Spiders associated with the meadow and tree canopies of orchards respond differently to habitat fragmentation

Abstract

The response of animal communities to habitat quality and fragmentation may vary depending on microhabitat associations of species. For example, sensitivity of species to woody habitat fragmentation should increase with their degree of association with woody plants. We investigated effects of local and landscape factors on spider communities in different microhabitats within Swiss apple orchards. We expected a stronger negative effect of woody habitat fragmentation on spiders inhabiting tree canopies compared to spiders living in the meadow. The 30 orchards that we sampled varied in woody habitat amount and isolation at landscape and patch scales. Local factors included management intensity and plant diversity. Spiders associated with meadow were affected by plant diversity, but not by fragmentation. In contrast, spiders associated with canopies responded to isolation from other woody habitats. Surprisingly, we found both positive and negative effects of habitat isolation on local abundance. This indicates that differences in dispersal and/or biotic interactions shape the specific response to habitat isolation. The relative importance of local and landscape factors was in accordance with the microhabitat of the spiders. Thus, considering microhabitat associations can be important for identifying processes that would be overlooked if sampling were pooled for the whole habitat.

Patch shape alters spider community structure: links between microhabitat choice and sensitivity to increased edge habitat

“…Indeed, by changing the orientation of jute strands in wire modules similar to ours, Robinson (1981) found that T. petraeum preferred horizontal substrates. The different trends in abundance across our two spider genera are reminiscent of the patterns of species replacement described by Schmidt et al (2008) and Herrmann et al (2010) in spiders, and by Summerville (2004) in lepidopterans, in which specialist species are lost from habitat fragments while habitat generalists increase in abundance.…”

Landscape characteristics affect animal control by urban residents

“…Humans create appealing wildlife habitat, wildlife use this habitat, presence of and actions by wildlife causes human reaction to wildlife, and humans repair and reinforce appealing habitat thereby attracting wildlife. We speculate whether further exploration of the social pattern and processes of pest control may reveal similar patterns of ecological processes at both local and landscape scales (Melles et al 2003, Chamberlain et al 2004, Sparks et al 2005, Herrmann et al 2010), but intra-site control patterns reflect landscape heterogeneity. From a policy and management perspective, such human-wildlife conflict may be resolved by encouraging residents in lower density areas and near open space to adhere to manufacturer guidelines for pest control product use and minimizing presence of attractants on their property.…”

Effect of lake size, isolation and top predator presence on nested fish community structure

“…Both aquatic and terrestrial studies have shown that spatial variables and biotic interactions can jointly structure communities (e.g. Scheffer et al, 2006;Chase et al, 2010;Herrmann et al, 2010), and that spatial variables such as the level of site isolation can affect richness when biotic interactions are strong (e.g. Scheffer et al, 2006;Chase & Shulman, 2009).…”