When considering conservation, we tend to immediately recognise designations such as Site of Special Scientific Interest (SSSI), country parks, local nature reserves and maybe even sites that have local designations, often called Local Nature Conservation Sites (LNCS) or Sites of Importance for Nature Conservation (SINC). There are of course many places that wildlife can thrive away from designated sites, ask any gardener. But maybe former industrial land is not the sort of location that springs to mind.
Yet it is now recognised that these sites, often designated as vacant or derelict land (VDL), can be a rich habitat, especially for invertebrates that are constantly under threat in managed urban environments. Buglife is a pioneering charity in the UK that has raised the profile of these areas by highlighting their value as habitats and their relationship to healthy and bio-diverse environments.
A specific habitat type, open mosaic habitat (OMH) has been defined that describes the sort of previously developed land that is rich in invertebrates and plants, and supports some uncommon and rare species. It is characterised by a patchwork of bare, previously disturbed ground and grassland or heath vegetation on thin, poor soils. As Open Mosaic Habitat on Previously Developed Land (OMHPDL), it is a UK biodiversity Action Plan habitat.
But OMH can be constantly under threat from the re-development of land and the consequential loss of habitat will mean the loss of the less mobile species that were associated with it. Buglife has developed a ‘stepping stones’ concept to encourage the retention of enough local OMH to allow species to move from one patch to another if they come under threat. However, in order to manage the sustaining of this habitat, we need to better understand the potential resource locally so that appropriate strategic decision making can be made.
Central Scotland Green Network Trust (CSGNT) has analysed the presence of OMH on VDL, the recording of which has been done by Buglife through funding from the CSGN Development Fund. CSGNT’s work has highlighted the fact that where OMH is evident on sites, these sites are far more likely to be in the range of between 10 and 20 years from when they were first classed as VDL. This relationship is consistent with more academic research recently carried out in Germany where it was shown that sites achieve their highest conservation value at around 15 years. It is also backed up by ecological knowledge of habitat succession which suggests that beyond this point, shrubs and trees start to dominate the lower growing species and these plants and more open ground is lost and shaded out.
The distribution of VDL sites shows a numerical peak coming onto the register in the period 2006 to 2010; a direct result of the economic downturn. This suggests that there may well be a short-term increase in OMH as more sites hit the 10+ years mark than are either re-developed or where OMH is lost due to habitat succession. So a boom time for OMH may be on the cards. But this should not mask the underlying need to ensure local species populations are sustained by allowing them to step from one location to another and, where possible, to actively manage the best habitats.
CSGNT will continue with its analysis of VDL and in doing so help to highlight the areas where these important species and habitats can thrive.