Mapping to inform conservation: A case study of changes in semi-natural habitats and their connectivity over 70 years

Intensification of human activities has caused drastic losses in semi-natural habitats, resulting as well in declining connectivity between remaining fragments. Successful future restoration should therefore increase both habitat area and connectivity. The first steps in a framework for doing so are addressed here, which involve the mapping of past habitat change. We present a method which is unique in: the large area covered (2500 km(2)), the high resolution of the data (25 x 25 m), the long period assessed (70 years), and a system for translation of land use maps into Broad Habitat Types using soil surveys. We digitised land use maps from the 19305 for the county of Dorset in southern England. The resulting map was compared to the UK Land Cover Map of 2000. For our example area, land use shifted dramatically to more intensive agriculture: 97% of all semi-natural grasslands were converted into agriculturally-improved grassland or arable land as were large proportions of the heathlands and rough grasslands (-57%). The other important driver of change was afforestation (+25%). The larger habitat areas became fragmented, with average fragment size of different habitats falling by 31-94%. Furthermore, the connectivity between fragments dropped drastically, by up to 98%. Analyses such as those presented here not only quantify the scale and pattern of habitat loss, but are important to inform land-use planning to restore biodiversity by both increasing the available habitat and facilitating dispersal among habitat fragments. We discuss the possible steps for such a framework. (c) 2011 Elsevier Ltd. All rights reserved.