Introduction
- Project description
- Demolition of residential property and construction of single replacement dwelling. A soprano pipistrelle maternity roost was to be impacted by the proposal. An appropriate mitigation strategy was devised and implemented under an EPSM licence and compensatory roosting opportunities installed. Monitoring surveys confirmed continued ecological functionality.
- Ecologist’s name and contact details
- Sally-Ann Hurry, Mountfield Ecology
- Planning authority
- Rother District Council
- Brief site description
- The site covered 0.1Ha and consisted of a single residential dwelling located in an exposed coastal location. The site's associated garden included a small pond, amenity grass, fruit trees and was bounded by mature hedgelines with adjoining amenity gardens. In the immediate locality are several statutory designated sites and these support habitats of scrub, sheep grazed pasture and a network of drainage ditches
Pre-works roost structure
- Type of structure
- Building
- Use
- Domestic Dwelling
- Condition
- In Use
- Main construction material of walls
- Timber
- Roof design
- Flat Roof
- Roof material
- Bitumen
- Internal roof structure
- Not Applicable
- Photos or annotated figures of roost structure
Pre-works roost description
- Species
- Soprano pipistrelle
- Number of bats max count
- 11
- Type of roost
- Maternity Roost
- Evidence of bats
- Droppings Visual
- Roost location
- Other
- Aspect of roost
- Various
- Height of roost entrance (m)
- 2.5-3m
- Roost material(s)
-
- Bitumen Felt
- Nearest commuting feature
- Hedge
- Distance to nearest commuting feature (m)
- 3m
- Photos or annotated figures of roost
Proposed works
- Description of works
- Demolition of original dwelling owing to poor condition of the structure and the owner requiring additional space. There was also a desire to construct a more ethically and environmentally friendly building. It was not going to be cost effective to renovate the original building to meet the need and so demolition was necessary.
- Type of impact upon the roost
- Long-Term Roost Modification and Roost Loss
Proposed mitigations
- Type of mitigation
- Compensation
- Specific technical detail of measure
- A mitigation strategy was devised to cause the least impact to the bats. This included the installation of a timber Kent-style bat box as an alternative roost site, timing the impactful works to avoid the maternity and hibernation periods, carrying out exclusion works and the ecologist overseeing the soft demolition of the roost area and immediate adjoining areas. The demolition works were timed to take place in the autumn, allowing the construction of the new building over the winter and spring period, so that the long-term roost compensatory features could be installed prior to the following bat maternity period. Long-term roost compensation was provided through the installation of two Schwegler 1WQ bat boxes upon the gable ends of the new building. The decision of the type of roost compensation features, considered the site’s exposed coastal location, the ecological requirements and adaptability of the species, client and design preferences and possible future human-bat conflict posed by integrated features. Two boxes were provided in order to create roosting opportunities throughout the year and with differing aspects and associated thermal conditions, similar to the previous roost opportunities. The position of the boxes considered the previous roost location, aspect etc. along with window and skylight positions.
- Relevant annotated figures
- Roost location
- Bat Box
- Aspect of roost
- Various
- Height of roost entrance (m)
- 4.5m
- Roost material(s)
-
- Woodcrete
- Nearest commuting feature
- Hedge
- Distance to nearest commuting feature (m)
- 2
- Photos or annotated figures of roost
Monitoring data
- Length of monitoring proposed
- 2
- Frequency of monitoring
- Once in each year of monitoring, between May to August
- Type of monitoring
- Dusk and Dawn Survey
- Date and time
- 6th August 2019 21:35
- Evidence recorded
- No bats emerged from the bat boxes during a dusk emergence survey and no evidence of bat droppings was found below the boxes.
- Type of monitoring
- Roost Inspection
- Date and time
- 6th March 2020 11:00
- Evidence recorded
- Pipistrelle bat droppings scattered below the bat box upon the NE gable end.
- Type of monitoring
- Dusk and Dawn Survey
- Date and time
- 1st July 2020 21:50
- Evidence recorded
- Pipistrelle bat droppings were adhered to the gable end wall and scattered upon the floor below the SW elevation gable wall. A total of 8 soprano pipistrelle bats emerged from the box upon the SW elevation, with pups audibly heard and seen at the box entrance and mothers returning to feed pups.
Final details
- Lessons learned
- The species adapted relatively quickly to a significant change to the roost structure provided and associated changes to access and locations etc (along with general changes to the site building). However, the retention of the original hedgrows (flight paths) is likely to have attributed to the bats locating the new roost sites, with one of the bat boxes having been installed as close as possible to the original roost access point.
