The abundance and diversity of natural populations are under threat from mechanisms including habitat loss and fragmentation, climate change and land use change. Although multiple mechanisms often overlap and there are synergies, land use change is considered one of the main drivers behind the aggressive transformation and loss of biodiversity. Changes in land use - along natural and anthropogenic land cover gradients - modify the composition and diversity of ecosystems, as well as their ecological processes and services. Our research capitalizes on the multilevel measurement (e.g. species interactions, abiotic factors, or evolutionary processes) of ecosystem transformation to address fundamental questions in ecology: how changes in species composition contribute to concomitant effects on ecosystem processes. We are therefore also interested in making projections and recommendations under certain scenarios related with ecosystem management, and the maintenance of biological, economic and social benefits of biodiversity. Below we describe primary areas of research topics developed in our research group:

Biodiversity Exploratories

Arthropods contribute significantly to the maintenance of terrestrial ecosystems and provide a variety of ecosystem services. A major challenge of conservation biology lies in understanding the effects of management practices on insect communities. This challenge is further complicated as responses to land use change may be species specific, might vary temporally and/or change in different habitats. Subsequently, the Biodiversity Exploratories project (https://www.biodiversity-exploratories.de/en/) provides a monitoring platform in grassland and forest ecosystems for large-scale field research to address crucial questions about the effects of different intensities of land use on insect biodiversity and ecosystem processes. The long-term nature of this experiment also allows for the examination of how biodiversity influences different ecosystem processes over time, such as pest control, biomass accumulation or deadwood decomposition.

Our group is also responsible for the coordination of the BELongDead experiment that takes place in the 30 “VIP” (very intensive plots) in the three Biodiversity Exploratories. Initiated by Ernst-Detlef Schulze of the Max-Planck-Institute of Biogeochemistry in Jena, logs (diameter 30-40cm, length 4m) of 13 different tree species were placed in triplicate in each of the plots in 2008. Since then we study insect colonization of these logs using emergence traps. Other groups study fungi, mites, other organisms or log decomposition, e.g. DOC flow. This unique experiment allows disentangling the effect of tree species from the effect of the surrounding forest in shaping the communities using deadwood and also decomposition.

Douglas-Fir and biodiversity of beech forests

Germany's forests face unprecedented challenges due to drought-induced tree mortality, highlighting the urgent need for adaptive forestry practices in the face of climate change. The collaborative project, "Future Potential of Douglas Fir and Silver Fir Mixture", is led by the Technical University of Munich (TUM) and the University of Göttingen, with support from the Bavarian State Institute of Forestry (LWF). At the Chair of Terrestrial Ecology, we are examining the ecological implications of incorporating Douglas fir and silver fir into managed European beech forests, which are predicted to have high future potential.

Our primary goal is to understand the impact of these mixed stands on native biodiversity, specifically focusing on taxonomic and functional diversity within communities of birds, bats, and insects. To achieve this, we conducted extensive field research across 63 plots (30 Douglas-fir-beech, 23 silver fir-beech, and 10 beech plots as control) in Lower Franconia (Spessart) during 2023-2024. The mixture plots represent a gradient of conifer proportions within the beech stands. Our data collection methodology for the diversity analysis includes:
•    Arthropod Collection: Utilizing Malaise and light traps to measure biomass and species richness of arthropods and nocturnal moths.
•    Bird and Bat Monitoring: Deploying audio recorders to analyze activity and diversity.
•    Bird Reproductive Success: Monitoring blue tit breeding in nest boxes installed on both beech and conifer trees to assess habitat quality.

Through these investigations, we additionally aim to identify potential thresholds for positive or negative impacts on faunal diversity associated with varying conifer proportions. Ultimately, our research will provide more insight into the ecological implications of these mixtures and guidance for forest managers to make informed decisions for resilient and biodiverse forests in the face of climate change.

