Ground-Dwelling Spiders (Arachnida: Aranei) as Anthropogenic Impact Indicators in the Norilsk Industrial Region: A Case Study
摘要
This paper discusses the suitability of spiders (Arachnida: Aranei) for use as bioindicators of anthropogenic impact in the Norilsk industrial region (NIR) and their prospects in this capacity. Ground-dwelling spiders are collected using pitfall traps on test sites established along three transects (Kayerkan, Norilsk, and Talnakh) in the vicinity of the city of Norilsk at various distances from major industrial enterprises. In total, 119 spider species have been recorded. Test sites located along the Norilsk transect feature the highest species richness (71 species). Spearman’s rank correlation coefficients indicate that relationships between distance from the closest industrial facility and diversity parameters of taxocenes were statistically significant in 2022 and 2023 only on test sites established along the Kayerkan transect, the direction of which largely coincides with the prevailing wind direction in the NIR. This transect features the lowest taxonomic diversity of spiders. The following diversity parameters positively correlate with distance from the plant: total number of species, diversity indices, number of species of the Linyphiidae family, number of individuals of the Linyphiidae family, and ratio between numbers of sheet weavers (Linyphiidae) and wolf spiders (Lycosidae). In 2023, only the last parameter correlated with distance statistically significantly. On the Norilsk transect, the correlation between dynamic density of spiders and distance from the plant was statistically significant only in 2022. The ordination of sites located along the three transects performed separately for the two years of research using non-metric multidimensional scaling (NMDS) show that (1) the differentiation of sites corresponds well to their biotopic differences on all transects and (2) the studied sites are better differentiated before the onset of phenological summer accompanied by the temperature rise and complete formation of various vegetation tiers. It is established that soil-dwelling spiders can be used as indicators of adverse anthropogenic impact. However, it is crucial to conduct such studies in similar biotopic conditions to minimize differences between sampling plots, and the subsequent analysis must take into account the seasonal dynamics of climatic factors and their year-to-year fluctuations.