My research interests focus on influence of adverse weather conditions on fitness and fitness relevant traits in Natterer’s bats (Myotis nattereri). Climate change will result in changing weather patterns, more extreme weather events and overall rising temperatures. Generally, organisms can respond to such changes with phenotypic plasticity, evolution or dispersal. Bats are long living mammals with a low reproductive rate, where adult survival largely shapes population dynamics. As a result, adaptive responses to variable weather conditions is likely to be driven by phenotypic plasticity. Nevertheless, to what degree Natterer’s bats are able to cope with negative weather influences in terms of fitness and population dynamics is still unclear. It is thus of crucial importance to understand the link between individual fitness and weather. To assess the ability of Natterer’s bats to deal with adverse weather conditions, I will collect information about activity, foraging success and roosting preferences under different weather conditions and analyse capture-mark-recapture data with regard to following questions: 1) Which effects have weather conditions (precipitation, temperature, extreme events, variability) on fitness (survival and reproduction) and fitness-relevant traits such as body size and phenology in M. nattereri? 2) How do different weather patterns influence foraging success? 3) Do temperatures affect activity, roost selection and foraging success during the hibernation period?

To reveal the link between weather and fitness, capture-mark-recapture data of >20 years, recorded by “Fledermausforschungsprojekt Wooster Teerofen e.V.”, will be analysed with respect to weather parameters. Moreover, I want to investigate which individual traits influence fitness and if these traits show plasticity in response to environmental parameters (e.g. if temperature during growing season affects body size). Because bats depend on ectothermous prey (arthropods), I will further investigate dependency of foraging success on weather patterns, to find an explanation for the link between weather and fitness. The nature park Nossentiner/Schwinzer Heide provides an ideal location with numerous summer roosts, several large hibernacula and the availability of long-term data. Here, I will collect faeces of bats during each time of the year and compare the dry weight of faeces per bat depending on different weather conditions to assess the link between foraging success and weather. The observed individuals are PIT-tagged, which allows it to estimate the number of individuals per box and, so, to calculate the amount of faeces per bat. Light-barriers in eight hibernacula, batcorders and camera trapping will record activity patterns of bats during winter. Based on these data, in combination with observations on the selection between roosting sites with different temperatures and foraging success of bats during winter, I want to assess the requirements and risks for Natterer’s bats in the hibernation season. Rising temperaturescould lead to novel challenges. A better understanding of behaviour and requirements with regard to weather patterns is of crucial importance for conservation of species in the context of climate change 

My project is funded by the “Landesgraduiertenförderung Mecklenburg-Vorpommern”

• Stapelfeldt, B., Tress, C., Koch, R., Kerth, G. & Scheuerlein A. (2023) Long-term field study reveals that warmer summers lead to larger and longer-lived females only in northern populations of Natterer’s bats. Oecologia. https://doi.org/10.1007/s00442-023-05318-9
• Stapelfeldt B, Scheuerlein A, Tress C, Koch R, Tress J, Kerth G. (2022). Precipitation during two weeks in spring influences reproductive success of first-year females in the
  longlived Natterer’s bat. R. Soc. Open Sci. 9: 211881. https://doi.org/10.1098/rsos.211881
• Stapelfeldt, B., Schöner, M., Kerth, G., van Schaik, J. (2020): Slight increase in bat activity after human hibernation count monitoring of a bunker complex in northern Germany. Acta Chiropterologica 22:383-390. https://doi.org/10.3161/15081109ACC2020.22.2.012