Research press release


Nature Sustainability

Conservation: Agricultural expansion could cause widespread biodiversity declines by 2050

将来の食料需要を満たすための土地の開墾によって、世界中の陸生脊椎動物種のほぼ90%が、2050年までに生息地の一部を失う可能性があることを明らかにしたモデル化研究について報告する論文が、今週、Nature Sustainability に掲載される。しかし、食料の生産方法、生産地、生産される食料の種類に重点を置いた積極的な政策によって、人間の幸福も支えながら、こうした脅威を低減できる可能性がある。


今回David WilliamsとMichael Clarkたちの研究チームは、現行の保全分析の幅と特異性の両方を拡大したモデルを開発した。Williamsたちは、約2万種について推定される農業拡大の影響を調べた。その結果、現状のままでは、分析した陸生鳥類種、両生類種、哺乳類種の87.7%(1万7409種)が、2050年までに生息地の一部を失う可能性があり、そのうち約1200種は、残っている生息地の25%以上を失うことが明らかになった。予測される生息地の平均損失は、サハラ以南のアフリカで最も大きく、ブラジルの大西洋森林、アルゼンチン東部、南アジアと東南アジアの一部でも大きな損失が予測された。


Almost 90% of terrestrial vertebrate species around the world might lose some of their habitat by 2050 as land is cleared to meet the future demand for food, according to a modelling study published in Nature Sustainability. However, proactive policies focusing on how, where and what food is produced could reduce these threats while also supporting human well-being.

Habitat loss driven by agricultural expansion is a major threat to terrestrial vertebrates. Projections based on human population growth and dietary needs estimate that we will need 2–10 million km2 of new agricultural land to be cleared at the expense of natural habitats. Conventional conservation approaches — which often focus on a small number of species and/or a specific landscape — may be insufficient to fight these trends. Adequately responding to the impending biodiversity crisis requires location- and species-specific assessments of many thousands of species to identify the species and landscapes most at risk.

David Williams, Michael Clark and colleagues developed a model that increases both the breadth and specificity of current conservation analyses. The authors examined the impacts of likely agricultural expansion on almost 20,000 species. They found that under current trajectories, 87.7% (17,409) of the terrestrial bird, amphibian, and mammal species in the analysis might lose some habitat by 2050, including around 1,200 species projected to lose more than 25% of their remaining habitat. Projected mean habitat losses were greatest in sub-Saharan Africa with large losses also projected in the Atlantic forest of Brazil, in eastern Argentina and in parts of South and Southeast Asia.

However, the authors also show that proactive policies, such as increasing agricultural yields, transitioning to healthier diets and reducing food waste, may have considerable benefits, with different approaches having bigger impacts in different regions.

doi: 10.1038/s41893-020-00656-5


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