HUMAN AND ANIMAL BIODIVERSITY
Our planet has undergone five mass extinctions of animal species since life began. The last one was that of the dinosaurs, some 66 million years ago. Many scientists agree that the Industrial Revolution has set us on the pathtowards a sixth mass animal extinction. Never before has the human impact on biodiversity and the rate of animal extinction been felt as keenly as it is today.
“It is worth mentioning that over 50 percent of my archive, collected since 1968, comes from sites that are now completely silent or so radically altered that the biophonies and geophonies can no longer be heard in any of their original form—mostly as a result of human endeavor.” BERNIE KRAUSE
THE HUMAN IN BIODIVERSITY
BY GILLES BOEUF
What is Biodiversity?
A contraction of “biological diversity,” the term “biodiversity” was coined in 1985 by the American biologist Walter G. Rosen. It is often associated with species diversity, defined as all the living species in an ecological community, divided into five main groups: prokaryotes (bacteria and archaeans), protists (single-celled eukaryotes), fungi, plants, and animals. But biodiversity is much more than species diversity alone; it includes both species and their relative abundance, and cannot be reduced to simple inventories or catalogues of species. Biodiversity was long defined as “all genetic information contained in an individual, species, population, ecosystem,” but we now prefer to refer to it as all the links created by living organisms, between themselves and with their environment. It concerns the living part of nature.
Since the beginning, life has been capable of creating an infinite number of organisms that have “interconnected,” in every meaning of the term, to construct close links with their environment. From this time to the modern day, life has been able to create well over a billion species with a vast array of shapes, sizes, colors, sounds, smells, behaviors, specificities, natural history traits, adaptations, and characteristics, the majority of which have emerged only to become extinct. While over billions of years, all this has been shaped by temperature and the composition of water and air, ocean salinity, light, day length, changing seasons (abiotic factors); food composition and availability, competition and links between species (biotic factors); as well as oxygen availability, it would seem that in recent times, the biggest evolutionary force on this planet is the presence of humans and human activity.1 Our impact on the earth is so significant that some scientists believe that the eighteenth century marks the transition into a new geological era, the “anthropocene.”2 […]
Are We Witnessing a “Sixth Extinction”?
In 2015, the International Union for Conservation of Nature (IUCN) documented over 815 species that have become extinct from our continents and 19 from our oceans in the last five centuries (it is considerably more difficult to confirm an extinction in the sea!). These figures are clearly biased by our lack of knowledge on many groups and the quality of the available data. Other projects estimate that, depending on the group, extinction rates are between 50 and 300 times higher than the expected “natural extinction” rates over the last 600 million years that paleontologists have calculated. At this rate, and if we do not change anything, half of all the species on earth will have become extinct by the end of the twenty-first century.
The IUCN estimates that 11,148 superior plant species and 7,781 vertebrates, 15 percent of which are mammals, are currently under threat worldwide. In March 2011, Anthony D. Barnosky and his colleagues asked a crucial question: “Has the sixth mass extinction already arrived?”3 Sixty mass extinctions, of which five are considered to be major, have taken place over 700 million years in the geological strata. The planet has not seen species becoming extinct at such a rapid rate since the last mass extinction, 66 million years ago, the mass extinction of dinosaurs. Recent research has succeeded in shedding light on the subject, but the distinction must be made between true extinctions, less foreseeable in the current human, short-term future (several decades), from sharp declines in population numbers, which have been increasing at a worrying rate for the last fifty years (for example, tropical and marine species).4 In the longer term, these significant declines in population could lead to species becoming extinct. Loss of biodiversity has been significantly worsened5 by two factors: human demography and the associated anthropogenic activities, both of which are linked to technological progress. When agriculture took its first tentative steps, between 10,000 and 12,000 years ago, the earth had a human population of 5 million, and the biomass of humans and their domestic mammals represented no more than 1 percent of the total mass of all mammals (5,000 known species); it now represents over 90 percent! The total population is estimated to have been less than 800 million inhabitants in 1750, 3 billion in 1960, 7 billion in 2012, and 9 billion in 2040: the trend curve for the human population in recent times (which has tripled since 1945) is enlightening. This demographic explosion coincides with the increase in human activities, which have grown very quickly since the end of the eighteenth century, the famous “great acceleration.” From the Industrial Revolution and the associatedagronomic and medical progress, humankind has increasingly believed in its ability to take on nature. Humans thinkabove all of subjugating and “dominating” nature, taking ownership of it; thus they let themselves wipe out and consistently destroy anything that rivals or hinders humanity’s activities and development (take, for example, the almost methodical destruction of all great predators). This dangerous mentality, exaggerated by the feeling that humans were “created,” and legitimately so, has led us to the current, very distressing, situation. Anthropological activities have not always been so disastrous and destructive for biodiversity. It is for this reason that, since the beginning of the 1970s, ecological science and political ecologism have developed simultaneously.
Why are Living Populations in Decline?
