1^st International Bat Research Online Symposium (IBROS):
Towards solving the wind energy-bat conflict

Attraction of bats to wind turbines and its implications for planning policies

Fiona Mathews

University of Sussex, UK

Thousands of bats are killed by wind turbines annually. However, efforts to reduce the impacts by careful positioning of wind farms in the landscape have been less effective than hoped. This is partly because habitat suitability mapping is a course tool for identifying sites of highest risk, but also because bat behaviour may differ pre- and post-construction.  In the UK, we assessed bat activity at paired turbine and control locations at 23 wind farms. The research focussed on Pipistrellus species, which were by far the most abundant bats recorded at these sites. P. pipistrellus activity was 37% higher at turbines than at control locations, whereas P. pygmaeus activity was consistent with no attraction or repulsion by turbines. Given that more than 50% of bat fatalities in Europe are P. pipistrellus, these findings help explain why Environmental Impact Assessments conducted before the installation of turbines are poor predictors of actual fatality rates. In future, developments should not only avoid sites considered to be of high bat activity pre-construction, but there should be post-construction monitoring and operational mitigation, since the presence of turbines alters bat activity.

Bat-wind turbine interactions studied by GPS tracking of common noctules (Nyctalus noctula)

Christian C. Voigt

Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin

Wind turbines are being erected on an increasing scale worldwide, with only minor efforts to mitigate the problem of bat fatalities and a poor understanding about factors driving bat mortality at turbines. Globally, there is by and large no clear commitment from governments to protect bats at wind turbines. Germany, with a total of about 30,000 onshore turbines (as of 2020), ranks third in the world in terms of the total number of turbines. Although carcasses were documented below wind turbines before the turn of the century, mitigation schemes such as curtailment were not implemented in Germany until around 2008. At that time, about 15,000 wind turbines were already in operation. These turbines have generated and still generate enormous losses of bats over the course of their guaranteed operation time of 20+ years. As of 2019, it is estimated that only 25% of onshore wind turbines in Germany operate under a mitigation scheme. In a recent study, we documented that mostly female and juvenile bats are killed at turbines. Indeed, juveniles were more likely to get killed by wind turbines than expected based on their frequency in the life population, highlighting that juveniles are particularly vulnerable at turbines. Since 2008, curtailments of turbine operation have been increasingly implemented, but efforts which place turbines in sensitive areas, such as forests or waterbodies, are also increasing. In Germany, Nyctalus noctula, the common noctule bat, has one of the highest fatality rates with turbines. Notably, populations of common noctules are declining in Germany. To better undstand, wind turbine-bat interactions, we analysed the spatial tracks of >70 bats equipped with GPS loggers at a coastal area dominated by farmland and at an inland area dominated by managed forests. We observed a highly variable response (attracted, neutral, avoidant) of common noctules towards turbines, with no sex differences. Bats were more likely to be encountered at wind turbines when turbines were located near foraging areas such as waterbodies and farmhouses. At our coastal site, the likelihood of common noctules being present at large turbines increased with proximity to roosts. At our inland site, the likelihood of common noctules being present at turbines was high when these were large or located in the periphery of wind parks. The current practice of erecting ever larger wind turbines in sensitive areas, i.e. close to daytime roosts and foraging areas, seems to be in conflict with the goal of protecting bats from colliding with wind turbines.

Challenges of mitigating wind energy impacts on bats

Christian Kerbiriou, Kévin Barré, Charlotte Roemer, Jeremy Froidevaux, Camille Leroux, Alejandro Sotillo, Yves Bas, Isabelle Le Viol, Julie Marmet, Jean François Julien

To limit the negative effects of project development on biodiversity, many countries adopt a mitigation hierarchy (avoidance, reduction and offsetting). Mitigation is intended to achieve a no net loss of biodiversity requiring a so-called ecological equivalence between biodiversity losses and biodiversity gains. Here we re-visited the different step of mitigation as part of the wind farm settlement and functioning, considering their impacts on bats. We focused on the limitations -mainly from the French case- and discussed solutions.

Despite some guidelines about the way to carry out environmental impact assessment and post-construction monitoring studies, we highlight the need to (i) improve data and metadata accessibility, and (ii) homogenize monitoring methods. Secondly, we underline the limits of the case-by-case approach advocated until now in France to efficiently mitigate impacts. Thirdly, we have examined how avoidance is currently addressed and how large-scale species distribution modelling could help a wind planning more biodiversity-friendly, raising questions about consideration scales and needed/available data. Fourthly, we investigated how reductions measures are so far implemented and documented. Finally, we sought to find how offset measures were implemented to compensate residual impacts and we are investigating their limits considering the maximum possible growth rate of bats.

