LAUSR

Terrestrial echimyid rodents typically use subterranean cavities and hollow logs as refuges. We examined habitat characteristics at refuges used by 2 such species of rodents, Proechimys semispinosus and Hoplomys gymnurus, to better understand coexistence of these morphologically similar sympatric species. The study was performed in a lowland moist forest in central Panama from 2009 to 2013. Sewing-bobbin tracking was used to locate refuges. We examined refuge habitat at 2 scales. At a coarser scale (microhabitat), we measured 10 variables within a 5-m radius around each refuge site and an associated random point, which represented available habitat. At a finer scale (refuge entrance), we measured 11 variables within a radius of 0.5 m centered on each refuge and an associated random point. We used discriminant function analysis to search for differences between refuge and available habitats at both scales and for both species separately. We located 70 refuges of both species. Refuges used by P. semispinosus were positively associated with litter depth, canopy openness, numbers and sizes of nearby logs, and proximity to tree-fall gaps, which all indicate forest disturbances. Hoplomys gymnurus refuges did not show any differences from available habitat. Lastly, we found no differences in refuge use between the sexes or age classes for either species. We conclude that interspecific competition for refuges is generally unlikely to be important because small-scale differences in refuge habitats facilitate coexistence.