Distribution and density of woodchucks burrow systems in relation to land-use practices [Répartition et densité des systèmes de terriers de marmottes en relation avec l'utilisation du sol].

Résumé

Étude menée dans une exploitation de l'Ontario entre mars et octobre. 552 terriers sur 85,7 ha de terrains agricoles. 91% de l'activité de fouissement se tient entre avril et juillet. et les nouveaux terriers sont creusés dans les zones récemment cultivées. Le nombre de terriers reste inchangés dans les haies. Some 552 Woodchuck (Marmota monax rufescens) burrow systems, defined by both Woodchuck use and spatial considerations, were found on 85.7 ha of mixed farmland at Cambridge. Ontario between March and October 1973. The distribution of burrow systems for the entire study area did not differ significantly from a Poisson distribution, but densities differed with land use. The number of actively-used burrow systems per hectare averaged 5.9 and ranged from l.8 in newly seeded pastures to 16.8 in undisturbed brushy fencerows. Uniform spacing in five fields was attributed to agnostic behavior primarily among juvenile Woodchucks during rapid invasion of new habitat. Ninety-one percent of all burrowing activity took place between April and July, and all new burrow systems were dug in recentIy cultivated areas. The rate of invasion of new habitat increased with the availability of vegetative cover. The number of burrow systems located in brushy fencerows remained virtually unchanged throughout the study. These fencerows served as Woodchuck "refuges" and repopulation centers for the adjacent cultivated fields.