Ecological Notes on Animals of the Churchill Region of Hudson Bay

Abstract

The distribution and ecology of 26 mammals, 6 birds, and 1 amphibian are described. Northern range extensions are recorded for the pygmy shrew, arctic shrew, muskrat, heather vole, northern bog lemming and wood frog. A southern range extension of the arctic ground squirrel is noted following its being observed for the first time in Manitoba. Observation of a great blue heron at Churchill, far from its usual range in southern Manitoba, is also recorded. The number of species of small mammals on two-hectare quadrats in marsh, prairie, shrub, and savanna along the grassland-coniferous forest transition in southern Manitoba was 1.8 to 3.0 times greater than in beach-meadow, tundra, shrub, and openforest quadrats along the coniferous forest-tundra transition of northern Manitoba, while the total population was 1.8 to 3.4 times greater. R h U M f i. Notes écologiques sur les animaux de la région de Churchill sur la mer d'Hudson. L'auteur décrit la distribution et l'écologie de 26 mammifères, 6 oiseaux et 1 amphibien. I1 enregistre une extension d'aire vers le nord pour la musaraigne pygmée, la musaraigne arctique, le rat musqué, le campagnol roux, le lemming des marais et la grenouille des bois. I1 note une extension d'aire vers le sud pour l'écureuil de terre arctique, par suite d'une première observation de cette espèce au Manitoba. I1 enregistre aussi l'observation d'un grand héron bleu h Churchill, loin de son aire habituelle dans le sud du Manitoba. Le nombre d'espbes de petits mammifères sur des carrés de deux hectares dans les marécages, la prairie, les broussailles et la savane le long de la transition entre la forêt coniférienne et la prairie dans le sud du Manitoba est de 1.8 h 3.0 fois plus grand que dans des carrés de prairie côtière, de toundra, d'arbustes et de forêt-parc le long de la transition forêt coniférienne-toundra dans le nord du Manitoba, alors que la population est de 1.8 3.4 fois plus grande. OT ee 06b19~mx MeCT O~E I T~H H R B IOJKHOa M a m~0 6 e. YHCJIeHHOCTb BHAOB MeJIKHX IOXCEIOa r p a H~q b~ X B O k O r O neca B M~H H T O~~ B 1,8-3,0 paaa 60nbme, 9eM BAOnb SHELFORD, V. E. 1943. The abundance of the collared lemming (Dicrostonyx groenlandicus (Tr.) var richardsoni Mer.) in the Churchill area, 1929 to 1940. Ecology, 24: 472-84.. 1963. The Ecology of North America. Urbana: University of Illinois Press. 610 pp.

Trends in Abundance of Collared Lemmings Near Cape Churchill, Manitoba, Canada

“…Although synchrony in arvicoline population cycles can occur across a broad spatial scale (200-1,000 km- Erlinge et al 1999), Wrigley (1974) suggested that population cycles of lemmings were asynchronous between the town of Churchill, Manitoba, and the Seal River to the north, a distance of only 56 km, and that further north (208 km) the phase of the population cycle was again different than at Churchill or the Seal River. In contrast, Shelford and Twomey (1941) asserted that peaks in abundance of lemmings near Cape Churchill roughly coincided with peaks in abundance near the town of Churchill.…”

The lemming community on the lichen-heath tundra at Churchill, Manitoba

“…However, D. richardsoni are commonly found in sympatric communities with Lemmus sibiricus (Gileva 1983) and C. rutilis (Hall and Kelson 1959;Banfield 1976) throughout most of their range. The southern range limit of the latter two species is near the Seal River (Hall and Kelson 1959;Wrigley 1974) at the southern limit of the continental tundra. Today at Churchill, D. richardsoni is found on upland sites with, among other species, the more southern C. gapperi and with M. pennsylvanicus.…”

“…Shelford and Twomey (1941) studied small mammals near Churchill from 1928-1939 and described D. richardsoni distributions in relation to the surrounding flora with an emphasis on beach ridge communities (see also Smith and Foster 1957). Brooks (1970) trapped D. richardsoni at Churchill during 1967-1969 and reported on burrow structure, dietary preference, and radiotracking studies within a beach community, Wrigley (1974) discussed small mammal distributions in northern Manitoba in general.…”

Patterns of evolution and migration in the arctic ground squirrel, Spermophilus parryii (Richardson)

“…parryii was unknown throughout its vast range extending eastward along the coast of the Arctic Ocean and southward across the tundra to Great Slave Lake, to its southernmost penetration at the tree line 5 mi north of Seal River, Manitoba, on the shore of Hudson Bay (latitude 59'09' N) (Wrigley 1974). Since only Tf 6 has now been found in populations between Baker and Schultz Lakes, Northwest Territories, and at Seal River, it appears that all S. p. parryii from the Northwest Territories (excluding the montane region between the Yukon and Mackenzie rivers occupied by S. p. plesius) evolved from ancestral stock with Tf 6, and that S. p. parryii populations ranging from the Brooks Range to Hudson Bay constitute a common evolutionary unit.…”