China Bowl Cave: An Early-Middle Holocene non-analog faunule from Grand Rapids, central Manitoba, Canada

Abstract

China Bowl, a small vadose cave in the northern Interlake Region of Manitoba, Canada (53+° N, 99+° W), yielded the first recorded cave assemblage from central Manitoba—an Early-Middle Holocene vertebrate faunule dating to 7715 rcy BP (8500 cal y BP). The faunule, comprising mainly small mammals and amphibians, suggests an open taiga punctuated by mixed groves of trees on drier uplands interspersed with low-lying wetlands in an area occupied only a few centuries previously by proglacial Lake Agassiz. Identified elements include 3368 teeth derived from 17 small mammalian species, most of which are today locally sympatric taxa. This late, non-analog fauna, which includes Bison sp. indet., also features collared lemming (Dicrostonyx, perhaps D. richardsoni) which is now disjunct from the China Bowl locality by some 400–500 km to the north. The early postglacial, post-Agassiz occurrence of Dicrostonyx in the northern Interlake supports hypotheses about (Richardson's?) collared lemming still recolonizing northward from a refugium south of the late-Wisconsin Glacial Maximum (LGM) limits as ice and Lake Agassiz shorelines retreated. More than 3800 amphibian bones were also recovered, along with a few snake and fewer avian remains.