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Disturbance Ecology

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Our research topics:

  • Climate Change and Ecosystem Functioning
  • Climate Extremes and Extreme Weather Events
  • Disturbance, Resilience and Biodiversity
  • Experimental Community Ecology
  • Mountain Invasion Ecology
  • Wilderness and Remote Landscape Ecology
  • Ecological Novelty and Ecosystems Engineers
  • Biotic Interactions and Conservation Biology
  • Grasslands and their community change by climate change
  • Fodder quantity and fodder quality of grasslands under climate change
  • Tree and forest ecology under climate change

Our research projects:

KlifW026 („Future Forests“)- Resistance of selected tree species to late frost followed by summer drought (interaction of different weather extremes)

With regard to the future forest management of Bavarian forests in times of climate change and extreme climatic events, forward-looking research concepts are required with regard to the selection of suitable tree species. Testing future suitable tree species in experiments with extreme climatic events is an important contribution to future cultivation recommendations. In an experimental approach with late frost treatments (end of April/mid-May) combined with a subsequent summer drought, the resistance and tolerance of young trees of 30 different tree species will be investigated in order to discuss future silvicultural suitability for changing climatic situations. Young trees are considered to be particularly sensitive to late frost and drought and therefore form a kind of bottleneck in the long-term establishment and development of stands. Analysing the resistance of young trees to the aforementioned extreme events is necessary because very different and surprising effects can occur. The climatic changes not only affect the abiotic growth conditions, but also influence the resistance to insect damage and fungal infestation.

Juniorprofessur Störungsökologie und Vegetationsdynamik
Juniorprofessur Störungsökologie und Vegetationsdynamik

Honey bees vs. Wild bees: Competition and Carrying Capacity of Different Forest Types in Bavaria

Very few studies have investigated the conditions under which competition between honey bees and wild bees is effective or measurable. A first comprehensive meta-study was conducted by us in 2022 (see publication list 2023: Arzt et al. 2023). However, a well-planned field experiment is more meaningful. What role do forest biotopes play? In forests, the range of possible disturbance factors for such an experiment (other beekeepers, open land with different flora, settlements) can be narrowed down well. In the first year, the complete flora (= food resources), the landscape structures and all wild bee species and their abundance and nesting habitats are recorded in 12 different forest areas in Bavaria. In the second year, 3 bee colonies are placed in the centre of the study area and the effects on the abundance of wild bees are recorded. In the third year, 10 bee colonies are placed at this point in order to deliberately get the habitat capacity above a threshold value at which the competition between honey bees and wild bees becomes effective and visible.

Biodiversity and ecosystem services variability across the El Niño gradient in the Peruvian and Brazilian forests

Goal of the project BESTROPS is to investigate the changes in biodiversity and ecosystem services, promote a fair distribution of resources, and preserve the Natural Capital in rural communities of tropical forests. Combining field data, experimental and modelling approaches, it will study plant and soil biodiversity and ecosystem services across an elevation and climate gradient in the main area of largest impact of ENSO (Dryland coast, the Andes mountains, and the Amazonian rainforest). The main outcome of BESTROPS is to provide new open knowledge on the cultural and social dimension of tropical ecosystems, and insight in policy making without risking the natural capital under the forecasted climate change scenarios.

GLORIA mit Logo

Global Observation Research Initiative in alpine Environments

The GLORIA programme operates a world-wide long-term observation network with permanent plot sites in alpine environments. Vegetation and temperature data collected at the GLORIA sites will be used to discern trends in species diversity, composition, abundance, and temperature, and to assess and predict losses in biodiversity in these fragile alpine ecosystems which are under accelerating climate change pressures. The GLORIA programme aims at building globally applicable indicators for comparing magnitudes and velocities of changes of different biodiversity components across the major terrestrial biomes and climate zones on Earth. The basic focus is on vegetation and vascular plants, but where experts and funding are available, other organism groups such as bryophytes, lichens, and different vertebrate and arthropod groups are included.

Mountain Invasion Research Network

The aim of MIREN is to understand the effects of global change on species’ distributions and biodiversity in mountainous areas. We have expanded our initial focus on non-native plant invasions to consider more generally species (re)distribution under different drivers of global change, including biological invasions, climate change and land-use change. We perform globally replicated observational and experimental studies along elevation gradients to understand the processes that are shaping mountain plant communities at regional to global scales.

MIREN mit Logo

kiwa -
KI-basierte Waldüberwachung

Das Projekt KIWA ergänzt bestehende Systeme zur Waldbrandfrüherkennung durch Künstliche Intelligenz (KI). Spezielle Drohnensysteme identifizieren über Luftbilder flächendeckend mögliche Gefahrenstellen, Feuer und Rauch. So können Waldbrandherde erkannt werden, solange sie noch kontrollierbar sind. KIWA stellt hochaufgelöste Fernerkundungsdaten zu Waldökosystemen, zu Waldbrandrisiken einzelner Baumarten und Regionen Deutschlands sowie KI-gestützte Auswertungen bereit. Dadurch werden sensible und schützenswerte Ökosysteme identifiziert, die Entwicklung von Wäldern begleitet und Daten für das Forstmanagement bereitgestellt. Dies unterstützt den Umbau zu multifunktionalen und an den Klimawandel angepassten Wäldern. Langfristig sichert und erhöht das die biologische Vielfalt. Die Waldbestände werden abwechslungsreicher und damit weniger brandgefährdet.

