The Ecology of Short-rotation Coppice Crops: Wildlife and Pest Management.

Abstract

I conducted field-based ecological studies in short-rotation coppice (SRC) willow and poplar crops in Britain and Ireland from 1992 to 1998. SRC crops are now being grown commercially on farmland as a renewable energy source. The studies aimed to investigate the status of wildlife including weed and insect pests in SRC and to provide the basis for management recommendations that maximise biodiversity potential and reduce the risk of pest damage. Using a database of 50 SRC sites planted before 1993, extensive surveys and intensive single-site monitoring and experimentation were undertaken.
Compared to other crop types, breeding songbirds were abundant in the SRC plots. Densities and species composition were affected by the age and structure of the crop. More invertebrate groups were recorded from the canopy of willow than poplar SRC. The most widespread and damaging herbivorous insects on both were leaf beetles (Coleoptera: Chrysomelidae). The diversity of other plants within the SRC plots was high for agricultural land and was affected by land use and plantation age.
Older plantations near accumulations of certain wild willow or poplar trees were particularly susceptible to damage by leaf beetles, enabling high-risk sites to be avoided or accommodated at the planning stage. Descriptions of winter dispersal behaviour, spring re-colonisation and movements within plantations by these potential pests provide the basis for control that avoids the need for overall insecticide sprays.
A ground-f1ora succession within SRC plantations over several years from competitive weed species to slow-growing perennials was identified. The impact of competition by other plants on crop-biomass accumulation was quantified for a typical established SRC site. These data enable economic thresholds for control to be calculated and indicate that established crops in some situations could tolerate substantial weediness. The potential biodiversity benefits of limited pesticide use in SRC crops are discussed.