Changes in spider (Araneae) assemblages in relation to succession and grazing management

Published source details Gibson C.W.D., Hambler C. & Brown V.K. (1992) Changes in spider (Araneae) assemblages in relation to succession and grazing management. Journal of Applied Ecology, 29, 132-142.
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This study is summarised as evidence for the following.

	Action	Category
	Delay mowing or first grazing date on pasture or grassland Action Link

Delay mowing or first grazing date on pasture or grassland

A replicated, randomised, controlled trial in 1985-1989 in Oxfordshire, UK (Gibson et al. 1992) found plots grazed in autumn-only had similar numbers of spider (Araneae) species and individuals (3.5-5.5 species, 69-197 individuals/m²) to those grazed in spring (3.3-5.3 species, 50-119 individuals) in 1989. An ungrazed control had 7.3-8.3 species and 111-207 individuals/m², while plots grazed in spring and autumn had lowest species richness and abundance (1.9-2.5 species, 16-51 individuals). Delaying mowing from spring to autumn did not have a clear effect on spider species richness or density in July over the three year period (autumn-only: 4.6-5.0 species, 69-99 individuals/m²; spring-only: 4.2-4.7 species, 50-99 individuals). The study took place in an ex-arable field (10 ha) and on old limestone grassland. In 1985, three treatments were applied (ungrazed, short-period spring or autumn sheep grazing) replicated six times in two square 3 x 3 grids of 30 x 30 m paddocks. Spring-and-autumn grazing was applied to larger areas outside the paddocks. Spiders were sampled by suction (using D-vac) and counting webs. Suction samples were taken in various months from May to October each year.