The Edge Effect on the Herb–Dwarf Shrub Layer of Urbanized Southern Taiga Forests

Abstract

We estimated when the edge effect appears in the herb–dwarf shrub layer of pine forests near Yekaterinburg (Central Urals; Southern Taiga subzone) on 14 transects (series of 6–10 plots of 400 m², conjugated in a line 140–260-m long from the edge into the forest, perpendicularly to the forest boundary). The boundaries of forests have differed in time of occurrence (less than nine years and older than 20 years) and type (adjacent to motorways and wastelands). The edge effect on the herb–dwarf shrub layer is manifested in the increasing diversity but not total abundance of herbs. The main components of the edge effect is manifested through an increase in species richness and abundance of plants of nonforest, meadow, and ruderal cenotic groups. The richness and abundance of alien plants and graminoids (cereals and sedges) also increased near forest edges. The depth of the edge effect was, on average, 32 m. For some characteristics, the edge effect contrast increased with time or at added transformation in conditions near highways.