Succession of boreal forest spider assemblages following wildfire and harvesting

Abstract

2000. Succession of boreal forest spider assemblages following wildfire and harvesting. -Ecography 23: 424-436.To test whether spider succession following harvest differed from succession following wildfire, spiders were collected by pitfall trapping and sweep netting over two years in aspen-dominated boreal forests. Over 8400 individuals from 127 species of spiders were identified from 12 stands representing three age-classes (stand origin in 1995, 1982, and 1968) and two disturbance types (wildfire and harvesting). The diversity of spider assemblages tended to be higher in fire-origin stands than in harvest-origin stands; the youngest fire-origin stands also supported more even distributions of spider species. Spider assemblages responded quickly to wildfire and harvesting as open habitat specialists colonized stands within one year after disturbance. Many web-building species common to older forests either survived harvesting, or re-colonized harvest-origin stands more rapidly than they re-colonized fire-origin stands. Cluster analyses and DCA ordination show faunal convergence by ca 30 years after wildfire and harvesting; trajectories in re-colonization, however, differed by disturbance type as the succession of spider assemblages from fire-origin stands lagged behind spider succession in harvest-origin stands. Comparison with cluster analyses using vegetation data and abiotic site conditions suggests spider assemblages recover from harvesting and fire more rapidly than do a variety of other site characteristics. Several spider species (e.g. Gnaphosa borea Kulczynski, Pirata bryantae Kurata, Arctosa alpigena (Doleschall) appear dependent on some of the conditions associated with wildfires as they were absent or rarely collected in harvest-origin stands.

Arthropods as ecological indicators of sustainability in Canadian forests

“…Some species in all groups of arthropods studied exhibit responses to disturbances; some (forest specialists) are adversely affected, others (open habitat specialists) are favoured and both groups have potential as ecological indicators (Niemelä et al 1993a, Buddle et al 2000. Species adapted to fire (a common natural disturbance in most Canadian forests) or to fire residuals (skips) are also potentially good indicators for natural disturbance regimes (Gandhi et al 2001).…”

“…Species adapted to fire (a common natural disturbance in most Canadian forests) or to fire residuals (skips) are also potentially good indicators for natural disturbance regimes (Gandhi et al 2001). Development of arthropod indicators will depend on quantifying their response to varying degrees of disturbance, either in the context of manipulative experiments (e.g., Spence et al 1999) or in retrospective approaches (e.g., Buddle et al 2000Buddle et al , 2006. Such efforts require due consideration of scale.…”

“…Two other ground-dwelling groups, rove beetles (Staphylinidae) and spiders (Araneae) are regularly caught along with carabids in pitfall traps. Taxonomic expertise on these groups is now more common in Canada, and recently they have also been studied as potential ecological indicators (Brumwell et al 1998;Buddle et al 2000Buddle et al , 2006Gandhi et al 2001). With increasing focus on the ecological values of dead wood and recognition that insects associated with dead wood are among the most sensitive groups to forest management in northern Europe (Siitonen 2001), saproxylic beetles (Coleoptera) are receiving increasing attention as potential ecological indicators in Canada (Hammond 1997, Spence et al 1997, Hammond et al 2001, Langor et al 2006b).…”

Salvage logging after wildfire in the boreal forest: Is it becoming a hot issue for wildlife?

“…Recent work on boreal invertebrates has shown that Coleoptera and spider assemblages in post-fire habitats are clearly distinct from those in other forest types (Buddle et al 2000, Saint-Germain et al 2004a. Several insect species greatly benefit from the conditions created by fire such as habitats free of competitors, exposed soils and high abundance of snags (Wikars 1992(Wikars , 1994Saint-Germain et al 2004a).…”

Occurrence of Parasitoid Wasps, <em>Baeus</em> sp. and <em>Gelis</em> sp., in the Egg Sacs of the Wolf Spiders <em>Pardosa moesta</em> and <em>Pardosa sternalis</em> (Araneae, Lycosidae) in Southeastern Idaho

“…Wolf spiders in the genus Pardosa are common ground-dwelling spiders throughout much of the northern hemisphere (Edgar 1971b;Dondale and Redner 1990;Buddle et al 2000). Their reproductive period may last several months (Edgar 1971b;Cobb 1992;Buddle 2000) and some species may produce multiple clutches during a single season (Edgar 1971b;Wolff 1981).…”