The response of heteroptera and coleoptera species to shade and aspect in rides of coniferised lowland woods in Southern England

The results of this study support the conclusion from studies on butterflies, namely that rides must be actively managed to keep light levels high if species richness and abundance are to be maintained.

Abstract

The relationship between shade and aspect and the species richness and abundance of Heteroptera and Coleoptera (Chrysomelidae and Curculionoidea) was examined in the rides of coniferised ancient woodlands. A total of 83 species of Heteroptera, and 31 and 58 species of Chrysomelidae and Curculionoidea respectively, were identified from samples taken from nine woodland sites in southern England. Shade, both direct and indirect, was measured by hemispherical photography. Regression models for each insect group related species richness and abundance to shade and inherent wood differences. Indirect shade was at least as good a predictor as direct shade. Both species richness and abundance declined with increasing levels of shade. Shrub-associated Heteroptera appeared in general to be more shade-tolerant than herb-associated species. The opposite was true for the Coleoptera, but numbers were generally small. Some significant relationships with aspect were found with several species showing an apparent preference for south-facing aspects. The results of this study support the conclusion from studies on butterflies, namely that rides must be actively managed to keep light levels high if species richness and abundance are to be maintained.