up
against the difficulty that human communities whose territory contains these living
resources do not have property rights over them. Economists are therefore now advocating the establishment of clearly defined property rights, whether private, public or
state-controlled. They also suggest that rights of access and rights of use be clearly
separated since any regulation of use is pointless in the absence of control over
access. Overexploitation of fishery resources is a good illustration of this because,
despite a huge number of regulations, the absence of any control over access to these
resources has allowed their overexploitation.
There is a wide range of tools available, but their effectiveness depends on having
clear goals and the means to verify their implementation. However, and sadly, up till
now users have always managed get round measures taken to manage ecosystems.
The range of measures available can restrict the quantities extracted (quotas), restrict
the number of users (licenses) or put rights of access and of use on to the market
(marketable permits or rights markets).
Biodiversity management is the management of conflicts of interest or of culture.
This is well illustrated by the misadventures involved in the reintroduction of bears to
the Pyrenees. The social sciences have developed methods of arbitration which can
facilitate dialogue between conflicting sides and the emergence of common long-term
goals. Some of these approaches have recourse to role games and modeling.
In all cases, the aim is to enable stakeholders to share a common representation
of the ecosystems which are to be managed, and to build a body of expertise which
will facilitate the decision-making process.
Griffon vultures, Gyps fulvus. These vultures
were reintroduced into the Gorges du Tarn
and the Gorges de la Jonte, which run
alongside the Causse Méjean limestone
plateau in southern France in the early 1980s.
This conservation program is run and
monitored locally by the Ligue pour la
protection des oiseaux (French Society for
Bird Protection) and by the Cévennes National
Park.
BIODIVERSITY AND CONTRACTS
The analysis of contracts for bioprospecting, extraction of non-renewable natural resources,
and access to biotechnological innovations in developed countries is at the center of social scientific
research into biodiversity. These contracts need to take into account the interactions and conflicts
between different stakeholders. To limit conflicts, scientists recommend defining and implementing
property rights. This step is crucial, since whereas the English-speaking countries advocate private
property as the only management model, French scientists are seeking alternative models for
property: common property, distinction between rights of access and rights of use, collective
administration of intellectual property, etc. The goal of these alternatives is to improve the economic,
social and environmental effectiveness of contracts associated with development projects,
and to facilitate access both of companies to natural resources and of the poorest populations
to pharmaceutical and agricultural innovations.
© CNRS Photothèque / Isabelle Olivieri
INTERNATIONAL GOVERNANCE
Planting out greenhouse germinated
seedlings of Senecio inaequidens, Cape ivy, in
an experimental set up at Montpellier. This
plant is native to South Africa and arrived in
Europe at the end of the 19th century in the
holds of boats carrying wool. The aim of this
experiment is to determine the evolutionary
consequences of the invasion of Europe by
this invasive species.
Biodiversity management is also an international issue and has given rise to the
establishment of conventions and international auditing mechanisms. The 1992
International Convention on Biological Diversity has been ratified by 188 countries.
Over the past fourteen years it has succeeded in getting these countries to agree on a
common method for defining problems, which is a remarkable result. It serves as a
reference for thinking about biodiversity management. In parallel, there exist other
specialized conventions about wetlands (Ramsar), desertification and biosafety.
The role of science in establishing this world governance is considerable. The
worldwide Diversitas program is exerting a great deal of influence on the ‘scientific
bodies’ involved in the support and implementation of the convention. Scientists provide counterintuitive results which influence international discussion, and will continue to do so in the future. For instance, this is the case regarding the management of
one of the biggest problems in biodiversity, i.e. biological invasions. The solutions are
both national (improved planning of land use, less fragmentation) and international.
This is because invasive species generally travel via international trade, like Crepidula
fornicata, an oyster parasite which is carried in the ballast tanks of merchant shipping,
or the corn rootworm, which invades via airports. It is estimated that 10% of introductions lead to naturalization and spread from the site of introduction, and that 10% of
these introductions subsequently cause problems. Research is being carried out in
order to attempt to develop diagnostic tests for quantifying the susceptibility of
ecosystems to such invasions and ways of controlling them.
© Roscoff
THE URGENT NEED FOR RECOGNIZED EXPERTISE
Left: flow cytometry. This device is used
to determine the abundance and
characteristics of phytoplankton cells thanks
to their fluorescent properties. Demonstration
of fluorescence using colored solutions.
Right: Chroodactylon ramnosum.
Decision-makers, politicians, administrators and
industrialists have become aware of the importance of
biodiversity, in other words, of preserving life on Earth.
They wish to act but don’t know how, and are seeking
established, recognized expertise.