There are four main causes for the sharp drop in biodiversity we are currently witnessing.6 The first of which, habitat destruction and pollution, is singularly at the root of twothirds of the problem. The other causes are the overexploitation of natural resources,7 as even if living resources are naturally “renewable,” humans are preventing their “renewability” by going significantly beyond “harmonious” exploitation levels; anarchic distribution of species across the globe, known as “ecological roulette”8 as certain species become “invasive species”; and, lastly, climate change,9 for which humankind is largely responsible. One of the most threatened marine ecosystems is coral; the threat is directly linked to the recent changes to which its habitat has been subjected. While all of the reefs worldwide represent 0,1 percent of the ocean’s total surface area, these reefs are home to a third of all marine species. Unfortunately, coral reefs have been heavily impacted by direct human activity, such as destruction or blast fishing using dynamite or cyanide, which has caused vast expanses to be lost— half of the Great Barrier Reef off the coast of Queensland in Australia has been destroyed in thirty years. Climate change and increasing pollution in our oceans related to indirect human activity also play a role in coral decay, causing bleaching. Reefs have to cope with the warming or cooling of the surface waters, and the rising of the overall sea level caused by melting ice caps. We know that coral will not survive if the two-degree increase in temperature forecast for the end of the century actually happens. […] Regarding land biodiversity, deforestation has had a particularly significant impact. According to the World Resources Institute, 80 percent of the world’s original forest cover has been cleared or degraded, with the vast majority disappearing over the last thirty years. What is more, each year every rainforest on the planet (Brazil, Haiti, Venezuela, Zambia, Madagascar, Nigeria, Ivory Coast, Cameroon, Indonesia, Malaysia, China, India, etc.) loses an area equivalent to a quarter of the size of France. At this rate, by the end of the twenty-first century they will have totally disappeared. In all, 23 million hectares of forest were destroyed in Indonesia between 2009 and 2013, largely to expand palm oil plantations. The dramatic decline in our large rainforests is extremely worrying. Firstly because it damages biodiversity— the Congo Basin, the Amazon, and the two large islands of Borneo and New Guinea in Southeast Asia are the three largest pools of specific diversity in the world and contain over half of all known species. Secondly, it condemns indigenous populations to misery. It is well known that the trees “make it rain,” that they increase humidity through evapotranspiration and that, without forests, there would be no more rain, making agriculture impossible. Many populations decide to leave their habitat and live in the suburbs of large cities in atrocious conditions, creating pockets of formidable geopolitical destabilization, as is often the case in Africa, but also in Asia and the Americas. […]
Sustainably Protecting Ecosystems
[…] Several tools have been put forward to evaluate the extent of current practices’ impact, such as the “ecological footprint,”10 which measures the “burden” placed on nature by an individual or a population (according to this indicator, we would need three planet earths for all humans to have the same “standard of living” as a North American or European!). Ecology has also been seen through the lens of economic models: the “services” paid every year to humanity by various ecosystems have an estimated value of $33,000 billion, or twice the annual GDP of every country on earth.11 Conservation, together with sustainable use,12 seems economically preferable to intensive exploitation; established cost/benefit ratios go from 1 to 100 between “ecological strategy” and “intensive exploitation.” Billions of dollars are spent each year to “restore” polluted water courses, replant destroyed spaces, or reconstruct hedges that have disappeared, but how much work is needed and at what cost? The loss of pollinators alone would cost us nearly $200 billion per year! While these considerations have little meaning for those who do not have to worry daily about what they will give their children to eat, or those who are not tormented with ensuring their immediate survival! However, the number of people in these situations is growing and will continue to grow if we continue to fail to offer better answers to the issues of distributing and sharing the resources on our planet.
Paris, February 2016
Gilles Boeuf is a professor at the Université Pierre-et-Marie-Curie (Paris) and scientific advisor to the Minister of the Environment, Energy, and the Sea. Translated by Rebecca Bell (CG Versailles)
1 See Patrick De Wever and Bruno David, La Biodiversité de crise en crise (Paris: Albin Michel, 2015); Stephan R. Palumbi, “Humans as the World’s Greatest Evolutionary Force,” Science 293 (2001), pp. 1786–90; Gilles Boeuf, Biodiversité, de l’océan à la cité (Paris: Fayard/Collège de France, 2014); Edward O.Wilson, Sauvons la biodiversité! (Paris: Dunod, 2007); Peter M. Vitousek et al., “Human Domination of Earth’s Ecosystems,” Science 277 (1997), pp. 494–99.
2 Paul J. Crutzen and Eugene F. Stoermer, “The ‘Anthropocene’,” Global Change Newsletter 41 (2000), pp. 12–13.
3 Anthony D. Barnosky et al., “Has the Earth’s 6th Mass Extinction Already Arrived?,” Nature 471 (2011), pp. 51–57.
4 See Living Planet Report, WWF, 2014 and 2015.
5 See Paul Ehrlich and Anna H. Ehrlich, “Can a Collapse of Global Civilization Be Avoided?,” Proceedings of the Royal Society, B, 280 (2013), pp. 1–9; Jean- François Toussaint, B. Swynghedauw, and Gilles Boeuf, L’Homme peut-il s’adapter à lui-même ? (Versailles: Editions Quæ, ?2012); Stuart H. M. Butchart et “Global Biodiversity: Indicators of Recent Declines,” Science 328 (2010), pp. 1164–68.
6 See Boeuf, La Biodiversité; Lévêque and Mounolou, Biodiversité.
7 See Boeuf, La Biodiversité.
8 See Jean-Claude Lefeuvre, Les Invasions biologiques, un danger pour la biodiversité (Paris: Buchet/Chastel, 2013); Gian-Reto Walther et al., “Alien Species in a Warmer World: Risks and Opportunities,” Trends in Ecology and Evolution 24, no. 12 (2009), pp. 686–93.
9 See Chris D. Thomas et al., “Extinction Risk from Climate Change,” Nature 427 (2004), pp. 145–48.
10 Ecological footprint measures the area (in hectares) of the planet earth needed per inhabitant to produce the resources consumed and dispose of the waste produced.
11 See Robert Costanza et al, “The Value? of the World’s Ecosystem Services and Natural Capital,” Nature 387 (1997), pp. 253–60.
12 See La Biodiversité à travers des exemples.