The influence of humidity gradient in a forest on ground spider assemblages: a preliminary study

Abstract

A forest is a dynamic formation developed through evolutionary transformations that have progressed over a long time. Bioindication can help us understand changes occurring in a forest. Spiders play a significant role in biomonitoring. The presence of stenotopic spiders is affected by several factors, of which water availability is vital. According to the assumptions underlying water retention programs, water accumulated in retention reservoirs is expected to stimulate higher biodiversity of habitats. An analysis of the effect of a moisture gradient on the appearance of epigeic spiders in the Dąbrówka Forest Subdistrict has demonstrated the highest species diversity in the transect located closest to retention reservoirs (93 species). The species diversity of epigeic spiders decreased with the growing distance from these water reservoirs (transect B: 84 species; transect C: 70). Inverse relationships were determined with regard to the numbers of captured spiders (transect A: 927 specimens; B: 1134; C:1288). The spider species that dominated quantitatively was the forest species Pardosa lugubris, caught most abundantly in the area assigned to transect C (76.28%). A higher humidity gradient of a habitat (transects A and B) favors the occurrence of characteristic species with specific habitat and moisture requirements, which are ecologically valuable.

Keywords

• Afforestation
• Araneae
• bioindicators
• managed forests
• species diversity
• water availability