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Trees are an essential part of the environment, providing a wide range of ecosystem services. Trees also provide food and shelter for wildlife. Cavities, splits and hollows, which were historically described as ‘defects’, are now known to provide habitat for numerous wildlife species. Among the wildlife species which use trees for shelter are bats, with 14 of the 17 UK bat species known to roost in trees. Despite the high level of legal protection, recent research has highlighted the difficulties of effectively surveying trees for bats. Bats frequently move roosts making it difficult to know if a tree is used by bats. As bat roosts are protected whether bats are present or not, this has serious implications for tree management. There is a growing number of ecologists who climb trees to look for bats and also a growing number of arborists developing an increase in ecology.
Bats and Trees - Speakers
University of Wolverhampton
Never underestimate a Potential Roost Feature
During routine pre-parturition monitoring of a known large maternity roost of noctule (Nyctalus noctula) bats with a previous (post-parturition) peak count 68 individuals, we observed and recorded 28 individual noctule bats emerging from a feature. This emergence was followed by the subsequent emergence of 51 Daubenton’s bats (Myotis daubentonii). Shared maternity roosts of this size have not been previously recorded. Later in the season, the entire limb supporting the roost feature (a north-facing knothole) came down in a storm. This afforded us the opportunity to create a transverse section of the entire feature, providing detailed schematics of the dimensions of characteristics of the 6m feature, including roosting locations of each species. We present the data including infra-red and thermal footage of the emergence. While inter-species cohabitation in roosts has been recorded before in some species in small numbers, this is the first record of a shared roost of this type and size between these two species, and a unique insight into the structure of a significant roost feature at the time of use.
Managing bat roosts in trees; an arborist’s perspective
Managing trees with bat roosts is a challenging activity, requiring close working between the ecologist and arborist. An detailed understanding of both bat roosting ecology and tree management are required if the work is to be planned and executed safely and without impacts on bats. But how effective is communication and partnership working at present, and what could be improved? Lee is a bat licensed arborist, specialising in habitat management. He will share some of his experiences managing trees with bats and share what works and where improvements are needed.
New approaches to surveying trees for bats
Through recent research, standard survey techniques used to determine whether a bat roost is present in a tree have been shown to have significant limitations. Guidance provided in the seminal ‘Bat Roosts in Trees’ book requires a significant increase in survey effort compared to the Bat Conservation Trust’s ‘Bat Surveys for Professional Ecologists: Good Practice Guidelines’. How do we address these limitations whilst not increasing an excessive financial burden? Jim will share new the results of an on-going research project which aims to improve the quality of surveys whilst not breaking the bank.
Can we create bat roosts in living trees?
Effective mitigation and compensation techniques are essential components for the conservation of any species. Despite good intentions, the success of most bat mitigation is either limited or not proven. To further complicate things, options for compensating for the loss of bat roosts in trees are almost entirely limited to the provision of bat boxes. The loss of old and hollow trees is cited as a reason for the decline of several of tree specialist bat species. With limited options of how to replace these lost roosts, how do we ensure the survival of these bat species? There is a growing interest in creating bat roost features in trees, however few studies have assessed the efficacy of these. Sean will outline the aims of an on-going research project which seeks to improve the prosects for tree roosting bat species.
Climb and Inspection: ecologists and arborists working together
- Potential Roost Features:
- where have bats been found
- survey notes: what should be recorded
- Mitigation types, installation and monitoring
- Ecologists and arborists combined forces are best
- Felling of roost trees under a European Protected Species Licence (EPSL)
- “standard” approach
- excluding bats
- working with bat in situ
- Unexpected Finds.
Two rope working and new technical guides in arboriculture; climbing and aerial rescue (TG1)
The evolution of tree climbing techniques and the guidance to support climbers, their supervisors and managers has developed considerably in recent years. Driven by technical innovation, arboricultural ingenuity and regulatory pressure, the standards expected, for both professional practice and legal compliance, have raised the bar beyond the expectations of many.
This presentation will set the scene for these developments and describe the key changes to professional tree climbing practice, as set out in the new suite of Technical Guides produced by the Association.