Spider Diversity in the Fragmented Forest-Steppe Landscape of Northeastern Ukraine: Temporal Changes under the Impact of Human Activity

Abstract

Semi-natural forests and dry grasslands are highly fragmented and influenced by human activity. Despite the small area, they serve as the refuge for habitat-specific species and enhance agrolandscape biodiversity. We studied spiders in Velykoburlutskyi Steppe Regional Landscape Park (northeastern Ukraine) for 10 years and found 224 species of 26 families; of these, 27 are rare and require protection. The araneofauna of small forests in gullies is poorer than that of the large oakeries and hosts fewer sylvatic species; the dry grassland fauna is rich, has typical steppe traits, and varies depending on topography and grazing history. The ungrazed gully hosted 125 spider species. The richest assemblages (97 species) were at the bottom, and they were similar to those of meadows and forest edges. The most typical steppe assemblages were formed on the ungrazed slope (77 species). The human-induced disturbance had a negative effect on spiders: we found only 63 species at the grazed bottom and 62 on the slope. After abrupt grazing cessation, four spider species appeared and occurred constantly at the bottom, while no species left this habitat. Grazing on the slopes declined gradually, and spider assemblages did not change significantly after the final cessation; moreover, they enriched on the abandoned slope (75 species). The presence of rare species and a variety of spider assemblages confirm the conservation value of the study site and the need to maintain its mosaic pattern.