Human expansion, growth, and development are pushing animal species out of their homes across the globe. By 2070, an estimated 1,700 species of amphibians, birds, and mammals will face a greater risk of extinction because of increased human land-use, according to new research conducted by Yale researchers.
Writing in Nature Climate Change, the researchers linked global land-use projects with socio-economic expectations to estimate future impacts of more than 19,000 wildlife species around the world. They found that human encroachment could spell steep population declines in more than 850 amphibians, 400 birds, and 350 mammals as their habitats change.
“Losses in species populations can irreversibly hamper the functioning of ecosystems and human quality of life,” said study co-author Walter Jetz in a statement. “While biodiversity erosion in far-away parts of the planet may not seem to affect us directly, its consequences for human livelihood can reverberate globally. It is also often the far-away demand that drives these losses – think tropical hardwoods, palm oil, or soybeans – thus making us all co-responsible.”
To play out how future human development would impact species around the world, ecologists combined existing information on the current geographic distributions of more than 19,000 species with predictions of how land use will change in the next half-century based on expectations of future socioeconomic developments. This “middle-of-the-road” scenario presents only moderate changes – under such circumstances, previous studies have indicated that more than 400 mammalian carnivores and ungulate species will decline by as much as one-third by 2050.
Central and East Africa, Mesoamerica, South America, and Southeast Asia will see the most habitat loss and increased extinction risk, but ecosystems know no political boundaries. The most impacted species include Indonesia's Lombok cross frog, South Sudan’s Nile lechwe, and Brazil’s pale-browed treehunter, which could see half of its range disappear. The authors note that assessments such as this one can be used to “support national conservation action and policies for addressing climate change and land-use change impacts on biodiversity.”
“Identifying species and locations most exposed to changing habitats is key for prioritizing the reduction and management of biodiversity threats,” write the authors, noting that comprehensive evaluations that incorporate the many socioeconomic dynamics of the world are pivotal for understanding what the future looks like and how to address threats to biodiversity.
In their research, the authors note that they made several important assumptions that limited their findings, specifically that they did not investigate the “adaptive potential” of species analyzed. They also didn’t include threats that might further imperil species, such as hunting, invasive species, and pollution.