Firstly, it is necessary to encourage the emergence of
professional ecological engineering. Based on the
progress made in fundamental and theoretical ecology, we now need to develop the tools necessary to
solve environmental problems and to invent adaptive and self-sustaining systems. This means learning how to direct or restore ecosystem functions and
restore degraded ecosystems, constructing ecosystems that are adapted to the survival of threatened
species, and so on. Ecological engineering will need
experimental evaluation under controlled condi50 μm
tions, the developments of predictive models and
experiments on real ecosystems.
It should not be forgotten that although management has a technical basis, it also
means reconciling what are frequently conflicting human interests. Ecological engineering will therefore also need to make use of social science skills. Thus to be credible, it will need to be interdisciplinary in nature.
On the international level, several mechanisms of expertise are under way, the
best-known being the Millennium Ecosystem Assessment, which is available on the
internet. The results of this work, which was carried out by 1,320 experts from all over
the world, including ten from France, are being carefully studied by both public and
private decision-making bodies. An international consultation is also in progress
whose goal is to draw up the outlines of an international mechanism of expertise at
the disposal of public and private decision makers. The consultation is the result of
the "Biodiversity, Science and Governance" conference held in Paris in January 2005,
which was attended by 1,500 people. The conference reviewed the current state of
knowledge and ignorance, and called for an immediate speeding up of the decisionmaking process.
38-39
SUSTAINABLE
MANAGEMENT
A CHALLENGE FOR SUSTAINABLE DEVELOPMENT
© CNRS Photothèque / Pascale Dollfus
Biodiversity management has major implications for the future of societies. The
disappearance of a large number of species alters the environment and makes it
more vulnerable. For instance, the loss of microbial diversity leads to the selection of
highly resistant strains of pathogen; lower diversity makes ecosystems less resistant
to biological invasions; in tropical countries, deforestation and concentration of property force the poor onto unproductive land and leave them with precarious rights of
use. Poverty, biodiversity and sustainable development are closely linked. Managing
biodiversity and preserving evolutionary potential means keeping the options open for
the future of humankind.
Flocks of sheep and goats being taken up to
summer pasture by nomads from Rupshu.
Eastern Ladakh, Northern India.
AMAZONIA: AN EXAMPLE OF BIODIVERSITY MANAGEMENT
The word ‘Amazonia’ tends to conjure up images of the rainforest, the "green hell"
or the "emerald-green forest", depending on your point of view. We also think of the
river, the biggest river system in the world, often as if it were somehow separate from
the forest. Of course, it’s true that much of Amazonia is covered by forest, the largest
in the world together with the Siberian forest. However, Amazonia is much more than
that. There are towns and villages forming a widely scattered habitat covering a huge
area; a large number of highly diverse human societies (in French Guiana alone, there
are around ten different languages spoken); a high biodiversity (not only terrestrial but
also aquatic) that is a potential and sometimes overestimated source of wealth; close
interdependence between rivers and forest; areas of savannah; a coastline with large
areas of wetland; a fluvial island system; one of the most ancient basements in the
world (the Proterozoic, or possibly even Archean, basement of the Guyana Plateau);
mineral resources; and a humid intertropical climate, with a strong Atlantic maritime
influence which can be felt right up to the Andes. How important is the role this system plays in the main dynamic processes on our planet?
B
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What role does biodiversity play? How did it evolve? How does it maintain itself
spontaneously? What resources are connected to it? What is the best way of managing and developing this vast territory with a view to the sustainable development of the
societies who live in and off it? What technologies should be adapted or developed in
order to bring about this development? How can this development be planned, how
can the health of the populations be improved, while at the same time preserving and
making the best use of the wealth of this environment, and minimizing the impact on
biodiversity?
The best, and most economical, way of preserving the diversity of a living system,
as well as its capacity to generate diversity, is probably to let it evolve spontaneously.
This doesn’t mean that monitoring should be neglected, or that exploration or a certain amount of forestry and farming should be banned, but it does mean that it’s
important to be careful not to disturb the spontaneous mechanisms that increase,
maintain or reduce biodiversity.
© CNRS Photothèque / P. Charles-Dominique
8
© Alain Pavé
A
8
Distribution model of trees in a tropical
forest and sensitivity to environmental
disturbance. The trees are shown as colored
dots. Each color corresponds to a particular
species. In practice, in the vast majority of
cases, a type B distribution will often occur
(individuals are distributed randomly, or else
they form small groups, which at a larger
scale are also distributed randomly). Although
they are distributed at random, this is not just
due to chance. This distribution ensures the
preservation of the maximum number of
species, and hence of biodiversity, in the event
of a major disturbance (D).
