Spring is coming meaning that bats are getting to get active again and bats like the Nathusius’ Pipistrelle are starting their migration throughout Europe. The coming of spring also means that bat experts are slowly getting back in the field for acoustic surveys and monitoring of bat fatalities under wind turbines.
Before the next fieldwork season really kicks off, we would like to ask you the following question: did you communicate your data of bat fatalities under wind turbines? If you are not aware yet, the State bird protection observatory of the Brandenburg State Office for the Environment is collecting bat fatalities at wind turbines in Germany and european countries. The last update of the database was made in August 2023, compiling 4058 bat fatalities at wind turbines for Germany and 12597 for Europe. You can download the excel tables of the fatalities at wind turbines for the birds and bats for Europe and Germany (“Deutschland). Several thousands of fatalities sound like a lot but it is nothing in comparison of the 250.000 bat fatalities at wind turbines estimated per year in Germany. It is not even the tip of the iceberg but more like the head of a pin. Several reasons for this discrepancy between the number of the database and the above-mentioned study include the following facts: - many wind turbines are not monitored (anymore) for bat fatalities - carcasses cannot be found in vegetation like forests or are taken away or hidden by predators - many different organisations are doing the monitoring and are not allowed to share the data But one reason for this discrepancy is simply that people who have made discoveries of bat fatalities under wind turbines have not yet been reporting their observations. This is a real pity because discovering bat carcasses under wind turbines is a lot of hard and meticulous work. In comparison, communicating the results is a simple step that helps understand bat biology and conservation issues. These data that are not communicated are unfortunately lost forever for bat conservation and nature conservation more generally. That is the reason why we strongly urge all people with data of bat fatalities at wind turbines to take the time to dive in their hard drives and observation notebooks. There is a simple formular to communicate your observations. If you are not sure how to do it, we can help. If you have problems with the German language, we can help. If you know of people with data, you can share this blog post with them. For more information about this database, you can: - visit the website of the LfU Brandenburg - write an e-mail to Tobias Dürr
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Being both an environmentalist and a climate activist, it took me a long time to find a satisfying position about wind farms. In this blog post, I want to share with you some thoughts on the topic. On one hand, I studied biology and I used to be a nature consultant working on the impact of wind turbines on bats. On the other hand, I joined the climate movement in July 2019 and started supporting a local group of Scientists for Future. In summary, I am both very aware and worried about the climate crisis and the biodiversity crisis.
Wind farms constitute an essential tool to get away from fossil fuels and decarbonise the electronic grids. The price of wind energy is already cheaper than other sources of energy. The dimensions and energy production of wind farms keep on pushing new limits. Some turbines are being repowered and offshore parks are being constructed. This source of energy is booming and it is just the beginning. As an essential climate solution, wind farms unfortunately have the drawback that they also inadvertently kill birds and – what is often unknown – bats. An estimated number of 250.000 bats are killed by wind farms per year only for Germany. These casualties are often compared to other threats to wildlife like cats and window glasses to name but a few. Such mathematical comparisons ignore completely that different species of birds and bats are affected differently by these threats. On one hand, cats and window glasses often affect species with bigger populations. On the other hand, wind farms affect high-flying species with critical conservation status like the red kite (Milvus migrans) or migratory bat species like the Nathusius’ Pipistrelle (Pipistrellus nathusii) or the Common Noctule (Nyctalus noctula). Wind parks located in migration corridors like in Germany can have a dramatic impact on populations from individuals born in other countries. An additional threat to bats is especially problematic considering that bats generally have only one offspring per year. Furthermore, it is not because one threat affects fewer individuals that we should not tackle this threat. One thing that I found especially important here: we are now building a better world for humans and nature, not just a less bad world. That is why we should all strive to switch from fossil fuels to renewable energy without adding an additional burden on wildlife. We should all push for wind farms that have reduced or no impact by promoting solutions such as:
