Domhnall Finch is a post-doctoral researcher at the University of Sussex. His research focuses on remote sensing, bioacoustics and movement ecology of bats, birds and mammals. Examining what acts as barriers to species movement and identifying practical solutions to maintaining landscape connectivity.
Original article: https://link.springer.com/article/10.1007/s10980-019-00953-1
Improving functional connectivity within the wider landscape has been identified as a critical conservation concern and an ever-pressing issue to allow species to cope with the anthropogenic effects of climate change and habitat fragmentation. These impacts, which are largely driven by industrialisation, urbanisation and agricultural change, have implications at an individual and population level. The consequences include isolation from habitats necessary for foraging, resting or community dynamics which influence gene flow; resulting in population declines and greater vulnerability to extinction. The identification of landscapes or habitats that provide high functional connectivity for vulnerable species has the potential to focus and spatially target resources to have the highest net gain for biodiversity.
However, many studies examining issues around connectivity focus on large scale movements or migrations of species, e.g. across entire countries, using coarse data resolution; but local scale changes to the landscape, e.g. a new development or individual lighting fixtures, could also significantly affect those daily dispersal patterns of vulnerable species between their habitat networks. Our research, using greater horseshoe bats (Rhinolophus ferrumequinum) as a model species, demonstrates that spatial accurate functional connectivity models can be created at a local scale using fine data resolution.
Greater horseshoe bat populations have undergone a dramatic decline over the last decade in North West Europe. This has mainly been attributed to land-use change, which is likely to vary at a local scale. In the face of heightened pressure from the cumulative effects of multiple new developments, the identification of wildlife ‘pinch-points’ in landscapes, where such developments are most likely to cause significant negative impacts, is essential. These alterations can lead to a loss of landscape permeability, reducing connectivity between both foraging grounds and meta-populations.
Using both bat activity and radio tracking data, from greater horseshoe roosts in Devon, we empirically validated functional connectivity models. Our results showed that the model predictions are better than expert opinion at identifying the locations of strategic conservation corridors; as well as having the ability to detect ‘pinch-points’ that are critical to the species movement and dispersal into the wider landscape. This research highlights that, within the first hour after sunset, the activity of light sensitive bats, such as greater horseshoe, will be more tightly constrained to hedgerows and features that are more sheltered. This means that individual streetlight placements can have a major impact on the overall functional connectivity of the study areas, with the ‘current’ of bat movements passing through narrow corridors of suitable dispersal habitat. The models also highlight that the greater horseshoe bat can be used as an umbrella species to aid the conservation of other bat species that do not have the same legal protection.
The results of such functional connectivity modelling can have the potential to facilitate evidence-based policy and management. The resultant models can help planners and conservationists reduce human-wildlife conflicts, by applying mitigation measures strategically at locations likely to be most sensitive to species movement and future land-use change. By highlighting landscape features that act as barriers to movement, this approach can be used by decision makers as a tool to inform local management strategies.