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Soprano Pipistrelle Maternity Roost in The New Forest

ECOSA was appointed to undertake an ecological assessment of a property in the New Forest, for which further bat surveys confirmed the presence of a soprano pipistrelle maternity roost. Through close liaison between ECOSA, the client, the New Forest National Park Authority and Natural England, the proposed works were undertaken in compliance with planning policy and legislation, and the best outcome for both the client and the maternity roost was achieved.

Objective: Alterations and upgrades to a cottage including works to the roof

The client had identified that remediation works were required to a roof of a cottage located in the New Forest and ECOSA was appointed to undertake an Ecological Impact Assessment of the site to support a planning application for this work. During the Preliminary Ecological Appraisal survey, the cottage showed signs of being highly suitable for roosting bats, with bat droppings recorded around possible access/egress points on the roof. Bats could be heard within the building and the client confirmed regularly seeing large numbers of bats emerging from the roof. Bat droppings were sent to a lab for DNA analysis and were found to belong to soprano pipistrelle Pipistrellus pygmaeus.

All bat species are designated as European Protected Species and are protected under the Conservation of Habitats and Species Regulations 2017 meaning it is an offence to deliberately kill, injure, disturb or capture bats and damage or destroy their breeding sites and resting places. It is also an offence under the Wildlife and Countryside Act 1981 to intentionally or recklessly disturb bats while they occupy a structure or place used for shelter or protection or obstruct access to a place of shelter or protection. Therefore, bat surveys were necessary to determine the nature of the bat roost present and the potential impacts of any works undertaken.

Following best practice guidelines three roost characterisation surveys comprising two dusk surveys and one dawn survey were undertaken between July - August 2022 on the cottage. The surveys confirmed the presence of a high-status soprano pipistrelle maternity roost with a peak count of approximately 250 bats roosting within the cottage. Other species recorded foraging and commuting around the site included common pipistrelle, noctule, long-eared bat, serotine, Myotis species and barbastelle.

The works to the cottage therefore posed a particular challenge as although it was clear that remediation works to the roof were required, the exact nature of the remediation could not be determined until the roof tiles had been removed and the state of the roofing materials underneath could be fully inspected by the relevant professionals. For this reason there was an element of uncertainty regarding the ultimate nature of the works. In addition, bats are highly loyal to their maternity roosts and use them in large numbers during the summer months, before dispersing to hibernation sites over the winter. Therefore, to minimise the risk of harm to individual bats and the risk of the maternity colony permanently abandoning the roost, it was very important that the roost location was not affected during the summer. Where works were undertaken outside of this period, when the maternity colony is absent, it was key that the roost location was fully reinstated by 1st May, before the colony returned to use the roost in the following breeding season. This meant that a large number of administrative and practical tasks had to be achieved within a narrow timeframe.

First, a European Protected Species Mitigation (EPSM) licence was sought from Natural England. The EPSM license was necessary because the proposed works to the roof would result in the loss of the maternity roost and possibly in the killing/injury of bats. This is an offence under Regulation 43 the Conservation of Habitats and Species Regulations 2017 (as amended). Regulation 55 of these regulations allows otherwise illegal activities to be undertaken where a licence has been granted. The licence was sought for investigative works to the roof of the cottage, allowing the removal of the roof tiles to reveal the underlying structure of the roof battens under permitted development. The licence specified that following the removal the inspection the roof would be reinstated with no changes to the roof structure or materials, as this provided Natural England with sufficient certainty of the scope to determine the licence application.

In order to gain the EPSM licence ECOSA were required to demonstrate that there were no feasible alternatives that would be less damaging or avoid damage to the site, that the proposals needed to be carried out for imperative reasons of overriding public interest, and that suitable compensatory measures could be secured. The licence was successfully obtained in October 2022.

The investigative works to the roof were undertaken under the supervision of a bat licensed ecologist. Works were undertaken during October, outside of both the bat maternity and hibernation season, to minimise disturbance to roosting bats. Three soprano pipistrelle bats were found roosting during the supervision works and, where possible, were transported to a bat box installed on the site grounds.

The investigative works revealed the need to improve the cottage roof through the addition of insulation and minor alterations to the roof structure. Given the additional works required, it was also cost effective for the client to incorporate dormer windows and roof lights into the new roof at this stage. A new full planning consent needed to be sought from the New Forest National Park authority for this additional work and consent was granted in January 2023. Due to the new consent and the change in the nature of the proposals, the granted EPSM licence also needed to be modified. A suitable mitigation strategy for the cottage was devised with the client to reinstate the original roof tiles where possible and to install modified bat roof tiles to maintain bat access/egress features, allowing continued use of the building by bats. This strategy was agreed by Natural England and the modification of the EPSM was consented in March 2023, allowing sufficient time for the roof to be reinstated for the start of the bat maternity season in May 2023.

Despite restricted timescales and significant administrative burden due to the nature of the works and the presence of the maternity roost, close liaison between ECOSA, the client, the New Forest National Park Authority and Natural England ensured all tasks were undertaken in compliance with planning policy and legislation and the best outcome for both the client and the soprano pipistrelle maternity colony was achieved.

Two bat boxes installed on the wider site will remain in-situ in the long term, providing additional roosting opportunities and enhancing the site for bats. Monitoring surveys will be undertaken during 2024 and 2025 to see if the roost status of the buildings has been affected by the works.