Grand Teton Np Report
Abstract
Monitoring populations of these species of voles (1982-1988) has shown that Microtus longicaudus exhibits relatively stable numbers while M. montanus has dramatic fluctuations in some habitats. The study sites for M. montanus have been chosen to include primary and secondary habitat, and proximate and isolated habitat patches. Vegetation has heretofore not been quantitatively analyzed. The purpose of the research begun in 1989 is to ascertain how selectively these species feed, and to assess vegetation as a factor in demographic processes in the two species.