© CNRS Photothèque / P. Charles-Dominique
In 2004, CNRS set up the Amazonia program. The goal of this interdisciplinary program is to give CNRS a
permanent footing in French Guiana, and to promote scientific policies and provide incentives to this end.
The vast Amazonian system, where there are still to be found extensive, almost totally undisturbed
areas of high biological diversity, is of enormous scientific interest, especially with respect to questions
relating to biodiversity. In the CNRS tradition, activities are carried out in cooperation with its partners,
universities and other research establishments.
The Amazonia program has three main roles. It looks after the setting up of research facilities in French
Guiana (field stations, laboratories, and accommodation of researchers participating in scientific
programs). It encourages research in line with the policies outlined in its scientific program. The subject
of biodiversity obviously plays a central role in several areas: the search for biologically active substances
and for bioinspired technologies; the dynamics and management of the Amazonian region; health ecology
(emerging and re-emerging infectious diseases); conservation biology; and the history and functioning
of Amazonian ecosystems. Finally, the Amazonia program aims to model and simulate the dynamics
of biodiversity and ecosystems on the basis of theoretical analysis of data gathered.
The money that can be made from biodiversity has raised a lot of hope, to such an extent
that this has boomeranged, with researchers in some areas being suspected of "biopiracy".
It is high time that this issue be discussed in a rational and reasonable manner,
emphasizing that this is not the same kind of resource as a mine, which is located in one
particular spot, and that developing it usually requires major investment.
© CNRS Photothèque / Nicolas Cegalerba
THE AMAZONIA PROGRAM
Once this is established, it is necessary to determine the size and location of the areas concerned, and have good assessments of their
biological diversity and its dynamics. These data
are frequently not available, not only because the
necessary means to obtain them were not implemented, but also because for a long time
researchers were more interested in finding and
describing new species than in quantifying them.
The development and management of a region
and its biodiversity require: reliable data; regular
monitoring of changing conditions; defining
which areas are to be protected, and where, and which are to be used for human use
such as farming and forestry; and the establishment of connections between them. It
is also necessary to set up flexible management methods which enable land-use
plans to be revised in a well-ordered and regular way. In this way, Amazonia will be
developed rather than devastated.
Identifying a sample of termites at the
Nouragues laboratory, a tropical ecology
research station (Nouragues Station, French
Guiana). Aerial view of the camp (Inselberg
site).
MANAGING NOT ONLY TERRITORIES, BUT ALSO RESOURCES AND TRADITIONS
Managing biodiversity is not just a question of managing a geographical area or
monitoring biological and ecological processes. We can mention two sensitive issues,
especially in Amazonia: on the one hand, traditional knowledge, and on the other, the
widespread hope of being able to make money from a living resource.
The AOC label ("appellation d’origine contrôlée" or Controlled Designation of
Origin), which designates the geographical area, the variety, and how, how much and
where a product is made, and the Protected Geographical Indication (PGI) label, which
only designates the geographical origin of the product, are based on the principle of
combining geographical origin with local knowledge. With respect to traditional
knowledge, this medium is effective in the case of food resources, materials or repellents. However, therapeutic knowledge is a much trickier thing to use and develop. A
therapeutic substance may only be effective because of the placebo effect, and an
antipyretic substance can be confused with an antibiotic substance. Moreover, knowledge, which is a source of power, is not shared in these societies.
40-41
SUSTAINABLE
MANAGEMENT
© CNRS Photothèque / Richard Schartzmann
The peptides secreted by the skin of this
tree-dwelling frog from French Guiana,
Phyllomedusa bicolor, made it possible to
characterize molecules with analgesic and
antibacterial properties which can be used in
pharmacology.
© CNRS Photothèque / P. Charles-Dominique
TOWARD A GLOBAL UNDERSTANDING OF BIODIVERSITY?
© CNRS Photothèque / Nicolas Cegalerba
View of the forest from the summit of the
Nouragues Inselberg.
It has to be admitted that we’re having some trouble building up a global understanding of biodiversity, in a scientific world which is still highly compartmentalized.
Only scientists can bring about the interdisciplinary approach required to achieve this
understanding, without which no major progress will be possible in a subject of such
complexity. Besides, the thing that distinguishes the current "big questions" about the
environment from the small ones is precisely what might be called the doubly global
nature of the former: they concern the whole planet, and they involve a host of scientific and technological disciplines, as well as various political, economic, health and
social aspects of the way our societies are run.
