Title

Evolutionary and ecological processes within dystrophic blackwater habitats: Dispersal, historic biogeography and trophic influences on distribution and speciation in Enneacanthini sunfishes

Date of Award

2004

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Sciences

First Advisor

Stephen T. Ross

Advisor Department

Biological Sciences

Abstract

Due to high rates of natural wetland habitat destruction and subsequent re-creation efforts, it is crucial to understand the processes involved in the biological interactions within these habitats. Unfortunately, functional knowledge, and therefore regulatory criteria, revolve primarily around wetland hydrology and physical vegetative structure, without regard to the rest of the biological community. My project utilizes molecular population genetic and ecomorphological approaches to investigate both historic evolutionary and current ecological processes in wetlands using a group of sunfishes that inhabit dystrophic blackwater habitats. The population genetics and phylogeography portion of this study indicates that the current regulatory assumption of natural recruitment in wetlands is not a valid management strategy for wetland communities as a whole. While Enneacanthus gloriosus represents the highest dispersal capabilities of the tribe and would likely be able to naturally recruit to new habitats, E. chaetodon on the other hand would not and E. obesus recruitment would be questionable. The ecomorphological portion of the study suggests an important role of assemblage-level interactions in determining wetland community structure and composition. Specifically, trophic ecology was a source of divergent selection for Enneacanthini fishes and probably played an important role in their speciation processes. Additionally, the observed interspecific differences in feeding ecology, morphology and function in combination with the high level of ecological variation explained by morphology and function suggest a high likelihood that their local distribution patterns are influenced by their foraging ecologies, potentially via competition processes. Hopefully, the results of this study will encourage a more detailed evaluation of isolated wetlands prior to impact and (at least for wetland specialists) development of additional permit requirements.