biodiversity in Berkshire
Examples of loss of habitats include:
- Lowland Heath. There has been an 83% decrease in lowland heathland since the 1800s. In West berkshire, heathland used to cover an area of 389km2. By the late 19th century the expansion of Newbury, together with the agricultural improvement of the heathland had reduced the area to 277km2. Commercial afforestation in the early 20th century together with further urban expansion in more recent decades has caused further loss and fragmentation. By the end of the 1990s it is estimated that no more than 58km2 of heathland will remain. Similar patterns of loss and fragmentation have taken place in other heathland areas.
- Hedgerows. Data on hedgerows has been collected by a number of surveys carried out by the Institute of Terrestrial Ecology in 1978, 1986 and 1990. Analysis of these data showed that between 1984 and 1990 hedgerows declined through removal or neglect, at an estimated rate of 22,000km per year. In the period since 1990, the rate of decline was lower, 18,000km per year. Much of this loss can be attributed to the drive for larger fields. Their absolute length, however, is not a good indication of the status of hedgerows as there is a continuous process of planting as well as removal. These recently planted hedgerows are less diverse than established hedgerows, which support over 600 plant, 1,500 insect, 65 bird and 20 associated mammal species.
- Grasslands. The vast majority of all managed grasslands are species poor, improved grasslands. In agricultural landscapes these have replaced species rich neutral, calcareous and acidic grasslands. Between 1930 and 1984, the area of unimproved neutral grasslands decreased by some 97%. The remaining patches of these grasslands are now important reserves of increasingly rare species. Countryside Surveys conducted by the Institute of Terrestrial Ecology indicated that between 1978 and 1990 wild flowers once commonly found in meadows and chalk grasslands had declined significantly. Losses of higher quality meadow habitats have also been recognised. While meadows are being created in an attempt to balance this loss, they are of a lower quality than the mature meadows.