The influence of vegetation structure on spider species richness, diversity and community organization in the Apšuciems calcareous fen, Latvia

Abstract

Štokmane, M. & Spuņģis, V., 2016. The influence of vegetation structure on spider species richness, diversity and community organization in the Apšuciems calcareous fen, Latvia. Animal Biodiversity and Conservation, 39.2: 221-236, https://doi. AbstractThe influence of vegetation structure on spider species richness, diversity and community organization in the Apšuciems calcareous fen, Latvia.-Calcareous fens are considered to be among the most threatened ecosystems of Europe. They are also one of the most diverse habitats as they support an incredibly rich and diverse range of plant and animal species. However, in spite of their diversity, calcareous fens are still poorly investigated, especially when referring to fen invertebrates, such as spiders. Because spiders are good bioindicators, knowledge of their ecology in rare and threatened habitats is of interest. The aim of this study was to document the composition and diversity of spider species, families and foraging guilds in the ground-and grass-layers of the Apšuciems calcareous fen, and to evaluate the influence of vegetation structure on spider community organization. In summer 2012, we collected ground-dwelling spiders using pitfall traps and grassdwelling spiders using sweep-netting. A total of 2,937 spider individuals belonging to 19 families and 80 species was collected in the Apšuciems fen. Our results indicate that spider species and families tend to be stratified across the vertical structure of the habitat; the spider composition in the ground stratum differed from that in the grass stratum. On the contrary, however, the spider foraging guild structure between the ground-layer and the grass-layer was similar. Each of the two studied strata presented similar guilds in similar proportions. Our results also showed that spider composition differed considerably between fen parts and that much of this variability could be explained by the architectural properties of the habitat. More diverse vegetation generally supported a higher number of spider species.

Preliminary Study of Araneofauna (Arachnida: Araneae) Inhabiting Quinoa Plants at Fayoum Governorate, Egypt

“…According to Simpson index which is a measure of dominance (responsive to changes for the most dominant species), it was found that 2 nd season included the highest number of dominant species. This is in accordance with Kacar (2015) who showed that the Shannon-Wiener diversity index of spider species were generally well distributed among the all samples (H=3.35).Also, Štokmane & Spuņģis (2016) found that the mean Shannon index for vascular plants was 1.44 (± 0.05) and it ranged from 0.49 to 2.10, while the mean evenness was 0.62 (± 0.02) and ranged from 0.23 to 0.85.Also, Tilman et al (2001) and Petchey and Gaston (2006) proved that guild structure implies its quantification. Functional diversity is one of the most important parameters used to explain how ecosystems work and adapt to change.…”

Revision of the calcareous fen arachnofauna: habitat affinities of the fen-inhabiting spiders

“…Also, sweep netting is relatively ineffective on sparsely vegetated ground (Sutherland 2006). Thus, we must conclude that it is very difficult to compare catches between different calcareous fens, since our studied fens differed quite greatly from each other in terms of the plant species composition and vegetation height (Štokmane et al 2013; Štokmane and Spuņģis 2014, 2016). Furthermore, pitfall trapping and sweep netting tend to collect spider species that exhibit different foraging strategies.…”

“…Unfortunately, arachnids from calcareous fens are very poorly studied. In Latvia, spiders within calcareous fens have been investigated in some of our previous studies (Štokmane et al 2013; Štokmane and Spuņģis 2014, 2016). These previous investigations had examined the influence of vegetation structure on spider diversity, while little attention was paid on the faunistic aspects of the fen spider communities.…”

Spider (Araneae) and harvestman (Opiliones) communities are structured by the ecosystem engineering of burrowing mammals

“…We guess that the disparity in spider response can be caused by different plant species richness between study sites. More diverse vegetation generally supports a higher number of spider species (Diehl et al ., ; Štokmane & Spungis, ). Plant community under high grazing intensity was relatively poor with 10 vascular plant species per m 2 only and ground squirrel mounds exhibit twofold plant species richness at this study site (Lindtner et al ., ).…”