Date of Award
Doctor of Philosophy (PhD)
This dissertation explores the influence of metacommunity size and landscape level processes, such as dispersal, on species diversity. A metacommunity is a group of local communities, or patches, connected by dispersal, and metacommunity size can be defined as the number of discrete local patches within a metacommunity. In chapter 1, I developed a framework to predict the effects of habitat destruction, or a reduction in metacommunity size, on the species richness of local patches of different sizes by integrating metacommunity theory with the equilibrium theory of island biogeography. The effect of metacommunity size on species richness in small and large patches within a metacommunity depends on whether immigration rates or extinction rates are more affected by metacommunity size. Immigration effects result in a lower turnover in species between small and large patches with increasing metacommunity size, while extinction effects cause a higher turnover in species between small and large patches with increasing metacommunity size. The results of this model have implications for the effect of habitat destruction, or a reduction in metacommunity size, on species richness in both small and large patches within a metacommunity.
In Chapter 2, I examined the effect of metacommunity size on species richness at local and regional spatial scales using a field survey of zooplankton species in replicate pond metacommunities. I found that metacommunity size has scale-dependent effects on zooplankton species richness. As the number of ponds in a metacommunity increase, the species richness of local ponds increases, but there is no change in richness at the regional spatial scale due to decreases in the turnover of species among communities.The results of this study provide one of the first examples of species richness patterns changing with metacommunity size in a non-experimental system.
In Chapter 3, I conducted an experiment investigating the effect of a natural drought disturbance on species richness in aquatic plant communities, and the importance of dispersal for the recovery of species richness. I found that local species richness decreased in response to drought, and communities became more similar in their species composition. Species richness in communities with increased amounts of dispersal recovered to their pre drought conditions, suggesting that even low amounts of species dispersal can facilitate the recovery of species richness in aquatic plant communities. In summary, this dissertation demonstrates that metacommunity size can affect species diversity, and highlights the importance of considering how landscape processes, such as dispersal, can influence the recovery and maintenance of species diversity.
Chair and Committee
Scott Mangan, Jonathan Myers, David Queller, Barbara Schaal, Kevin Smith
Woods, Lauren, "The Influence of Metacommunity Size on Species Diversity across Spatial Scales" (2014). Arts & Sciences Electronic Theses and Dissertations. 341.