The trans-European catchment area of common noctule bats killed by wind turbines in France

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Soto, Christian C. Voigt This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5347084/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 09 Jan, 2025 Read the published version in Scientific Reports → Version 1 posted 12 You are reading this latest preprint version Abstract Wind turbines used to combat climate change pose a green-green dilemma when endangered and protected wildlife species are killed by collisions with spinning blades. Here, we investigated the geographic origin of bats killed by wind turbines along an east-west transect in France to determine the spatial extent of this conflict in Western Europe. We analysed stable hydrogen isotopes in the fur keratin of 60 common noctule bats ( Nyctalus noctula ) killed by wind turbines during summer migration in four regions of France to predict their geographic origin using models based on precipitation isoscapes. We first separated migratory from regional individuals based on fur isotope ratios of local bats. Across all regions, 71.7% of common noctules killed by turbines were of regional and 28.3% of distant origin, the latter being predominantly females from northeastern Europe. We observed a higher proportion of migratory individuals from western sites compared to eastern sites. Our study suggests that wind-turbine-related losses of common noctule bats may impact distant breeding populations across whole Eurasia, confirming that migratory bats are highly vulnerable at wind turbines and that effective conservation measures, such as temporary curtailment of turbine operation, should be mandatory to protect them from collisions with wind turbines. Biological sciences/Ecology Biological sciences/Zoology Earth and environmental sciences/Ecology conservation bat migration stable isotopes deuterium IsoriX Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Our planet is facing several major environmental crises that threaten ecosystems and jeopardise the survival of humanity 1,2 . Solving these environmental crises should therefore be of primary concern to society 3 . The biodiversity crisis, commonly known as the sixth mass extinction event 4 , is mainly caused by land-use changes and intensification 5,6 , processes that are widely underestimated in their impact on biodiversity 7 . While more and more land is being converted or used more intensively for human needs, ecosystems are also increasingly suffering from global warming and unpredictable weather extremes 8 . Measures intended to solve one of these specific environmental crises may conflict with the solution to the other environmental crisis, which is commonly referred to as a green-green dilemma 9 . One such dilemma lies in the fact that large numbers of threatened and legally protected wildlife are killed at wind turbines 10 . Indeed, an increasing number of studies suggests that wind energy production is leading to habitat losses and degradation and to casualties of vulnerable wildlife 11-13 . For example, over the past two decades high fatality rates have been documented for bats and birds at wind turbines on all continents where wind turbines are operating 9,10,14 . In fact, it has been suggested that turbine-induced casualties may represent the most likely cause for multiple mortality events in bats 15 . In line with this notion, past studies have estimated that each year millions of bats may get killed at wind turbine facilities of the northern hemisphere 9 . This massive loss of individuals translates into population declines of high collision risk species because of the high vulnerability of female and juvenile bats 16 and the overall low reproductive rate of bats, as illustrated by studies from North America and Europe 17-19 . This scenario is unfortunate given the availability of effective avoidance and mitigation measures. For example, guidelines recommend that wind turbines should be placed at a large distance from ecologically sensitive areas 20 . In addition, the rotation of blades should be slowed by feathering the blades prior to the cut-in speed. Finally, wind turbine operation should be stopped temporarily at times of high bat activity, a mitigation scheme called curtailment 21 . However, these measures are not systematically applied in any of the areas where wind energy production is expanding 9,22,23 . The noctule bat ( Nyctalus noctula ) is one of the most common bat species found dead under wind turbines in Central Europe 22,24,25 . This species is an aerial insectivorous bat that hunts for insects above arable land, forests and urban areas 26-32 . It is also known for its migratory behaviour. In northeastern Europe, where summer populations consist mainly of reproducing females, all individuals migrate to Central and Western Europe in autumn 33,34 . Whereas in Central Europe, the common noctule forms partially migratory populations, i.e. in late summer, colonies may consist of migratory individuals originating from northeastern populations, resident individuals that remain year-round in the region and others that migrate to Western Europe in autumn 35 . During migration, common noctule bats cover several hundred kilometres between their summer and wintering habitat 33,34 . Some banded individuals have also been found travelling distances of up to 1,500 km in one direction 33,34 . As a migratory bat species, common noctules are particularly affected by the expansion of wind energy production in Europe 36-38 , because their flight altitude overlaps largely with the rotor-swept area of turbines 28,39,40 . Current monitoring schemes and analyses report a negative population trend in western and central Europe for this species 19,41,42 . Also, previous geographic assignments indicated that a relatively large proportion of common noctule bats killed by wind turbines in Central Europa originates from the summer range in northeastern Europe 36,43 . Due to their cryptic roosting behaviour in tree hollows 27 , population monitoring is highly difficult in their summer range. It is therefore important to determine the proportion of migrating individuals in those regions where wind energy production is expanding to assess the potential impact of casualties at wind turbine for remote and local populations. Here, we ask what the relative proportion of long-distance migratory bats is among bats killed by wind turbines in four regions of France, stretching from west to east from the Bretagne/Pays-de-la-Loire to the Bourgogne-Franche-Comté/Grand-Est, covering a distance of about 500 km in west-east direction across France. We hypothesised that wind turbines in France kill not only local (hereafter referred to as regional) common noctule bats, but also long-distance migrants, thus affecting populations at a large spatial scale in central and north-eastern Europe. Given that France is in the western geographic range of common noctule bats in Europe 27 , we predicted that the relative proportion of long-distance migratory common noctule bats killed by wind turbines in France would be similar to or even higher than observed for common noctule bats killed by wind turbines in Germany (28% of all carcasses studied 43 ). Secondly, we predicted that the relative proportion of long-distance migratory common noctules is higher at the western than at the eastern study sites in France, because the western study sites are at the border of the species’ geographic range, leading potentially to a higher proportion of migratory to regional bats. We used stable isotopes to shed light on the geographic origin of bats, because stable hydrogen isotope ratios, depicted in the delta notation (δ 2 H) as per mille deviation from an international standard, in fur keratin inform about the geographic area of the summer range of bats 44 . Fur is a suitable matrix for this approach, as stable isotopes are conserved in the inert keratin after growth 45 . Furthermore, we use stable carbon and nitrogen isotope ratios (δ 13 C and δ 15 N values, respectively) to elucidate the extent of foraging on limnic or terrestrial insects in common noctule bats across Europe 46,47 . Fur keratin enriched in 15 N and depleted in 13 C, is indicative of foraging on insects with limnic larval stages 46 . Our study is particularly important for stakeholders and political decision makers since common noctule bats are not only protected by French legislation (Loi de protection de la nature, §76-629, 1976), but also by international legislation (EU habitat directive, 92/43/EWG). Further to that, European migratory bats are covered by the convention on migratory species of wild animals (CMS convention, UNEP/EUROBATS agreement, Bonn 1979, London 1991). Accordingly, the protection of this and other migratory bats should be in the core interest of national and international conservation efforts of authorities and governments. Results Variations of δ 2 H, δ 13 C, and δ 15 N values in fur keratin Stable isotope values in fur keratin of common noctules ranged from − 74.3‰ to -25.0‰ for δ 2 H, from − 27.4‰ to -21.4‰for δ 13 C, and 6.8‰ to 13.6‰ for δ 15 N values. δ 2 H and δ 15 N values were negatively correlated (Spearman’s r (57) = -0.359, p = 0.005), while δ 2 H and δ 13 C values showed a weak positive correlation (Spearman’s r 57 = 0.302, p = 0.020). No correlation was found between δ 13 C and δ 15 N values (Pearson’s r 57 = -0.167, p = 0.205). Compared to the fur keratin of regional common noctule bats, the fur keratin of long-distance migratory bats was depleted in 2 H on average by 23.7‰ and by 0.7‰ in 13 C (t 57 = -2.68, p = 0.009), while it was enriched in 15 N, on average, by 1.3‰ (t 26.3 = 3.57, p < 0.001) in relation to the corresponding lighter isotopes. The isotopic composition of fur keratin did not differ between sexes (δ 2 H: U = 149.5, p = 0.284; δ 13 C: t 39 = -1.20, p = 0.239; and δ 15 N: t 39 = 1.31, p = 0.199) or between samples across the autumn period (δ 2 H: F 1,58 = 0.004, P = 0.95; δ 13 C: F 1,57 = 0.01, P = 0.92; and δ 15 N: F 1,57 = 0.02, P = 0.89). We found differences in δ 15 N values between sampling groups (F 3,55 = 7.14, p < 0.001) with bats collected in Western France (G1) presenting higher δ 15 N values than all other groups (Fig. 3 ). We observed no significant differences in δ 2 H and δ 13 C values between sampling groups (H 3 = 6.91, p = 0.075; and F 3,55 = 1.04, p = 0.383, respectively). Relative proportion of regional and long-distance migratory bats We categorized 71.7% (n = 43) of the bats collected in wind farms as of regional origin and 28.3% (n = 17) as of long-distance migratory origin. The sex ratio in our sample collection and among migratory individuals was female-biased (Χ² = 4.1, p = 0.042 and Χ² = 4.5, p = 0.035, respectively). The proportion of females was greater among migratory individuals compared to the total sample (82% and 67%, respectively). Among regional individuals, the female to male ratio was more balanced (60% females, 40% males, Χ² = 1.2, p = 0.273). Bats collected in Western France (G1) presented the highest proportion of migrants (60%) while none of the bats from the easternmost sampling group (G4) were categorized as migratory, owing to their high δ 2 H values. Bats from sampling groups in central France, G2 and G3, had intermediate proportions of migratory bats (30% and 26%, respectively). Isotope-based geographic assignments Common noctule bats were separated into five probable areas of origin using k-means clustering analysis: cluster 1 (centroid δ²H = -29.2‰, n = 13), cluster 2 (centroid δ²H = -35.8‰, n = 21), cluster 3 (centroid δ²H = -45.4‰, n = 11), cluster 4 (centroid δ²H = -55.7‰, n = 10), and cluster 5 (centroid δ²H = -71‰, n = 5, Table 1 ). The clusters explained 96.7% of the variation in δ²H values. Males originated predominantly from cluster 2, while females were more equally distributed between clusters 1 to 4 (Fig. 4 ). Among the common noctule bats killed at wind farms in France, 57% most likely originated from Southern and Western Europe (clusters 1 and 2) and 43% originated from Central, Northern and Eastern Europe (clusters 3–5) (Table 1 ; Fig. 5 ). Table 1 Number of bats assigned to the clusters of origin in each sampling group. Cluster 1 Cluster 2 Cluster 3 Cluster 4 Cluster 5 G1 0 2 0 2 1 G2 2 4 1 2 1 G3 9 14 10 6 3 G4 2 1 0 0 0 Total 13 (22%) 21 (35%) 11 (18%) 10 (17%) 5 (8%) Discussion Wind energy production generates a green-green dilemma by killing legally protected and endangered animals. This dilemma could be solved by considering stronger conservation actions during the expansion of wind energy production 9 . Our study aimed to contribute to a better understanding of how wind turbines in Western Europe may impact distant population of migratory species, using common noctule bats as an example for a migratory bat species. Our study shows that almost a third of all common noctules killed by wind turbines in France originated from distant locations in northeastern Europe, which is consistent with data from noctule carcasses found at wind turbines in Germany 43 . Our geographic assignments suggest a likely origin of long-distance migrants from Romania, Poland, Belarus, Russia, the Baltic countries and Fennoscandia, similar to findings from past studies on the geographic origin of long-distance migrating noctule bats in Europe 38 , 43 , 48 . Our study therefore goes beyond previous findings by suggesting that the migratory movements of common noctule bats killed at wind turbines cover the entire Eurasian continent in a west-east direction. We also observed an increase in the relative proportion of long-distance migrants at collection sites in western France, in line with our prediction. Our results show that current permitting procedures in France do not adequately