Targeting sites for habitat creation: an investigation into alternative scenarios

To date, habitat expansion in the United Kingdom has been on a case-by-case basis, without consideration of the current state, in terms of biodiversity, or the future sustainability of the habitat reserve. It was hypothesised that spatially targeted habitat expansion is beneficial for habitat and species' persistence. Five spatially explicit scenarios for new habitat creation were devised, each with a different conservation aim: increase habitat patch size, reduce patch perimeter-area ratio, decrease habitat patch isolation, increase biodiversity and ensure sustainability. For beech woodlands in part of the Chilterns Natural Area, UK, we investigated changes to six landscape metrics (total area (TA), patch density (PD), largest patch index (LPI), mean patch size (MPS), mean nearest-neighbour distance (MNN) and mean shape index (MSI)) as a result of the addition of new habitat, in accordance with the level of increase indicated in the United Kingdom's Habitat Action Plan for beech woodland. Significant differences were found between the landscape metrics produced by spatially targeting new habitat and those produced by randomly adding new habitat. Random habitat addition performed poorly when compared with spatially explicit habitat addition even with relatively modest habitat expansion targets. We conclude that spatial targeting of habitat creation can counter the adverse effects of habitat fragmentation.