Canadian Forest Service Publications
Diversity, species richness, and abundance of spiders (Araneae) in different strata of boreal white spruce stands. 2013. Pinzon, J.; Spence, J.R.; Langor, D.W. Canadian Entomologist 145:61-76.
Available from: Northern Forestry Centre
Catalog ID: 34372
Available from the Journal's Web site. †
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Spiders (Araneae) were sampled in white spruce (Picea glauca (Moench) Voss (Pinaceae)) dominated stands from the ground and shrub layers, and from several overstorey strata to assess patterns in species composition and diversity (alpha and beta) along the vertical gradient (0–12m above ground). Overall, 3070 adult spiders in 15 families and 76 species were collected, with the ground layer accounting for the highest species richness (40 species) followed by the mid-overstorey (36 spp.) and the shrub layers (33 species). Vertical stratification was apparent in the samples: richness clearly decreased with height, and species turnover between the ground, shrub, and mid-overstorey levels was evident, suggesting that species composition in each layer was highly distinctive. Within the mid-overstorey stratification was less obvious but both species richness and spider abundance were predicted significantly by height from the ground and branch size. Given the role of late-seral conifer stands for maintaining old-growth species, understanding diversity patterns across strata provides basic knowledge to support forest management decisions that effectively conserve spider species and assemblages. It is clearly important to include higher canopy layers in considering impacts of forestry on biodiversity in the boreal mixedwood.
Plain Language Summary
Spider species are often used to examine how human and natural disturbances such as harvesting and fires affect forest biodiversity, and to find ways to change forest management practices to better emulate wildfire. This paper provides a baseline examination of which spider species are found at different heights in white spruce stands. It will be followed by studies of the impacts of various types of harvesting on the spiders. This is the first work of its kind in western Canada. It shows that species composition changes from the ground to the shrub layer and as you go up the stems of trees. The practical advice coming from this work is that future studies of the impact of harvesting on spider species should include higher canopy levels, not just species on the ground. This finding will influence the design of future experiments, including those within the large Ecosystem Management Emulating Natural Disturbance (EMEND) project.
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