protect migratory bats, despite the fact that this species is covered by national and international legislation and conventions, including the Convention on Migratory Species of Wild Animals (CMS Convention; UNEP/EUROBATS Agreement, Bonn 1979, London 1991). We therefore agree with the recent conclusions that current European wind energy practices are failing to effectively protect endangered and legally protected bat species 23 . Our study also corroborates previous work on other migratory bat species, which showed a higher proportion of female than male bats among carcasses found at wind turbines in Europe 16 . The relatively high proportion of females among long-distance migrants highlights the fact that the north-eastern populations of this species consist predominantly of reproducing females. We therefore expect that the potential impact of wind turbine fatalities in France could lead to significant declines in the affected populations, as juvenile production is driven by the number of females in the colonies. This could exacerbate the predicted population declines for migratory bats 17 , 18 , particularly for populations at the northeastern edge of the species' range. We also observed high δ 15 N and low δ 13 C values in long-distance migrating noctule bats, suggesting that these bats feed mainly on insects with limnic larval stages in their summer range in northeastern Europe 46 , 47 . In contrast, stable isotope ratios indicated a higher proportion of terrestrial insects in the diet of regional conspecifics 46 , 47 . Feeding on insects with limnic larval stages may provide long-distance migrating bats with a relatively high proportion of polyunsaturated fatty acids, such as linoleic acid, which are useful for torpor and endurance exercise 49 , and which are rare in the mammalian body in general, and in that of common noctule bats specifically 50 . In our stable isotope approach, we used a combination of elements to offer insights into the ecology and geographic origin of animals. The value of this approach for bat species has been confirmed in previous work 34 , 35 , 38 , 43 , 51 – 53 . Although the isotopic approach is robust for geographic assignment of bats 44 , it is important to note the underlying assumptions. To this end, we acknowledge that 1) the stable isotope composition of fur keratin only correlates with the isotopic composition of food and water consumed during the moulting period of bats 45 . In migratory bats, including noctule bats, moulting occurs typically in summer, after the reproductive period of females and before migration between late July and early August 46 , 54 . Accordingly, the stable isotope composition of fur keratin is representative of the habitats where noctule bats live between late July and mid-August. If common noctule bats begin to migrate before moulting is complete, our stable isotope approach will provide less robust geographic assignments for the summer origin of bats 44 . 2) Our observation of common noctule bats feeding on insects with limnic larval stages suggests that δ 2 H values in fur keratin might be lower in this bats than in those with a diet of terrestrial insects 47 . Since our transfer function was obtained from bat species with a terrestrial diet, a diet of insects with limnic larval stages could potentially bias our geographic assignments to higher latitudes. A multi-species comparison of the isotopic composition of fur keratin in several aerial insectivorous bats showed that median δ 2 H values varied over a range of 20‰, suggesting that we may have placed some of the long-distance migrants one or two isoclines further north than they originated (Fig. 2 ). Although we cannot refuse this possibility, we concur that our inferences are still robust, since a deviation by one or two isoclines still suggest a long-distance origin of bats from northeastern Europe, and since the cluster areas include several isocline zones (Fig. 5 ). 3) Our isoscape origin approach accounts for variation in stable isotope ratios in bat fur and also in precipitation water 55 . Therefore, assignment areas are relatively large. We acknowledge this low spatial resolution. However, given the migratory distances covered by some common noctules, our approach was sufficiently robust to separate long-distance migrants from regional bats. 4) Our sampling effort in France were concentrated along a west-east transect covering 500 km across France. Therefore, we cannot infer the geographic origin and relative proportion of long-distance migrants in other regions of France, such as northern and southern France. Furthermore, 5) our conclusions are based on 60 individuals collected from four regions. Although we consider this sample size to be sufficient to draw robust conclusions, we acknowledge that the sample size varies along the west-east transect. We suggest larger sampling efforts at wind turbines across larger areas in Europe to generate a comprehensive picture on the migration of common noctule bats in Europe, and also about the potential impact wind energy production may have on distant populations of this migratory species. Lastly, 6) our study identifies the relative proportion of long-distance migrating noctule bats, but cannot quantify with empirical data the absolute number of long-distance migrating noctule bats killed by wind turbines in France. Given these limitations, we estimate here the impact of wind energy production in France on migratory bats. To do this, we assume that mortality estimates from central Europe of 14 bats killed per wind turbine per year are representative for France 9 , which currently hosts about 9,700 onshore wind turbines with a total power capacity to 22.1 GW 56 . This leads to the inference that about 140,000 bats are killed per year at French wind turbines. In addition, we assume a relative proportion of about 18% for common noctule bats among bat carcasses found at wind turbines 57 , of which about 30% are long-distance migrants (this study, 43 ). This corresponds to an estimated 25,200 common noctule bats killed at wind turbines per year in France, of which 17,640 are of regional and 7,560 of a north-eastern origin. Considering that common noctule bats are only one of several vulnerable migratory bat species, we suggest that the total impact of bat fatalities at French wind turbines is far greater than estimated for this single species. Other migratory species such as Nathusius' Pipistrelle ( Pipistrellus nathusii ), parti-coloured bats ( Vespertilio murinus ), Leisler's Bat ( Nyctalus leisleri ), Greater Noctule ( Nyctalus lasiopterus ) and Schreiber's Bat ( Miniopterus schreibersii ) have also been documented to be killed by wind turbines in France 57 . This highlights the urgent need for implementing mitigation schemes at the operating wind turbines in France as well as during the project development phase and environmental risk assessments of new onshore wind farms, by using established and highly effective curtailment protocols 21 , 51 . We plead for the implementation of these mitigation schemes in all European countries 36 , 38 . Conclusions We demonstrate that about one third of common noctule bats killed by wind turbines in France are migratory and of distant geographic origin. The discovery of dead bats at wind turbines in France in general and the discovery of long-distance migrating bats in particular is contrary to the legislation, both on the national (Loi de protection de la nature, § 76–629, 1976) and EU level (habitat directive, 92/43/EWG), and it also conflicts with international agreements, such as the CMS Convention (UNEP/EUROBATS agreement, Bonn 1979, London 1991). We call for immediate action to implement efficient mitigation measures for newly installed wind turbines and also for retroactive implementation of mitigation measures for wind turbines already in operation 22 . These measures are important as the expansion scenarios for wind energy production in Europe envisage the installation of thousands of wind turbines in France and across Europe 9 . Failing to practice optimal siting of wind turbines, i.e. away from ecologically sensitive areas, and to implement curtailment schemes, may have far-reaching consequences for European biodiversity in general and vulnerable bat species in particular. Methods Study area and fur sample collection We analysed fur samples collected from 60 common noctule bats ( Nyctalus noctula ) that were found dead under wind turbines during routine carcass searches following general monitoring schemes 20 . This monitoring was conducted by local environmental consulting firms and organizations between 2010 and 2023 at 23 multi-wind turbine facilities across three provinces in France: Bretagne/Pays-de-la-Loire (n = 3 surveyed multi-wind turbine facilities), Centre-Val de Loire (n = 18) and Bourgogne-Franche-Comté/Grand-Est (n = 2). All carcasses included in our study were collected between July and October. The collection sites were grouped into four geographic clusters based on location and proximity. Specifically, wind farms in Bretagne/Pays-de-la-Loire and Bourgogne-Franche-Comté/Grand-Est were classified in one group each, namely G1 and G4, respectively. Wind farms in Centre-Val de Loire were divided into G2 (central-north), and G3 (central-south), according to administrative boundaries (Fig. 1 ). The fur samples were obtained by the Natural History Museum in Bourges (Centre-Val de Loire, France). From each carcass, we assessed the sex and age of the bat based on epiphyseal closure of finger bones where possible. Small tufts of fur were collected from the interscapular region using scissors and then transferred to dry Eppendorfs tubes for shipment to the stable isotope laboratory at the Leibniz Institute for Zoo and Wildlife Research (IZW, Berlin, Germany) for isotopic analysis. Juvenile bats were not included in our analysis due to potential age-related differences in isotopic composition between juvenile and adult bats 59 . Stable isotopes analysis All fur samples were cleaned with a 2:1 chloroform-methanol solution to remove surface oils and contaminants, then dried in an oven at 50°C for 24h. Stable hydrogen isotope analysis To account for the isotope exchange of hydrogen between fur keratin and ambient air, we used a comparative equilibration approach with the fur samples and previously calibrated keratin reference materials with ‘known’ non-exchangeable δ²H values 60 . For this purpose, we used in-house keratin laboratory reference materials, which included Swedish and Spanish sheep fur and Tanzanian goat fur (SWE-SHE; ESP-SHE; AFR-GOA, respectively). These in-house reference materials were previously calibrated against the revised and most updated isotope values of CBS, KHS, USGS42/43 61,62 . Subsamples of bat fur and keratin reference materials were weighed with a microbalance to target a mass of about 0.3 mg of material, and placed in silver capsules (IVA Analysetechnik e.K., Meerbusch, Germany). These capsules were placed into microplates and left to equilibrate with lab ambient air for a week. After equilibration, samples were placed in an auto-sampler (Uniprep system 63 ), flushed with helium, and combusted at 1350°C in a high-temperature (HT) reactor of an elemental analyser (TCEA, Thermo Scientific; or HT pyrolysis system, HEKAtech). A gas chromatography separated the H 2 , N 2 , and CO gases produced during the pyrolysis. The resulting H 2 from samples were measured for δ²H values using a continuous flow isotope ratio mass spectrometer (Delta V Advantage, Thermo Scientific, Bremen, Germany). Isotopic ratios were expressed in parts per mil (‰) deviations from the international standard: Vienna Standard Mean Ocean Water (VSMOW). The within-run analytical precision based on repeated analyses of keratin reference materials was better than 1.5‰ for δ²H. Stable carbon and nitrogen isotope analysis For δ 13 C and δ 15 N analysis, fur samples were weighed to a target mass of 0.5 to 0.6 mg and placed in tin capsules (IVA Analysetechnik. Meerbusch, Germany). These subsamples were subsequently combusted at 1020°C in an elemental analyser. The resulting N 2 and CO 2 gases were separated in a gas chromatography column and analysed with a continuous flow isotope ratio mass spectrometer (Delta V Advantage, Thermo Scientific, Bremen, Germany). Values of δ 13 C and δ 15 N were expressed in parts per mil (‰) deviations from international standards: Vienna Pee Dee Belemnite carbonate (V-PDB) for carbon and atmospheric nitrogen for nitrogen. The within–run analytical precision based on repeated analyses of keratin reference materials was better than 0.2‰ for δ 13 C, and 0.1‰ for δ 15 N values. Statistical and spatial analysis Transfer function Using the R package ‘IsoriX’ (v. 0.9.2) 56 , we used a Linear Mixed Model to establish the transfer function between δ²H p and δ²H in fur keratin (δ²H f ) using the “ calibfit() ” function and a calibration dataset that included δ²H f values from sedentary bats of known origin (IsoriX:CalibDataBat) 44 . This calibration dataset contained δ²H f values measured on 111 Nyctalus noctula during their sedentary period 48 , along with 224 bats from five non-migratory species ( Barbastella barbastellus, Eptesicus serotinus, Eptesicus isabellinus, Plecotus auritus , and Plectotus austriacus ) 51 . These published isotope values were re-calibrated to align with the current δ²H assigned values for keratin reference materials 61 , ensuring comparability with our isotope measurements. Using the European isoscape of predicted amount-weighted mean annual δ 2 H in precipitation and the stable hydrogen isotope values from 335 known-origin European bats, we established the following transfer function for common noctule bats: δ 2 H f = 11.91 (± 5.11) + 0.93 (± 0.09) * δ 2 H p . By using the “ isoscape() ” function, we