Did the bat cross the road?
by Domhnall Finch
Movement ecology is fast becoming a key aspect to species conservation; not only do we need to know which habitats species occur in or are abundant within but we also need to identify how they move between these habitats. This issue is becoming ever more critical with the rapid expansion of urbanisation and intensification of agricultural practices acting as barriers or large ‘deserts’ of unsuitable habitat causing fragmentation at a landscape scale. These challenges are particularly important for mobile species such as bats.
Due to these pressures, my PhD research aims to inform landscape scale management of the greater horseshoe bat (Rhinolophus ferrumequinum). This PhD is in association with the University of Sussex, Devon Wildlife Trust and the Vincent Wildlife Trust. As part of this work, we are using experimental designs to mimic the impacts of traffic noise as well as streetlights on bat activity and behaviour. To test the impact of traffic noise on bat activity we created a phantom road by playing traffic noise through speakers along linear features that had not been exposed to such noise before. Our results suggest that traffic noise alone affects both activity and feeding levels of the entire bat community; highlighting yet another mechanism to which roads can act as barriers to the movement of bat species.
Currently there is overwhelming evidence that bat communities are strongly affected by light pollution. To try to reduce such impacts, this summer we have been testing new ‘eco-friendly’ streetlights on bat activity, particularly for the highly light sensitive greater horseshoe bat. For this, we created a phantom street in the environment erecting streetlights with either ‘normal’ white LED streetlights on them or new red lights (a description of a similar project can be found here https://royalsocietypublishing.org/doi/10.1098/rspb.2017.0075). We are currently working our way through the data now and hope to have the results of this experiment very soon.
The more we learn about the impacts of anthropogenic pressures, such as lights or traffic noise, the more we can strategically plan to limit their impact on our landscape. For this, we are currently developing a predictive tool to investigate functional connectivity within the landscape for greater horseshoe bats. We hope that this tool will allow authorities, such as county councils, to visualise where the bats might be flying, which routes they are taking at a landscape scale and how best to plan future developments. We hope that these sorts of innovative designs can help us mitigate the impact of anthropogenic pressures on nocturnal species, increasing free movement at a landscape scale. Resulting in higher connectivity between habitats and meta-populations in the environment.
One of the best things you can do to help bats from the comfort of your home is to turn off the lights! If you can’t turn off your indoor lights, at least consider turning off outdoor lights when they’re not needed, and keeping curtains closed to prevent your indoor light from spilling out into the night.
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