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The effect of global warming on marine diversity

Posted on 5 October 2016

Warming temperatures can reduce marine diversity but increase freshwater species – showing responses to climate change could be habitat dependent.

A hermit crab emerges from its shell

Historically, the speciation rate of marine crustaceans, such as hermit crabs, king crabs, and squat lobsters, has increased when global temperatures have decreased.

However, for one freshwater group (Anomura) speciation rate increased with increasing temperature.

Dr Katie Davis, who recently moved to the Department of Biology at the University of York, investigated the relationships between speciation rate and climate over the last 200 million years.

The study, carried out at the University of Bath, found that significant shifts in the rates of speciation have only occurred in the last 100 million years.

For marine species, speciation rate was negatively correlated with temperature.

Dr Davis said: “While other research found that species diversity increased with global warming our findings suggest that this is not a universal rule.

“We find that the freshwater group follow this pattern, but their marine relatives show the opposite - they speciate with global cooling and diversity decreases with warming.

“This is the first research to suggest that species response to climate change, whether warming or cooling, could be habitat dependent.

“It's not easy to disentangle the causes in the case of Anomura, but it's possible that shallow marine organisms might be affected by factors such as sea level changes and tectonics because both these things affect the amount of shelf habitat available. These factors wouldn't affect freshwater organisms in the same manner.”

“Given that crustaceans play a crucial role in marine ecosystems, as well as providing an important food source for many societies, it is important that management of marine ecosystems accounts for this potential loss in biodiversity.”

The paper is published in Nature Communications.

Further information:

  • The study was funded by the Biotechnology and Biological Sciences Research Council (BBSRC).
  • For more information about the University of York's Department of Biology, visit:

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