fitted a geostatistical mixed model including topographic features (elevation, longitude and latitude) to predict the variations in amount-weighted mean annual stable hydrogen isotope ratios in precipitation (δ²H p ) across Europe. The δ²H p values were obtained from the Global Network of Isotopes in Precipitation (GNIP) ( IAEA/WMO, 2024 ) to build a European δ²H p isoscape covering the distribution range of Nyctalus noctula . To separate bats of local origin from those of long-distance migratory origin, we employed the “ isofind() ” function in ‘ IsoriX’ . By applying the established δ²H p isoscape and the transfer function between δ²H p and δ²H f values, we defined an isoscape of expected δ²H f values for local bats across Europe (Fig. 2 ). Bats were classified as long-distance migratory if their δ²H f values significantly differed from the expected δ²H f values for local bats at their sampling location (P 0.05), the local origin could not be ruled out, and the bats were considered as of regional origin. Variations in δ²H f , δ 13 C and δ 15 N values All statistical analyses were performed with R (v. 4.3.2, R Core Team 2023). We used Shapiro-Wilk tests to assess the normality of the isotope values. We explored the relationship between the three stable isotope values (C, N, H) using Pearson’s correlations and Spearman rank correlation. T-tests and one-way ANOVAs (or Mann-Whitney U tests and Kruskal-Wallis tests, when appropriate) were performed to evaluate the effects of sex, sampling groups, and migratory behaviour (i.e., regional or long-distance migratory, see below) on the isotope values. To assess seasonal variations in isotope values across years, the collection date was converted into “day of year” (Julian date). Geographic assignments based on δ²H f , values We separated bats into clusters with similar δ²H f values using a k-means clustering analysis. The optimal number of clusters (k = 5) was determined when the within-cluster variation was only marginally reduced by the addition of a new cluster (elbow method). The probable geographic origin of bats within each cluster was inferred using group assignments in IsoriX 56 . The assignment probabilities of all individuals within the same cluster were combined for each location using Fisher’s method (Fisher, 1925) resulting in one map of probable origin per cluster. Using the same method, we produced a map of probable origin for all migratory individuals. Declarations Author Contribution C.C.V. conceived the study and ensured funding, L.A. curated the specimens and collected samples, C.C.V. and D.X.S. analyzed the samples, D.X.S. and M.M. analyzed the data, C.C.V., D.X.S. and M.M. wrote the manuscript, all authors commented on the paper. Acknowledgement This project was supported by an Erasmus fellowship to MM. We thank all helpers involved in carcass searches and preparation, e.g., research offices, Groupe Mammalogique Breton (GMB) and Chauve-Qui-Peut. We also acknowledge the support of Anja Luckner and Michelle Busse from the stable isotope laboratory at the Leibniz Institute for Zoo and Wildlife Research (IZW). Data Availability The datasets used and/or analysed during the current study available from the corresponding author on reasonable request. References Rockström, J., et al. A safe operating space for humanity. Nature 461(7263), 472–475 (2009). Steffen, W., et al. Planetary boundaries: Guiding human development on a changing planet. Science 347 , 1259855 (2015). O’Neill, D. W., Fanning, A. L., Lamb, W. F. & Steinberger, J. K. A good life for all within planetary boundaries. Nature Sust. 1, 88–95 (2018). McCallum, M. L. Vertebrate biodiversity losses point to a sixth mass extinction. Biodiv. Conserv. 24, 2497–2519 (2015). Powers, R. P. & Jetz, W. Global habitat loss and extinction risk of terrestrial vertebrates under future land-use-change scenarios. Nat. Clim. Chang. 9, 323–329 (2019). Flynn, D. F., et al. Loss of functional diversity under land use intensification across multiple taxa. Ecol. Lett. 12, 22–33 (2009). Winkler, K., Fuchs, R., Rounsevell, M. & Herold, M. Global land use changes are four times greater than previously estimated. Nat. Comm. 12, 2501 (2021). Scheffers, B. R., et al. The broad footprint of climate change from genes to biomes to people. Science 354, aaf7671 (2016). Voigt, C. C., et al. Toward solving the global green–green dilemma between wind energy production and bat conservation. BioScience 74, 240–252 (2024). Thaxter, C. B., et al. Bird and bat species' global vulnerability to collision mortality at wind farms revealed through a trait-based assessment. Proc. Roy. Soc. B 284(1862), 20170829 (2017). Kuvlesky Jr, W. P., Brennan, L. A., Morrison, M. L., Boydston, K. K., Ballard, B. M. & Bryant, F. C. Wind energy development and wildlife conservation: challenges and opportunities. J. Wildl. Manag. 71, 2487–2498 (2007). Saidur, R., Rahim, N. A., Islam, M. R. & Solangi, K. H. Environmental impact of wind energy. Renew. Sust. Energy Rev. 15, 2423–2430 (2011). Tolvanen, A., Routavaara, H., Jokikokko, M. & Rana, P. How far are birds, bats, and terrestrial mammals displaced from onshore wind power development?–A systematic review. Biol. Conserv. 288, 110382 (2023). Arnett, E. B., Baerwald, E. F., Mathews, F., Rodrigues, L., Rodríguez-Durán, A., Rydell, J., … Voigt, C. C. Impacts of wind energy development on bats: a global perspective. In: Bats in the Anthropocene: conservation of bats in a changing world , (eds. Voigt, C.C., & Kingston T.) 295–323 (Springer, 2016). O'Shea, T. J., Cryan, P. M., Hayman, D. T., Plowright, R. K. & Streicker, D. G. Multiple mortality events in bats: a global review. Mammal review, 46(3), 175–190 (2016). Kruszynski, C., et al. High vulnerability of juvenile Nathusius' pipistrelle bats ( Pipistrellus nathusii ) at wind turbines. Ecol. Appl. 32, e2513 (2022). Frick, W. F., et al. Fatalities at wind turbines may threaten population viability of a migratory bat. Biol. Conserv. 209, 172–177 (2017). Friedenberg, N. A. & Frick, W. F. Assessing fatality minimization for hoary bats amid continued wind energy development. Biol. Conserv. 262, 109309. (2021). Printz, L., Tschapka, M. & Vogeler, A. The common noctule bat ( Nyctalus noctula ): population trends from artificial roosts and the effect of biotic and abiotic parameters on the probability of occupation. J. Urban Ecol. 7, juab033 (2021). Rodrigues, L., et al. Guidelines for consideration of bats in wind farm projects – Revision 2014. EUROBATS Publication Series No. 6., 133 pp (UNEP/EUROBATS secretariat, Bonn, Germany, 2015). Whitby, M. D., O'Mara, M. T., Hein, C. D., Huso, M. & Frick, W. F. A decade of curtailment studies demonstrates a consistent and effective strategy to reduce bat fatalities at wind turbines in North America. Ecol. Sol. Evid. 5, e12371 (2024). Voigt, C. C., Kaiser, K., Look, S., Scharnweber, K. & Scholz, C. Wind turbines without curtailment produce large numbers of bat fatalities throughout their lifetime: A call against ignorance and neglect. Global Ecol. Conserv. 37, e02149 (2022). Barré, K., et al. Over a decade of failure to implement UNEP/EUROBATS guidelines in wind energy planning: A call for action. Conserv. Sci. Pract. 4 , e12805 (2022). Rydell, J., Bach, L., Dubourg-Savage, M. J., Green, M., Rodrigues, L., & Hedenström, A. Bat mortality at wind turbines in northwestern Europe. Acta Chiropt. 12(2), 261–274 (2010). Dürr, T. Schlagopferdatenbank Fledermäuse Europa https:// lfu.brandenburg.de/lfu/de/aufgaben/natur/artenschutz/vogelschutzwarte/arbeitsschwerpunkt-entwicklung-und-umsetzung-von-schutzstrategien/auswirkungen-von-windenergieanlagen-auf-voegel-und-fledermaeuse/ accessed on 28.10.2024 (2024) Denzinger, A. & Schnitzler, H. U. Bat guilds, a concept to classify the highly diverse foraging and echolocation behaviors of microchiropteran bats. Front. Physiol. 4, 164 (2013). Lindecke, O., et al. Common noctule Nyctalus noctula (Schreber, 1774). In Handbook of the Mammals of Europe (Hackländer, K. & Zachos, F.E.) 1–25 (Cham: Springer International Publishing, 2020). Roeleke, M., Blohm, T., Kramer-Schadt, S., Yovel, Y. & Voigt, C. C. Habitat use of bats in relation to wind turbines revealed by GPS tracking. Sci. Rep., 6(1), 28961 (2016). Roeleke, M., Teige, T., Hoffmeister, U., Klingler, F. & Voigt, C. C. Aerial-hawking bats adjust their use of space to the lunar cycle. Mov. Ecol. 6, 1–10 (2018). Roeleke, M., et al. Landscape structure influences the use of social information in an insectivorous bat. Oikos 129, 912–923 (2020). Voigt, C. C., et al. Movement responses of common noctule bats to the illuminated urban landscape. Landsc. Ecol. 35, 189–201 (2020). Scholz, C. & Voigt, C. C. Diet analysis of bats killed at wind turbines suggests large-scale losses of trophic interactions. Conserv. Sci. Pract. 4, e12744 (2022). Steffen, R., Zöphel, U. & Brockmann, D. 40th anniversary bat marking Centre Dresden – Evaluation of Methods and Overview of Results . 1–132 (Sächsisches Landesamt für Umwelt, Landwirtschaft und Geologie, 2004). Hutterer, R., Ivanova, T., Meyer-Cords, C & Rodrigues, L.L. Bat migrations in Europe a Review of Banding Data and Literature (Federal Agency for Nature Conservation, 2005). Lehnert, L. S., et al. Variability and repeatability of noctule bat migration in Central Europe: evidence for partial and differential migration. Proc. Roy. Soc.: Biol. Sci. 285, 20182174 (2018). Voigt, C. C., Popa-Lisseanu, A. G., Niermann, I. & Kramer-Schadt, S. (2012). The catchment area of wind farms for European bats: a plea for international regulations. Biological conservation , 153 , 80–86 (2012). Voigt, C. C., Lehnert, L. S., Petersons, G., Adorf, F. & Bach, L. Wildlife and renewable energy: German politics cross migratory bats. Eur. J. Wildl. Res. 61, 213–219 (2015). Măntoiu, D. Ş., et al. Wildlife and infrastructure: impact of wind turbines on bats in the Black Sea coast region. Eur. J. Wildl. Res. 66, 1–13 (2020). Reusch, C., Lozar, M., Kramer-Schadt, S. & Voigt, C. C. Coastal onshore wind turbines lead to habitat loss for bats in Northern Germany. J. Environm. Manag. 310, 114715 (2022). Reusch, C., Paul, A. A., Fritze, M., Kramer-Schadt, S. & Voigt, C. C. Wind energy production in forests conflicts with tree-roosting bats. Curr. Biol. 33, 737–743 (2023). BfN. National Implementation Report to EUROBATS. https://www.eurobats.org/sites/default/files/documents/pdf/Meeting_of_Parties/Inf.MoP8_.21_NIR_Germany.pdf (2018) Bas, Y., Kerbiriou, C., Roemer, C., Julien, J.F. Bat population trends. Muséum National d’Histoire Naturelle. https://croemer3.wixsite.com/teamchiro/population-trends (accessed 24.10.2024) (2020). Lehnert, L. S., Kramer-Schadt, S., Schönborn, S., Lindecke, O., Niermann, I. & Voigt, C. C. Wind farm facilities in Germany kill noctule bats from near and far. PloS one 9, e103106 (2014). Voigt, C. C. & Lehnert, L. S. Tracking of movements of terrestrial mammals using stable isotopes. In Tracking animal migration with stable isotopes (pp. 117–135). Academic Press. Fraser, E. E., Longstaffe, F. J. & Fenton, M. B. Moulting matters: the importance of understanding moulting cycles in bats when using fur for endogenous marker analysis. Can. J. Zool. 91, 533–544 (2013). Voigt, C. C., Lindecke, O., Schönborn, S., Kramer-Schadt, S. & Lehmann, D. Habitat use of migratory bats killed during autumn at wind turbines. Ecol. Appl. 26, 771–783 (2016). Voigt, C. C., Lehmann, D. & Greif, S. Stable isotope ratios of hydrogen separate mammals of aquatic and terrestrial food webs. Meth. Ecol. Evol. 6, 1332–1340 (2015). Voigt, C. C., et al. The trans-boundary importance of artificial bat hibernacula in managed European forests. Biodiv. Conserv. 23, 617–631 (2014). Voigt, C. C., Rosner, E., Guglielmo, C. G. & Currie, S. E. Fatty acid profiles of the European migratory common noctule bat ( Nyctalus noctula ). Sci. Nature 106, 1–8 (2019). Voigt, C. C., Sörgel, K., Šuba, J., Keišs, O. & Pētersons, G. The insectivorous bat Pipistrellus nathusii uses a mixed-fuel strategy to power autumn migration. Proc. Roy. Soc.: Biol. Sci. 279, 3772–3778 (2012). Popa-Lisseanu, A. G., et al. A triple-isotope approach to predict the breeding origins of European bats. PLoS One , 7, e30388 (2012). Pylant, C. L., Nelson, D. M. & Keller, S. R. Stable hydrogen isotopes record the summering grounds of eastern red bats (Lasiurus borealis). PeerJ , 2, e629 (2014). Kruszynski, C., et al. Identifying migratory pathways of Nathusius' pipistrelles ( Pipistrellus nathusii ) using stable hydrogen and strontium isotopes. Rapid Comm. Mass Spectr. 35, e9031 (2021). Ilyin, V. Y. The seasonal shedding of Pipistrellus nathusii and Nyctalus noctula . Pages 86–89 in V. Yu Ilyin, P. P. Strelkov and V. A. Rodionov, editors. Proceedings of the Fifth All-Union Bat Conference, Penza, Russia. Penza State Educational Institute, Penza, Russia. (1990). Courtiol, A., et al. Isoscape computation and inference of spatial origins with mixed models using the R package IsoriX. In Tracking animal migration with stable isotopes (pp. 207–236). Academic Press (2019). Anonymous. https://www.statistiques.developpement-durable.gouv.fr/edition-numerique/chiffres-cles-energies-renouvelables-2023/11-eolien- (accessed 22.10.2024) (2024) Anonymous. https://ssm-ecologie.shinyapps.io/suivi_eolien/ (accessed 22.10.2024) (2024). Barré, K., Froidevaux, J. S., Sotillo, A., Roemer, C. & Kerbiriou, C. Drivers of bat activity at wind turbines advocate for mitigating bat exposure using multicriteria algorithm-based curtailment. Sci. Total Environm. 