Humphrey J, Watts K, Fuentes-Montemayor E, Macgregor N & Park K (2013) The evidence base for ecological networks: lessons from studies of woodland fragmentation and creation. Report from the WrEn Project, Forest Research, Farnham, Surrey. The Research Agency of the Forestry Commission. http://www.stir.ac.uk/media/schools/naturalscience/bes/images/WrEN_FR_report_2013.pdf
Landscape-scale conservation and ecological networks form a major component of policy responses to biodiversity loss in fragmented landscapes in the UK and other countries. Ecological networks are typically conceptualised as a suite of core areas of habitat connected by buffer zones, corridors and smaller stepping stone patches that allow movement of species or their propagules. Many conservation actions are now being targeted towards the establishment of ecological networks. Site or local level actions are aimed at restoring, improving and expanding existing habitats, while landscape level actions focus more heavily on creating new habitats, establishing corridors/stepping stones and improving the matrix between habitat patches. There is on-going debate about the relative merit of, and balance between, these alternative conservation actions. The evidence needed to inform the targeting of actions towards particular network components, or combinations of components, is lacking. This uncertainty appears to be hindering the implementation of effective ecological networks on the ground. A large number of test projects to implement landscape-scale ecological networks have been established, but it will be many years or decades until they can provide the necessary evidence base. However, lessons can be learnt from ecosystems with a long history of habitat loss and fragmentation followed by many decades of habitat creation and restoration, such as woodlands in temperate agricultural landscapes. This review forms part of a wider project (WrEN) aimed at extending the evidence base underpinning the implementation of ecological networks. Particular emphasis is given to reviewing studies of the impact on biodiversity of past woodland creation and secondary1 woodland development.