| Bobcats (Lynx rufus), once common in the prairie-woodland mosaic of the Midwest, were largely extirpated from the Corn Belt region by 1900. In the 1990's, sightings of bobcats in Iowa began to increase, and they are now abundant in southern Iowa. With the dramatic expansion of rowcrop agriculture resulting in loss of habitat, wildlife managers do not know whether bobcats will again be widespread throughout Iowa. In order to predict where bobcats will eventually repopulate the state, I attempted to identify important variables that correlate with current bobcat distribution and to build models that predict the relative abundance and occurrence of bobcats. I used the programs ArcGIS and FRAGSTATS to calculate landscape composition and configuration from publicly available sources including landcover, census, road, hydrologic, and elevation data. I constructed classification and regression tree (CART) models to identify important variables for predicting bobcat distribution in Iowa. I built linear regression models of bobcat relative abundance at the county resolution. Models were based on bobcat sightings from the Iowa Department of Natural Resources Bowhunter Observation Survey. I also built logistic regression models of bobcat occurrence at the finer sub-watershed resolution. Sub-watersheds were classified by presence or absence based on locations from reported bobcat sightings, live captures, and carcass recoveries. In all models, both probability of bobcat presence and bobcat relative abundance were consistently influenced by the quantity and configuration of perennial grassland across Iowa. None of the models revealed favorable habitat outside of areas known to be occupied by bobcats in Iowa, suggesting that bobcats are already occupying areas of favorable habitat and will not substantially disperse to other parts of the state. These results have practical implications for wildlife conservationists regarding expected bobcat habitat use and distribution as the species becomes more abundant in the agricultural landscape of the Midwest. |