866, 161404 (2023). Kravchenko, K. A., Lehnert, L. S., Vlaschenko, A. S. & Voigt, C. C. Multiple isotope tracers in fur keratin discriminate between mothers and offspring. Rapid Comm. Mass Spectr., 33, 907–913 (2019). Wassenaar, L. I. & Hobson, K. A. (2003). Comparative equilibration and online technique for determination of non-exchangeable hydrogen of keratins for use in animal migration studies. Isot. Env. Health Stud. 39, 211–217. Soto, D. X., Koehler, G., Wassenaar, L. I. & Hobson, K. A. Re-evaluation of the hydrogen stable isotopic composition of keratin calibration standards for wildlife and forensic science applications. Rapid Comm. Mass Spectr . 31 , 1193–1203. (2017). Coplen, T. B. & Qi, H. A revision in hydrogen isotopic composition of USGS42 and USGS43 human-hair stable isotopic reference materials for forensic science. Forensic Sci. Int, 266, 222–225 (2016) Wassenaar, L. I., Sisti, L., Pilecky, M. & Kainz, M. Reproducible measurements of the δ2H composition of non-exchangeable hydrogen in complex organic materials using the UniPrep2 online static vapour equilibration and sample drying system. MethodsX , 10 , 101984 (2023). 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5347084","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":374805272,"identity":"dc5f5c7e-9610-4f1a-9408-50e91c076ab7","order_by":0,"name":"Maela Merlet","email":"","orcid":"","institution":"Leibniz Institute for Zoo and Wildlife Research (IZW)","correspondingAuthor":false,"prefix":"","firstName":"Maela","middleName":"","lastName":"Merlet","suffix":""},{"id":374805274,"identity":"6a542f73-0b93-4ccc-be56-6d72229c0ce5","order_by":1,"name":"Laurent Arthur","email":"","orcid":"","institution":"Museum of Natural History","correspondingAuthor":false,"prefix":"","firstName":"Laurent","middleName":"","lastName":"Arthur","suffix":""},{"id":374805275,"identity":"ba8d2ebb-e55a-42fe-85b1-34e1c713c03c","order_by":2,"name":"David X. Soto","email":"","orcid":"","institution":"Leibniz Institute for Zoo and Wildlife Research (IZW)","correspondingAuthor":false,"prefix":"","firstName":"David","middleName":"X.","lastName":"Soto","suffix":""},{"id":374805276,"identity":"9e69e601-b6c8-41a6-9fcf-940ac343bcc6","order_by":3,"name":"Christian C. Voigt","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2klEQVRIie2QvwrCQAyHUwS7nLqmbxGX2q2vYukqKrh0EDko1NHVQXwM57tFl76DhUIXHdrRzfhvcDk7OtwHgRzk45ccgMXylzgSIEFuBNf80YxbKCr/KNRKYXQGHwV+K3RK00uzD0JSPV0mFEzBjZVZyXUW6AN2SPXjYU64AFGZY7xtlBErXf989T1JGEmcUAtlh8JXYnR7KbPaqAwwSgstEVnxnXeK0YCB4O/Kj0gh3/JcLBOVebGuuy7rZLkKPdnTjUxW0caNC3MMW/j9/DXPdMzXWiwWi+UO0tNDdYkMorgAAAAASUVORK5CYII=","orcid":"","institution":"Leibniz Institute for Zoo and Wildlife Research (IZW)","correspondingAuthor":true,"prefix":"","firstName":"Christian","middleName":"C.","lastName":"Voigt","suffix":""}],"badges":[],"createdAt":"2024-10-28 12:23:35","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5347084/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5347084/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-85636-5","type":"published","date":"2025-01-09T15:57:43+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":68478504,"identity":"714426dd-e00d-4c7f-bd12-ec38d612e93f","added_by":"auto","created_at":"2024-11-07 16:37:27","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":140520,"visible":true,"origin":"","legend":"\u003cp\u003eGeographic distribution of the sampled multi-wind turbine facilities and their respective groupings (G1 Bretagne/Pays-de-la-Loire: black squares; G2 and G3 Centre-Val de Loire (north and south): grey and white triangles, respectively; G4 Bourgogne-Franche-Comté/Grand-Est: grey circles).\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-5347084/v1/1ea622794b363eb18b2b5cfc.png"},{"id":68478251,"identity":"1b0cb429-e61f-4575-a24b-256d35c22bb2","added_by":"auto","created_at":"2024-11-07 16:29:27","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":358132,"visible":true,"origin":"","legend":"\u003cp\u003eBat fur\u0026nbsp;δ\u003csup\u003e2\u003c/sup\u003eH\u0026nbsp;model isoscape for Europe. The prediction raster was based on the amount-weighted mean annual hydrogen isoscape in precipitation modelled in this study using IsoriX and the derived transfer function from water to bat tissue H.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-5347084/v1/671e0be7b8fde5581ca52dcc.png"},{"id":68478505,"identity":"a1b7e9b2-da9b-48d8-9858-1a48cd1eaf88","added_by":"auto","created_at":"2024-11-07 16:37:27","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":120845,"visible":true,"origin":"","legend":"\u003cp\u003eDifferences in the δ\u003csup\u003e2\u003c/sup\u003eH, δ\u003csup\u003e13\u003c/sup\u003eC and δ\u003csup\u003e15\u003c/sup\u003eN values in the fur keratin of noctule bats from the four sampling groups (G1 Bretagne/Pays-de-la-Loire; G2 and G3:\u003cem\u003e \u003c/em\u003eCentre-Val de Loire north and south; G4\u003cem\u003e \u003c/em\u003eBourgogne-Franche-Comté/Grand-Est).\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-5347084/v1/f88e19302955cd4475284957.png"},{"id":68478253,"identity":"2c3b7ee1-7b7f-4593-9b87-194d30204ff2","added_by":"auto","created_at":"2024-11-07 16:29:27","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":57080,"visible":true,"origin":"","legend":"\u003cp\u003eNumber of female (F) and male (M) common noctule bats originating from five isotopic clusters.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-5347084/v1/88ac9a8c3f4e0504df4a2e12.png"},{"id":68478254,"identity":"ef112b91-fca8-4127-bc80-2db8af9453b8","added_by":"auto","created_at":"2024-11-07 16:29:27","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":624257,"visible":true,"origin":"","legend":"\u003cp\u003eInferred geographic origin of Nyctalus noctula killed in wind farms in France. Areas of likely summer origin of bats from each cluster (1-5) and of all long-distance migratory bats (6). Mountains with elevations above 400m were excluded from the assignment maps and appear in white. The striped layer represent the areas outside of the species distribution range.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-5347084/v1/2dfd8a3373837ef7d1a4d269.png"},{"id":73693941,"identity":"48873f48-1390-498b-ae85-1d2f0d7d72a3","added_by":"auto","created_at":"2025-01-13 16:09:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2597890,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5347084/v1/99af4d07-6875-41d8-a1ec-f350b352ce67.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The trans-European catchment area of common noctule bats killed by wind turbines in France","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOur planet is facing several major environmental crises that threaten ecosystems and jeopardise the survival of humanity\u003csup\u003e1,2\u003c/sup\u003e. Solving these environmental crises should therefore be of primary concern to society\u003csup\u003e3\u003c/sup\u003e. The biodiversity crisis, commonly known as the sixth mass extinction event\u003csup\u003e4\u003c/sup\u003e, is mainly caused by land-use changes and intensification\u003csup\u003e5,6\u003c/sup\u003e, processes that are widely underestimated in their impact on biodiversity\u003csup\u003e7\u003c/sup\u003e. While more and more land is being converted or used more intensively for human needs, ecosystems are also increasingly suffering from global warming and unpredictable weather extremes\u003csup\u003e8\u003c/sup\u003e. Measures intended to solve one of these specific environmental crises may conflict with the solution to the other environmental crisis, which is commonly referred to as a green-green dilemma\u003csup\u003e9\u003c/sup\u003e. One such dilemma lies in the fact that large numbers of threatened and legally protected wildlife are killed at wind turbines\u003csup\u003e10\u003c/sup\u003e. Indeed, an increasing number of studies suggests that wind energy production is leading to habitat losses and degradation and to casualties of vulnerable wildlife\u003csup\u003e11-13\u003c/sup\u003e. For example, over the past two decades high fatality rates have been documented for bats and birds at wind turbines on all continents where wind turbines are operating\u003csup\u003e9,10,14\u003c/sup\u003e. In fact, it has been suggested that turbine-induced casualties may represent the most likely cause for multiple mortality events in bats\u003csup\u003e15\u003c/sup\u003e. In line with this notion, past studies have estimated that each year millions of bats may get killed at wind turbine facilities of the northern hemisphere\u003csup\u003e9\u003c/sup\u003e. This massive loss of individuals translates into population declines of high collision risk species because of the high vulnerability of female and juvenile bats\u003csup\u003e16\u003c/sup\u003e and the overall low reproductive rate of bats, as illustrated by studies from North America and Europe\u003csup\u003e17-19\u003c/sup\u003e. This scenario is unfortunate given the availability of effective avoidance and mitigation measures. For example, guidelines recommend that wind turbines should be placed at a large distance from ecologically sensitive areas\u003csup\u003e20\u003c/sup\u003e. In addition, the rotation of blades should be slowed by feathering the blades prior to the cut-in speed. Finally, wind turbine operation should be stopped temporarily at times of high bat activity, a mitigation scheme called curtailment\u003csup\u003e21\u003c/sup\u003e. However, these measures are not systematically applied in any of the areas where wind energy production is expanding\u003csup\u003e9,22,23\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;The noctule bat (\u003cem\u003eNyctalus noctula\u003c/em\u003e) is one of the most common bat species found dead under wind turbines in Central Europe\u003csup\u003e22,24,25\u003c/sup\u003e. This species is an aerial insectivorous bat that hunts for insects above arable land, forests and urban areas\u003csup\u003e26-32\u003c/sup\u003e. It is also known for its migratory behaviour. In northeastern Europe, where summer populations consist mainly of reproducing females, all individuals migrate to Central and Western Europe in autumn\u003csup\u003e33,34\u003c/sup\u003e. Whereas in Central Europe, the common noctule forms partially migratory populations, i.e. in late summer, colonies may consist of migratory individuals originating from northeastern populations, resident individuals that remain year-round in the region and others that migrate to Western Europe in autumn\u003csup\u003e35\u003c/sup\u003e. During migration, common noctule bats cover several hundred kilometres between their summer and wintering habitat\u003csup\u003e33,34\u003c/sup\u003e. Some banded individuals have also been found travelling distances of up to 1,500 km in one direction\u003csup\u003e33,34\u003c/sup\u003e. As a migratory bat species, common noctules are particularly affected by the expansion of wind energy production in Europe\u003csup\u003e36-38\u003c/sup\u003e, because their flight altitude overlaps largely with the rotor-swept area of turbines\u003csup\u003e28,39,40\u003c/sup\u003e. Current monitoring schemes and analyses report a negative population trend in western and central Europe for this species\u003csup\u003e19,41,42\u003c/sup\u003e. Also, previous geographic assignments indicated that a relatively large proportion of common noctule bats killed by wind turbines in Central Europa originates from the summer range in northeastern Europe\u003csup\u003e36,43\u003c/sup\u003e. Due to their cryptic roosting behaviour in tree hollows\u003csup\u003e27\u003c/sup\u003e, population monitoring is highly difficult in their summer range. It is therefore important to determine the proportion of migrating individuals in those regions where wind energy production is expanding to assess the potential impact of casualties at wind turbine for remote and local populations.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Here, we ask what the relative proportion of long-distance migratory bats is among bats killed by wind turbines in four regions of France, stretching from west to east from the Bretagne/Pays-de-la-Loire to the Bourgogne-Franche-Comt\u0026eacute;/Grand-Est, covering a distance of about 500 km in west-east direction across France. We hypothesised that wind turbines in France kill not only local (hereafter referred to as regional) common noctule bats, but also long-distance migrants, thus affecting populations at a large spatial scale in central and north-eastern Europe. Given that France is in the western geographic range of common noctule bats in Europe\u003csup\u003e27\u003c/sup\u003e, we predicted that the relative proportion of long-distance migratory common noctule bats killed by wind turbines in France would be similar to or even higher than observed for common noctule bats killed by wind turbines in Germany (28% of all carcasses studied\u003csup\u003e43\u003c/sup\u003e). Secondly, we predicted that the relative proportion of long-distance migratory common noctules is higher at the western than at the eastern study sites in France, because the western study sites are at the border of the species\u0026rsquo; geographic range, leading potentially to a higher proportion of migratory to regional bats. We used stable isotopes to shed light on the geographic origin of bats, because stable hydrogen isotope ratios, depicted in the delta notation (\u0026delta;\u003csup\u003e2\u003c/sup\u003eH) as per mille deviation from an international standard, in fur keratin inform about the geographic area of the summer range of bats\u003csup\u003e44\u003c/sup\u003e. Fur is a suitable matrix for this approach, as stable isotopes are conserved in the inert keratin after growth\u003csup\u003e45\u003c/sup\u003e. Furthermore, we use stable carbon and nitrogen isotope ratios (\u0026delta;\u003csup\u003e13\u003c/sup\u003eC and \u0026delta;\u003csup\u003e15\u003c/sup\u003eN values, respectively) to elucidate the extent of foraging on limnic or terrestrial insects in common noctule bats across Europe\u003csup\u003e46,47\u003c/sup\u003e. Fur keratin enriched in \u003csup\u003e15\u003c/sup\u003eN and depleted in \u003csup\u003e13\u003c/sup\u003eC, is indicative of foraging on insects with limnic larval stages\u003csup\u003e46\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOur study is particularly important for stakeholders and political decision makers since common noctule bats are not only protected by French legislation (Loi de protection de la nature, \u0026sect;76-629, 1976), but also by international legislation (EU habitat directive, 92/43/EWG). Further to that, European migratory bats are covered by the convention on migratory species of wild animals (CMS convention, UNEP/EUROBATS agreement, Bonn 1979, London 1991). Accordingly, the protection of this and other migratory bats should be in the core interest of national and international conservation efforts of authorities and governments.