Understanding drivers of system stability at different levels of organization: From traits, via populations to communities
I am a quantitative ecologist, broadly interested in factors affecting the dynamics of a system at different levels of organization: from an individual level (traits) to community level. To obtain general understanding, my research attempts addressing the research questions across systems (species and habitats). To this end I combine diverse modelling tools, from simulation and statistical modelling. In particular, my toolkit includes projection matrix models, agent-based model and a set of advanced statistical techniques as meta-analysis, mixed-effects models, structural equation models.
My research has three main foci:
- Understanding stability. I am fascinated by stability concept both from the theoretical and applied points of views. In particular, the questions that I aim to answer are: how can we measure stability and to what extent can we unify the measures of stability across studies? Further, what are the mechanisms rendering a system stable?
- Population and community dynamics under disturbance and stress, especially considering the spatial aspect (i.e. meta-populations and meta-communities).
- Mechanisms allowing populations and communities to cope with the effects of environmental factors (understanding trait changes via phenotypic plasticity and microevolution). For example, one project focusing on this topic is a sTraitChange sDiv workshop, which I am leading together with Prof. Marcel Visser. In this project we ask to what extent the effects of climate on phenotypic traits propagate to the effects on demographic rates, and eventually, population growth rates. To address this question we apply meta-analyses on the dataset assembled on animal species from the studies around the world.
I am a behavioural ecologist, interested in the role of individual animal movements in ecology. More specifically, I am asking how fluctuating resource availability, landscape characteristics, and anthropogenic factors shape movement decisions and eventually space use of animals. During the last five years, I’ve been studying movements and interactions of bats, mostly in anthropogenically shaped landscapes in northern Germany, by the use of GPS loggers.
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.
However, many bat species are threatened, e.g. by the loss of foraging habitat or roosting opportunities. Although all European bat species are legally protected, effective conservation strategies suffer from incomprehensive knowledge of ecology and behaviour of bats. My 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. The ultimate goal is to identify agricultural management strategies that are in concordance with conservational and commercial goals alike.
This work is part of several projects that build on the latest telemetry system ATLAS. The system consists of several receiver stations that are deployed in our common study area in the agricultural landscape of northern Germany. The system allows automatic and simultaneous recording of the spatial position of up to a hundred flying animals that are equipped with extremely light-weight radio transmitters.
I will equip a colony of Common noctule bats that are known to hunt over agricultural fields in the area with radio transmitters to record their space use during foraging trips. The recordings will last for about two weeks, allowing me to see how the noctule bats react towards different agricultural measurements such as harvesting, soil cultivation, or the use of agrochemicals. Simultaneously, my colleagues from the other ATLAS projects and I will quantify insect abundance and diversity at foraging grounds, thereby shedding light on how prey availability influences the space use of foraging insectivores in human landscapes.
The empiric data on insect distribution, and movement behavior and space use of flying insectivores will be used to model the impact of different agricultural practices on biodiversity and ecosystem services.
The Act on the development of Renewable Energies (EEG 2017) has laid important foundations for promotion of wind energy production in the Federal Republic of Germany. Nevertheless, sometimes relatively high numbers of dead bats can be found at wind turbines (WEA). Bats are strictly protected by the Federal Nature Conservation Act (§44) and the European Habitat Directive (Annex IV). Thus, this leads to a conflict between the two goals of sustainable development: transition to renewable energies and the conservation of the native biodiversity. Recent studies, as well as our own GPS based data on common noctule (Nyctalus noctula), revealed indications that bats are attracted to WEA. However, the patterns behind it and the environmental stimuli potentially responsible for an enticement are still unknown. The identification of environmental stimuli for common noctule bats as well as investigating whether those stimuli potentially can be avoided, reduced or compensated for is one of the main goals of our project. Such mechanisms could lead to a reduced mortality risk, a potential redundancy of some official requirements and, therefore, an optimization of the wind turbine operation with regard to sustainable nature conservation. We use miniaturized GPS trackers, each with a microphone and an acceleration sensor, to investigate behaviour of common noctule bats, a species with a relatively high mortality risk by WEA. Using a spatial modelling approach we aim to derive specific habitat and WEA parameter which can be relevant for an attraction or deterrence of common noctule bats at WEA. We expect the results to be a specific starting point for combining a bat friendly and economic operation of WEA and, thus, to be a contribution to the smart energy transition. Involving the different stakeholders from the beginning onwards allows us to identify detailed questions of interest and it can be an advantage in applying our results in the field of wind energy and environmental sensor systems. The constructive and solution-oriented interaction with the stakeholders, especially at the planned final symposium, should ensure the transformative character and the economic relevance of our study.
