Enjeux - Agriculture : a threat to biodiversity?

Agriculture : a threat to biodiversity?

The scientific community is in agreement that the number of plant and animal species populating our planet is decreasing. The main reason for this erosion of biodiversity is likely human activity. What role do agricultural practices play in this phenomenon? What share of the blame can be placed on those who cultivate the earth and raise livestock? Does modern farming as it is practiced today in France hasten the loss of biodiversity? Are the measures being taken since the recognition of the problem by our governments and the Rio Summit in 1992 sufficient? In this report, we have tried to shed some light on a major issue for our planet in the years ahead.

THE CONCEPT

What does biodiversity mean?

The term biodiversity is a contraction of biological and diversity. It refers to the biological diversity prevailing on the earth’s surface. But beyond the cataloguing and description of living species, biodiversity also has to do with the relations of these species with each other and with their environment. Biodiversity is, in a way, the living fabric of the planet.

An official definition was formulated at the Rio Conference in 1992: "the variability among living organisms from all sources, including, inter alia, terrestrial, marine, and other aquatic ecosystems, and the ecological complexes of which they are part: this includes diversity within species, between species and of ecosystems."

A recent concept … but a long history

It was the American biologist Thomas Lovejoy who first introduced the concept of biological diversity in 1980. The term biodiversity first appeared a few years later, in 1985, when another American, Walter G. Rosen, used it during the preparation of the National Forum on Biological Diversity being organised by the National Research Council. However, interest in preserving nature dates back much further than the twentieth century. It was, for example, mentioned in the writings of the Greek philosophers Aristotle and Theophrastus.

The first truly scientific approach to the diversity of species is Systema Naturae, a work by the Swede Carl Linneaus, which for the first time classified very large numbers of plant and animal species. We are indebted to him not only for the classification of plants but also for the principle of using names in Latin juxtaposing a generic name and a specific epithet to designate species. The Englishman Charles Darwin published The Origin of Species in 1859. In the early twentieth century, British explorers in particular were very concerned about the extermination of animals such as elephants, giraffes and rhinoceros. The First International Convention on the Protection of Wild Birds during their periods of reproduction and migration was held in Paris in 1950. Thereafter, interest in protecting species grew ever stronger, leading to the initiatives taken at the Rio Summit in 1992.

The Rio Summit: a decisive step

The Convention on Biological Diversity was adopted at the first Earth Summit in Rio de Janeiro in 1992. The first international agreement on this issue, it has been signed by 190 countries so far. This event received extensive media coverage and heightened the awareness of people all over the world of the need to protect living things. The objective of the Convention is “the conservation of biological diversity, the sustainable use of its components and the fair and equitable sharing of the benefits arising out of the utilization of genetic resources”.

Diversity, from ecosystems to genes

The notion of biodiversity applies not just to the diversity of species but also to the diversity of genes and the diversity of ecosystems. Genetic diversity is the diversity among individuals within the same species.
Ecosystem diversity concerns all types of ecosystems – oceans, swamps, prairies, forests, ponds, limestone or volcanic ground…. even down to the content of our cells, which may be home to parasites.

Almost 1.9 million species populate the earth

From bacteria and viruses to redwoods and whales, between 1.8 and 1.9 million plant and animal species have been identified to date on our planet. Seventy-five per cent are invertebrates (e.g. insects, molluscs and crustaceans), 11% plants, and almost 7% per cent vertebrates. But scientists coming from different horizons (May, Barnes, Brusca and Brusca, Groombridge and Jenkins, Chapman, and some others) believe that there are still many more for us to discover and that the earth could be home to, depending on who you ask, between 10 million and 100 million species.

The number of species catalogued is also tending to increase. The Australian Biological Resources Study, which is one of the most recent efforts to evaluate the number of identified species on our planet, calculates that they increased by 6.3% between 2006 and 2009.

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