A review of the cave fauna of Canada, and the composition and ecology of the invertebrate fauna of caves and mines in Ontario

Abstract

Caves and cave-inhabiting faunas of Canada are reviewed. Four species of troglobitic (cave-limited) crustaceans (Amphipoda and Isopoda) are known from Alberta and British Columbia, and one troglobitic mite from Alberta. A study of the subterranean fauna of Ontario involved investigating 35 caves and mines. Collections of 1274 invertebrate specimens contained 301 species in 5 phyla, with spiders and insects being most numerous. Diptera were the most abundant insects with 140 species, mainly in the families Culicidae, Mycetophilidae, and Tipulidae. The fauna is predominantly composed of trogloxenes, in the "parietal association." Few troglophiles and no troglobites were found. The fauna is most abundant in individuals and richest in species diversity within the first 10 m of the entrances, just inside the dark zone, and at 12–14 °C. The total "community" of terrestrial invertebrates does not show significant preferences in either caves or mines for precise locations on environmental gradients of light, temperature, or relative humidity. Faunal movements and changes occur on a daily and a seasonal basis. There is no clear difference between the faunas of "old" caves and those of "young" mines. The cave and mine faunas are generally scavengers or predators recruited from nearby forest litter and soil populations. None of the species were significantly outside their previously known distributional range.