An empirical, cross-taxon evaluation of landscape-scale connectivity

Connectivity is vital for the maintenance of spatially structured ecosystems, but is threatened by anthropogenic processes that degrade habitat networks. Thus, connectivity enhancement has become a conservation priority, with resources dedicated to enhancing habitat networks. However, much effort may be wasted on ineffective management, as conservation theory and practice can be poorly linked. Here we evaluate the success of landscape management designed to restore connectivity in the Humberhead wetlands (UK). Hybrid pattern-process models were created for six species, representing key taxa in the wetland ecosystem. Habitat suitability models were used to provide the spatial context for individual-based models that predicted metapopulation dynamics, including functional connectivity. To create models representing post-management conditions, landscape structure was modified to represent local improvements in habitat quality achieved through management. Models indicate that management had limited success in enhancing connectivity. Interventions have buffered existing connectivity in several species’ habitat networks, with inter-patch movement increasing for modelled species by up to 22% (for water vole, Arvicola amphibius), but have not reconnected isolated habitat fragments. Field surveys provided provisional support for the accuracy of baseline models, but could not identify predicted benefits from management interventions, likely due to time-lags following these interventions. Despite lacking clear empirical support as yet, models suggest the management of the Humberhead wetlands has successfully enhanced the landscape-scale ecological network, achieving management targets. However we identify key limitations to this success and provide specific recommendations for improvement of future landscape-scale management. Our developments in model application and integration can be developed further and be usefully applied to studies of species and/or community dynamics in a range of contexts.