Conservation of bats during building insulation: results of the international workshop

The online workshop organised by the Czech Bat Conservation Society and Ministry of Environment of the Czech Republic was held on 8 December 2021.

Applications were received from 45 people coming from 18 countries (Albania, Algeria, Bulgaria, Estonia, France, Georgia, Germany, Hungary, Ireland, Lebanon, Netherlands, Norway, Portugal, Romania, Slovakia, Slovenia, Spain, United Kingdom). In the end, 35 people from 14 countries participated actively in the webinar, together with 6 speakers from the Czech Republic and Slovakia.
During the morning session, experience with the issue of bat conservation during building insulation in the Czech Republic was shown in four presentations (time-proven methods of enforcement and raising public awareness, suitable technical solutions, examples of good and bad practice, and results of a study assessing the effectiveness of bat boxes used as substitute roosts). In the afternoon, experience from Slovakia and Great Britain was presented, followed by a Q&A session and a free discussion.
The participants, coming from different backgrounds (governmental authorities, national park administrations, NGOs, universities, museums etc.) discussed the various aspects of the workshop. From the presentations, discussion and feedback, the following conclusions can be drawn:
1) Threats to bats during insulation of buildings are a widespread problem faced in different countries across Europe, in the former Eastern Bloc as well as western Europe. The topic is of great interest also to other EUROBATS range states (Georgia, Algeria, Lebanon).
2) Boom of insulation works is connected with improving economic situation in many countries, and also with the availability of EU subsidies aimed to improve energy efficiency.
3) Despite the existing national legislations on bat conservation, mechanisms to ensure proper protection of bats and their roosts in buildings during insulation and renovation works are often missing. It is thus crucial to establish such mechanisms in cooperation with governmental and regional authorities.
4) At the same time, cooperation with nature conservation NGOs (aimed at conservation of bats and birds) and expert organisations working in building industry is very important. Working together, suitable measures can be developed which are acceptable for both sides.
5) Education of all target groups – authorities, engineers, construction companies as well as the general public – is a necessary part of the whole system. Different methods can be used (guidance materials, educational workshops, consultancy service, public awareness events etc.). Presentation of good-practice examples from your country (at a web site, during the workshops) is a very good tool.
6) The primary effort should always be to preserve the existing bat roosts. In situations when the original roosts cannot be preserved, substitute roosts should be provided. It is also very important to time the construction works properly. If this is not possible, it is necessary to allow bats leave the roost in advance, using a careful exclusion method.
7) Suitable action and technical solutions always depend on the specific situation of the particular building(s). A pre-insulation survey, carried out by a bat expert, is thus necessary.
8) Data from the Czech Republic and Slovakia show quite a good acceptancy of bat boxes used as substitute roosts in insulated buildings. In general, it is recommended that the substitute roosts should be placed as close to the original roost as possible. However, it seems that (at least in panel blocks of flats in CZ and SK) bats do not have difficulties to find a new box even when it is rather far from the original place. Bat boxes can thus be situated at places which are better acceptable to people (away from windows, balconies etc. where problems with bat droppings falling from the boxes could arise). In any case, further research is needed to obtain a more general picture of effectiveness of this measure.
9) Moreover, certain problems (although exceptional) with staining of the facade below bat boxes should be studied, since the cause of this phenomenon has not been explained sufficiently so far.

Leaflet „Bats and building insulation“ (basic information for stakeholders) is attached.


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