I am a behavioural ecologist, interested mainly in the interplay of individual animal movement and ecology. More specifically, I am asking how resources, inter-individual interactions, and anthropogenic factors shape movement decisions and eventually space use of animals. Here, I am focusing on bats, one of the most diverse yet inconspicuous mammalian groups. In this project I record the movement of bats with miniaturized GPS loggers, trying to shed light on the questions:
What affects movement decisions and space use of bats?
What role do life history states play for space use and interactions of bats?
Which mechanisms facilitate the co-existence of bat species with a high niche overlap?
All European bats are insectivorous. Equipped with a unique ultrasonic sonar, they most effectively hunt for night active insects even in complete darkness. Insectivorous bats thus provide an irreplaceable ecosystem service, granting free pest control in many kinds of environments, including also intensively used arable landscapes.
Furthermore, the seasonal migration of some bat species is one of the largest recurring animal movements in Europe, with several species crossing the continent twice a year when migrating between wintering grounds in south-western and summering grounds in north-eastern Europe.
However, many bat species are threatened, e.g. due to the loss of foraging habitat or roosting opportunities. Thus all European bat species are legally protected, yet effective conservation strategies suffer from incomprehensive knowledge of ecology and behaviour of bats, as well as uncertain political responsibilities when migrating species cross numerous European countries. Our aim is to improve the knowledge of fine scale bat movements in order to identify resources that are crucial for preserving bat communities, especially in landscapes that are heavily influenced and used by humans. We want to inform political decision makers about conservation strategies that are in accordance with ecological as well as commercial goals.
Furthermore, we want to use bats as a model to understand how a group of similar species can stably co-exist although depending on a very narrow bandwidth of resources. While the overall diversity of European bats is quite high with respect to feeding and roosting habitats and also prey choice, several species in our study area show a high overlap in their niches. In this project we will focus on the common noctule bat (Nyctalus noctula). It is one of the largest bats in the study area, roosting in old forest stands, and preferentially hunting midges and beetles near small water bodies. We propose that there is a strong competition between noctule bats and two smaller bat species, the Nathusius’ bat (Pipistrellus nathusii) and the Common pipistrelle (Pipistrellus pipistrellus), which both have the same requirements for roosting and feeding as common noctule bats.
We will repeatedly equip common noctule bats with miniaturized GPS loggers and microphones for short periods throughout the whole activity season. The records will show how the movement decisions and space use of individual bats depends on season (non-migratory vs. migratory), sex, and age of the bats. Furthermore, the combination of GPS positions and on-board ultrasound recordings will enable us to link the movement of bats to encounter rates of con- and heterospecifics.
Furthermore, we will simulate different competitive environments by broadcasting bat calls in different habitats in different seasons to investigate whether interactions of bats are context depended. Variability in these interactions might help stabilizing the diversity of bat communities, for example when competitors influence movement decisions leading to temporal or seasonal resource partitioning.