An 11-year study of small mammal populations at Mont St. Hilaire, Quebec

Abstract

Mont St. Hilaire has an area of about 10 km² covered by sugar maple and beech forest. Longworth traps were used on 46 grids from 1966 to 1976 in the snow-free period, mainly in June. One thousand and fifty-one individuals of 10 species of small mammals were captured. Two-thirds of these were Peromyscus, mainly P. maniculatus. Six female and one male Microtus pennsylvanicus were captured, all at least 1000 m from the nearest grassland, which is the usual habitat of this species.Within the forest the species apparently do not segregate into different habitats. Distribution, as measured by the number of grids on which each species was captured, is a function of total numbers. The relationship holds intraspecifically and interspecifically. Peromyscus (species combined), Clethrionomys gapperi, and Blarina brevicauda varied in June numbers from year to year. The range of variation was greatest for Peromyscus. Numbers of Peromyscus and Clethrionomys did not vary synchronously, and neither showed evidence of a regular periodicity in their fluctuations. Regular periodicity in fluctuations appears to be more prevalent in boreal forest populations than in deciduous forest populations. Some of the relevant factors are discussed.Le Mont Saint-Hilaire a une superficie d'environ 10 km² et est recouvert d'une forêt d'érables à sucre et de hêtres. On a utilisé des pièges Longworth dans 46 sections d'un quadrillage, de 1966 à 1976, durant la période sans neige, surtout en juin. On a recueilli de cette façon 1051 petits mammifères appartenant à 10 espèces. Les deux-tiers de ces animaux appartiennent au genre Peromyscus, et ce sont surtout des P. maniculatus. Six femelles et un mâle de Microtus pennsylvanicus ont été capturés, tous à au moins 1000 m de la prairie la plus proche, environnement habituel de cette espèce.