Spatial ecology of the mink (Mustela vison): I. Spatial variation in genetic structure of mink (Mustela vison) populations. II. Spatial variation in body size of American mink (Mustela vison). III. Spatial patterns of sexual dimorphism in mink (Mustela

Spatial ecology of mink (Mustela vison) was investigated using genetic and morphological features. The work resulted in assessments of genetic structure, body size, and sexual dimorphism over geographic space. In the examination of genetic structure, eight populations were investigated using four polymorphic microsatellite loci. The hypothesis that genetic structure was partitioned within streams due to the close association of mink with riparian habitats was tested. FST values, genetic distance measures, estimates of numbers of migrants per generation (Nm), were derived, localities were subjected to clustering analysis and grouped according to most similar populations. Results indicated no statistically significant relationship between genetic and geographic distances. Genetic structure was not found to be partitioned within streams, but it suggested substantial gene flow among streams. Populations were best described by the island model of gene flow.;Variation in body size was assessed with 26 morphological characters for mink from 35 localities in North America. All twenty-six characters for males and 25 of 26 for females exhibited significant interlocality variation. For males and females, mink were largest in populations from Alaska, Manitoba, and Alberta; smallest mink were found in Florida and Quebec. As for genetic data, there appeared to be little relationship between body size and geographic proximity. Collectively, 16 environmental variables were found to be associated with size for both sexes. However, based on results of this study and those reported for river otter (Lontra canadensis), it was concluded that body size of mink is likely the result of more than one factor that includes biotic and abiotic factors.;The pattern of sexual dimorphism in mink from 35 localities in North America was examined using 25 cranial characters. Five characters exhibited no sexual dimorphism, while twenty of twenty-five characters were significantly larger in males. Greatest dimorphism was found between males and females in Pennsylvania and Florida, and least dimorphism was found between males and females in Alaska and Quebec. There was not a strong degree of similarity between the pattern of sexual dimorphism and geographic proximity among locations. Only one environmental variable, mean summer temperature, was found to be correlated to degree of sexual dimorphism. Predictions of the resource partitioning hypothesis were not supported. Across all localities, male characters were highly correlated with female characters. Female crania appeared to be essentially scaled-down models of male crania. (Abstract shortened by UMI.).