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Climate change could alter future predator-prey equilibria

A new study published in Nature Climate Change explains that future climate change could be cause an upset in the equilibrium and interactions within the natural food chain that links predators to herbivores. Researchers believe that climate change — specifically warming temperatures — could redistribute the power within the ecological relationship between predator and prey.

A more stable climate and less seasonal changes in temperate areas could put immense pressure of predation whereas increased climate instability in the tropics due to climate change would cause a decline in predation pressure.

“The study describes the causes of this disruption and shows it can be explained by the components of climate that will change in future, especially temperature,” said lead author Gustavo Quevedo Romero, a professor at the University of Campinas’s Biology Institute (IB-UNICAMP) in São Paulo State, Brazil. “This reorganization of the forces of species interactions could have disastrous consequences for terrestrial ecosystems and for the ecosystem services they provide, such as biological control and nutrient cycling.”

Romero and colleagues based this new study on a 2017 study published in Science that measured bites on artificial caterpillars and found that the higher an ecosystem’s latitude, the lower the herbivore predation. The new study compared this data to present and future bioclimatic data based on climate models that predict climate change from carbon dioxide emissions.

“All the existing research on the role of global climate change with respect to biotic interactions has been theoretical, as far as I know. Our study is the first to investigate the link between biotic interactions and climate change at a global scale on the basis of empirical data,” Romero said. “Furthermore, it’s the first time anyone has used niche modeling to study biotic interactions, as this method was developed to predict species distributions.”

Romero and his team first withdrew a set of bioclimatic variables from the WorldClim 2 database, which contains 19 bioclimatic variables applied globally to a 1 km² resolution grid. They then used a structural equation modeling method to figure out the significance of the direct and indirect effects of latitude, elevation, and local climate, including precipitation and temperature, on predation pressure. Romero concluded that the predation data was directly linked to temperature variation.

“Generally, we found that by 2070, predation pressure may be significantly affected by temperature changes but may not be affected by precipitation changes,” Romero said. “Temperature instability rather than warmer temperatures will reduce predation pressure. This impact will be exacerbated in tropical regions, where the climate is projected to become more unstable.”

Predation pressure will increase in temperate climates ranging from North America to Asia, and will decrease in biodiverse regions near the equator like equatorial Africa, Southeast Asia, tropical South America, Central America, and the Caribbean. The team suggests that Brazil and Colombia will be the most affected by temperature-affected predation.

“The most important consequence is simple. If the current climate affects current predation pressure, then we can expect climate change to lead to a change in predation pressure,” Romero explained. “Climate change is reflected by not only changes in species distributions but also changes in the interactions among species. A decrease in predation pressure in the tropics could affect tropical crop yields, and in turn, this effect would increase risks to food security owing to a reduction in the efficiency of biological control in areas that are already more vulnerable due to climate change.”

By Olivia Harvey, Staff Writer

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