Soil arthropoda of post-fire successions in northern taiga of West Siberia

The soil arthropoda population of northern taiga was investigated in the primary pine forest which had not been subject to any fire for at least 100 years and at two burnt sites of different opost-fire successions. The population of the primary nonburnt forest is represented by 54 microarthropoda species. The mesofauna is composed almost exceptionally of spiders: 10 species of them were identified. The foliage underwood develops on young burnt sites; the soil is covered with thick mossy cushions, with spots of reedgrass. The density of collembolan and oribatid mite population there is about two times lower than in nonburnt pine forests; gamasid mites are absent. The microarthropoda population is represented by the species which are common in the surrounding primary pine forests. The mesofauna consists mainly of ground beetles, open-land predators, and myxophytophagans. Spiders are represented by some widespread mobile species of low density. A mixed forest with mossy-lichen cover is formed on old burnt sites (of an age of about 50 years). Diversity and density of microarthropoda increase reaching the values characteristic of the primary forest; however, the species composition and dominance are still different. The fraction of spiders in mesofauna increases. The ground beetle population is the most abundant and diverse.