Biodiversity: The ravages of guns, nets and bulldozers. By Sean L. Maxwell, Richard A. Fuller, Thomas M. Brooks & James E. M. Watson (Nature, 10 August 2016)

22 Avril 2018 , Rédigé par Béthune

There is a growing tendency for media reports about threats to biodiversity to focus on climate change.

Here we report an analysis of threat information gathered for more than 8,000 species. These data revealed a contrasting picture. We found that by far the biggest drivers of biodiversity decline are overexploitation (the harvesting of species from the wild at rates that cannot be compensated for by reproduction or regrowth) and agriculture (the production of food, fodder, fibre and fuel crops; livestock farming; aquaculture; and the cultivation of trees).

Early next month, representatives from government, industry and non-governmental organizations will define future directions for conservation at the World Conservation Congress of the International Union for Conservation of Nature (IUCN). High on the agenda for political leaders, non-governmental organizations, conservationists and many others will be taking steps to turn the 2015 Paris climate agreement into action. It is also crucial that the World Conservation Congress delegates — and society in general — ensure that efforts to address climate change do not overshadow more immediate priorities for the survival of the world's flora and fauna.

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What next?

Of all the plant, amphibian, reptile, bird and mammal species that have gone extinct since AD 1500, 75% were harmed by overexploitation or agricultural activity or both (often in combination with the introduction of invasive alien species⁷). Climate change will become an increasingly dominant problem in the biodiversity crisis³. But human development and population growth mean that the impacts of overexploitation and agricultural expansion will also increase.

The aim of the World Conservation Congress is to translate sustainable development and carbon neutrality agreements into action. We urge delegates to focus on proposing and funding actions that prioritize the biggest current threats to biodiversity.

Thankfully, there are effective tools and approaches to alleviate harm caused by overexploitation and agricultural activities⁸. These include the development and governance of sustainable harvest regimes; the enforcement of hunting regulations and no-take marine protected areas; the maintenance of international policy mechanisms; such as the Convention on International Trade in Endangered Species; and public education (for instance, on where ivory comes from) to reduce demand. Also powerful are the establishment of protected areas to safeguard key biodiversity areas⁹; the management of agricultural systems in ways that allow threatened species to persist within them; the regulation of pesticide and fertilizer use; the certification of agricultural sustainability; and the reduction of food waste, for example, using urban food-transfer programmes.

Crucially, ensuring that overexploitation and agricultural activities today do not compromise ecosystems tomorrow will help to ameliorate the challenges presented by impending climate change. Healthy ecosystems are better repositories for carbon. They are also more likely to provide the physical connectivity and genetic diversity needed to enable species to adapt to the large shifts in climate expected later this century¹⁰.

Conservationists, weary of tackling herculean, long-standing problems, could be forgiven for being drawn to newer ones. Nonetheless, we appeal to all concerned with the sustainability of life on Earth to take stock of the current balance of threats — and refocus their efforts on the enemies of old.

Nature 536,143–145 (11 August 2016) doi:10.1038/536143a