Data from: Morphological convergence and coexistence in three sympatric North American species of Microtus (Rodentia: Arvicolinae)

Niche theory predicts that ecologically identical species cannot stably
coexist in local communities. My aim was to investigate morphological
diversity as a possible factor enabling the coexistence of a species-rich
Microtus (Rodentia: Arvicolinae) fauna in a hotspot of North American
mammalian diversity, the Greater Yellowstone Ecosystem (GYE). LOCATION:
The Greater Yellowstone Ecosystem, North America. METHODS: Using in-hand
morphological measurements of size and shape, I compared the morphologies
of three North American vole species (Microtus spp.), in sympatry in the
GYE and in allopatry across their ranges, in order to examine: (1) whether
morphologies are fixed or plastic and (2) the degree of morphological
character displacement or convergence in sympatric species. RESULTS:
Support was found for plasticity of morphology for all three vole species:
M. longicaudus, M. montanus and M. pennsylvanicus. However, Microtus
individuals of all species from the GYE area of sympatry were more similar
to each other than to allopatric individuals of the same species. MAIN
CONCLUSIONS: Competition among these congeners is not manifested in
morphological overdispersion. The response of these congeneric species to
the same local ecological conditions is convergent. The relative strength
of environmental conditions appears to be stronger than the strength of
competitive interactions among the study species.