Edge structures and edge effects on plants and birds in ancient oak-hazel woodlands

Structural differences between centres and edges of ancient oak-hazel woodlands within a conifer forest matrix were established and significant differences were related to the occurrence and abundance of vascular plants and birds. The edges did not demonstrate any higher abundance of dead trees, fallen limbs or branches or stumps. However, edges kept a higher proportion of young deciduous trees. The frequencies of invading plant species from the conifer forest were negatively, and of total bird species positively, related to the proportion of large old trees in the edges. Total number of plant species, woodland plants, or breeding pairs of birds were not clearly related to the proportion of old trees. Light-excluding bushes and young trees may favour conifer forest plants adapted to a similar dark environment. Old trees may provide more niches for temporary exploitation by mobile birds. Thus, the more rapid tree regeneration at forest edges should be circumvented by selection of large reserves, suitable juxtaposition of similar habitat types or by management particularly directed against excessive tree regeneration.