Completed projects:

Spongy moth outbreaks and forest biodiversity

Every year, the control of spongy moths in mixed oak forests is the subject of public debate when they reproduce en masse. On the one hand, high densities of spongy moth caterpillars can lead to defoliation of oak and other tree species. This should be prevented by timely control measures to protect forest owners from damage and even destruction of their stands. On the other hand, mixed oak forests are very species-rich and home to a large number of endangered butterflies, moths, birds and other species, so there is concern that these will suffer in the short or long term from the use of insecticides. However, the spongy moth outbreak itself also has negative consequences for other species in an oak forest, as the species community is dominated by a single species, the pest, for some time. While the biology of the spongy moth is well known and there are already many good studies on the effects of defoliation on oak trees, there are still some gaps in our knowledge that are important for risk management, e.g. with regard to the short- and long-term effects of the spongy moth on oak growth depending on the location. There are also too few studies comparing the short- and long-term effects on non-target organisms between untreated areas (with high spongy moth densities) and treated areas (with reduced spongy moth densities). Finally, some international results cannot be easily transferred to Bavaria. The interactions between spongy moth densities, site conditions, the chosen management approach and the responses of oak forests and their communities can only be investigated in years of mass reproduction, as is expected in the coming years.
In order to gain further insights that are important for spongy moth management, the Bavarian State Ministry of Food, Agriculture and Forestry (StMELF) is therefore funding a research project from 2019 to 2021 in which the Bavarian State Institute for Forest and Forestry (departments of forest protection, remote sensing, forestry and forestry economics) is participating. Agriculture and Forestry (StMELF) is therefore funding a research project from 2019 to 2021 involving the Bavarian State Institute for Forestry and Forest Management (Departments of Forest Protection, Remote Sensing, Biodiversity, Nature Conservation, Hunting), the Technical University of Munich (Forest Growth, Terrestrial Ecology) and the University of Würzburg (Institute of Zoology).

Biodiversity in mixed beech forests

In the past, studies on biodiversity in forests were mainly conducted in unmanaged forests. However, the majority of forest land in Germany is used for forestry. Integrative forestry aims to coordinate the use and protection of biodiversity, thereby enabling the preservation of species diversity across the entire forest area. Integrative forest management includes measures such as promoting biotope wood structures in the form of habitat trees and deadwood, designating stepping stone areas and preserving special sites with specific biodiversity. The project ‘Biodiversity in mixed beech forests’ helped to provide the scientific foundations for decision-making processes that have an impact on biodiversity in the course of forest management.  Pure beech forests were compared with stands where beech was mixed with other species, such as spruce, oak, or other species. In addition, the role of small protected areas was considered. 

Brazilian grasslands

Land-use changes such as conversion of semi-natural grasslands to agriculture, silviculture, or highintensity pastures affect biodiversity and ecosystem functions and services. However, which ecosystem functions are affected when highly diverse grasslands are converted remains largely unknown. As a model system, we studied 80 grasslands in Rio Grande do Sul, southern Brazil, comprising exceptionally diverse permanent grasslands that are traditionally managed with burning of accumulated biomass and moderate grazing, and four additional grassland types with different present or historical management: Permanent grasslands with reduced or increased current management intensity and secondary grasslands after past agricultural or silvicultural use. We measured ten ecosystem functions covering all major below- and aboveground ecosystem components and the processes that link them, using the novel rapid ecosystem function assessment approach.

BIOLOG Diva-Jena

The collaborative BIOLOG DIVA-Jena research project 'The relationship between Biodiversity and Ecosystem Functioning in Grassland Ecosystems' funded by the German Federal Ministry of Education and Research (BMBF) between 2000 and 2010 used extensively managed grasslands in the states of Thuringia and Bavaria as model ecosystems, to study the relationship between biodiversity and ecosystem functioning. Using a gradient in plant species richness a finding of the project was that there was a relationship between plant species richness and ecosystem variables also in these semi-natural ecosystems. 

Agripopes

The importance of land-use intensity for biodiversity and ecosystem functioning was also the focus of the AGRIPOPES project, an ESF-funded network of 12 research teams across Europe. Using European agroecosystems, in particular wheat fields, as a model ecosystem, the project analyzed the effects of land use intensification parameters on biodiversity and the biocontrol potential of biodiversity. In a unique approach, more than 1300 wheat fields across were assessed and information about land use, biodiversity and ecosystem functioning assembled.