Management and diversity of arthropods in Calluna heathland

Published source details Usher M.B. (1992) Management and diversity of arthropods in Calluna heathland. Biodiversity and Conservation, 1, 63-79.
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Summary

Heathlands and moorlands dominated by heather Calluna vulgaris, are confined to Western Europe. Management by fire or cutting generally aims to restart the growth cycle by burning mature phase heather (at the stage when production is declining) and prevent colonization by trees. Managed upland heathland (moorland) is generally burnt at 20 to 25 years of age, before heather plants become degenerate. Burning, and opening of the canopy, stimulates heather seeds to germinate. The study described here investigated the effects of age of heather, in combination with burning or cutting management on invertebrate community composition.

Study area: The research was undertaken on the North York Moors National Park (54º25’N, 0º55’W), northeast England, at numerous sites on three grouse moors: Danby Low Moor (260 m), Danby High Moor (410 m) and Kildale Moor (270 m).

Danby Low Moor - 10 in heather; 6 burnt, 6 cut;

Danby High Moor - 10 in heather; 6 burnt, 6 cut;

Kildale Moor - 5 in heather; 5 burnt.

Invertebrate sampling: Invertebrate communities were assessed during the summers and autumns of 1987 and 1988 using three methods:

Pitfall trapping - 8 traps/site, opened for 1 week in every 4 week period;

Water traps - 21 white plastic containers, containing approximately 1 cm of detergent solution were sited approximately 40 cm above the heather canopy, on a flat board secured to a post; 4 traps/site, each active for 2 days in every 4 week period;

Suction sampling - using a D-VAC vacuum sampler when the heather was dry, approximately once every four weeks.

Analyses focused on two abundant arthropod groups, ground beetles (Coleoptera: Carabidae) and spiders (Arachnida).

A total of 54 ground beetle species (6,336 individuals) were trapped, the five most abundant species contributed to over half (54.2%) of all individuals: Trechus obtusus 21.0%, Calathus melanocephalus 11.1%, Carabus problematicus 8.7%, Nebria salina 8.0% and Olisthopus rotundatus 5.4%.

A total 127 spider species (8,160 individuals) were trapped. The five most abundant species contributed to about a quarter (24.5%) of individuals: Pirata piraticus 6.9%, Lepthyphantes zimmermanni 5.1%, Robertus lividus 4.4 %, Pelecopsis mengei 4.1% and Gnaphosa leporine 4.0%.

Analysis of spider and beetle data showed that whilst there was a clear separation of the heather community between burnt and cut areas, species assemblages were primarily influenced by the heather growth-phase. Some nationally rarer species found are associated with open conditions of recently cut or burnt areas. An altitudinal effect was evident; moorland at 410 m above sea level tended to be less species-rich than heathlands at c. 260 m.

Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at: http://www.springerlink.com/content/k1287834236551u7/fulltext.pdf