Bats and infrasturcture

Background of the seminar

Bats are impacted by roads and railways through barrier effects, collisions, noise and light disturbance, and direct loss of habitats. The general knowledge is however limited about these nocturnal mammals.

Bats occur in basically all habitats and landscape types, but for most species we know little about demography and population density or the significance of the above impacts. In the same time, bats have an extraordinary position in conservation with all species listed in the EU Habitats directive (in Sweden implemented by the Species Conservation Ordinance, Artskyddsförordningen).

Any development – urban, industrial, infrastructure – is prohibited if it can jeopardize the conservation status of bats. Accordingly, bats are often a particular limitation to infrastructure development.

Because of the limited knowledge of bat population ecology, it may be difficult to prove that a new road or railway does not have a significant effect on bat conservation status. Also it is difficult for the developer to propose appropriate mitigation or compensation measures. There is an obvious risk for erroneous decisions, either allowing new developments that compromises bat conservation or inducing conservation action that lacks foundation. Moreover, conservation guidelines from the Swedish Transport Administration state that important conflicts with bat conservation along existing roads and railways should be known, and measures taken to minimize this conflict.

Legislation and guidelines hence point out the urgent need for better knowledge of bat ecology and of the impacts from road and railways.

The goals of this seminar were:

• to present current knowledge about impacts from roads and railways on Swedish bats,
• to present useful decision tools to minimize and mitigate these impacts,
• to discuss when and where conservation action is needed and when not.

Focus was on the Swedish situation, but because the impacts and legislation is largely similar in all EU countries the seminar was given in English to allow international participation. Some 60 participants attended, from six countries, representing research, road planning and management, nature conservation, and technical consultants.