Dispersal pattern and effective population size of the beaver.

摘要: The dispersal pattern of the beaver (Castor canadensis) was studied by intensive livetrapping, tagging, and observation in Allegany State Park its vicinity New York from 1984 to 1996. majority (74%) dispersing beavers (n = 46) initiated a downstream direction after spring ice-out. Females dispersed significantly far - ther away their natal colonies than males (10.15 ± 2.42 (SE) km vs. 3.49 0.86 km). Movements neighboring sites were common (16 46 dispersers), indicating that beavers, especially males, may prefer disperse near est available sites. Most (64%) dispersers 2-year-olds. Three-year-olds also constituted considerable pro portion (21%) dispersers, but 1-year-old relatively rare (14%). Many adults underwent secondary successful our study area. Male more inclined take over male (10 13 3 13). effective population size 250-km 2 area estimated be 161-228 individuals areal method 267-378 85th percentile method. Resume : La dispersion ete etudiee chez le Castor du Canada par capture d'animaux vivants, marquage et observation, dans parc ses environs l'etat de New-York majorite (74 %) des castors qui ont quitte leur lieu d'origine se sont d'abord orientes vers l'aval ruisseau apres la disparition glaces. Les femelles eloignees significativement plus colonie que les mâles (10,15 2,42 (erreur type) 3,49 0,86 deplacements endroits avoisinants observes frequemment animaux sur 46), ce indique castors, particulierement mâles, prefe- rent gagner disponibles moins eloignes. plupart non sedentaires (64 etaient âges ans. ans constituaient aussi une proportion importante (21 nons sedentaires, mais 1 an s'est averee relativement (14 %). Dans notre zone d'etude, plusieurs adultes nouveau sejour premiere tentative reussie. Ces secondaires avaient tendance s'approprier primaires