Realizing the niche: Species interactions drive biotic responses to climate change

Background/Question/Methods

Climate change requires that species move or adapt to changing climates.  To date, most research has centered on understanding how climate change will shape new ranges by affecting abiotic components of the fundamental niche.  Yet, we know that species interactions also can affect species ranges by affecting the realized niche.  Climate change can alter species interactions and biotic range limits by directly modifying species interactions (e.g., temperature-dependent competition) or by altering range overlaps.  This latter effect occurs if range boundaries change independently because species track climate changes differently.  Changing range boundaries can lead to novel ‘no-analogue’ communities and break apart obligate relationships among coevolved organisms. Here, I review our current theoretical and empirical understanding of how species interactions alter responses to climate change.

Results/Conclusions

Species interactions can lead to dramatic changes in predictions about future communities and extinctions. Species interactions can slow a species’ ability to track climate, alter local and regional diversity, and increase extinction rates. Species interactions become even more important when species differ in their abilities to track climatic changes because fast moving species run into slow moving species along a climate gradient. Trophic interactions are especially important because they can multiply effects from sensitive species through the rest of the food web. Current forecasts likely underestimate climate change impacts on biodiversity by neglecting the impacts of species interactions.  In the future, we will need to estimate the climate sensitivities of the many species that make up real food webs and then parameterize models that can predict future changes in realistically complex communities.