What Determines the Distribution of Forest Flightless Bush Cricket <em>Pholidoptera griseoaptera</em> in the Eastern Part of Its Range (the Kaluga Region, Russia)?

(1) Pholidoptera griseoaptera (De Geer, 1773) (Orthoptera, Tettigoniidae) is known as a common and widespread inhabitant of forest edges in Europe, so it may be a suitable model to understand a dealing of forest wildlife in the past and the future. (2) We registered the presence or absence of the species in 189 edge/forest plots in the Kaluga Region using acoustic observations and pitfall traps, and performed a logit regression. (3) Across the region, the main factor that positively affected the presence of the species was the presence of nemoral herbs as dominants of the herb layer. The main negative factors were the isolation of habitat patches by physical barriers and belonging to the moraine plains of the last stage of the Moscow glaciation. The presence of coniferous species in the tree layer and spatial autocovariation were significant factors with small contributions. Abundance of Ph. griseoaptera was higher in the forest located in the river valleys. Across Kaluga City, the long existence of tree vegetation in place of plots and the isolation were the main significant factors affecting the presence of the species. The smallest urban site where the species lives is about 13 ha, and the summary square of unmowed patches in this habitat is about 0.2 ha. (4) Ph. griseoaptera can be used as a marker of the persistence of the broadleaved deciduous (nemoral) forests in the past. In a high level of urbanization, it can become a threatened species.