As we can see, different solutions exist and some are even applied. In Germany, new or repowered wind farms automatically have cut-in speed. The problem is that many older wind farms (ca. 75% of wind farms in Germany) do not have this conservation measure. Due to the increase of goals for the deployment of renewable energy, there is a higher pressure to find suitable areas for the installation of wind farms. While wind farms were previously installed in agricultural areas with lower biodiversity, some turbines are now installed in sensible areas like forests or conservation areas. This new situation increases the green-green dilemma between climate and nature protection. Wind farms are a great solution to tackle the climate crisis but should not be given a “free-out-of-jail card” by ignoring birds and bat casualties. Solutions to limit/reduce casualties exist and should be applied and researched more. A crucial aspect is to bring all actors to the table and find trade-offs eventually thanks to mediation. We should all strive to build this better world where we tackle the climate crisis without accelerating the nature crisis at the same time. Acknowledgements This idea of a “better world, not less bad” comes from the book “How to be a climate optimist” by Chris Turner. I thank Marcus Fritze for the photo and providing elements about the situation in Germany about how to improve the text. We are currently finding ourselves in a multitude of crises with a multitude of effects including the climate crisis and the biodiversity crisis. There are special situations where a solution to one crisis can also be a problem for another crisis. This is typically the case of wind energy for the climate crisis and the biodiversity crisis. When talking about wind energy as a threat to birds in Germany, a comparison is very often made with other threats. Based on estimates, many more birds are killed by cats or due to collisions with glass buildings than by wind farms. But one very important aspect is that these different human threats affect different species with variable conservation statuses. Simply comparing the sum of bird deaths from the different threats is the same as comparing apples and oranges. Furthermore, the estimates are given without confidence intervals so we do not know how reliable they are. We all know for example that it is very difficult to search for animal cadavers under wind farms. Lastly, the impact of wind energy on bats is often totally forgotten. Several species like the migratory Nathusius’ Pipistrelle (Pipistrellus nathusii) or the Common Noctule (Nyctalus noctula) are especially affected. It is estimated that 250.000 bats are killed by wind farms per year in Germany alone. And finally, such a graphic totally ignores the time axis. Thus, we expect more victims with the booming of wind energy offshore and onshore including the installation in natural areas like forests and landscape conservation areas. This comparison between threats is often used as a reason to minimize or ignore the urge to do something against the bird and bats casualties from wind energy. This is a dangerous reasoning because wind energy is emerging as a new and additional threat for some species and populations already under high stress. No technology should be given a “carte blanche” even if it helps tackling the climate crisis. This is the same situation when talking about the carbon footprints of different countries, the country releasing 1% of the global heat-trapping gasses also has to reach carbon neutrality. As bat conservationists, we do not want to block the development of wind energy but we want to make sure that its development takes into account wildlife. We already know of different measures such as curtailing and the creation of nature sanctuaries. And even if the task is immense, we should also engage more in taclking other threats for example by democratising colored collars for cats or bird-friendly glass for buildings. What is crudely missing is money and political will to tackle all these threats together. The task is immense but we have to strive in parallel for zero emission of heat-trapping gasses (climate neutrality) as well as zero impact for wildlife. This is extremely challenging but it is our common responsibility to create a better future for us and the next generations, not just a less bad future. As the IPBES and IPCC reported in 2021: “Biodiversity loss and climate change are both driven by human economic activities and mutually reinforce each other. Neither will be successfully resolved unless both are tackled together”. Acknowledgments: Thanks to Charlotte Roemer for her precious feedback. This text was initially published in german and english on the website of Deutsche Fledermauswarte.
