Lesser horseshoe bats (Rhinolophus hipposideros) are under threat in the UK. Emma Stone, a PhD student at the Bat Ecology and Bioacoustics Lab of the Mammal Research Unit at the University of Bristol investigates.
Bats are good indicators of countryside health as they eat massive numbers of insects. If we are using lots of pesticides, there isn’t as much prey, and we see the numbers and types of bats falling. They also need mature hedgerows for their prey, so if bat numbers are dropping, it is a good indication that local biodiversity is dropping.
Emma is testing the impact of street lighting on a rare species of UK bat, the lesser horseshoe bat. She has a bank of lights she can set up where bats are known to forage at night to see how light affects their behaviour. It was thought the lights might attract insects and the bats would feed, but bats are of course nocturnal and so are averse to light. During the day they would be vulnerable to predators and similarly, artificial lights could make them vulnerable to predators such as barn owls. Lesser horseshoe bats have been found through this research to be threatened by expansion of street lighting.
Much of the countryside is a difficult place for wildlife to survive as it is farmed very intensively; the remaining areas that are left wild are often the in-between bits of land that aren’t being actively farmed. They may be adjacent to roads that are increasingly being lit. Initial research indicates that if there is significant lighting, it discourages the bats from using the area. It does not necessarily mean they move somewhere else, but potentially they do not feed enough to reproduce. This is the first time this research has ever been done, and it has shown for the first time the threat of street lights to bat populations. Emma has worked so far from North Wales to the tip of Cornwall, where there are populations of lesser horseshoe bats.
Partners: Bat Conservation International, Natural England, ARUP, Countryside Council for Wales, CSA Environmental Planning, Jacobs Ltd, DW Windsor, Dulverton Trust.
Wetlands: important foraging habitats
Many species of bat, including Bechstein’s bat (Myotis bechsteinii), Barbastelle bat (Barbastella barbastellus), soprano pipistrelle (Pipistrellus pygmaeus), noctule (Nyctalus noctula) and the lesser horseshoe bat depend to some degree on the presence of high-quality freshwater habitats and the diverse insect communities they sustain. The soprano pipistrelle is known to feed predominantly on insect species that live in and around freshwater habitats. Through supporting the work of The Ponds Conservation Trust One World WIldlife hopes to increase the quality of foraging habitats for these bat species.
Protected roost in Oxfordshire
In 2003, One World Wildlife funded the construction of two barriers at either end of a disused railway tunnel in Horspath, near Oxford, that acts as an important over-wintering site for a range of declining or endangered bat species. One World Wildlife provided grilles that do not obstruct access to bats across the entrances, ensuring these ecologically important animals will remain undisturbed. Their numbers and diversity should increase with time as has occurred at a similar site in the village of Chipping Norton, Oxfordshire. As a result of the actions of the Oxfordshire Bat Group, the endangered lesser horseshoe bat now overwinters at Chipping Norton. The Horspath site will be continually monitored by members of the Oxfordshire Bat Group.
We undertake ecological monitoring of threatened species or of those whose current status is unclear. We have, for example assisted in monitoring and have located populations of the rare moth species the buttoned snout (Hypena rostralis) and the four-spotted moth (Tyta luctuosa). Similarly we are consulted on habitat management schemes including a large-scale wetland creation project and long-term management planning for land owned by another UK-based trust.
Small mammal research – UK
A grant from One World Wildlife also enabled The Northmoor Trust to purchase a significant number of Longworth small mammal traps. Importantly, these do not harm the animals they capture. The traps have allowed this important organisation to monitor populations of small mammals on their conservation research farm and to make agricultural policy recommendations based on their findings. We intend to support an ongoing research project looking at, for example, mobility and colonisation of newly created woodlands by invertebrates and changes in plant diversity resulting from more environmentally friendly agricultural practices. One World Wildlife considers that more sustainable and more environmentally friendly farming is the way forward and is keen to encourage and support similar work. We believe that alternative approaches developed as a result of research such as that undertaken by The Northmoor Trust will benefit a host of rare and endangered animals and plants, the people employed on the land and the many of us who value the British countryside.