Home ranges and space use of muskrats Ondatra zibethicus in restricted linear habitats

Modern farming practices in the midwestern United States have drastically altered the landscape. Most wetlands have been drained, and small streams are channelized to transport excess water away from tile-drained agricultural fields. Loss of critical wetland habitat has shifted the distribution of muskrats Ondatra zibethicus, an economically important furbearer in the region, to highly altered riparian habitats with unstable flow regimes. However, information regarding home-range size and space use for muskrats occurring in these linear habitats is lacking. We used location data from 26 radio-marked muskrats to estimate home-range size and space use in riparian habitats in an agroecosystem in east-central Illinois, USA. Home ranges were highly linear and confined to stream bank edges. Contrary to our prediction, muskrats did not freely move to upland habitat (e.g. row-crop agriculture) adjacent to stream edges to forage. Linear home ranges were longer for adults than for juveniles. Home-range size also was related positively to number of burrows used by individuals. As expected, muskrats used space non-randomly within linear home ranges with most movements aggregated around established bank burrows. Muskrats in riparian habitat are multiple central-place foragers. Our study provides insight into how muskrats, a semi-aquatic species affected by large-scale landscape change, use space within highly restricted linear habitats.