Spatial and temporal spider abundance and emergence data for five temperate alley-cropping agroforestry sites from 2022

This dataset is provided by the SIGNAL subproject “Macrofauna diversity and pest control in temperate agroforestry systems” and contains spider count data from emergence traps of five cropland alley-cropping sites in Northern Germany. Each site comprised a paired alley-cropping agroforestry system (AF) and an adjacent open cropland system (OC) serving as a reference land-use system without trees. At each agroforestry system, four subplots were arranged along linear transects orthogonal to the orientation of the tree rows, with a sampling point at the center of the tree row and at 1, 7, and 24 m (center of the crop row) distance from the tree row edge into the crop row. Open cropland systems had 4 subplots (sampling point) with a minimum distance of 25 m between each other and at least 30 m to the field margins. In total, 20 emergence traps (16 agroforestry, 4 open cropland) were set up at each site. Emergence traps consisted of a white gauze tent covering an area of 0.36 m2 (60 x 60 cm; height: 60 cm) with sides buried 10 cm deep to ensure no exchange between inside and outside. Inside the tents, a pitfall trap (95mm opening diameter, 639 ml volume) and a bottle at the top of the tent were filled with a 50/50 mixture of propylene glycol and water to catch arthropods. Traps were emptied from March to July 2022 monthly, yielding five trapping periods. Adult spiders were identified to species level.

Research domain: Ecology of Agricultural Landscapes

Research question: Do alley-cropping agroforestry systems provide more spider overwintering and emergence habitats than open cropland systems and therefore enable earlier build-up of predator communities?