Habitat changes in the British lowland landscapes and their implications for bird populations

by Rob Fuller

5. Expansion of the built environment

Britain is becoming an increasingly developed country yet the implications for birds and other wildlife are not well understood (Hill et al. 1997). Where particular development schemes involve the direct destruction of habitats such as such as heathland, downland and ancient woodland it is possible to quantify the loss of habitat and the populations that will be affected directly. The effects of many developments are not, however, confined to the actual land on which they are situated.

The construction of large roads or the increase of traffic volume on existing roads may have several effects on birds. These include increased mortality through road deaths and deterioration of habitat quality as a result of pollution, visibility of cars and traffic noise. Work in The Netherlands (Reijnen et al. 1994a,b, 1995) indicates that reduction in habitat quality as a result of traffic noise is a major factor leading to lower densities of several woodland bird species close to major roads.

Another indirect effect of road construction and elevated traffic levels is that more carrion is available for scavenging birds. This increase in carrion is probably not entirely attributable to extra traffic volume because there have been recent increases in numbers of deer, rabbits and released gamebirds in many areas. Nonetheless, Magpies and Crows in particular have benefited from this increased food resource and this may be one factor that has facilitated their population increases.

Increasing levels of human recreation is another issue that should be considered as a by-product of certain developments such as some housing schemes close to sensitive areas. It is not intended to give a review of the effects of human disturbance here but it should be recognized that some species are potentially vulnerable to disturbance, especially in open habitats such as heaths and moors.

In conclusion, the increasing urbanization and development of the countryside and its effects on wildlife is an issue that deserves more attention in the future.