The effects of scrub management regimes on the spider fauna of chalk grassland, Castor Hanglands National Nature Reserve, Cambridgeshire, UK

Published source details Rushton S.P. (1988) The effects of scrub management regimes on the spider fauna of chalk grassland, Castor Hanglands National Nature Reserve, Cambridgeshire, UK. Biological Conservation, 46, 169-182.
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Summary

The effects of different scrub management regimes on chalk grassland spider communities at Ailsworth Heath, Castor Hanglands National Nature Reserve (National grid ref. TF 0111), Cambridgeshire (southeast England) were assessed over one year using pitfall trapping.

The site comprised grass and scrubland overlying limestone. Management entailed sequential removal of 0.25 ha blocks of scrub so that a series of successional stages of grassland to scrub are present. Twelve sample plots were selected from cleared scrub areas and grassland on which scrub was developing:

1) Four 50 x 50 m scrub plots, cleared at yearly intervals from 1983 to 1986 (i.e. one cleared in 1983, one cleared 1984, and so on);

2) Four 50 × 50 m scrub plots, cleared at yearly intervals (1979 to 1982) and flailed in four successive autumns. The clearance sequence was begun 4 years prior to the above sites so that successional states were comparable;

3) Three approx. 25 × 25 m grassland plots, each separated by 2 years in an 8-year cutting rotation initiated in 1980 (i.e. plots uncut for 2, 4 and 6 years). The final plot (100 × 100 m) was managed as a hay meadow (cut in July, aftermath sheep-grazed).

From August 1986 to October 1987 (excluding November-March), spiders were sampled by pitfall trapping (nine pots/plot, 8.5 cm diameter). Diversity indices were calculated. Vegetation data were derived from an earlier study.

A total of 12,647 spiders (87 species) were caught.Total number of individuals and species caught in relation to time since last cut (years) was:

Cleared scrub: 4 yr - 453 (29 sp.); 3 yr - 1,267 (36 sp.); 2 yr - 2,813 (34 sp.); 1 yr - 1,050 (38 sp.)

Cleared + flailed: 4 yr - 508 (33 sp.); 3 yr - 1,039 (32 sp.); 2 yr - 763 (31 sp.); 1 yr - 1,427 (39 sp.)

Grass cutting rotation: 6 yr - 312 (34 sp.); 4 yr - 326 (30 sp.); 2 yr - 410 (33 sp.); 0 yr - 2,279 (22 sp.)

In scrub plots the number of species caught varied little, and number of individuals and diversities were broadly similar. Most of these plots comprised large areas of tussocky vegetation resulting in similar spider communities. The hay meadow had the lowest diversity and lowest catch of species (22); on the-other-hand it had high abundance of some open ground specialists.

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