Climate Change and Resource Competition

by Marina de Castro Deus

Species that live in competition are always susceptible to shifts in competitive abilities. Variable conditions such as temperature, rainfall, soil condition, food availability, and many other environmental factors may result in different responses. Higher temperatures related to climate change have the potential to dramatically change how species interact. If one considers the large time scale from the time species originated often millions of years ago, recent climate change is relatively fast. Each population responds differently and may be benefited or harmed with these changes. Those that benefit from warmer temperatures can adversely alter the organisms they interact with.

Stenseth et al. (2015) studied the competitive changes between blue tits (Cyanistes caeruleus) and great tits (Parus major) in response to climate change. These species of bird compete for food in the breeding season and for roosting sites in the winter time. The authors analyzed long-term data on the dynamics of the competing species along with climate data in order to correlate changes in the competitive interaction in response to year-to-year climate variation. For that they developed a model incorporating inter- and intraspecific competition and environmental variables. The data were analyzed looking at a short-term and long-term responses to climate variations. Great tits have higher abundance in cooler springs, and blue tits are predicted to be more abundant in warmer springs. If these changes in population density continue to happen progressively with climate change, it could lead to significant consequences in the community density and interactions not only with the two competing birds, but with every other species that may be living in the same system, eventually leading to extinction events and restructuring of the local foodweb.

Stenseth N.C., Durant J.M., Fowler M.S., Matthysen E., Adriaensen F., Jozen N., Chan K., Liu H., Laet J., Sheldon B.C., Visser M.E., Dhondt A.A., 2015, Testing for effects of climate change on competitive relationships and coexistence between two bird species, Proc. R. Soc. B 282, 20141958

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