We conclude that first of all, the avoidance is the key point to reconciling wind energy production and bats conservation.

Bats and wind energy development in Africa – where are we at in our understanding?

Kate L. MacEwan¹, Caroline A. Lötter^2,3, Eleanor J. Richardson³

¹ Western EcoSystems Technology, Inc. 415 West 17th Street, Suite 200 Cheyenne, Wyoming 82001, US
² Inkululeko Wildlife Services (Pty) Ltd. 710 Penge Street, Faerie Glen, Pretoria, Gauteng, 0043, South Africa
³ South African Bat Assessment Association, 52 Bowen Ave, Glenmore, Durban, 4001, South Africa

Since the late 1900s, wind energy has been produced on the African continent, starting in the north in countries like Egypt and Morocco, with the largest wind energy facility (365 turbines) on the continent going live in Kenya in 2019, and several projects having been developed further south since the early 2000s. In South Africa, it has been 14 years since the first pilot wind farm was commissioned, and there are well over 40 wind farms in various stages of development. Over 3.5 GW (24%) of the approximately 14.4 GW of wind energy capacity planned for South Africa by the year 2030 has already been commissioned. Across the continent, the wind energy capacity is already contributing approximately 20 GW to the electricity grid, and it is estimated to be at over 50 GW by 2025. However, despite decades of wind power in Africa, we understand very little about the interactions between African bats and wind turbines. Individual, site-specific operational monitoring studies (mostly unpublished) have been completed but, until now, there has been no coordinated collation of bat fatality data. We present here bat fatality data from operational wind farms in South Africa, and where available, bat fatality information from other African countries. We describe how lessons learned from South Africa and Global North countries, could inform the impact of wind turbines on bats in Africa, and lead to a more proactive approach to fatality minimization and adaptive management, whilst recognising the unique challenges and opportunities in different regions of Africa.

Why evidence-based solutions are necessary but insufficient to resolve the threat of wind energy to bats in North America

Winifred F. Frick

Bat Conservation International, 500 N Capitol of Texas Hwy, Austin, Texas, 78746, USA
Ecology and Evolutionary Biology, University of California, Santa Cruz, California 95060 USA

Mortality of bats at wind energy facilities has been recognized as a potential threat to bat populations for nearly two decades. Since the early 2000s, researchers have worked to identify which species are most at risk, to better characterize the spatial and temporal conditions associated with high mortality events, and to understand how, why, and when bats interact with turbines to better assess collision risk. Numerous replicated experimentally designed studies have measured the efficacy of turbine operational strategies to lower bat fatality rates in various contexts since the mid 2000s. Operational curtailment, the strategy that increases the wind speed at which turbine blades spin to generate energy, has now been widely shown to be effective at reducing bat fatalities in North America. A recent meta-analysis estimates that across different wind energy facilities and years, a 5.0 m/s cut-in speed reduces total bat fatalities by an average of 62% per year (54-69% CI) in North America. Concurrent with the evidence that curtailment works to reduce bat fatalities, modelling efforts have quantified the population-level risk to the hoary bat (Lasiurus cinereus), a long-distance migratory species that accounts for over a third of observed fatalities at wind energy facilities in North America. Modelling results indicate that current levels of wind energy build-out in the United States and Canada may have already caused substantial declines of hoary bats in North America. Risk of future decline and extinction may still be mediated with rapid adoption of measures to reduce bat fatalities by roughly half, a level achievable by curtailing turbines at lower wind speeds. Despite strong empirical evidence that curtailment reduces bat fatalities, there has been little incentive for wind industry to voluntarily adopt curtailment practices given that the practice reduces power generation and thus profit. Creative policy solutions that either impose regulatory measures or provide economic incentives are urgently needed to enable the wind energy industry to contribute renewable energy without negative impacts to biodiversity.

Landscape features associated with bat fatalities at wind energy facilities in North America

Erin F. Baerwald

Department of Ecosystem Science and Management, University of Northern British Columbia, Prince George, BC, V2N 4Z9, Canada