Migratory animals vitally connect distant ecosystems worldwide, impacting key ecological processes by transporting nutrients, seeds, parasites and pathogens. Understanding animal migration strategies thus provides important insights into ecosystem connectivity. As the only flying mammals, bats represent a unique and widespread group of migratory animals, serving important ecosystem service functions as pollinators, seed dispersers and pest controllers. Bats comprise one fifth of all mammal species, over 1300 species. Despite their global abundance and pivotal role in ecosystem functioning, little is known about their migration ecology.
A single bat population can contain a fascinating mix of migration strategies, including individuals that remain resident throughout the year and individuals that migrate over short or long distances. These populations are referred to as partial migratory and offer an excellent opportunity to study individual migration strategies within populations. Partial migration is widespread in nature and considered to be an early stage in the evolution of full migration, although some species are also known to switch (back) from full migration to partial migration.
Migration poses a trade-off: migration can lead individuals to more favourable habitats, but is also risky and energetically costly. Individuals have to balance these costs and benefits of migration and are likely to differ in how they do so. Bats fundamentally differ from many migrating bird species in key life-history traits (e.g. hibernation and lactation). These traits profoundly impact the energy balance of individual bats and are thus likely to impact migration decisions. Knowledge about bat migration strategies in comparison to birds, may thus lead to crucial insights into the maintenance of partial migration across varying life-history strategies.
Hitherto, research on partial migration has almost exclusively focused on birds, yet novel tools have recently become available to study partial migration in the only other extant group of vertebrates with self-powered flight: bats. New and improved techniques, such as non-invasive isotopic geo- location, now allow for estimating the breeding origins of a large number of European bats, by using a stable isotope approach in combination with spatial movement data collected over decades of bat banding research.
Using this novel technique of isotopic geo-location in combination with bat personality assays, I will test whether migratory female noctule bats (Nyctalus noctula) have more exploratory personality- types than non-migrants.
Behavioural adjustment to anthropogenic environments
Consistent among-individual differences are found in most areas of biological research, and appear to constrain animals’ plasticity and thus the possibility to adapt optimally to the environment. My main interest is he interplay between cognitive abilities and behavioural differences, and their evolutionary causes and consequences. During my doctoral studies I developed and implemented an experimental approach to determine whether individual differences in cognition, behaviour and physiology are linked, and whether individuals that present different profiles display ecologically-relevant differences that might affect their fitness.
My current project is aimed individual variation can drive and constrain small mammals’ adaptations to human-induced rapid environmental changes. Behavioural and cognitive adaptations are likely to play a major role in coping with anthropogenic change because behaviour largely determines how individuals interact with their surroundings. Also, behavioural responses typically occur faster, and are more rapidly reversible, than other responses to environmental change. Anthropogenic environments provide a natural laboratory for in which to improve our understanding of the reciprocal interactions between ecological and evolutionary processes, key theoretical concepts including niche construction and community assembly, as well as the role humans play in eco-evolutionary dynamics since the accelerated rates and increased magnitude of landscape-level changes mark them as hotspots of contemporary evolution.
Using small mammals as model species, I empirically test for changes in risk-taking and exploration behaviour, behavioural and cognitive flexibility, space use and spatial skills along a gradient from rural to urban environmental conditions with varying degrees of anthropogenic influences (e.g. novel food availability, disturbance, light and noise pollution). Thereafter we investigate the drivers of such changes adopting a common-garden approach.
This work is part of the Collaborative Project “Bridging in Biodiversity Science (BIBS)”.
The Role of Transition Zones for Maintaining Functional Diversity in Agricultural Landscapes
I am an ecological modeller, interested in biodiversity across different spatial scales especially in agricultural landscape. I am working with spatially explicit, individual- and population-based models to increase the understanding of community dynamics emerging from the interaction at lower organisational levels (individuals or populations).
Especially in agricultural landscapes, the expansion and intensification of agriculture leads to the loss of biodiversity. Transition zones such as flowering strips or hedges are frequently mentioned as suitable mitigation measures which promote diversity in agricultural landscapes. In my current project, I develop a spatially explicit modelling approach to analyse the role of transition zones for functional diversity in a typical agricultural landscape. The model simulates population dynamics of interacting functional types of typical pollinating insects in an agricultural area in Northeast Germany (AgroScapeLabs). I am interested in the influence of the structural characteristics of transition zones within the regional landscape context (i.e. amount, area and location) for maintaining and promoting functional biodiversity.