Modelling populations of Erigone atra and E. dentipalpis (Araneae: Linyphiidae) across an agricultural gradient in Scotland

摘要: Linyphiid spiders are important generalist predators of insects in agricultural habitats. Their ability to rapidly disperse and colonise disturbed habitats makes them as a natural form pest control, often present before other predatory groups arrive. This paper examines the distribution Erigone atra E. dentipalpis, which amongst commonest linyphiid species be found on land Scotland. The habitat preferences these were assessed using abundance proportion data from 71 independent sites sampled pitfall traps over 2 years selection repeat first-year during second year, incorporating range land-uses extensive moorland, through grasslands intensive arable fields. dominated autumn sown crops, dentipalpis at end management spectrum low-intensity grasslands. Both considered absent upland moorland Linear regression modelling was used create model best estimated variance proportions catch across vegetation, soil, landscape variables. based 58 where abundant explained 66% variation atra. variables included increasing vegetation biomass above 50 mm levels mixed grazing (both positive), combination plant richness stem density (negative). efficiency examined 13 subsequent year assess effects no changes land-use two species. Only inaccurate (more than 20% different model), suggesting relatively high level accuracy. Interaction between tested for not explain differences observed. Comparisons with studies carried out, showing similar trends some identified important. influence specific each is described light possible allometric-type effects, importance conservation control agriculture discussed.