Climate change effects on community composition and species distributions: The relative influence of species interactions

Background/Question/Methods

Climate change is altering the environmental conditions that determine the distributions of species, and no-analog communities are expected to form as a result. Across taxa, significant distribution changes and local extinctions have been documented, providing evidence that climate change is already affecting communities. The main avenue for predicting responses to climate change has been a static, single-species environmental niche modeling approach that lacks biotic interactions, despite their fundamental influence on patterns of species’ abundance, community assembly, and geographic distribution. We take a multi-species modeling approach that assesses species distributions from long-term datasets. Specifically, we assess whether models including species interactions provide more robust predictions of changes in species distributions and community composition than models with only environmental and climatic variables. We further assess the influence of species interaction type (trophic or non-trophic), strength, and character (positive, negative, or neutral). By investigating how species interactions and changing climate have already influenced shifts in species and community composition, we gain much needed insight about how they will affect species and communities under future climate change scenarios. 

Results/Conclusions

We used Bayesian and regression techniques to model the distributions and abundances of interacting species within each community. Models were more accurate when species interactions were included. We found that with increasing temperature, species interactions were important to shifts in the distributions of species within predator-prey relationships as well as facilitative relationships. These results suggest that environment and climate variables alone are not sufficient for anticipating the effects of climate change on species distributions and community composition. Instead, models should incorporate different types of biotic interactions because the collective responses of species will likely result in species reshuffling into new communities for which there is no modern analog.