With the increase of goals to tackle the climate crisis, the energy industry is logically looking for new areas to install wind farms. Similar to Germany, the energy companies in France are installing more and more wind farms in forests – a clear red line for nature conservationists. Despite a negative opinion of the Superior council of nature protection in Brittany, the local prefect gave his green light for the installation of wind farms in the second biggest forest of the region. From February 2023 on, the company Boralex is producing electricity using 17 wind farms installed in the forest of Lanouée. A mortality survey conducted between the 12th of June and the 25th of September 2023 led to a morbid record of 48 bat cadavers [1]. This number is of course an underestimate because other dead individuals were likely not found in vegetation or carried away by predators. Three species would be impacted:the common Pipistrelle Pipistrellus pipistrellus, the Nathusius Pipistrelle Pipistrellus nathusii and the common serotine bat Eptesicus serotinus. After only a few months of use, this park is already the second most impactful for bats in the region in terms of cumulated bat victims. These results are especially worrying considering that the wind farms are already curtailed at night based on meteorological conditions. Two local associations involved in nature conservation – the Groupe Mammalogique Breton and Bretagne Vivante are asking for two simple but clear measures: – a complete stop of wind production at night for this very impactful forest park – a complete stop of the development of wind parks in French forests. As nature conservationists, we support climate goals including the deployment of renewable energy. However, it is our responsibility that bat conservation is also considered and taken into account. This is especially important for bats considering their low reproduction rate and the many other conservation threats affecting them. After several months of work, I am proud to announce the realease of the book Bats by sound that I translated from english to french for the editor Delachaux et Niestlé. This book is a must-have for all french-speaking people working with bat ultrasounds in Europe. The book edited by Jon Russ and co-authored by many people is 480 pages long. It contains monographies about ultrasounds and social calls from 44 species. Last but not least, it contains a library of 450 downloadable calls to help you with your species identification. I hope that this book will be of interest to many of you, it contains an incredible amount of information about bat ultrasounds and social calls!
Please make sure to repost here or to share with friends or colleagues that might be interested. Each scientific publication has a very specific journey and faced numerous challenges before being published.
My third published paper from my PhD is probably one of my strongest stories of resilience. This is a paper that was included as the first chapter of my Phd but that I could only publish after submitting and defending. Started at the end of 2011, this paper was paused and restarted multiple times. I wrote this publication in different places of the world. For example, I worked on an earlier version of this paper in a writing course organised by my doctoral school in Scotland. I also worked on the paper in the bat lab of Gamboa (Panama) before doing fieldwork during the night. And I remember writing later versions of this paper after ending in my PhD, when my first daughter was having naps. I submitted the paper in July 2018 and it was finally accepted in October 2018. This publication is called „Information transfer as a reason for sociality in bats“ and there are many reasons why I like it. First of all, it is a literature review about my PhD with an evolutionary framework including a glossary. Writing a review is a challenge because of the number and diversity of topics but it helps you get a clearer idea oft he topic. Second, I am proud that I managed to publish in Mammal Review which is a guarantee of quality. Last but not least, this is my first peer-reviewed published as a single author. Importantly, this paper could not have reached its current state without the feebdack of all the people listed in the acknowledgments. This is a small „behind the scenes“ story about this publication like there are so many others. Next time you see a publication, ask yourself: „What is the story behind this paper?“. You can have a look at this publication on the website of Mammal Review. Glad to see that the paper was already cited 16 times. Financial and spatial instability is what I experienced as the biggest challenges to combine professional and personal life in academia.
Before the end of my PhD, I found a great opportunity to do a post-doc. It proved unfortunately incompatible to similarly wrap up my PhD and write a funding proposal as I was expecting my first child. I had to leave academia with regrets because I wanted to become a bat professor. Years after, I can say that I am quite happy to be in the private sector because I can better juggle with my job and my private time. And I am still connected to many bat researchers that became mentors and friends. I am convinced that this is one of too many stories. Too bad that academia is not better at keeping their young researchers. But this is a win for the private sector which benefit from workers with a lot of experience in project management, critical thinking and many other topics. Feel free to share your thoughts in the replies! A lot of things have happened since my last blogpost. First of all, I am now officially a doctor since my defense in April 2016 at the University of Konstanz (Germany). My PhD thesis 'Causes and consequences of sociality in a neotropical bat' includes four chapters. With the help of many collaborators, I managed to publish two of these chapters in 2016:
