Nonrandom Dispersal of Interacting Species in Heterogeneous Landscapes

Ohio State University, The, Columbus OH

Investigators

Abstract

This project investigates the effects of non-random dispersal on competing species and consumer-resource interactions in heterogeneous environments via reaction-diffusion-advection models. Dispersal of organisms is a key component of ecological and evolutionary processes and the dispersals of many organisms depend upon local biotic and abiotic factors (e.g., food, climate, competitors, predators) and as such are often nonrandom. In contrast with random movements, there is limited knowledge of the consequences of nonrandom dispersal, especially in the context of the spatial dynamics of interacting species. If two competing species adopt biased movement in response to habitat quality, there can be selection against both small and large advection rates. Is there some intermediate advection rate which is evolutionarily stable? If random dispersal rate and biased movement rate represent values for two different traits of species, how will two traits simultaneously evolve? Compared to variation in space only, how will nonrandom dispersal evolve in spatiotemporally varying environments? If organisms make dispersal decisions purely based on fitness differences between habitat locations, does it always compare favorably with strategies based only on environmental cues? Can nonrandom dispersal promote the spatial coexistence of interacting species? All of these questions are studied in the project. From habitat degradation and climate change to spatial spread of invasive species, dispersals play a central role in determining how organisms cope with a changing environment. Understanding dispersal of organisms can significantly enhance our understanding of how diversity is maintained in complex foodwebs. The spatial spread of invasive species is an important and challenging issue. While a great deal is known about the spatial spread of organisms in a single species context, very little is known about how species interactions influence the spatial spread of invasive species. For instance, one might expect spatial spread to be influenced by competition with native species for common, limiting resources, and it is very important to understand the dispersal strategies that exotic species use in response to interactions with native species, be they competitors or natural enemies. It may be that invasive species use a different set of dispersal strategies compared to native species and such differences may be crucial in explaining why certain invasive species are able to spread quickly and displace native species while others tend to spread slowly and become integrated into the native community. Understanding the answers to these questions can help develop better management strategies for invasive species control. Additionally, this project involves extensive training of postdoctoral researchers, graduate students and undergraduate students in mathematical modeling and analysis of emerging biological issues related with spatial spread of invasive species and disease.