\u0026nbsp;\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e \u003ch2\u003eVariations of δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH, δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC, and δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN values in fur keratin\u003c/h2\u003e \u003cp\u003eStable isotope values in fur keratin of common noctules ranged from \u0026minus;\u0026thinsp;74.3\u0026permil; to -25.0\u0026permil; for δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH, from \u0026minus;\u0026thinsp;27.4\u0026permil; to -21.4\u0026permil;for δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC, and 6.8\u0026permil; to 13.6\u0026permil; for δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN values. δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH and δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN values were negatively correlated (Spearman\u0026rsquo;s r\u003csub\u003e(57)\u003c/sub\u003e = -0.359, p\u0026thinsp;=\u0026thinsp;0.005), while δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH and δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC values showed a weak positive correlation (Spearman\u0026rsquo;s r\u003csub\u003e57\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;0.302, p\u0026thinsp;=\u0026thinsp;0.020). No correlation was found between δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC and δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN values (Pearson\u0026rsquo;s r\u003csub\u003e57\u003c/sub\u003e = -0.167, p\u0026thinsp;=\u0026thinsp;0.205).\u003c/p\u003e \u003cp\u003eCompared to the fur keratin of regional common noctule bats, the fur keratin of long-distance migratory bats was depleted in \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH on average by 23.7\u0026permil; and by 0.7\u0026permil; in \u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC (t\u003csub\u003e57\u003c/sub\u003e= -2.68, p\u0026thinsp;=\u0026thinsp;0.009), while it was enriched in \u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN, on average, by 1.3\u0026permil; (t\u003csub\u003e26.3\u003c/sub\u003e = 3.57, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) in relation to the corresponding lighter isotopes. The isotopic composition of fur keratin did not differ between sexes (δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH: U\u0026thinsp;=\u0026thinsp;149.5, p\u0026thinsp;=\u0026thinsp;0.284; δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC: t\u003csub\u003e39\u003c/sub\u003e = -1.20, p\u0026thinsp;=\u0026thinsp;0.239; and δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN: t\u003csub\u003e39\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;1.31, p\u0026thinsp;=\u0026thinsp;0.199) or between samples across the autumn period (δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH: F\u003csub\u003e1,58\u003c/sub\u003e = 0.004, P\u0026thinsp;=\u0026thinsp;0.95; δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC: F\u003csub\u003e1,57\u003c/sub\u003e = 0.01, P\u0026thinsp;=\u0026thinsp;0.92; and δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN: F\u003csub\u003e1,57\u003c/sub\u003e = 0.02, P\u0026thinsp;=\u0026thinsp;0.89).\u003c/p\u003e \u003cp\u003eWe found differences in δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN values between sampling groups (F\u003csub\u003e3,55\u003c/sub\u003e = 7.14, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) with bats collected in Western France (G1) presenting higher δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN values than all other groups (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). We observed no significant differences in δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH and δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC values between sampling groups (H\u003csub\u003e3\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;6.91, p\u0026thinsp;=\u0026thinsp;0.075; and F\u003csub\u003e3,55\u003c/sub\u003e = 1.04, p\u0026thinsp;=\u0026thinsp;0.383, respectively).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eRelative proportion of regional and long-distance migratory bats\u003c/h2\u003e \u003cp\u003eWe categorized 71.7% (n\u0026thinsp;=\u0026thinsp;43) of the bats collected in wind farms as of regional origin and 28.3% (n\u0026thinsp;=\u0026thinsp;17) as of long-distance migratory origin. The sex ratio in our sample collection and among migratory individuals was female-biased (Χ\u0026sup2; = 4.1, p\u0026thinsp;=\u0026thinsp;0.042 and Χ\u0026sup2; = 4.5, p\u0026thinsp;=\u0026thinsp;0.035, respectively). The proportion of females was greater among migratory individuals compared to the total sample (82% and 67%, respectively). Among regional individuals, the female to male ratio was more balanced (60% females, 40% males, Χ\u0026sup2; = 1.2, p\u0026thinsp;=\u0026thinsp;0.273). Bats collected in Western France (G1) presented the highest proportion of migrants (60%) while none of the bats from the easternmost sampling group (G4) were categorized as migratory, owing to their high δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH values. Bats from sampling groups in central France, G2 and G3, had intermediate proportions of migratory bats (30% and 26%, respectively).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eIsotope-based geographic assignments\u003c/h3\u003e\n\u003cp\u003eCommon noctule bats were separated into five probable areas of origin using k-means clustering analysis: cluster 1 (centroid δ\u0026sup2;H = -29.2\u0026permil;, n\u0026thinsp;=\u0026thinsp;13), cluster 2 (centroid δ\u0026sup2;H = -35.8\u0026permil;, n\u0026thinsp;=\u0026thinsp;21), cluster 3 (centroid δ\u0026sup2;H = -45.4\u0026permil;, n\u0026thinsp;=\u0026thinsp;11), cluster 4 (centroid δ\u0026sup2;H = -55.7\u0026permil;, n\u0026thinsp;=\u0026thinsp;10), and cluster 5 (centroid δ\u0026sup2;H = -71\u0026permil;, n\u0026thinsp;=\u0026thinsp;5, Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The clusters explained 96.7% of the variation in δ\u0026sup2;H values. Males originated predominantly from cluster 2, while females were more equally distributed between clusters 1 to 4 (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Among the common noctule bats killed at wind farms in France, 57% most likely originated from Southern and Western Europe (clusters 1 and 2) and 43% originated from Central, Northern and Eastern Europe (clusters 3\u0026ndash;5) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e; Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eNumber of bats assigned to the clusters of origin in each sampling group.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCluster 1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCluster 2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCluster 3\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCluster 4\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCluster 5\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTotal\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e13 (22%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e21 (35%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e11 (18%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e10 (17%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e5 (8%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eWind energy production generates a green-green dilemma by killing legally protected and endangered animals. This dilemma could be solved by considering stronger conservation actions during the expansion of wind energy production\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Our study aimed to contribute to a better understanding of how wind turbines in Western Europe may impact distant population of migratory species, using common noctule bats as an example for a migratory bat species. Our study shows that almost a third of all common noctules killed by wind turbines in France originated from distant locations in northeastern Europe, which is consistent with data from noctule carcasses found at wind turbines in Germany\u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e. Our geographic assignments suggest a likely origin of long-distance migrants from Romania, Poland, Belarus, Russia, the Baltic countries and Fennoscandia, similar to findings from past studies on the geographic origin of long-distance migrating noctule bats in Europe\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e,\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e,\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e\u003c/sup\u003e. Our study therefore goes beyond previous findings by suggesting that the migratory movements of common noctule bats killed at wind turbines cover the entire Eurasian continent in a west-east direction. We also observed an increase in the relative proportion of long-distance migrants at collection sites in western France, in line with our prediction. Our results show that current permitting procedures in France do not adequately protect migratory bats, despite the fact that this species is covered by national and international legislation and conventions, including the Convention on Migratory Species of Wild Animals (CMS Convention; UNEP/EUROBATS Agreement, Bonn 1979, London 1991). We therefore agree with the recent conclusions that current European wind energy practices are failing to effectively protect endangered and legally protected bat species\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Our study also corroborates previous work on other migratory bat species, which showed a higher proportion of female than male bats among carcasses found at wind turbines in Europe\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. The relatively high proportion of females among long-distance migrants highlights the fact that the north-eastern populations of this species consist predominantly of reproducing females. We therefore expect that the potential impact of wind turbine fatalities in France could lead to significant declines in the affected populations, as juvenile production is driven by the number of females in the colonies. This could exacerbate the predicted population declines for migratory bats\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e, particularly for populations at the northeastern edge of the species' range.\u003c/p\u003e \u003cp\u003eWe also observed high δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN and low δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC values in long-distance migrating noctule bats, suggesting that these bats feed mainly on insects with limnic larval stages in their summer range in northeastern Europe\u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e,\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e. In contrast, stable isotope ratios indicated a higher proportion of terrestrial insects in the diet of regional conspecifics\u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e,\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e. Feeding on insects with limnic larval stages may provide long-distance migrating bats with a relatively high proportion of polyunsaturated fatty acids, such as linoleic acid, which are useful for torpor and endurance exercise\u003csup\u003e\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e\u003c/sup\u003e, and which are rare in the mammalian body in general, and in that of common noctule bats specifically\u003csup\u003e\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn our stable isotope approach, we used a combination of elements to offer insights into the ecology and geographic origin of animals. The value of this approach for bat species has been confirmed in previous work\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e,\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e,\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e,\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e,\u003cspan additionalcitationids=\"CR52\" citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e\u003c/sup\u003e. Although the isotopic approach is robust for geographic assignment of bats\u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e, it is important to note the underlying assumptions. To this end, we acknowledge that 1) the stable isotope composition of fur keratin only correlates with the isotopic composition of food and water consumed during the moulting period of bats\u003csup\u003e\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e. In migratory bats, including noctule bats, moulting occurs typically in summer, after the reproductive period of females and before migration between late July and early August\u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e,\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e\u003c/sup\u003e. Accordingly, the stable isotope composition of fur keratin is representative of the habitats where noctule bats live between late July and mid-August. If common noctule bats begin to migrate before moulting is complete, our stable isotope approach will provide less robust geographic assignments for the summer origin of bats\u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e. 2) Our observation of common noctule bats feeding on insects with limnic larval stages suggests that δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH values in fur keratin might be lower in this bats than in those with a diet of terrestrial insects\u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e. Since our transfer function was obtained from bat species with a terrestrial diet, a diet of insects with limnic larval stages could potentially bias our geographic assignments to higher latitudes. A multi-species comparison of the isotopic composition of fur keratin in several aerial insectivorous bats showed that median δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH values varied over a range of 20\u0026permil;, suggesting that we may have placed some of the long-distance migrants one or two isoclines further north than they originated (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Although we cannot refuse this possibility, we concur that our inferences are still robust, since a deviation by one or two isoclines still suggest a long-distance origin of bats from northeastern Europe, and since the cluster areas include several isocline zones (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). 