Most Irish land mammals including bats are originally woodland creatures, although many have adapted to open habitats since woods were cleared.
Small mammals are an important element of woodland habitats. Not only do they add to the overall diversity of a site, but they also act as predators providing top-down pressure and diversity within invertebrate communities. They may also act as prey species for predatory birds.
The small mammal survey was conducted using humane Longworth small mammal traps. Wood mouse Apodemus sylvaticus and Pygmy shrew Sorex minutus were collected in traps in Barna Wood.
In the Biodiversity Survey, evidence of mammal presence and activity was established by recording direct sightings and all field signs( e.g. droppings, footprints, feeding remains, burrows, tracks, etc.) encountered.
Using these methods, sSigns of foxes, badger and otters were recorded at Barna Wood. Otter is a protected species and is listed in Annex II and V of the EU Habitats Directive.
Bats particularly like woodland, although they live in other places as well, because of the abundance of insects available to eat and the variety of niches trees offer for bat roosts (defined as any site a bat uses for shelter and protection).
Provided it has plenty of places for them to roost, any woodland can be home to bats. However, woods that are large, semi-natural, broadleaved, mixed or under-managed, and contain lots of trees with splits, cracks flaking bark and crevices, are more likely to attract bats.
Bats like veteran and ancient trees. Older trees have more roosts than younger ones for the following reasons:
- Potential for roost sites increases with a trees age, size and presence of damage
- Once a tree is used by bats, there is a greater chance it will be used again
Older, ancient, and/or damaged trees usually have lots of nooks and crannies. Rot holes, snags and cracks, gaps made by splits and loose bark, dead and dying wood, behind ivy and other dense climbers, can all make potentially good roost sites.
In the Biodiversity survey, bats were surveyed using a Anabat SD-1 recording detector. This was placed at three different locations throughout the wood, and provides an indication of the species using the wood.
Anabat SD-1 recording detector
Two bat species were recorded in Barna Wood using this method: Soprano Pipistrelle Pipistrellus pygmaeus and a Myotis species that is likely to be Natterer’s Bat Myotis nattereri.