Sustainable use of alpine and pre-alpine grassland soils in a changing climate

The aim of the SUSALPS project is to improve our knowledge on the effects of current and future climate and management on ecosystem functions performed by grasslands. In the process, the general framework of the socio-economy of the specific geographic region will be considered. Based on this improved knowledge, sustainable management options for grasslands in the alps and the foothills of the alps will be developed. These management options will be especially designed to support the climate protection function of grassland soils.


DroughtNet -
International Drought Experiment

All ecosystems will be impacted to some extent by climate change, with forecasts for more frequent and severe drought likely to have the greatest impact on terrestrial ecosystems. Terrestrial ecosystems are known to vary dramatically in their responses to drought. Coordinated experimental networks, however, are ideally suited for comparative studies at regional to global scales. The Drought-Net Research Coordination Network (RCN) - funded by the US National Science Foundation – is coordinated experimental network aimed at advancing understanding of how and why terrestrial ecosystems across the globe may differ in their sensitivity to drought.

NutNet -
Nutrient Network

Two of the most pervasive human impacts on ecosystems are alteration of global nutrient budgets and changes in the abundance and identity of consumers. In spite of the global impacts of these human activities, there have been no globally coordinated experiments to quantify the general impacts on ecological systems. The Nutrient Network (NutNet) is a grassroots research effort to address these questions within a coordinated research network comprised of more than 130 grassland sites worldwide.


DarkDivNet -
Dark Diversity Network

DarkDivNet is a global network to explore the dark diversity of plant communities. In January 2019 we have >100 potential study areas all across the world. Why are some species present and others absent in a locality? To answer this central ecological and biogeographical question, we have to explore biodiversity at different spatial scales while also considering species’ habitat preferences. Only a subset of all species in a region can tolerate the ecological conditions of a given site (the site-specific species pool). Of those, not all are realized in local communities. The absent part of the species pool forms the dark diversity of a community.

HerbDivNet -
The Herbaceous Diversity Network

The Herbaceous Diversity Network (HerbDivNet) is a network of researchers working at herbaceous grassland sites in 19 countries located on 6 continents performing coordinated distributed experiments and observations. All HerbDivNet sites are located in areas dominated by herbaceous vegetation representing the regional species composition.


Gypsum mining in Germany -
assessing challenges and chances for biodiversity

Gypsum mining in Germany creates open, vegetation-free areas in an otherwise densely vegetated cultural landscape. Many animal and plant species depend on such pioneer stages of succession, including rare and endangered Red List species. Gypsum mining creates high structural and habitat diversity for many species that no longer find a refuge in the often structure-poor agricultural landscape or in commercial forests. On the other hand, gypsum deposits are partly located in high-quality landscape areas with species-rich ecosystems. In some places, this results in conflicting goals.
In a joint research project between the University of Bayreuth and the Association of the German Gypsum Industry, the species diversity of different age and succession stages is being investigated in gypsum mining sites throughout Germany. The research question is which mechanisms and disturbance stimuli lead to a higher nature conservation value. It is this biodiversity in resource-limited open habitats that makes many gypsum mining sites special in terms of species and nature conservation during and after the active phase. The current research provides an opportunity to engage mining companies, conservation groups, the public, and decision-makers in the interests of species and nature conservation in gypsum mining regions and to develop spatially differentiated bases for decision-making.

Pressemitteilung vom 14.02.2022 (in German)


Imagefilm (in German) (YouTube)

Analysis of the relevance of intrinsic and anthropogenically induced (e.g. as a result of climate change) dynamics of ecosystems in Germany for the conservation of biodiversity.

The aim of the project is to compile and analyze the current state of research on the importance of dynamic processes of ecosystems in Germany on the different scale levels within the framework of a literature study. In doing so, we survey the state of research in the German-language as well as in the English-language literature. The aim of this literature study is not only to provide a technical overview for all relevant decision-makers, but also to develop a broad discussion, so that practical nature conservation receives concrete implementation concepts and proposals for measures, in order to be able to take dynamic processes in ecosystems more into account in the future. Based on a sound literature review, success controls can be better planned, implemented and adapted in times of climate change.

Funded by the Federal Agency for Nature Conservation (BfN, Bonn)


Effects of extreme weather events and diversity on ecosystem functions in experimental and natural plant communities

The experiment is carried out in a two-factorial design manipulating
(1) weather events (drought, heavy rain, freeze-thaw cycles, control)
(2) community composition (10 species divided a priori into grasses, dwarf shrubs, and herbs, of which one dwarf shrub and one herb were legumes).

