Communities of ground-living spiders in six habitats on a mountain in Quebec, Canada

Ground-living spiders were studied, using pitfall traps, in six habitats between 580 and 960 m (deciduous forest, fir forest, forest-line and three alpine mountain top sites) on Mont du Lac des Cygnes. Altogether 88 species of spiders were found during the study summer (June-mid-September 1985), of which 51 belonged to Linyphiidae (s. lat.), 9 to Lycosidae and 8 to Gnaphosidae. The highest species number and diversity were found in the forest-line habitat, the highest individual number on the main summit and the lowest in deciduous forest, the lowest site. Lycosidae and Gnaphosidae species and individuals characterized the alpine habitats, Linyphiidae (especially Linyphiinae) the forested sites and Amaurobiidae and Agelenidae the deciduous forest site. Erigoninae occurred commonly at all sites; their individual numbers were very high at coniferous forest sites. The dominant species in all three alpine habitats was Pardosa concinna, on the forest-line Hybocoptus gibbosus, in balsam fir forest Sisicottus montanus and in deciduous forest Amaurobius borealis. The material included several (sub)arctic-alpine species.