Possible Past Hybridization Among Desmognathus ochrophaeus in Canadice Lake: An Ecological Survey Exploring Desmognathine Salamanders and the Competitive Exclusion Hypothesis in the Western Finger Lakes of New York State
Dusky Salamanders are a varied group of sister taxa found in Northeastern North America. Two species, Desmognathus fuscus and Desmognathus ochrophaeus, have geographically overlapping ranges. In addition, they are very morphologically similar, share many niche requirements, and are found in extremely similar or even the same salamander communities. These shared traits have been posited to arise from the influence of niche conservatism during their species’ evolutions. Also, despite their physical similarities they are historically found not to hybridize on a large scale, nor have ever had a full population merge recorded. Therefore, it appears that the community ecology of these species does not seem to follow the ecological theory of Competitive Exclusion. This study consists of both an ecological and genetic survey to determine if there are any variables that separate both populations observed in the field. The hypothesis is that there will be a low instance of hybridization in both populations, and that there will be ecological differences associated with population densities where they overlap. Also, where they do overlap, I predicted that there was an observable benefit to both species that overrides their need for competition of resources. The results of this study were that the two distinct morphological groups observed shared identical haplotypes in the mitochondrial gene tested, showing a single population. In addition, it was also concluded that there was no statistical difference in the measured ecological variables for both morphologies, thus failing my hypothesis by both measures. This study took place in the Western Finger Lakes (NY) basin, within the wetland/stream around Canadice Lake.
Library of Congress Subject Headings
Salamanders--Hybridization; Salamanders--New York (State)--Finger Lakes--Classification
Environmental Science (MS)
Gadson, Aisha L., "Possible Past Hybridization Among Desmognathus ochrophaeus in Canadice Lake: An Ecological Survey Exploring Desmognathine Salamanders and the Competitive Exclusion Hypothesis in the Western Finger Lakes of New York State" (2016). Thesis. Rochester Institute of Technology. Accessed from
RIT – Main Campus