Currently, fatalities at wind energy facilities are one of the greatest known sources of mortality for migratory bats in North America. Between 840,000 and 1.7 million bats were killed by wind turbines in the U.S. and Canada from 2000-2011 but fatalities across North America increase by several hundred thousand annually. Of these fatalities, approximately 72% are of three species of migratory tree-roosting bats: hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and silver-haired bats (Lasionycteris noctivagans). Recent analyses suggest that fatalities at wind energy facilities are negatively affecting populations of hoary bat and these three species are being considered for listing in Canada. To reduce the impacts of wind energy on bat populations, developers and operators can locate projects in “low fatality risk” areas, but this is challenging because habitat use by migratory tree-roosting species of bat is not well-understood. Intuitively, high-risk areas are within spaces that provide high quality habitat for bats (i.e., places with lots of trees and water) and/or concentrate migrating bats (e.g. riparian corridors or ridgelines), but these spaces are not well-defined. However, modelling based on fatality data og migratory tree-roosting bats from >50 wind energy facilities in Ontario, Canada suggest that fatality risk is correlated with habitat features such as distance to forest and proportion of water, cropland, and urban areas. The data also suggest that fatality rates are correlated more with habitat surrounding a facility (i.e. within a 25 km radius) than within a facility (i.e. within a 1 km or 5 km radius). Landscape features associated with increased fatality rates vary among species however, highlighting the need for species-specific management plans.

Large improvements are needed in the environmental assessment of bats and wind energy in Brazil

Enrico Bernard

Laboratório de Ciência Aplicada à Conservação da Biodiversidade, Departamento de Zoologia, Universidade Federal de Pernambuco, Brazil

As of August 2021, Brazil has 726 wind farms and ~8,500 turbines producing 19 GW, setting the country as the 8th largest wind energy producer in the world. Wind power installed in the country will reach 25.5 GW by 2024 with an estimated investment of U$ 1.2 billion per year. Although important and necessary as an energy source, the environmental aspect of the wind energy production in Brazil needs improvements. Despite evidence of bat mortality in wind farms in Brazil, the knowledge about the impacts of wind turbines on bats in the country is still poor given the number of wind farms in operation and the magnitude of investments already made. Wind farms´ locations overlaps with potentially bats species-rich – but poorly studied – areas, stressing the need for correct environmental assessments. Regulations for the licensing of wind farms in Brazil are mostly state-determined, but heterogeneous, superficial and incomplete, especially for the assessment of impacts on bats. Few states require a detailed environmental impact assessment, with some accepting simple literature review data. There is an increase in the use of echolocation calls for bat species identification, but the frequent use of software for the unsupervised automatic species identification is producing questionable results on species richness and activity at the parks. The search for bat carcasses is poorly conducted, at unrealistic time intervals and without calibration for carcass removal, resulting in biased information on real bat mortality. Overall, the data produced during such assessments is kept private, with a lack of transparency in the process. Long-term site-specific monitoring must be mandatory, avoiding generalizations for environmental licensing purposes. Brazil is probably one of the most competitive countries in the world when it comes to renewable energies, but in order to be considered really green, the wind energy sector in Brazil must adopt higher environmental standards. In this process, environmental agencies must be seen as key stakeholders for a better regulatory system, complete and detailed environmental assessments are very necessary and, facing the booming of ESG standards, companies need to present concrete commitments to reduce the negative effects of their activities on bats.

Wind Energy and Bats in the Caribbean Basin: Navigating in the Dark

Armando Rodríguez-Durán

Universidad Interamericana, Bayamón Puerto Rico

The 21^st century’s increasing cost of fossil fuels and greater awareness of climate change catapulted the interest in renewable sources of energy. In 2008, the Caribbean Sustainable Energy Program was established with the assistance of the Organization of American States (OAS) and funded by the European Union. An OAS study in 2011 called Energy Policy and Sector Analysis in the Caribbean underlined the opportunities for renewable energy in some of the Lesser Antilles. The implementation of wind-energy projects in the region has been limited by low wind speeds and difficulties integrating renewable energy into existing energy grids., and promoted by exceedingly high cost of fossil fuels energy. Nevertheless, wind parks continue to develop throughout the region. Although renewable energy is a positive development, secretiveness in the analyses and lack of publication of the environmental assessments is a major problem in the region. In most jurisdictions, the companies managing the facilities oversee evaluating and reporting the environmental assessments to government agencies, and both sequester the information from the public. Based on data from Puerto Rico, tropical Mexico, and the Dominican Republic, it is evident that many bat species in the region are impacted by wind turbines, and understory foragers, some with very small foraging areas, are unexpected but common fatalities. Placing bat fatalities from wind parks in context remains a problem, because population data is lacking for virtually every species. This may be partially remedied through comparisons of fatalities at wind parks and other natural and anthropogenic agents causing bat deaths. Unlike temperate areas, year-round bat activity in the Neotropic complicates implementing typical mitigation strategies, although local studies suggest differences in the impact of turbines based on location. This information can only be verified with independent research, currently been limited by governments and investors. On at least some islands, greater reliance on photovoltaic energy seems to be occurring. The difficulties and potential approaches within the Caribbean basin are further described and analysed.