Print PageUrbanization negatively affects biodiversity by increasing disturbance and habitat fragmentation. Arthropods are an important part of ecosystem processes but fragmentation and changes in habitat structure can alter arthropod communities. More specifically, spiders, important predators that occupy a wide range of niches, are excellent indicators of habitat disturbance. However, few have examined spiders in urban areas, despite their importance as providers of ecosystem services. We sampled ground spider communities in three urban habitats (gardens, vacant lots, and forest fragments) in Toledo, Ohio to examine spider activity-density and species richness, and differences in species composition. We additionally examined differences in female carapace size as a measure of habitat quality, and examined which site characteristics correlated with changes in the spider community. We sampled spiders with pitfall traps four times during the summer of 2007 in 12 sites (4 of each habitat type). We additionally sampled 24 vegetation and site characteristics (e.g. canopy cover, plant richness, area with concrete) as correlates of abundance and richness data. Spiders were stored and later identified to family and divided into morphospecies.
Results/Conclusions
We collected a total of 556 individuals from 78 morphospecies. The most common families collected included Lycosidae, Liocranidae, Nesticidae and Cybaeidae. Spider activity-density and richness were highest in the vacant lots (287 individuals, 63 morphospecies) and lowest in forest (105 individuals, 25 morphospecies) with intermediate values in gardens (164 individuals, 39 morphospecies). Species similarity, but not size of spiders, differed significantly between different habitats and sampling dates.SSpi Species similarity of park sites were significantly different from gardens and lots, but no significance was seen between lots and gardens. Adult spider activity-density did not change with sample date. Amount of bare ground and forb abundance correlated with spider richness and species composition. Specifically, spider richness negatively correlated with bare ground, litter cover and number of forbs in 1 x 1 m plots, but these factors did not significantly differ with habitat type. Thus, spider communities differ in different urban habitats, likely affecting their functional role and conservation within urban areas. Specifically, vacant lots harbor more spiders and likely provide an important refuge habitat refuge in urban centers.
