Habitat change and woodland birds in Britain: implications for management and future research

There is increasing evidence that changes in habitat structure in the form of reduced understorey and loss of open habitats, both probably a result of increases in shading and deer browsing, may be responsible for causing recent changes in the composition of breeding bird communities in many lowland British woods and forests. In contrast, management of upland coniferous forests may prevent the attainment of mature and old-growth structures which would benefit community development in these new ecosystems. We suggest that the key challenge for woodland conservation policy is to create larger areas of both young-growth and old-growth habitat. These objectives need not necessarily conflict with each other, or with other multipurpose forestry objectives, provided that they inform strategic plans and are targeted at appropriate locations and scales. In the lowlands, the current large stock of middle-aged, often unmanaged and species-poor woodland provides an opportunity to restore or create new woodland habitats of high biodiversity value. The development of woodfuel markets may effectively increase the amount of young-growth but it is unclear exactly what habitat structures might be created. In the uplands, allowing more natural development of native woodland in mosaics with other habitats may provide opportunities for both old- and young-growth species. For the foreseeable future, deer impacts will continue to be widespread and probably increasingly severe in many areas. In view of the uncertainty about the implications of climate change for woodland ecosystems, a strong case can be made for attempting to buffer valued wildlife communities against damaging effects by creating and maintaining high structural diversity at a range of scales and increasing the area of woodland.