Naturindholdet i hegn på økologiske og konventionelle bedrifter

Abstract

Many attempts have been suggested to reduce the impact of modern conventional farming on the environment and semi-natural ecosystems. One of the attempts has been to introduce organic farming, which is known primarily for the absence of pesticides and artificial fertilising. The objective of this paper is to present differences found in the spontaneous vegetation and associated arthropods of comparable hedgerows situated within organic and conventional farming systems. We found significantly more plant and moss species in organic hedges, both in the individual plots, the individual hedges and when comparing the farming systems. Six species (Brachythecium rutabulum, Cerastium fontanum, Ranunculus repens, Cirsium arvense, Sonchus arvensis, Plantago lanceolata) were found to be indicators of organic hedges. Arthropods were distributed in relation to the same parameters as the flora (mainly soil characteristics and farming practice). However, differences between the two farming systems were smaller than for plants. The occurrence of herbivorous groups as a total correlate significantly with the major plant gradients and weevils correlate significantly with grass lay fields beneath the hedges and organic farming. Psylloidae, Syrphidae and the weevils (Curculionidae) Ceutorrhynchus floralis and Apion virens proved to indicate organic farming