Diversity of litter spiders (Araneae) in a successional Douglas-fir forest in British Columbia

Litter spiders were collected at two locations by pitfall trapping: Victoria Watershed South, and Koksilah, located on south-eastern Vancouver Island, British Columbia. Sites were in Douglas-fir forest (in the Coastal Western Hemlock region) and contained four forest successional stages: Regeneration (3-8 years), Immature (25-45 years), Mature (65-85 years), and Old-Growth (>200 years). Thirty-two species were collected in families selected to represent litter spiders. Several of the collected species are listed as potentially rare and endangered in British Columbia. The collection of Zora hespera is the first record of the family Zoridae in Canada. Intraspecific comparisons revealed three distinct distribution patterns: generalists, regeneration specialists, and intermediate forest specialists (spiders prefering the Immature and Mature successional stages). These patterns can be related to biological information regarding individual species. Species richness measures and diversity indices indicated that the regeneration sites have the greatest species richness. There was no significant difference between the remaining three successional stages. Factors affecting the distribution of spider species in the forest litter are discussed.Science, Faculty ofZoology, Department ofGraduat