3) Our isoscape origin approach accounts for variation in stable isotope ratios in bat fur and also in precipitation water\u003csup\u003e\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e\u003c/sup\u003e. Therefore, assignment areas are relatively large. We acknowledge this low spatial resolution. However, given the migratory distances covered by some common noctules, our approach was sufficiently robust to separate long-distance migrants from regional bats. 4) Our sampling effort in France were concentrated along a west-east transect covering 500 km across France. Therefore, we cannot infer the geographic origin and relative proportion of long-distance migrants in other regions of France, such as northern and southern France. Furthermore, 5) our conclusions are based on 60 individuals collected from four regions. Although we consider this sample size to be sufficient to draw robust conclusions, we acknowledge that the sample size varies along the west-east transect. We suggest larger sampling efforts at wind turbines across larger areas in Europe to generate a comprehensive picture on the migration of common noctule bats in Europe, and also about the potential impact wind energy production may have on distant populations of this migratory species. Lastly, 6) our study identifies the relative proportion of long-distance migrating noctule bats, but cannot quantify with empirical data the absolute number of long-distance migrating noctule bats killed by wind turbines in France.\u003c/p\u003e \u003cp\u003eGiven these limitations, we estimate here the impact of wind energy production in France on migratory bats. To do this, we assume that mortality estimates from central Europe of 14 bats killed per wind turbine per year are representative for France\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e, which currently hosts about 9,700 onshore wind turbines with a total power capacity to 22.1 GW\u003csup\u003e\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003e. This leads to the inference that about 140,000 bats are killed per year at French wind turbines. In addition, we assume a relative proportion of about 18% for common noctule bats among bat carcasses found at wind turbines\u003csup\u003e\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e\u003c/sup\u003e, of which about 30% are long-distance migrants (this study, \u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e). This corresponds to an estimated 25,200 common noctule bats killed at wind turbines per year in France, of which 17,640 are of regional and 7,560 of a north-eastern origin. Considering that common noctule bats are only one of several vulnerable migratory bat species, we suggest that the total impact of bat fatalities at French wind turbines is far greater than estimated for this single species. Other migratory species such as Nathusius' Pipistrelle (\u003cem\u003ePipistrellus nathusii\u003c/em\u003e), parti-coloured bats (\u003cem\u003eVespertilio murinus\u003c/em\u003e), Leisler's Bat (\u003cem\u003eNyctalus leisleri\u003c/em\u003e), Greater Noctule (\u003cem\u003eNyctalus lasiopterus\u003c/em\u003e) and Schreiber's Bat (\u003cem\u003eMiniopterus schreibersii\u003c/em\u003e) have also been documented to be killed by wind turbines in France\u003csup\u003e\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e\u003c/sup\u003e. This highlights the urgent need for implementing mitigation schemes at the operating wind turbines in France as well as during the project development phase and environmental risk assessments of new onshore wind farms, by using established and highly effective curtailment protocols\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e,\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u003c/sup\u003e. We plead for the implementation of these mitigation schemes in all European countries\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e,\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eWe demonstrate that about one third of common noctule bats killed by wind turbines in France are migratory and of distant geographic origin. The discovery of dead bats at wind turbines in France in general and the discovery of long-distance migrating bats in particular is contrary to the legislation, both on the national (Loi de protection de la nature, \u0026sect;\u0026nbsp;76\u0026ndash;629, 1976) and EU level (habitat directive, 92/43/EWG), and it also conflicts with international agreements, such as the CMS Convention (UNEP/EUROBATS agreement, Bonn 1979, London 1991). We call for immediate action to implement efficient mitigation measures for newly installed wind turbines and also for retroactive implementation of mitigation measures for wind turbines already in operation\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. These measures are important as the expansion scenarios for wind energy production in Europe envisage the installation of thousands of wind turbines in France and across Europe\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Failing to practice optimal siting of wind turbines, i.e. away from ecologically sensitive areas, and to implement curtailment schemes, may have far-reaching consequences for European biodiversity in general and vulnerable bat species in particular.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStudy area and fur sample collection\u003c/h2\u003e \u003cp\u003eWe analysed fur samples collected from 60 common noctule bats (\u003cem\u003eNyctalus noctula\u003c/em\u003e) that were found dead under wind turbines during routine carcass searches following general monitoring schemes\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. This monitoring was conducted by local environmental consulting firms and organizations between 2010 and 2023 at 23 multi-wind turbine facilities across three provinces in France: Bretagne/Pays-de-la-Loire (n\u0026thinsp;=\u0026thinsp;3 surveyed multi-wind turbine facilities), Centre-Val de Loire (n\u0026thinsp;=\u0026thinsp;18) and Bourgogne-Franche-Comt\u0026eacute;/Grand-Est (n\u0026thinsp;=\u0026thinsp;2). All carcasses included in our study were collected between July and October. The collection sites were grouped into four geographic clusters based on location and proximity. Specifically, wind farms in Bretagne/Pays-de-la-Loire and Bourgogne-Franche-Comt\u0026eacute;/Grand-Est were classified in one group each, namely G1 and G4, respectively. Wind farms in Centre-Val de Loire were divided into G2 (central-north), and G3 (central-south), according to administrative boundaries (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe fur samples were obtained by the Natural History Museum in Bourges (Centre-Val de Loire, France). From each carcass, we assessed the sex and age of the bat based on epiphyseal closure of finger bones where possible. Small tufts of fur were collected from the interscapular region using scissors and then transferred to dry Eppendorfs tubes for shipment to the stable isotope laboratory at the Leibniz Institute for Zoo and Wildlife Research (IZW, Berlin, Germany) for isotopic analysis. Juvenile bats were not included in our analysis due to potential age-related differences in isotopic composition between juvenile and adult bats\u003csup\u003e\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eStable isotopes analysis\u003c/h3\u003e\n\u003cp\u003eAll fur samples were cleaned with a 2:1 chloroform-methanol solution to remove surface oils and contaminants, then dried in an oven at 50\u0026deg;C for 24h.\u003c/p\u003e\n\u003ch3\u003eStable hydrogen isotope analysis\u003c/h3\u003e\n\u003cp\u003eTo account for the isotope exchange of hydrogen between fur keratin and ambient air, we used a comparative equilibration approach with the fur samples and previously calibrated keratin reference materials with \u0026lsquo;known\u0026rsquo; non-exchangeable δ\u0026sup2;H values\u003csup\u003e\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e\u003c/sup\u003e. For this purpose, we used in-house keratin laboratory reference materials, which included Swedish and Spanish sheep fur and Tanzanian goat fur (SWE-SHE; ESP-SHE; AFR-GOA, respectively). These in-house reference materials were previously calibrated against the revised and most updated isotope values of CBS, KHS, USGS42/43 \u003csup\u003e61,62\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eSubsamples of bat fur and keratin reference materials were weighed with a microbalance to target a mass of about 0.3 mg of material, and placed in silver capsules (IVA Analysetechnik e.K., Meerbusch, Germany). These capsules were placed into microplates and left to equilibrate with lab ambient air for a week. After equilibration, samples were placed in an auto-sampler (Uniprep system\u003csup\u003e\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e\u003c/sup\u003e), flushed with helium, and combusted at 1350\u0026deg;C in a high-temperature (HT) reactor of an elemental analyser (TCEA, Thermo Scientific; or HT pyrolysis system, HEKAtech). A gas chromatography separated the H\u003csub\u003e2\u003c/sub\u003e, N\u003csub\u003e2\u003c/sub\u003e, and CO gases produced during the pyrolysis. The resulting H\u003csub\u003e2\u003c/sub\u003e from samples were measured for δ\u0026sup2;H values using a continuous flow isotope ratio mass spectrometer (Delta V Advantage, Thermo Scientific, Bremen, Germany). Isotopic ratios were expressed in parts per mil (\u0026permil;) deviations from the international standard: Vienna Standard Mean Ocean Water (VSMOW). The within-run analytical precision based on repeated analyses of keratin reference materials was better than 1.5\u0026permil; for δ\u0026sup2;H.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eStable carbon and nitrogen isotope analysis\u003c/h2\u003e \u003cp\u003eFor δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC and δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN analysis, fur samples were weighed to a target mass of 0.5 to 0.6 mg and placed in tin capsules (IVA Analysetechnik. Meerbusch, Germany). These subsamples were subsequently combusted at 1020\u0026deg;C in an elemental analyser. The resulting N\u003csub\u003e2\u003c/sub\u003e and CO\u003csub\u003e2\u003c/sub\u003e gases were separated in a gas chromatography column and analysed with a continuous flow isotope ratio mass spectrometer (Delta V Advantage, Thermo Scientific, Bremen, Germany). Values of δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC and δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN were expressed in parts per mil (\u0026permil;) deviations from international standards: Vienna Pee Dee Belemnite carbonate (V-PDB) for carbon and atmospheric nitrogen for nitrogen. The within\u0026ndash;run analytical precision based on repeated analyses of keratin reference materials was better than 0.2\u0026permil; for δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC, and 0.1\u0026permil; for δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN values.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eStatistical and spatial analysis\u003c/h2\u003e \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e \u003ch2\u003eTransfer function\u003c/h2\u003e \u003cp\u003eUsing the R package \u0026lsquo;IsoriX\u0026rsquo; (v. 0.9.2)\u003csup\u003e\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003e, we used a Linear Mixed Model to establish the transfer function between δ\u0026sup2;H\u003csub\u003ep\u003c/sub\u003e and δ\u0026sup2;H in fur keratin (δ\u0026sup2;H\u003csub\u003ef\u003c/sub\u003e) using the \u0026ldquo;\u003cem\u003ecalibfit()\u003c/em\u003e\u0026rdquo; function and a calibration dataset that included δ\u0026sup2;H\u003csub\u003ef\u003c/sub\u003e values from sedentary bats of known origin (IsoriX:CalibDataBat)\u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e. This calibration dataset contained δ\u0026sup2;H\u003csub\u003ef\u003c/sub\u003e values measured on 111 \u003cem\u003eNyctalus noctula\u003c/em\u003e during their sedentary period\u003csup\u003e\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e\u003c/sup\u003e, along with 224 bats from five non-migratory species (\u003cem\u003eBarbastella barbastellus, Eptesicus serotinus, Eptesicus isabellinus, Plecotus auritus\u003c/em\u003e, and \u003cem\u003ePlectotus austriacus\u003c/em\u003e)\u003csup\u003e\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u003c/sup\u003e. These published isotope values were re-calibrated to align with the current δ\u0026sup2;H assigned values for keratin reference materials\u003csup\u003e\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e\u003c/sup\u003e, ensuring comparability with our isotope measurements. Using the European isoscape of predicted amount-weighted mean annual δ\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eH in precipitation and the stable hydrogen isotope values from 335 known-origin European bats, we established the following transfer function for common noctule bats: δ\u003csup\u003e2\u003c/sup\u003eH\u003csub\u003ef\u003c/sub\u003e = 11.91 (\u0026plusmn;\u0026thinsp;5.11)\u0026thinsp;+\u0026thinsp;0.93 (\u0026plusmn;\u0026thinsp;0.09) * δ\u003csup\u003e2\u003c/sup\u003eH\u003csub\u003ep\u003c/sub\u003e.