DISTANCES MOVED BY STEPHENS KANGAROO-RAT (DIPODOMYS-STEPHENSI MERRIAM) AND IMPLICATIONS FOR CONSERVATION

Movements by Dipodomys stephensi were assessed by live-trapping and ra diotelemetry to evaluate consequences of habitat fragmentation for thi s endangered species. The median of the maximum distances moved betwee n captures was 29.2 m for the 557 individuals with greater-than-or-equ al-to 2 captures. The median distance between first and last monthly h ome-range centers was 17.6 m for individuals captured in greater-than- or-equal-to 2 months. Males moved longer distances than did females; l actating females were especially sedentary. Dispersal distances were s imilar for juveniles and adults and for two sites with different geome tries of habitat patches. The median distance between first and last h ome-range center of adults radiotracked for 15-127 days was 9.5 m, ind icating stable home ranges. However, radiotracked individuals moved gr eater maximum distances than most live-trapped individuals apparently moved over a lifetime. Much dispersal, therefore, occurs within an are a about which animals have knowledge. This should facilitate habitat s election and decrease the cost of dispersal in terms of fitness. The f requency distribution of maximum dispersal distances underestimated th e frequency of moves >400 m. Two processes may have contributed to thi s bias. First, the frequency of long-distance moves was underestimated because we measured dispersal away from a single grid. Second, our tr apping grids were located in homogeneous habitat without dirt roads, w hich appear to facilitate long-distance movement. Unvegetated corridor s show promise for increasing the connectedness of local populations o f D. stephensi. Connectedness should be considered in management of en dangered species such as D. stephensi, because the expected persistenc e of metapopulations is sensitive to the extent of dispersal and the f itness of dispersers.