Territorial behavior of the plethodontid salamander Plethodon kentucki: influence of habitat structure and population density.

To investigate the possible influence of variation in ecological and demographic factors on the spatial organization of the terrestrial plethodontid salamander Plethodon kentucki, I conducted a 3-year capture-recapture study and determined home-range characteristics and spatial relationships of individuals at two field sites that differed in predominant cover type and population density. Home ranges of adults were fixed and the home ranges of same-sex adult neighbors were mostly exclusive. The spatial arrangement of adult home ranges exhibited overall regularity or regularity within aggregations, whereas the distribution of juvenile home ranges was usually random. Analysis of nearest-neighbor sex indicated a positive intersexual association of adult home ranges. Removal studies provided evidence for defense of adult home ranges only at the high-density site. The distribution of home ranges was influenced by the presence of cover objects, but there was no significant relationship between adult body size and percent of home-range area with cover. Males overlapped the home ranges of gravid females significantly more often than those of non-gravid females, indicating that the distribution of gravid females had a strong influence on the distribution of male home ranges. In laboratory tests, increased male-male aggression during the breeding season suggests that males may compete for access to mates. At the high-density site, larger males may have benefited by having greater reproductive success than smaller males because they were more dominant and their home ranges overlapped a greater number of gravid-female home ranges. My results indicate that habitat structure and population density may influence the spatial organization and mating system of P. kentucki.