A Review of the Impacts of Onshore Wind Energy Development on Biodiversity

Abstract

  1. The UK Government is committed to the conservation of indigenous biodiversity as well as renewable energy targets. Renewable electricity currently represents nearly 19% of total electricity consumption with a target of 40% by 2020. At present there are 34 operational onshore wind energy developments (> 1 turbine) in Northern Ireland consisting of 313 turbines with a capacity of 533.10MW. In addition there are currently 38 single turbines operating with a capacity of 15.61MW. A further 291 wind energy developments are consented (35 wind developments (> 1 turbine) and 258 single turbines); consisting of 486 turbines with a capacity of 598.12MW (82.77MW from single turbine developments).
  2. In Northern Ireland, the Department of Enterprise, Trade and Investment (DETI) is responsible for the promotion of renewable energy whilst the Natural Heritage Directorate (NHD) of the Northern Ireland Environment Agency (NIEA) is responsible for habitat and species conservation targets. Potential conflicts of interest require an assessment of the impact of onshore wind energy developments on biodiversity.
  3. We reviewed the evidence for the impact of wind energy developments on biodiversity, examining scientific peer-reviewed publications and relevant grey literature, to evaluate effects on habitats (e.g. peatlands), birds, bats and other organisms.
  4. Our results indicate that onshore wind energy construction and operation can have significant negative effects on local and regional biodiversity. However, the occurrence and magnitude of these effects varies between taxa, species, habitats and site. It should be recognised that publication bias is likely to favour the dissemination of negative results.
  5. The interaction between onshore wind energy facilities and birds has been the focus of the majority of research to date. However, there has been a recent increase in research on the interaction between bats and wind energy facilities particularly in North America and continental Europe. The recognition of the potential negative impacts on migratory and tree roosting bats has increased in British and Irish research which has focused on their interactions with centralised wind energy development (i.e. wind farms). However, there is limited research on both the immediate and cumulative impacts that single wind turbines may have on biodiversity.
  6. In general, the impact of wind energy developments can be summarised in 3 categories:
    1. Displacement through disturbance,
    2. Direct mortality through collision with operational turbine blades or powerlines,
    3. Direct habitat loss through construction of windfarm infrastructure.
  7. The majority of studies report varying levels of bird mortality or displacement at onshore wind energy facilities. However, impacts varied within- and between-sites and were highly species-specific. Birds of prey (particularly soaring species) were notably vulnerable to collision with rotating blades and direct mortality whilst other aerial species may be vulnerable to barrier effects and/or displacement.
  8. An increasing body of evidence also indicates that wind energy developments can have a negative impact on bats, which are more vulnerable than previously thought. In particular, tree roosting species and those that migrate appear to be at greatest risk from wind farm related mortality especially if wind energy developments are close to utilized habitats or migratory routes (e.g. ridges). There may also be impacts in the vicinity of bat swarming sites but this has, hitherto, received little or no research.
  9. Although there is little direct research on the effects of siting wind energy development on peat bogs, inferences can be made about the potential impacts from research into the effects of peat cutting and forestry. Studies suggest that site drainage can be affected which affects the ecology of the bog and also has implications for downstream river catchments and consequently water quality.
  10. Compared to birds and bats there has been relatively little work conducted on the impacts, if any, on terrestrial mammals, reptiles, amphibians, invertebrates, vascular plants, habitats or ecosystems. Therefore, it is difficult to generalise the wider impacts of wind energy on biodiversity per se.