\u003c/p\u003e \u003cp\u003eBy using the \u0026ldquo;\u003cem\u003eisoscape()\u003c/em\u003e\u0026rdquo; function, we fitted a geostatistical mixed model including topographic features (elevation, longitude and latitude) to predict the variations in amount-weighted mean annual stable hydrogen isotope ratios in precipitation (δ\u0026sup2;H\u003csub\u003ep\u003c/sub\u003e) across Europe. The δ\u0026sup2;H\u003csub\u003ep\u003c/sub\u003e values were obtained from the Global Network of Isotopes in Precipitation (GNIP) (\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eIAEA/WMO, 2024\u003c/span\u003e) to build a European δ\u0026sup2;H\u003csub\u003ep\u003c/sub\u003e isoscape covering the distribution range of \u003cem\u003eNyctalus noctula\u003c/em\u003e.\u003c/p\u003e \u003cp\u003eTo separate bats of local origin from those of long-distance migratory origin, we employed the \u0026ldquo;\u003cem\u003eisofind()\u003c/em\u003e\u0026rdquo; function in \u0026lsquo;\u003cem\u003eIsoriX\u0026rsquo;\u003c/em\u003e. By applying the established δ\u0026sup2;H\u003csub\u003ep\u003c/sub\u003e isoscape and the transfer function between δ\u0026sup2;H\u003csub\u003ep\u003c/sub\u003e and δ\u0026sup2;H\u003csub\u003ef\u003c/sub\u003e values, we defined an isoscape of expected δ\u0026sup2;H\u003csub\u003ef\u003c/sub\u003e values for local bats across Europe (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Bats were classified as long-distance migratory if their δ\u0026sup2;H\u003csub\u003ef\u003c/sub\u003e values significantly differed from the expected δ\u0026sup2;H\u003csub\u003ef\u003c/sub\u003e values for local bats at their sampling location (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Conversely, if no differences was detected (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05), the local origin could not be ruled out, and the bats were considered as of regional origin.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eVariations in δ\u0026sup2;H\u003csub\u003ef\u003c/sub\u003e, δ\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC and δ\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003eN values\u003c/h2\u003e \u003cp\u003eAll statistical analyses were performed with R (v. 4.3.2, R Core Team 2023). We used Shapiro-Wilk tests to assess the normality of the isotope values. We explored the relationship between the three stable isotope values (C, N, H) using Pearson\u0026rsquo;s correlations and Spearman rank correlation. T-tests and one-way ANOVAs (or Mann-Whitney U tests and Kruskal-Wallis tests, when appropriate) were performed to evaluate the effects of sex, sampling groups, and migratory behaviour (i.e., regional or long-distance migratory, see below) on the isotope values. To assess seasonal variations in isotope values across years, the collection date was converted into \u0026ldquo;day of year\u0026rdquo; (Julian date).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eGeographic assignments based on δ\u0026sup2;H\u003csub\u003ef\u003c/sub\u003e, values\u003c/h2\u003e \u003cp\u003eWe separated bats into clusters with similar δ\u0026sup2;H\u003csub\u003ef\u003c/sub\u003e values using a k-means clustering analysis. The optimal number of clusters (k\u0026thinsp;=\u0026thinsp;5) was determined when the within-cluster variation was only marginally reduced by the addition of a new cluster (elbow method). The probable geographic origin of bats within each cluster was inferred using group assignments in \u003cem\u003eIsoriX\u003c/em\u003e\u003csup\u003e\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003e. The assignment probabilities of all individuals within the same cluster were combined for each location using Fisher\u0026rsquo;s method (Fisher, 1925) resulting in one map of probable origin per cluster. Using the same method, we produced a map of probable origin for all migratory individuals.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eC.C.V. conceived the study and ensured funding, L.A. curated the specimens and collected samples, C.C.V. and D.X.S. analyzed the samples, D.X.S. and M.M. analyzed the data, C.C.V., D.X.S. and M.M. wrote the manuscript, all authors commented on the paper.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThis project was supported by an Erasmus fellowship to MM. We thank all helpers involved in carcass searches and preparation, e.g., research offices, Groupe Mammalogique Breton (GMB) and Chauve-Qui-Peut. We also acknowledge the support of Anja Luckner and Michelle Busse from the stable isotope laboratory at the Leibniz Institute for Zoo and Wildlife Research (IZW).\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets used and/or analysed during the current study available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eRockstr\u0026ouml;m, J., et al. A safe operating space for humanity. \u003cem\u003eNature\u003c/em\u003e 461(7263), 472\u0026ndash;475 (2009).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSteffen, W., et al. Planetary boundaries: Guiding human development on a changing planet. \u003cem\u003eScience 347\u003c/em\u003e, 1259855 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eO\u0026rsquo;Neill, D. W., Fanning, A. L., Lamb, W. F. \u0026amp; Steinberger, J. K. A good life for all within planetary boundaries. \u003cem\u003eNature Sust.\u003c/em\u003e 1, 88\u0026ndash;95 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcCallum, M. L. Vertebrate biodiversity losses point to a sixth mass extinction. \u003cem\u003eBiodiv. Conserv.\u003c/em\u003e 24, 2497\u0026ndash;2519 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePowers, R. P. \u0026amp; Jetz, W. Global habitat loss and extinction risk of terrestrial vertebrates under future land-use-change scenarios. \u003cem\u003eNat. Clim. Chang.\u003c/em\u003e 9, 323\u0026ndash;329 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFlynn, D. F., et al. Loss of functional diversity under land use intensification across multiple taxa. \u003cem\u003eEcol. Lett.\u003c/em\u003e 12, 22\u0026ndash;33 (2009).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWinkler, K., Fuchs, R., Rounsevell, M. \u0026amp; Herold, M. Global land use changes are four times greater than previously estimated. \u003cem\u003eNat. Comm.\u003c/em\u003e 12, 2501 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eScheffers, B. R., et al. The broad footprint of climate change from genes to biomes to people. \u003cem\u003eScience\u003c/em\u003e 354, aaf7671 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C., et al. Toward solving the global green\u0026ndash;green dilemma between wind energy production and bat conservation. \u003cem\u003eBioScience\u003c/em\u003e 74, 240\u0026ndash;252 (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThaxter, C. B., et al. Bird and bat species' global vulnerability to collision mortality at wind farms revealed through a trait-based assessment. \u003cem\u003eProc. Roy. Soc. B\u003c/em\u003e 284(1862), 20170829 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKuvlesky Jr, W. P., Brennan, L. A., Morrison, M. L., Boydston, K. K., Ballard, B. M. \u0026amp; Bryant, F. C. Wind energy development and wildlife conservation: challenges and opportunities. J. Wildl. Manag. 71, 2487\u0026ndash;2498 (2007).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSaidur, R., Rahim, N. A., Islam, M. R. \u0026amp; Solangi, K. H. Environmental impact of wind energy. Renew. Sust. Energy Rev. 15, 2423\u0026ndash;2430 (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTolvanen, A., Routavaara, H., Jokikokko, M. \u0026amp; Rana, P. How far are birds, bats, and terrestrial mammals displaced from onshore wind power development?\u0026ndash;A systematic review. \u003cem\u003eBiol. Conserv.\u003c/em\u003e 288, 110382 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eArnett, E. B., Baerwald, E. F., Mathews, F., Rodrigues, L., Rodr\u0026iacute;guez-Dur\u0026aacute;n, A., Rydell, J., \u0026hellip; Voigt, C. C. Impacts of wind energy development on bats: a global perspective. In: \u003cem\u003eBats in the Anthropocene: conservation of bats in a changing world\u003c/em\u003e, (eds. Voigt, C.C., \u0026amp; Kingston T.) 295\u0026ndash;323 (Springer, 2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eO'Shea, T. J., Cryan, P. M., Hayman, D. T., Plowright, R. K. \u0026amp; Streicker, D. G. Multiple mortality events in bats: a global review. Mammal review, 46(3), 175\u0026ndash;190 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKruszynski, C., et al. High vulnerability of juvenile Nathusius' pipistrelle bats (\u003cem\u003ePipistrellus nathusii\u003c/em\u003e) at wind turbines. \u003cem\u003eEcol. Appl.\u003c/em\u003e 32, e2513 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFrick, W. F., et al. Fatalities at wind turbines may threaten population viability of a migratory bat. \u003cem\u003eBiol. Conserv.\u003c/em\u003e 209, 172\u0026ndash;177 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFriedenberg, N. A. \u0026amp; Frick, W. F. Assessing fatality minimization for hoary bats amid continued wind energy development. \u003cem\u003eBiol. Conserv.\u003c/em\u003e 262, 109309. (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePrintz, L., Tschapka, M. \u0026amp; Vogeler, A. The common noctule bat (\u003cem\u003eNyctalus noctula\u003c/em\u003e): population trends from artificial roosts and the effect of biotic and abiotic parameters on the probability of occupation. \u003cem\u003eJ. Urban Ecol.\u003c/em\u003e 7, juab033 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRodrigues, L., et al. Guidelines for consideration of bats in wind farm projects \u0026ndash; Revision 2014. EUROBATS Publication Series No. 6., 133 pp (UNEP/EUROBATS secretariat, Bonn, Germany, 2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWhitby, M. D., O'Mara, M. T., Hein, C. D., Huso, M. \u0026amp; Frick, W. F. A decade of curtailment studies demonstrates a consistent and effective strategy to reduce bat fatalities at wind turbines in North America. \u003cem\u003eEcol. Sol. Evid.\u003c/em\u003e 5, e12371 (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C., Kaiser, K., Look, S., Scharnweber, K. \u0026amp; Scholz, C. Wind turbines without curtailment produce large numbers of bat fatalities throughout their lifetime: A call against ignorance and neglect. \u003cem\u003eGlobal Ecol. Conserv.\u003c/em\u003e 37, e02149 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarr\u0026eacute;, K., et al. Over a decade of failure to implement UNEP/EUROBATS guidelines in wind energy planning: A call for action. \u003cem\u003eConserv. Sci. Pract. 4\u003c/em\u003e, e12805 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRydell, J., Bach, L., Dubourg-Savage, M. J., Green, M., Rodrigues, L., \u0026amp; Hedenstr\u0026ouml;m, A. Bat mortality at wind turbines in northwestern Europe. \u003cem\u003eActa Chiropt.\u003c/em\u003e 12(2), 261\u0026ndash;274 (2010).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eD\u0026uuml;rr, T. Schlagopferdatenbank Flederm\u0026auml;use Europa https://\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003elfu.brandenburg.de/lfu/de/aufgaben/natur/artenschutz/vogelschutzwarte/arbeitsschwerpunkt-entwicklung-und-umsetzung-von-schutzstrategien/auswirkungen-von-windenergieanlagen-auf-voegel-und-fledermaeuse/\u003c/span\u003e\u003cspan address=\"http://lfu.brandenburg.de/lfu/de/aufgaben/natur/artenschutz/vogelschutzwarte/arbeitsschwerpunkt-entwicklung-und-umsetzung-von-schutzstrategien/auswirkungen-von-windenergieanlagen-auf-voegel-und-fledermaeuse/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e accessed on 28.10.2024 (2024)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDenzinger, A. \u0026amp; Schnitzler, H. U. Bat guilds, a concept to classify the highly diverse foraging and echolocation behaviors of microchiropteran bats. \u003cem\u003eFront. Physiol.\u003c/em\u003e 4, 164 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLindecke, O., et al. Common noctule \u003cem\u003eNyctalus noctula\u003c/em\u003e (Schreber, 1774). In \u003cem\u003eHandbook of the Mammals of Europe\u003c/em\u003e (Hackl\u0026auml;nder, K. \u0026amp; Zachos, F.E.) 1\u0026ndash;25 (Cham: Springer International Publishing, 2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRoeleke, M., Blohm, T., Kramer-Schadt, S., Yovel, Y. \u0026amp; Voigt, C. C. Habitat use of bats in relation to wind turbines revealed by GPS tracking. Sci. Rep., 6(1), 28961 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRoeleke, M., Teige, T., Hoffmeister, U., Klingler, F. \u0026amp; Voigt, C. C. Aerial-hawking bats adjust their use of space to the lunar cycle. \u003cem\u003eMov. Ecol.\u003c/em\u003e 6, 1\u0026ndash;10 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRoeleke, M., et al. Landscape structure influences the use of social information in an insectivorous bat. \u003cem\u003eOikos\u003c/em\u003e 129, 912\u0026ndash;923 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C., et al. Movement responses of common noctule bats to the illuminated urban landscape. \u003cem\u003eLandsc. Ecol.