1. The first one 'Group size, survival and surprisingly short lifespan in socially foraging bats' was published in BMC ecology. Overview of the publication: To test if and how social group size affects survival in bats, we studied Pallas’s mastiff bat Molossus molossus (Pallas, 1766), a species that forms stable social groups that roost and forage together. Based on recaptures from 14 mixed-sex groups of thespecies in Panama, we found relatively small and intermediate, but stable groups, with a mean size of 9.6 ± 6.7 adults and juveniles. Strong selection towards small group size may result from psychoacoustic and cognitive constraints related to acoustic interference in social foraging and the complexity of coordinated flight. The short lifespans were unexpected and may result from life at the energetic edge due to a highly specialized diet. Median survival of females was very short with 1.8 years and a maximum estimated longevity of 5.6 years. Contrary to our expectations, we found no relationship between variation in group size and survival, a result similar to few other studies. The absence of a relationship between group size and survival may reflect a similar but optimized survival within the selected range of group sizes. We expect the pattern of small group sizes will be consistent in future research on species dependent on social information transfer about ephemeral resources. 2. The second one 'The value of molecular vs. morphometric and acoustic information for species identification using sympatric molossid bats' was published in Plos One. A press release of the publication is available in german on the website of the IZW Berlin. Overview of the publication: A fundamental condition for any work with free-ranging animals is correct species identification. However, in case of bats, information on local species assemblies is frequently limited especially in regions with high biodiversity such as the Neotropics. The bat genus Molossus is a typical example of this, with morphologically similar species often occurring in sympatry. We used a multi-method approach based on molecular, morphometric and acoustic information collected from 962 individuals of Molossus bondae, M. coibensis, and M. molossus captured in Panama. We distinguished M. bondae based on size and pelage coloration. We identified two robust species clusters composed of M. molossus and M. coibensis based on 18 microsatellite markers but also on a more stringently determined set of four markers. Phylogenetic reconstructions using the mitochondrial gene co1 (DNA barcode) were used to diagnose these microsatellite clusters as M. molossus and M. coibensis. To differentiate species, morphological information was only reliable when forearm length and body mass were combined in a linear discriminant function (95.9% correctly identified individuals). When looking in more detail at M. molossus and M. coibensis, only four out of 13 wing parameters were informative for species differentiation, with M. coibensis showing lower values for hand wing area and hand wing length and higher values for wing loading. Acoustic recordings after release required categorization of calls into types, yielding only two informative subsets: approach calls and two-toned search calls. Our data emphasizes the importance of combining morphological traits and independent genetic data to inform the best choice and combination of discriminatory information used in the field. Because parameters can vary geographically, the multi-method approach may need to be adjusted to local species assemblies and populations to be entirely informative. Some fresh news from southern Germany! After the lab session in London to retrieve genetic data, I spent most of my time analyzing survival data and writing my first manuscript. The manuscript - first chapter of my thesis - is approaching its final version and I expect it to be ready for submission by the end of this year or early next year ...
I have already presented most of the results of this manuscript at the European Research Symposium bats held in Croatia from 1 to 5 September. My next talk will be held Dec. 15 at my old institute, the Institute of Evolutionary Sciences, in Montpellier. I will present some results of survival analysis and also new results about foraging efficiency, based on the automatic scales installed at the entrance of the roosts of my social groups of Molossus molossus... Back to Panama, for the fifth fieldwork season of data collection of my PhD. I have three determined goals for this session : (i) collecting survival data, (ii) collecting DNA samples and (iii) manipulating group size. This is the third consecutive season where I am catching a network of a dozen roosts where I can determine group size.
During captures, animals are marked individually with transponders. With relevant statistical analyses, I will try and estimate survival based on recapture rates and detection probabilities. My species foraging in groups, group size probably has an effect on individual survival, that’s what we are trying to determine with these analyses. In parallel, I am collecting wing biopsies. These DNA samples will be genotyped to obtain microsatellites. They will be used to study relatedness of individuals within groups. I am especially interested in male reproductive success in function to group size. I assume it will be more difficult for the dominant male to insure paternity in groups with more females. And the main goal of this mission is to study the foraging efficiency (weight gain relative to time spent out of roost) in function to group size. Several roosts studied are equipped with automated systems with automated transponder reader and integrated scale. To investigate the effect of group size, I am comparing foraging efficiency for a group of normal size and of modified size. To modify group size, I capture individuals of the group that I keep for several days in captivity. Captive individuals are fed each night with mealworms and released within few days. I have already manipulated three groups, a fourth is ongoing and a fifth will come in the days to come. I have now collected a lot of data, in parallel I am now working on the analyses. |
AuthorLittle blog about my bat research and conservation action |