research

Ongoing projects:

Closing the seed dispersal loop: quantitatively linking plant-frugivore interactions to the recruitment cycle of plant communities

The ability to quantitatively link frugivore activity to later recruitment is the key to the understanding of seed dispersal processes and plant demography, especially in view of environmental impact factors such as forest degradation. However, owing to the high complexity of the cascade of seed dispersal and recruitment processes, establishing this link has so far largely been impossible. The proposed project aims at filling this gap by quantitatively linking plant-frugivore interactions to recruitment of associated plant populations in the light of forest degradation. To achieve this, we will use a novel molecular technique that determines the identity of seed dispersers from fecal material enclosing dispersed seeds. We will combine this approach with classic matrix population models based on empirical assessments of a fleshy-fruiting plant community in the field. This will allow us to track the impact of frugivore activity on recruitment of a plant community in logged and old-growth forest. Our study system is the Białowieża Primeval Forest (BPF) in Eastern Poland, the last pristine forest ecosystem of the European lowland. The forest provides a unique reference site, as species communities and ecological processes have evolved nearly uninterrupted since the last ice age. The project builds on comprehensive datasets from our previous studies on interactions among frugivore and plant communities in BPF, which show a significant loss of interactions and partners in plant-frugivore interactions in logged compared to old-growth forest. By assessing the impact of dispersers through recruitment, our project will allow for unique insights into the consequences of the loss of seed disperser species in degraded forest habitats for population dynamics in plant communities.

This project is funded by: DFG

Remote sensing as surrogate for phylodiversity and functional processes along land use and elevation gradients

The proposed project aims at investigating how changes in land use and elevation affects the functional and phylodiversity of trees, ants and birds and how this translates into the associated processes in particular herbivory and predation. As it is time consuming to quantify these measures of biodiversity and processes we need a simple indicator system for routine monitoring across large areas. New developments in remote sensing provide promising information for predicting biodiversity as well as ecosystem processes. Spectral diversity derived from remote sensing is for example positively linked to biochemical diversity of trees. In addition, the vegetation reacts on subtle changes due to herbivory by detectable changes in netto primary production and leaf pigment status. Therefore, we expect that we can predict variables describing the status of biodiversity as well as certain processes by measures of spectral and structural diversity derived from remote sensing. This would provide the ground to develop a simple and integrative indicator for ecosystem services. Such an indicator system based on remote sensing would be an important step towards an integrative monitoring of the status of biodiversity, ecosystem functioning and finally ecosystem services that can be used across large areas and even in areas with rough terrains.

This project is funded by: DFG

Former projects:

Identification of reserach gaps for sustainable forest management

Tropical forests are being lost at an alarming rate. This overexploitation is partly accompanied by illegal logging activities. As tropical forest habour more 50% of the terrestrial biodiversity it is essential to develop suitable indicators for the status of ecosystems. This holds not only for natural forest but also for commercially used forests. Thus, we aim to test suitable indicators to assess the status of differently managed forests.

This project was funded by: WWF Deutschland

Pollinator-plant interactions in agroecosystems 

Land-use intensification results in a decrease of pollinators in agro-ecosystems with potentail consequences for associated ecosystem services such as pollination. For this reason we study plant-pollinator interation networks in flowering strip that were planted within the agri-environmental scheme HIAP. We aim at sheding light into the structure and functionality of plant-pollinator interaction in these flowering strips in different landscape context. Our findings will likely contribute to concrete recommendations for sustainable land management.

This project was funded by: Universitätsstiftung Marburg

Avian monitoring program in Cajas National Park, Ecuador

All national parks of the Ecuadorian Andes harbour extremely high levels of biodiversity. At the same time they are highly threatened by human disturbance such as recreation activities or extraction of natural resources. Further, climatic changes are predicted for the Andean region with a reduction in rainfall and an increase in seasonality. It is therefore essential to know how species persistence varies among the remaining natural habitats. To achieve this, we will monitor the abundance, species composition and movement of birds as an important indicator group across their habitats. Thus, our approach will provide a broad array of information for park management that are urgently needed to develop better tools of conservation for the avifauna of the natural habitats in Cajas National Park.

