Are spider communities influenced by urbanisation? An approach using species and guilds resolutions and their interaction with the anthropogenic environment

Abstract

Spiders, natural enemies of several insects of economical and sanitary relevance, are sensitive to anthropogenic disturbances. Urban habitats, home to nearly half of the world’s human population, are growing in number and size. Consequently, natural habitats are lost and impervious surfaces increase. We compared the overall spider species and guilds assemblage characteristics associated with vegetation, between sites located within different urbanisation levels (urban and suburban) and in relation to local and landscape traits. The most abundant guilds were sheet web weavers and ambush hunters. The overall richness of spiders and richness and abundance of two guilds (space web weavers and stalker hunters) were higher in suburban than urban sites. The overall spider abundance, Shannon-Weaver diversity and the Shannon evenness index did not change between urban and suburban sites. While the species composition differed between urban and suburban sites, comprising the urban spider species a subset of those found in the suburban pool. Species abundances were negatively related with the percentage of bare ground, canopy cover, and urban level. Richness was positively related to low vegetation. Guilds’ responses differed concerning their life histories. At a landscape level, high consolidation (impervious surface) degree surrounding the green patches had negative effects while medium values had positive effects. Higher diversity was associated with intermediate mixtures of vegetation and impervious cover. In conclusion, the spider’s community and guild characteristics were associated with environmental, landscape and local factors through the urbanised landscape.