Biotic resistance in marine ecosystems: community processes and macroecological patterns

Background/Question/Methods

Biotic resistance, operating via consumptive or competitive interactions, is one of the most studied biological mechanisms affecting marine invasions.  Consumers in particular can be important agents of biotic resistance in marine ecosystems, but their impacts can range from limiting the abundance of a single non-native species to preventing local establishment of multiple species.  Even within a single system, I will demonstrate how both of these extremes can be observed, suggesting that external factors may dictate the relative strength of biotic resistance in communities.  I will use my research on marine epifaunal communities as a springboard to discuss biotic resistance in marine ecosystems more broadly and the factors that may help predict the relative outcome of biotic resistance mechanisms in diverse environments.  I will also draw parallels between local scale dynamics that are the backbone of biotic resistance, and macroecological patterns of invasion. 

Results/Conclusions

I will use data on marine epifaunal communities to illustrate the spectrum of biotic resistance outcomes and factors that may promote local exclusion of non-native species. I will discuss the utility of using exclusion as a baseline for assessing the importance of biotic resistance to invasion success.  I will also highlight the use of comparative studies to evaluate the relative strength of biotic resistance in different environments and the importance of local scale dynamics to macroecological patterns of invasion.