Transformation of upland meadow’s biogeocenosis during processes of overgrowth by the gray alder (Alnus incana (L.) Moench)

Abstract

The article presents results of a study of the environmental conditions transformation during the formation of new phytocenoses by the grey alder. Processes of overgrowing meadows by alder entail a change of habitat characteristics, in particular, reduction of brightness and temperature, a signifi cant increase in litter thickness. In addition, abundance and biomass of earthworms per area unit is reduced in upper soil horizons under the alders, compared to the meadow. Conversion of environmental factors signifi cantly affects the development of herbaceous vegetation: species richness and abundance (cover) of herbaceous vegetation plummets under the influence of alder, as well as floristic heterogeneity of the cover. Undergrowth of spruce — indigenous tree species does not develop in the 60-year-old alder. Overgrowing meadows through the gray alder (compared with aspen and birch) inhibits the passage of autogenous succession, aimed at establishing indigenous vegetation type — spruce. Refs 29. Figs 5. Tables 3.