Diversity and abundance of the coleopteran fauna from organic and conventional management systems in southern England

Abstract

1 Studies of the epigeal coleopteran fauna on five pairs of organic and conventional farms were carried out between May and July 1994 in southern England using pitfall trapping. A total of 27 749 individuals and 140 species were identified. Overall, abundance of Coleoptera was greatest on organically managed farms. 2 Ground beetles (Coleoptera: Carabidae) and staphylinid beetles (Col. Staphylinidae) formed 79.7% and 16.7%, respectively, of the total catch. Pterostichus melanarius was the dominant carabid among the 45 species captured and significantly higher numbers were found in organic farms. Tachinus signatus was the most common of 44 staphylinid species, and was significantly more abundant on conventional farms. 3 For carabids, the log-series a diversity index was higher on conventional farms but was not statistically different from that calculated for organic farms. The a index was identical for staphylinid species from organic and conventional farms. Diversity was significantly higher from conventional farms when data were combined for all of the recorded coleopteran species. 4 From this study, it appears that the main effect of farming practice is to influence the overall abundance and dominance of particular species, and the lower diversity of organic farms is a consequence of the large increase in dominance of a single species, namely P. melanarius.

Rove beetle (Coleoptera: Staphylinidae) communities in transgenic Bt (MON810) and near isogenic maize

“…We found that H` was relatively high compared to other studies and varied between 2.40 and 3.57. Other authors reported lower value for different agricultural fields (conventional winter wheat 2.2-2.4 reported by Lubke 1991 in Austria; 1.6 in organic and 1.5 in conventional winter cereals in southern England reported by Shah et al 2003). There is no similar report about the diversity from Central European apple and pear orchards under different structural and environmental conditions.…”

“…The Shannon-Weiner (H) and the log series Fisher alpha (ά) diversity index were computed as a measure of biodiversity (Fisher et al 1943;Pielou 1984). The alpha diversity index is considered to be superior to commonly used indices because the sensitivity to sample size is low and uses high discriminate ability (Fisher et al 1943;Shah et al 2003). The maximum likelihood estimate ά can be devided from the following formula:…”

Invertebrate responses to the management of genetically modified herbicide–tolerant and conventional spring crops. II. Within-field epigeal and aerial arthropods

“…Increased and more diverse vegetation have been suggested to be important for their abundance. Shah et al (2003) recorded greater abundances of Carabidae in organic cereals, where there has been shown to be increased weed flora (Moreby et al 1994), than in conventional cereals. Nevertheless, the absolute values of the estimated multiplicative ratio, R, were always less than 1.5, and, consequently, the effect of managing GMHT crops on this family was relatively slight.…”

Field Margins as Rapidly Evolving Local Diversity Hotspots for Ground Beetles (Coleoptera: Carabidae) in Northern China

“…Generally, these results may not seem surprising, as carabids have been well known to react sensitively to differing intensities of agricultural management (Thiele 1977;Kromp 1989Kromp , 1990Andersen and Eltun 2000;Shah et al 2003). More surprising was the speed and extent to which these changes occurred, with more than a third of all species encountered in this study restricted to the newly established field margin.…”