Increasing connectivity in fragmented landscapes: An investigation of evidence for biodiversity gain in woodlands

Increasing connectivity is frequently proposed as an effective strategy to address biodiversity decline within fragmented habitats. Woodland habitats in Great Britain have been significantly reduced in area and are described as having 'fragmented' distribution. Many researchers have associated declines in woodland species with fragmentation. Currently, there is a concerted effort to increase connectivity (through increasing the number of physical links) between woodlands, often through the development of habitat networks, with the aim of increasing biodiversity. This aim is driven through rising interest in the role of landscape scale processes in biodiversity conservation and increasing concern of the fate of populations facing a predicted increase in habitat isolation through climate change. In this paper, the evidence behind the assumption that increasing connectivity will increase biodiversity is reviewed, together with the assumptions made during development of models that identify potential networks within which connectivity is to be increased. Gaps identified within the evidence base lead to the suggestion of new research areas that will provide a firm basis from which more informed evaluation of increasing connectivity for biodiversity gain can be developed. Alternative approaches to enhancing woodland biodiversity in fragmented landscapes are proposed. (c) 2006 Published by Elsevier B.V.