For years, many ecologists have argued that as global warming intensifies, nature should change more quickly. The logic seems straightforward. Rising temperatures and shifting climate zones would force species out of some areas while opening new habitats elsewhere, triggering faster local extinctions and rapid colonization. In theory, ecosystems should be reshuffling at an accelerating pace.
However, new research from Queen Mary University of London (QMUL), published in Nature Communications, challenges that assumption.
After examining a vast global database of biodiversity surveys covering marine, freshwater, and land ecosystems over the past century, the team found the opposite trend. The rate at which species are replaced in local habitats, known as “turnover,” has not increased. Instead, it has slowed significantly.
Dr. Emmanuel Nwankwo, the study’s lead author, described the shift this way: “Nature functions like a self-repairing engine, constantly swapping out old parts for new ones. But we found this engine is now grinding to a halt.”
Global Warming and Slower Species Turnover
The researchers concentrated on changes since the 1970s, when global surface temperatures began rising more rapidly and environmental changes became more pronounced. They compared species turnover rates, meaning how quickly one species replaces another, before and after this period of accelerated warming.
If climate change were the main driver, turnover should have increased. Instead, the analysis showed that over short periods of 1-5 years, turnover generally declined. This pattern appeared across a wide range of ecosystems, from bird communities on land to life on the ocean floor.
Professor Axel Rossberg, a co-author at Queen Mary University of London, said: “We were surprised how strong the effect is. Turnover rates typically declined by one third.”
The Role of Internal Ecosystem Dynamics
To understand this unexpected result, the team looked beyond external climate forces and examined how ecosystems organize themselves internally. Their findings suggest that ecological communities are not simply reacting to temperature changes. Rather, they often operate in what is called the “Multiple Attractors” phase, a concept predicted in 2017 by theoretical physicist Guy Bunin.
In this multiple attractors phase, species continually replace one another because of internal biological interactions, even when environmental conditions remain stable. The process can resemble a giant, ongoing game of rock-paper-scissors, where no single species dominates for long. The new research provides strong real-world evidence that this multiple attractors phase exists and plays a central role in shaping ecosystems.
Biodiversity Loss and Environmental Degradation
If these internal dynamics typically keep ecosystems in motion, why are turnover rates slowing?
The researchers argue that environmental degradation and shrinking regional species pools are likely responsible. In a healthy “Multiple Attractors phase” ecosystem, a broad regional pool of species supplies a steady stream of potential newcomers. This keeps the cycle of replacement active.
But as human activities damage habitats and reduce biodiversity across regions, the number of possible colonizers falls. With fewer species available to move in, the pace of turnover declines.
Dr. Nwankwo noted: “In other research we are seeing clear indications that human impacts cause the slowing of turnover. It is worrying.”
The findings suggest that stable-looking ecosystems are not necessarily healthy ones. A slowdown in local species change may actually signal that biodiversity is being depleted at a larger scale, weakening the natural processes that normally keep ecosystems dynamic and resilient.
