For years, ecologists have operated under the assumption that a warming planet would lead to a corresponding acceleration in the rate of change within ecosystems. The logic was straightforward: rising temperatures and shifting climate zones would force species to migrate or face extinction, leading to faster species turnover – the replacement of one species by another – and a more dynamic reshuffling of life. However, a new study challenges this long-held belief.
Published in Nature Communications, research from Queen Mary University of London (QMUL) reveals a surprising trend: species turnover is not increasing, but rather slowing down significantly. The study, which analyzed a vast global database of biodiversity surveys spanning marine, freshwater and terrestrial ecosystems over the past century, suggests that nature’s self-repairing mechanisms are, counterintuitively, grinding to a halt.
“Nature functions like a self-repairing engine, constantly swapping out old parts for new ones,” explains Dr. Emmanuel Nwankwo, the study’s lead author. “But we found this engine is now grinding to a halt.”
Global Warming and a Slowdown in Species Replacement
The researchers focused specifically on changes observed since the 1970s, a period marked by a pronounced acceleration in global surface temperatures and increasingly visible environmental shifts. By comparing species turnover rates before and after this period, they aimed to determine whether climate change was indeed driving a faster pace of ecological change. The results were unexpected.
Instead of an increase, the analysis showed a general decline in turnover rates over short intervals of 1-5 years. This pattern was observed across diverse ecosystems, from bird communities to marine life. Professor Axel Rossberg, a co-author at QMUL, highlighted the magnitude of the effect: “We were surprised how strong the effect is. Turnover rates typically declined by one third.”
Beyond Climate: The Role of Internal Ecosystem Dynamics
To understand this counterintuitive finding, the research team shifted their focus from external climate forces to the internal dynamics of ecosystems. Their investigation revealed that ecological communities aren’t simply passive responders to temperature changes. Instead, they often operate within a state known as “Multiple Attractors,” a concept initially proposed in 2017 by theoretical physicist Guy Bunin.
In the Multiple Attractors phase, species continually replace one another due to inherent biological interactions, even in stable environmental conditions. This process can be visualized as a complex, ongoing interplay – akin to a game of rock-paper-scissors – where no single species achieves lasting dominance. The QMUL research provides compelling real-world evidence supporting the existence and significance of this Multiple Attractors phase in shaping ecosystems.
Biodiversity Loss and the Erosion of Ecosystem Resilience
If these internal dynamics are responsible for maintaining ecosystem activity, why are turnover rates now slowing? The researchers posit that environmental degradation and a shrinking pool of regional species are key factors.
In a healthy Multiple Attractors ecosystem, a diverse regional species pool provides a continuous supply of potential colonizers, fueling the cycle of replacement. However, as human activities degrade habitats and reduce biodiversity, the number of available species dwindles. With fewer potential newcomers, the pace of turnover inevitably slows.
“In other research we are seeing clear indications that human impacts cause the slowing of turnover. It is worrying,” notes Dr. Nwankwo. This suggests that ecosystems appearing stable may not necessarily be healthy. A slowdown in local species change could, in fact, be a warning sign of underlying biodiversity loss, weakening the natural processes that maintain ecosystem dynamism and resilience.
The findings, as reported by ScienceDaily on , align with broader concerns about the accelerating impacts of climate change and biodiversity loss. While the initial expectation was for ecosystems to speed up in response to warming temperatures, this research suggests a more complex and potentially alarming scenario: a slowing down of nature’s fundamental processes, indicating a loss of the biodiversity needed to sustain healthy, functioning ecosystems. Further research is needed to fully understand the long-term implications of this trend and to develop effective strategies for mitigating the impacts of environmental degradation and preserving biodiversity.
A related study, published in Philos Trans R Soc Lond B Biol Sci in January 2025, explores the concept of “clustered warming tolerances” and the nonlinear risks of biodiversity loss, further emphasizing the interconnectedness of climate change and ecosystem health. This research, available via PMC, highlights the potential for disruptions to ecological interactions as the planet warms.
The slowdown in species turnover, as detailed in a report from Nature, underscores the need for a more nuanced understanding of how ecosystems respond to environmental change. The research suggests that attributing changes in species composition solely to climate change may be an oversimplification, and that intrinsic ecosystem dynamics play a crucial role.