However, above all, biodiversity concerns the living world, and it is also only by
improving our understanding of the biological and ecological processes involved in the
three mechanisms that increase, maintain or reduce biodiversity (whether they be
spontaneous or induced) that we will have a better basis on which to manage our
common heritage. Finally, a major effort must be made with respect to the gathering
and classification of reliable data, as well as to a frequently neglected area, namely
the creation of sound theoretical foundations on which to build evolutionary models of
biodiversity.
An adult homopteran (Membracidae) with
larvae.
SUSTAINABLE MANAGEMENT
Coordinator: Jacques Weber
Centre de coopération internationale en
recherche agronomique pour le
développement (Cirad) and Institut français de
la biodiversité (IFB)
Avec les contributions de :
Denis Couvet
Species Conservation, Restoration and
Monitoring of Populations Unit, CNRS/Muséum
national d’histoire naturelle/Université Paris 6
Alain Pavé
CNRS French Guiana Unit, CNRS.
Franck Courchamp
Ecology, Taxonomy and Evolution Unit,
CNRS/Université Paris 11/École nationale du
génie rural des eaux et forêts
André Micoud
Centre de recherches en sciences sociales
(Center for Social Science Research) (Cresal),
CNRS/Université Saint-Étienne/Université Lyon 2
Luc Abbadie
Biogeochemistry and Ecology of Terrestrial
Environments Unit, CNRS/Inra/Université Paris
6/INA-PG/ENS Paris/ENSCP
Michel Trometter, Inra Grenoble
BIODIVERSITY: A FEW STATISTICS
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2,300 people do work on biodiversity in CNRS laboratories, of whom 1,000 are CNRS staff members
1.8 million species have been described.
It is estimated that there are between 10 and 15 million animal and plant species living on the Earth.
About 16,000 new species are described every year, of which 600 are found in Europe.
Species are going extinct 100 to 1,000 times faster than in the past as revealed by the geological record.
FURTHER READING
Un éléphant dans un jeu de quilles : L’homme dans la biodiversité, Robert Barbault, ed. Seuil, 2006
Biodiversité et savoirs naturalistes locaux en France, Collective edition, Inra-Cirad-Iddri-IFB, 2005
La nature a-t-elle encore une place dans les milieux géographiques ?, Paul Arnould and Éric Glon (eds),
Publications de la Sorbonne, 2005
Actes de la Conférence internationale Biodiversité, science et gouvernance – Paris, 24-28 janvier 2005,
Robert Barbault, coordinated by Jean-Patrick Le Duc.
MNHN
Biodiversité et changements globaux – Enjeux de société et défis pour la recherche,
Robert Barbault and Bernard Chevassus-au-Louis (eds) Coordinated by Anne Teyssèdre.
Adpf / Ministère des Affaires étrangères, 2004
Les biodiversités. Objets, théories, pratiques, coordinated by Pascal Marty, Franck-Dominique Vivien,
Jacques Lepart and Raphaël Larrère, CNRS éditions, 2005
TO FIND OUT MORE:
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www.biodiv.org – Official site of the Convention on Biodiversity.
www.comite21.org – French site on the implementation of Agenda 21.
www.csf-desertification.org – Site of the French scientific committee for the Convention to Combat Desertification.
www.unfccc.int/ - Official site of the United Nations Framework Convention on Climate Change
(the complete text of the Kyoto convention can be downloaded in pdf format).
www.agora21.org – Site in French on sustainable development, where Agenda 21 can be consulted
www.brg.prd.fr – Site of the (Genetic Resources Bureau). Bureau des ressources génétiques
www.millenniumassessment.org/en/index.aspx - Site of the Millenium Ecosystem Assessment.
www.fao.org – Site of the United Nations Food and Agriculture Organization.
www.undp.org - Site of the United Nations Development Program. An excellent site
to get a clear picture of world economic and social development.
www.unesco.org/mab – Site of UNESCO’s Program on Man and the Biosphere. Information
about the Seville Strategy and the Global Network of Biosphere Reserves.
www.unep.org - Site of the United Nations Environment Program.
www.gbif.org – Site of the Global Biodiversity Information Facility (GBIF) whose goal is to make available
all the disparate data on biodiversity already collected.
This brochure is published by the CNRS Communications Office.
Institutional publications manager: Stéphanie Lecocq (01 44 96 45 67)
Design and coordination: Aude Philippe
Scientific coordination: Luc Abbadie, René Bally, Robert Barbault,
Pierre-Henri Gouyon, François Renaud and Jacques Weber
Picture research: Aude Philippe
Graphic design: Sarah Landel
Graphics: LaserGraphie
Printed by: C.print
December 2006
FOCUS
DECEMBER
2006
www.cnrs.fr