Performance of communities and single species is measured with a variety of parameters, covering all important stages in the life cycle of plants (inter alia cover, above and belowground biomass production, flowering, seed production, germinability, or photosynthetic activity). Furthermore, abiotic parameters like soil moisture, precipitation and temperature are recorded on site. Through cooperation partners, other important ecosystem parameters are analyzed, e.g. gas exchange, soil fauna or microbial activity.

Consequences of more extreme precipitation regimes interacting with land use practices for productivity and diversity of temperate grassland

In EVENT 2, 5 factors are manipulated:
(1) weather events (early summer drought, late summer drought, weekly irrigation, control)
(2) mowing regimes (2- and 4-strike)
(3) Warming (summer or winter)
(4) winter sprinkling
(5) fertilization.

Performance of communities and single species is measured with a variety of parameters, covering all important stages in the life cycle of plants (cover, above and belowground biomass production, phenology, seed production, germinability or photosynthetic activity). Furthermore, abiotic parameters like soil moisture, precipitation and temperature are recorded on site. Through cooperation partners, other important ecosystem parameters are analyzed, e.g. microbial activity, soil fauna, N-cycle, stable isotopes.


Plasticity and adaptation of key plant species from different provenances to extreme climate events

As growth conditions will change significantly within the next century it is important to know how key plant species will respond to climate change, and, in particular, if they are able to cope with climatic extreme events. Intraspecific genetic differentiation (genotypes/ecotypes/provenances) might provide a chance to adapt to this changing environment.

The aim of this project is to identify suitable provenances of selected key species, which are able to contribute to the conservation of persistent ecosystems with high area occupancy in Bavaria like forests and grassland. In forestry, these provenance trials have a long tradition. However, in agriculture they are hardly established. Besides, traditional experiments focus on transplant-experiments and exposition to local climate. It is now necessary to test provenances with regard to more frequent and severe extreme events.

Events hidden in winter warming: Effects of recurrent soil freeze-thaw cycles on plant performance in the temperate zone

Ongoing global warming is expected to increase the recurrence of soil freeze-thaw cycles (FTC) in cool-temperate and other high-latitude regions due to decreases in snow cover and increased variability of air temperature in winter. FTC currently occur in more than half of the land surface of the northern hemisphere, therefore it is important to explore the ecological implications of their altered regimes due to climate change.
Within this project, we want to analyze the effects of intensified soil FTC in winter for the above and below-ground biomass production of two common vegetation types, grassland and heath, in a controlled field experiment in Central Europe.


Terminal drought experiment

The response of various ecological parameters to annually repeated climatic extreme events is investigated in the experiment EVENT 1. Surprisingly, productivity of the plant communities remains stable while a number of other parameters show strong reactions to drought.
In this experiment we monitor reactions to drought in the ecosystem in high temporal resolution until the total breakdown of the system. The main research questions are:

(1) Which ecosystem functions get lost first?
(2) Which species and species compositions tolerate drought stress longer?
(3) How long has a drought to last until lethal damage occurs?

This research is relevant in order to study early warning signs for breakdown of ecosystem functions and to allow for estimations of the effectiveness of future, more extreme drought occurrences. Own research in EVENT shows that single plants can adapt to repeated drought events even within one growing season.

Provenance trials of key European tree and grass species prone to drought and late frost

Climate warming is expected to shorten the duration of winter. However, in temperate grasslands, increased temperature variability and changes to cold acclimation cues could challenge plants by exposing them to frost at times when they are not fully cold acclimated. In particular, basal meristems of grasses at the soil surface are vulnerable to air temperature extremes if there is reduced snow cover, and the latter is predicted for temperate regions with climate warming.
When challenged by climate extremes, genetic variation within populations or dispersal from other populations enables species to persist at a specific location. High inter-specific variation in frost toler-ance can alter species composition if dispersal of frost tolerant ecotypes is limited.

In this experiment we compare inter-versus intraspecific variation in the responses of grassland plants to winter climate change. Specifically, we examine

(1) plant responses to variation in the frequency and intensity of soil freeze thaw cycles
(2) cold acclimation responses to warmer winters of shorter duration
(3) deacclimation and frost vulnerability in response to mid-winter thaw events

in controlled-environment chamber experiments.


European gradients of resilience in the face of climate extremes

The SIGNAL research project, funded by the BiodivERsA call of the ERA-Net, focuses on the effects of extreme weather events on biodiversity, ecosystem functions, resilience and tipping points in grasslands along a pan-European climatic gradient. Studying the effects of extreme drought on biodiversity and ecosystem functions is a key facet of current climate change research.
SIGNAL will investigate mechanisms of resilience in European grassland prone to novel climate extremes and identify early warning signals of thresholds and regime shifts by installation of replicated experimental manipulations of climate extremes at 8 grassland sites across Europe (field experiments and mesocoms including legumes, invasive species, species richness and within-species diversity). SIGNAL results will provide experimental evidence on mechanisms of resilience across European gradients, which may serve to regulate ecosystem services in the face of climate extremes and foster the identification of early warning signals of thresholds of regime shift.

previous projects





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