Access Type

Open Access Dissertation

Date of Award

January 2018

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Biological Sciences

First Advisor

Christopher F. Steiner

Abstract

Understanding the processes influencing the spatial and temporal distribution of species is the main focus of ecological studies. Community structure and organization is affected by local and regional processes. Local processes affect population persistence and abundance of species through biotic interactions and abiotic environmental conditions within local sites. Regional processes, such as species dispersal among patches and colonization/extinction dynamics, can also affect the dynamics and structure of local populations and communities. Metacommunity theory considers the interplay of both local and regional processes as drivers of species distributions among isolated patches. Recent studies suggest considering features such as habitat type, dispersal mode, and spatial scale, along with examining time-series to obtain a more comprehensive understanding of the processes affecting community structure. To address how temporal variation impacts the relative effects of local and regional processes on metacommunity organization, we performed a two-year study of seasonal variation in Notonecta metacommunity structure in fishless ponds in southern Michigan. Our result showed that notonectid community composition was affected by environmental, spatial, and spatially structured environmental processes. Notonectid metacommunity structure was affected by several ponds’ environmental factors and fine to intermediate spatial scales. We also found significant seasonal changes in the relative contribution of environmental and spatial processes to notonectid community structure. The, with a series of pond in situ studies, we experimentally tested the effects of local conditions versus dispersal limitation on the heterogeneous distribution of Notonecta species in fishless ponds using adult and juveniles’ responses. Our results provide some support for the importance of local environmental control of N. irrorata's distribution. They also suggest that dispersal limitation, rather than local environmental factors, may be responsible for the absence of N. undulata from Lux 2. Findings of our research confirm the inclusion of both spatial and environmental variables for understanding the factors affecting community organization. Moreover, our findings make clear the importance of examining time-series to obtain a more comprehensive understanding of the processes affecting community structure. Finally, our work makes clear that the inclusion of features such as the spatial scale of the study and dispersal behavior may be vital for comprehending the structure of metacommunities.

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