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Medientyp:
E-Artikel
Titel:
Subpopulation Structure and Dispersal in Two Populations of Chamois
Beteiligte:
Loison, Anne;
Jullien, Jean-Michel;
Menaut, Pierre
Erschienen:
American Society of Mammalogists, 1999
Erschienen in:Journal of Mammalogy
Sprache:
Englisch
ISSN:
1545-1542;
0022-2372
Entstehung:
Anmerkungen:
Beschreibung:
<p>Subdivision of a population into reproductive units and rates of exchanges among them may influence population dynamics. Unfortunately, subpopulation units and flows of immigration and emigration are difficult to estimate because of the lack of data on spatial behavior of individuals. By studying two populations of chamois (Rupicapra), 244 marked animals, and a 10-year monitoring program, we determined that subpopulation units were related closely to topographic limits in which >90% of the females were philopatric. Males had a greater tendency to disperse than females, especially before reproduction, but females did more exploratory movements. We found no difference in sex-specific dispersal rates between sites, despite differences in densities and sex-ratio. The relatively high dispersal rate of males and the lack of effects of sex-ratio and density on dispersal rates support the inbreeding-avoidance hypothesis as a main cause of dispersal. High rates of exploratory movements, especially among females, indicates that local resource competition within female groups also may play a role. Dispersal patterns have to be explained in the context of possible different motivations between sexes, related to social and spatial segregation. Moreover, we argue for an effect of topography, which determines where dispersal is possible. Accordingly, dispersal occurred at a site with continuous connections with favorable habitat. Colonization of new areas from protected reserves is limited by low dispersal rates of females and increasing isolation between favorable areas in mountains. Management and conservation policies have to take these aspects into account to predict distribution of chamois on a large scale and cope with high local densities resulting from female philopatry.</p>