Dr. George Batzli of the University of Illinois, Urbana.Champaign and several other ecologists have suggested that the local patterns of distribution and abundance of microtine rodents (lemmings and voles) in arctic tundras are largely determined by characteristics of the vegetation because plants provide both food and cover for these animals. The research described here is designed to test this and related hypotheses and to examine more closely some mechanisms (availability and quality of food, protection from predators and interactions with competitors) that might explain the patterns observed for two species of voles. Experimental manipulations, which are being conducted on 18 sites in the arctic tundra of Northern Alaska, include the provision of supplemental food, the removal of shrub cover and the removal of closely related species that may compete for these resources. Population density and demography are monitored throughout the summer using live.trapping techniques. In addition, the relative abundance of microtine species will be predicted with multiple regression equations that are based upon data on trapping success and vegetational composition. The validity of these equations can be tested by comparing predicted abundance of each microtine species to that actually observed on sites where the vegetation has been disturbed by man. These approaches should produce a rigorous evaluation of the effects of vegetation on the distribution and abundance of these widespread and important herbivores and inform us of how revegetation of disturbed areas may best be designed to encourage repopulation by small rodents. Also it is expected that this work will expand our understanding of tundra food chains. The institution and individuals conducting the research are world renowned for this kind of work. The Program recommends funding.