This project was funded by: DFG

Impact of human disturbance on mutualistic interaction networks in a forest ecosystem of eastern Poland

Human disturbance changes species communities, structure and dynamics of forest ecosystems. It is therefore essential to understand the consequences for biodiversity, biotic interactions and ecological processes such as pollination and seed dispersal. Analysing networks of mutualistically interacting communities along a human disturbance gradient allows visualizing the complexity of such interactions in diverse communities. A major challenge of network analyses is to understand how the architecture and structural characteristics of pollinator and seed disperser networks can be related to ecological consequences for the system. Moreover, it is important to study such networks through time as species composition can show considerable variability among years. For this reason we are currently studying pollination and seed dispersal networks in differently modified forests areas of Białowieża Forest, Eastern Poland. This forest represents a unique study system for Europe providing the opportunity to compare ecological processes of differently disturbed areas to control sites. First results show a decrease of visitation rate, linkage density and interaction diversity with increasing modification. Further, interacting species and networks were more specialized in modified than in natural forests.

This project was funded by: DBU

Ecological processes as driving forces for sustainable forest management

Robert Bosch StiftungForests disappear at an alarming rate leading to changes in species diversity and composition. It is therefore essential to study in which way modified forest conditions affect interactions among species and consequently ecosystem stability and function. Fundamental processes for ecosystem function are mutualistic and antagonistic interactions such as pollination, seed dispersal, seed predation and regeneration. This project aims at studying the regeneration potential of differently sized forest patches in the highly fragmented landscape of South Africa. Thereby, we will investigate the effects of forest type on biodiversity (insects, birds, small mammals, trees) and ecosystem processes (pollination, seed dispersal, seed predation and regeneration) in coastal scarp forests in KwaZulu-Natal, South Africa. These findings will help to develop sound management recommendations such as establishment of corridors and creation of forest patches and to foster the development of community-based natural management programmes improving people’s livelihood.

This project was funded by: Robert Bosch Stiftung

Human impact on avian diversity, seed dispersal and regeneration proBIOTAcesses of East African rainforests: management tools and recommendations (subproject E11)

BIOTA Africa (BIOdiversity Monitoring Transect Analysis) is a cooperative, interdisciplinary and integrative research project with contributions from and in Benin, Burkina Faso, Germany, Ivory Coast, Kenya, Uganda, Namibia and South Africa funded by the German Ministry for Education and Research (BMBF).

Human impact leads to considerable loss of global biodiversity, but its consequences for ecosystem processes such as seed dispersal are hardly understood. More than 90% of tropical plants rely on animals for the dispersal of their seeds. Thus, a loss of animal dispersers might lead to a break-down of seed dispersal processes with long-term consequences for forest regeneration. In the third phase of BIOTA the aim of E11 coordinated by Prof. Böhning-Gaese (University of Mainz) is to:

1. up-scale our studies on the relationship between human disturbance, species diversity and ecosystem processes from the local over the regional to the continental level and evaluate Ficus-diversity as predictor for high biodiversity and “healthy” functional relationships in ecosystems;

2. investigate the contribution of pollination and seed dispersal to gene flow in Prunus africana to provide management recommendations for sustaining high genetic diversity in remaining populations of this endangerd species;

3. use a multi-disciplinary analysis of all data in the BioDiversity Observatories (BDO) to identify indicator groups and particularly sensitive processes for long-term monitoring of biodiversity and ecosystem function;

4. link biodiversity with socio-economy and land use in the farmland to provide tools and recommendations for land-use planning in highly utilized areas;

5. implement conservation education and outreach activities through further development of the community-based long-term bird monitoring program, production of information material, technical know-how and capacity building at the local as well as scientific level.

This project was funded by: German Ministry of Ecudation and Reserach