A telemetric study of the movement patterns and habitat use of Rana muscosa, the mountain yellow-legged frog, in a high-elevation basin in Kings Canyon National Park, California

In a high-elevation (3470 m) lake basin (upper Dusy Basin) in Kings Canyon National Park, California, we used radio transmitters on 24 mountain yellow-legged frogs (Rana muscosa) to gather basic information on their movement patterns. Rana muscosa have declined throughout their range in the Sierra Nevada and restoration plans require information on their movement ecology. Our study indicates that R. muscosa had different movement patterns and habitat associations during the 1997 summer period (August and September) compared to October when winter dormancy began. In August, visual surveys found frogs in 10 of the 11 lakes in upper Dusy Basin. During August most tagged frogs moved little (mean movement 77 m over five day periods) and all were found in the lake or adjacent stream where they were originally tagged. During September, movement increased compared to August Frogs moved from the original capture lake mean distances of 145 m, and moved cumulative distances of 315-466 m. By October, frogs were again sedentary (mean distance moved 43 m) and frogs were found in three of the II lakes in the basin. Moreover, mean home ranges (adaptive kernel 90% contours) also were different throughout the summer and were highest for frogs tracked during September (5336.2 m(2)) compared to August (385 m(2)); and October (52.8 m(2)). Before this study it was assumed that R, muscosa over-wintered in the deepest portion of the lake. However, most lakes were frozen when our study ended, and tagged frogs were found nearshore under ledges and in deep underwater crevices suggesting that at least some R. muscosa over-winter in these nearshore areas. In this study, we found R. muscosa in different aquatic habitats over the course of their activity period and that they readily moved between these habitats using both aquatic and overland pathways. The movements appear to be associated with seasonal migrations between summer and over-wintering sites.