A food-web perspective on range shifts in a changing climate

Background/Question/Methods

As the global climate changes, many species are shifting their geographic distributions. Typically, species have been observed moving up in elevation and/or latitude. As a result, there has been renewed discussions about the mechanisms that generate species range margins and the consequences of range shifts. Much of this discussion has centered around the range-shifting species themselves and the relative importance of abiotic variables and biotic interactions in their population dynamics. Specifically, this conversation has focused on the isolated effects of abiotic variables or pair-wise interactions with the range-shifting species themselves being the primary focus. However, these range-shifting species will be entering into established, complex communities. Here, we propose a new framework that focuses on recipient food webs to understand the causes and consequences of range shifts.

Results/Conclusions

In this framework, we propose that climate change will alter the structure and stability of ecological communities which will determine whether range-shifting species are able to establish. Moreover, the traits of a range-shifting species, such as trophic position, will influence how its establishment influences the structure and stability of recipient communities. Using three hypothetical examples we show how we can use known food-web theory to predict how climate change might alter recipient food webs, whether this allows for range-shifting species to establish, and what the consequences of such establishment might be. Additionally, we outline the ways in which these predictions may be tested empirically.