Researchers led by Emmanuel Nwankwo and Axel Rossberg analyzed nearly 9 million records from the BioTIME database and found that global species turnover has slowed by about one-third in one-to-five-year intervals. The slowdown, reported in Nature Communications, is attributed to shrinking regional pools of potential colonizers caused by anthropogenic environmental degradation. The authors warn that stable local species lists can mask declining ecosystem resilience and note that short-term climate variability and survey methods can affect turnover estimates.
Study Finds Climate Change Is Slowing Global Species Turnover — Not Speeding It Up
Climate Change Is Freezing Earth’s Fauna in PlaceAndriy Onufriyenko - Getty Images
New research suggests a surprising consequence of human-driven environmental change: instead of accelerating, global species turnover appears to be slowing. A team from Queen Mary University of London analyzed millions of biodiversity surveys and found that ecosystems across land, freshwater and oceans are experiencing fewer replacements of species than expected.
What the Study Did
Emmanuel Nwankwo and Axel Rossberg examined nearly 9 million species-identification records drawn from the open-source BioTIME database and published their results in Nature Communications. To focus on contemporary trends, the researchers concentrated on records from the 1970s onward and analyzed changes in species composition across one-to-five-year monitoring intervals.
Key Finding
Across ecosystems, the authors report an average slowdown in species turnover of roughly one-third within those short monitoring windows. That result runs counter to common expectations: as climate change forces local extinctions and shifts species ranges, many scientists predicted turnover would increase as new colonizers filled vacated niches.
"Nature functions like a self-repairing engine, constantly swapping out old parts for new ones," said Nwankwo. "But we found this engine is now grinding to a halt."
Why Turnover Might Be Slowing
The researchers propose that widespread anthropogenic environmental degradation—driven in part by climate change—is shrinking regional pools of potential colonizers. In dynamical terms, many communities may now be in a "multiple attractors" regime where species interactions can support continual replacement, but the regional supply of species able to move in and replace others has been reduced. With fewer candidates available to colonize newly vacated niches, turnover declines.
The study emphasizes that reduced local turnover is not necessarily a sign of healthy ecosystems. Instead, it can indicate a loss of resilience: static species lists may hide an inability of communities to renew themselves as environments change.
Caveats and Implications
The authors caution that short-term climate variability—such as El Niño–Southern Oscillation events—and differences in survey methods can influence turnover estimates. They also note that as climate change proceeds, direct environmental drivers could alter turnover dynamics in different ways. Nonetheless, the evidence raises an important conservation concern: declining regional species pools may limit nature's capacity to respond to rapid environmental change, amplifying long-term biodiversity loss.
Implication for conservation: Monitoring stable species lists alone is insufficient. Managers should track regional species pools and connectivity to detect hidden declines in ecosystem resilience and prioritize actions that maintain or restore species' capacity to move between habitats.
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