About the project

• Background

  While wind energy production stands to be a powerful tool for the shift away from fossil fuels, it raises concerns due to the mortality of wildlife and loss of biodiversity caused by wind turbines and their development. There is growing scientific evidence that wind turbines represent a threat to bat species in particular.

  Bats contribute towards approximately 20% of all terrestrial mammal species in Norway. The bat community in Norway includes both migratory and resident populations of bat species. Wind energy infrastructure may impact bats directly (mortality from contact with turbines i.e., collisions or barotrauma) or indirectly through avoidance of areas with turbines or habitat loss. This creates the potential for long-term, cumulative impacts on populations.

  Bats are long-lived with low fecundity, such that sudden or repeated losses of multiple individuals can cause dramatic population declines. Furthermore, the life history strategies, morphology and ecology of bats are diverse, and this influences their varying risk of fatally colliding with wind turbines.

  Cumulative effects on bat populations – i.e., the combined effects of multiple developments, that act together to affect bat populations and communities, require thorough long-term studies before and after development to assess
  the impacts.

• Objectives

  The overall objective is to map the year-round spatio-temporal activity of bats along the Norwegian North Sea coast from Utsira to Lista.

  More specifically, in this project we will answer the following questions:

  (1) Which bat species are present along the Norwegian North Sea coast?

  (2) Is the bat activity along the coast evenly distributed, or do some areas have
  higher/lower activity?

  (3) How does bat activity vary throughout the year? Are there clear seasonal patterns and peaks in bat activity, for example during spring and autumn? Studies from other countries around the Baltic and North seas have found that approximately 90% of the migratory Nathisius’ pipistrelle activity can happen within 10 days in spring and 20 days in autumn. These types of specific ‘windows’ could also be possible to identify in Norway.

  (4) How active are bats during daytime? In Northern Europe, several species of bats, including migratory species, are frequently observed flying during daytime in the spring. Short summer nights and migration over the ocean with no opportunities to rest until they reach the shore may require bats to be active during daytime

  (5) How is bat activity modified by environmental conditions like temperature, wind speed, wind direction, and precipitation.

  Knowledge about which bats species – as well as when, where and under what environmental conditions they are active – can be used to inform decisions about siting and operation of offshore wind farms to prevent substantial loss of biodiversity.

  Studying spatiotemporal patterns in activity over larger areas can be used to understand bat migration routes. For example, if peaks bat activity occurs in a sequential pattern (“waves”) along the coast, this can indicate that bats migrate along the coast.

  Whereas peaks in bat activity at many different locations which are situated far apart at the same time, this would suggest that migrating bats are crossing the North Sea many places. And finally, very high activity in certain locations may indicate important “landing” og “departure” areas for migrating bats.

• Methods

  We will deploy acoustic detectors along coast from Lista to Utsira in Norway to collect information on bat community composition an activity. Detector locations will be deployed in areas with similar topography and habitat as area found to be important to migrating bats in the UK; i.e., areas of low elevation, close to sea level.

  The dectors will be used to track bat migration and activity along the southwest coast of Norway. The data can be used to identify bat species in the project area, calculate the activity levels across species and throughout the project area.

  Bat acoustic activity cannot reflect the number of individual bats in a population but can be used to measure relative activity, and to some extent behavior, across species in a community. Acoustic data can be used to calculate a "bat activity index" (number of bat passes per hour).

• Researchers