Ecosystem service provision in dynamic heath landscapes.

Abstract

Conservation policy and management is undergoing a step-change, moving from focusing conservation resources on individual sites such as protected areas, to include the wider landscape. Landscape-scale initiatives may focus on either managing the entire landscape or they may focus on managing particular sites but attempt to address landscape-scale patterns and processes, such as habitat fragmentation. Whilst there is a vast body of research investigating the impacts of habitat fragmentation on individual species, much less is known about the impacts of habitat fragmentation on ecological processes, for example woody succession. Woody succession is an ecological process which has particular implications for conservation management as it drives ecosystem dynamics which can alter the value of the habitat for species of conservation concern. At the same time there is a move to incorporate ecosystem service protection into conservation policy. Understanding the synergies and trade-offs that exist between biodiversity conservation and ecosystem service provision is therefore an important priority. Few studies have examined the influence of habitat fragmentation on woody succession and, in turn, the impact of woody succession on the value of the habitat for both biodiversity conservation and ecosystem service provision. In addition, there is still very little evidence suggesting to what extent areas managed for biodiversity conservation also provide ecosystem services. There is a need to understand how management approaches aimed at increasing the biodiversity value of conservation areas will impact ecosystem services, particularly at the level of the landscape. This thesis aimed to explore all these themes in the Dorset lowland heathlands, UK. The Dorset lowland heathlands are highly fragmented and a priority habitat for nature conservation because they are rare and threatened and support a characteristic flora and fauna. The main threat to this habitat is now woody succession. Without conservation management, the characteristic dwarf shrub heath undergoes succession and is replaced by scrub and woodland. The objectives of this thesis were to (1) assess the impact of fragmentation on the process of succession on lowland heathlands and quantify lowland heathland vegetation dynamics; (2) determine biodiversity and ecosystem service values of major cover types along a successional gradient on lowland heathlands and assess how trade-offs and synergies between biodiversity and ecosystem service provision vary along this gradient and (3) explore how alternative management approaches aimed at increasing the biodiversity value of lowland heathlands impact ecosystem service provision. Fragmentation was found to promote succession with smaller heaths undergoing succession faster than larger heaths. Trade-offs were found between biodiversity value and ecosystem service provision. Biodiversity value was highest in heath habitats and lowest in woodland. Carbon storage, aesthetic value and timber value were highest in woodland. However, recreation value was associated with heathland habitats and not woodland. Conservation management for biodiversity increased the biodiversity value of lowland heaths but not the provision of ecosystem services.