\u003c/em\u003e 35, 189\u0026ndash;201 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eScholz, C. \u0026amp; Voigt, C. C. Diet analysis of bats killed at wind turbines suggests large-scale losses of trophic interactions. \u003cem\u003eConserv. Sci. Pract.\u003c/em\u003e 4, e12744 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSteffen, R., Z\u0026ouml;phel, U. \u0026amp; Brockmann, D. \u003cem\u003e40th anniversary bat marking Centre Dresden \u0026ndash; Evaluation of Methods and Overview of Results\u003c/em\u003e. 1\u0026ndash;132 (S\u0026auml;chsisches Landesamt f\u0026uuml;r Umwelt, Landwirtschaft und Geologie, 2004).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHutterer, R., Ivanova, T., Meyer-Cords, C \u0026amp; Rodrigues, L.L. \u003cem\u003eBat migrations in Europe a Review of Banding Data and Literature\u003c/em\u003e (Federal Agency for Nature Conservation, 2005).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLehnert, L. S., et al. Variability and repeatability of noctule bat migration in Central Europe: evidence for partial and differential migration. \u003cem\u003eProc. Roy. Soc.: Biol. Sci.\u003c/em\u003e 285, 20182174 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C., Popa-Lisseanu, A. G., Niermann, I. \u0026amp; Kramer-Schadt, S. (2012). The catchment area of wind farms for European bats: a plea for international regulations. \u003cem\u003eBiological conservation\u003c/em\u003e, \u003cem\u003e153\u003c/em\u003e, 80\u0026ndash;86 (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C., Lehnert, L. S., Petersons, G., Adorf, F. \u0026amp; Bach, L. Wildlife and renewable energy: German politics cross migratory bats. \u003cem\u003eEur. J. Wildl. Res.\u003c/em\u003e 61, 213\u0026ndash;219 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMăntoiu, D. Ş., et al. Wildlife and infrastructure: impact of wind turbines on bats in the Black Sea coast region. \u003cem\u003eEur. J. Wildl. Res.\u003c/em\u003e 66, 1\u0026ndash;13 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReusch, C., Lozar, M., Kramer-Schadt, S. \u0026amp; Voigt, C. C. Coastal onshore wind turbines lead to habitat loss for bats in Northern Germany. \u003cem\u003eJ. Environm. Manag.\u003c/em\u003e 310, 114715 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReusch, C., Paul, A. A., Fritze, M., Kramer-Schadt, S. \u0026amp; Voigt, C. C. Wind energy production in forests conflicts with tree-roosting bats. \u003cem\u003eCurr. Biol.\u003c/em\u003e 33, 737\u0026ndash;743 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBfN. National Implementation Report to EUROBATS. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.eurobats.org/sites/default/files/documents/pdf/Meeting_of_Parties/Inf.MoP8_.21_NIR_Germany.pdf\u003c/span\u003e\u003cspan address=\"https://www.eurobats.org/sites/default/files/documents/pdf/Meeting_of_Parties/Inf.MoP8_.21_NIR_Germany.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2018)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBas, Y., Kerbiriou, C., Roemer, C., Julien, J.F. Bat population trends. Mus\u0026eacute;um National d\u0026rsquo;Histoire Naturelle. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://croemer3.wixsite.com/teamchiro/population-trends\u003c/span\u003e\u003cspan address=\"https://croemer3.wixsite.com/teamchiro/population-trends\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (accessed 24.10.2024) (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLehnert, L. S., Kramer-Schadt, S., Sch\u0026ouml;nborn, S., Lindecke, O., Niermann, I. \u0026amp; Voigt, C. C. Wind farm facilities in Germany kill noctule bats from near and far. \u003cem\u003ePloS one\u003c/em\u003e 9, e103106 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C. \u0026amp; Lehnert, L. S. Tracking of movements of terrestrial mammals using stable isotopes. In \u003cem\u003eTracking animal migration with stable isotopes\u003c/em\u003e (pp. 117\u0026ndash;135). Academic Press.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFraser, E. E., Longstaffe, F. J. \u0026amp; Fenton, M. B. Moulting matters: the importance of understanding moulting cycles in bats when using fur for endogenous marker analysis. \u003cem\u003eCan. J. Zool.\u003c/em\u003e 91, 533\u0026ndash;544 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C., Lindecke, O., Sch\u0026ouml;nborn, S., Kramer-Schadt, S. \u0026amp; Lehmann, D. Habitat use of migratory bats killed during autumn at wind turbines. \u003cem\u003eEcol. Appl.\u003c/em\u003e 26, 771\u0026ndash;783 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C., Lehmann, D. \u0026amp; Greif, S. Stable isotope ratios of hydrogen separate mammals of aquatic and terrestrial food webs. \u003cem\u003eMeth. Ecol. Evol.\u003c/em\u003e 6, 1332\u0026ndash;1340 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C., et al. The trans-boundary importance of artificial bat hibernacula in managed European forests. Biodiv. Conserv. 23, 617\u0026ndash;631 \u0026lt;uvertical-align:super;\u0026gt;(\u0026lt;/uvertical-align:super;\u0026gt;2014\u0026lt;uvertical-align:super;\u0026gt;)\u0026lt;/uvertical-align:super;\u0026gt;\u0026lt;uvertical-align:super;\u0026gt;.\u0026lt;/uvertical-align:super;\u0026gt;\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C., Rosner, E., Guglielmo, C. G. \u0026amp; Currie, S. E. Fatty acid profiles of the European migratory common noctule bat (\u003cem\u003eNyctalus noctula\u003c/em\u003e). \u003cem\u003eSci. Nature\u003c/em\u003e 106, 1\u0026ndash;8 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoigt, C. C., S\u0026ouml;rgel, K., Šuba, J., Keišs, O. \u0026amp; Pētersons, G. The insectivorous bat \u003cem\u003ePipistrellus nathusii\u003c/em\u003e uses a mixed-fuel strategy to power autumn migration. \u003cem\u003eProc. Roy. Soc.: Biol. Sci.\u003c/em\u003e 279, 3772\u0026ndash;3778 (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePopa-Lisseanu, A. G., et al. A triple-isotope approach to predict the breeding origins of European bats. \u003cem\u003ePLoS One\u003c/em\u003e, 7, e30388 (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePylant, C. L., Nelson, D. M. \u0026amp; Keller, S. R. Stable hydrogen isotopes record the summering grounds of eastern red bats (Lasiurus borealis). \u003cem\u003ePeerJ\u003c/em\u003e, 2, e629 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKruszynski, C., et al. Identifying migratory pathways of Nathusius' pipistrelles (\u003cem\u003ePipistrellus nathusii\u003c/em\u003e) using stable hydrogen and strontium isotopes. \u003cem\u003eRapid Comm. Mass Spectr.\u003c/em\u003e 35, e9031 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIlyin, V. Y. The seasonal shedding of \u003cem\u003ePipistrellus nathusii\u003c/em\u003e and \u003cem\u003eNyctalus noctula\u003c/em\u003e. Pages 86\u0026ndash;89 \u003cem\u003ein\u003c/em\u003e V. Yu Ilyin, P. P. Strelkov and V. A. Rodionov, editors. Proceedings of the Fifth All-Union Bat Conference, Penza, Russia. Penza State Educational Institute, Penza, Russia. (1990).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCourtiol, A., et al. Isoscape computation and inference of spatial origins with mixed models using the R package IsoriX. In \u003cem\u003eTracking animal migration with stable isotopes\u003c/em\u003e (pp. 207\u0026ndash;236). Academic Press (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAnonymous. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.statistiques.developpement-durable.gouv.fr/edition-numerique/chiffres-cles-energies-renouvelables-2023/11-eolien-\u003c/span\u003e\u003cspan address=\"https://www.statistiques.developpement-durable.gouv.fr/edition-numerique/chiffres-cles-energies-renouvelables-2023/11-eolien-\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (accessed 22.10.2024) (2024)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAnonymous. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://ssm-ecologie.shinyapps.io/suivi_eolien/\u003c/span\u003e\u003cspan address=\"https://ssm-ecologie.shinyapps.io/suivi_eolien/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (accessed 22.10.2024) (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarr\u0026eacute;, K., Froidevaux, J. S., Sotillo, A., Roemer, C. \u0026amp; Kerbiriou, C. Drivers of bat activity at wind turbines advocate for mitigating bat exposure using multicriteria algorithm-based curtailment. \u003cem\u003eSci. Total Environm.\u003c/em\u003e 866, 161404 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKravchenko, K. A., Lehnert, L. S., Vlaschenko, A. S. \u0026amp; Voigt, C. C. Multiple isotope tracers in fur keratin discriminate between mothers and offspring. Rapid Comm. Mass Spectr., 33, 907\u0026ndash;913 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWassenaar, L. I. \u0026amp; Hobson, K. A. (2003). Comparative equilibration and online technique for determination of non-exchangeable hydrogen of keratins for use in animal migration studies. \u003cem\u003eIsot. Env. Health Stud.\u003c/em\u003e 39, 211\u0026ndash;217.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSoto, D. X., Koehler, G., Wassenaar, L. I. \u0026amp; Hobson, K. A. Re-evaluation of the hydrogen stable isotopic composition of keratin calibration standards for wildlife and forensic science applications. \u003cem\u003eRapid Comm. Mass Spectr\u003c/em\u003e. \u003cem\u003e31\u003c/em\u003e, 1193\u0026ndash;1203. (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCoplen, T. B. \u0026amp; Qi, H. A revision in hydrogen isotopic composition of USGS42 and USGS43 human-hair stable isotopic reference materials for forensic science. Forensic Sci. Int, 266, 222\u0026ndash;225 (2016)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWassenaar, L. I., Sisti, L., Pilecky, M. \u0026amp; Kainz, M. Reproducible measurements of the δ2H composition of non-exchangeable hydrogen in complex organic materials using the UniPrep2 online static vapour equilibration and sample drying system. \u003cem\u003eMethodsX\u003c/em\u003e, \u003cem\u003e10\u003c/em\u003e, 101984 (2023).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"conservation, bat migration, stable isotopes, deuterium, IsoriX","lastPublishedDoi":"10.21203/rs.3.rs-5347084/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5347084/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cb\u003eWind turbines used to combat climate change pose a green-green dilemma when endangered and protected wildlife species are killed by collisions with spinning blades. Here, we investigated the geographic origin of bats killed by wind turbines along an east-west transect in France to determine the spatial extent of this conflict in Western Europe. We analysed stable hydrogen isotopes in the fur keratin of 60 common noctule bats (\u003c/b\u003e \u003cb\u003eNyctalus noctula\u003c/b\u003e \u003cb\u003e) killed by wind turbines during summer migration in four regions of France to predict their geographic origin using models based on precipitation isoscapes. We first separated migratory from regional individuals based on fur isotope ratios of local bats. Across all regions, 71.7% of common noctules killed by turbines were of regional and 28.3% of distant origin, the latter being predominantly females from northeastern Europe. We observed a higher proportion of migratory individuals from western sites compared to eastern sites. Our study suggests that wind-turbine-related losses of common noctule bats may impact distant breeding populations across whole Eurasia, confirming that migratory bats are highly vulnerable at wind turbines and that effective conservation measures, such as temporary curtailment of turbine operation, should be mandatory to protect them from collisions with wind turbines.\u003c/b\u003e \u003c/p\u003e","manuscriptTitle":"The trans-European catchment area of common noctule bats killed by wind turbines in France","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-11-07 16:29:22","doi":"10.21203/rs.3.rs-5347084/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-12-13T16:29:36+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-12-13T12:11:14+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-12-05T15:47:50+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-11-29T09:58:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"260260566801327440654539138795114470647","date":"2024-11-28T08:46:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"135525741282238766273571419998051927120","date":"2024-11-13T08:33:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"175408550887761752860490594503407776139","date":"2024-11-13T07:25:16+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-11-06T11:00:00+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-11-06T10:58:59+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-10-30T06:25:36+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-10-29T04:21:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-10-28T12:20:11+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"10a4664c-18a1-475a-ab94-6acdf5c5cc3a","owner":[],"postedDate":"November 7th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":39894464,"name":"Biological sciences/Ecology"},{"id":39894465,"name":"Biological sciences/Zoology"},{"id":39894466,"name":"Earth and environmental sciences/Ecology"}],"tags":[],"updatedAt":"2025-01-13T16:02:56+00:00","versionOfRecord":{"articleIdentity":"rs-5347084","link":"https://doi.org/10.1038/s41598-025-85636-5","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-01-09 15:57:43","publishedOnDateReadable":"January 9th, 2025"},"versionCreatedAt":"2024-11-07 16:29:22","video":"","vorDoi":"10.1038/s41598-025-85636-5","vorDoiUrl":"https://doi.org/10.1038/s41598-025-85636-5","workflowStages":[]},"version":"v1","identity":"rs-5347084","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5347084","identity":"rs-5347084","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}