Individual study: Sown wildflower areas to enhance spiders in arable fields.
Schmidt-Entling M.H. & Dobeli J. (2009) Sown wildflower areas to enhance spiders in arable fields. Agriculture, Ecosystems & Environment, 133, 19-22
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Plant nectar flower mixture/wildflower strips
A replicated, controlled, paired sites study in summer 2005 in northwest Switzerland (Schmidt-Entling & Dobeli 2009) found densities of several spider (Araneae) families were higher in wheat fields with adjoining sown wildflower areas than in fields with grassy margins. Crab spiders (Thomisidae), ground spiders (Gnaphosidae) and wolf spiders (Lycosidae) as well as young orb weaver spiders (Araneidae) had higher densities in fields with adjacent sown wildflower areas. However spider diversity and the total number of spider species were not significantly different in wheat fields adjoined by sown wildflower areas than fields with grassy margins. Twenty winter wheat fields were studied (0.5-4.1 ha in size), 10 fields had adjoining sown wildflower areas, 10 were adjoined by grassy margins. Wheat fields were treated with herbicides, fungicides and mainly mineral fertilizers but no insecticides. Sown wildflower areas (a Swiss agri-environment scheme) were sown with a mixture of 25 wildflower species, and were not treated with pesticides, fertilizers or mown. Sown wildflower areas were 0.4-2.3 ha in size (minimum 25 m wide) and between two and six years-old. Grassy margins were about 0.7 m wide and mown several times/year. Spiders were sampled from May to June using pitfall traps (0.2 l, 6.5 cm diameter) and a suction sampler (0.1 m diameter).