Do Orthoptera need human land use in Central Europe? The role of habitat patch size and linear corridors in the Bialowieza Forest, Poland

We studied Orthoptera, Dermaptera, and Blattodea of the Bialowieza Forest (Poland) in order to assess (1) the minimum patch size of open habitat necessary for each species, (2) the role of linear corridors as habitat, and (3) the impact of herbivores on diversity by comparing the fauna at periods of different ungulate densities. Many species occurred in the farthest clearings from the forest edge to arable land. Two third of species occurred in clearings smaller than 10,000 m(2). Dry linear corridors of 10-40 m width and wet linear corridors of 100-200 m width had a species richness that corresponded to that of clearings of about 10,000 m(2). Four species disappeared from the Bialowieza Forest when ungulate density decreased from 20 individuals/km(2) (3000 kg/km(2) biomass) at the beginning of the 20th century to 10 individuals/km(2) (1000 kg/km(2)) at the end of the 20th century. We conclude that most Orthoptera, Dermaptera, and Blattodea species could survive in Central Europe if human land use was replaced by intensive grazing and browsing by wild herbivores.