Research Weisser Group

Biodiversity underlies many of the ecosystem services demanded by humans. To maintain biodiversity and ecosystem services, the creation of a ‘green infrastructure’ has been proposed for Europe. The basic idea is that this green infrastructure is as important for the human society as other infrastructures such as the electricity grid.

It is unclear, however, how such a green infrastructure should be created. Urban open spaces are currently planned by landscape architects with a primary focus on aesthetic design, or by city planners with little expertise in ecology. As a consequence, standard planning procedures do not create a green infrastructure. On the other hand, conservation often targets the few remaining areas with little influence of humans, also in cities. While this will conserve biodiversity and maintain certain ecosystem services, it also does not represent a targeted planning process aimed at providing a green infrastructure also in places where there are no wilderness areas left. In fact, conservation and urban planning often work against one another rather than together, for example when a planning process is executed with little reference to biodiversity and when nature protection laws interfere with this planning process by requiring adaptation of the design due to the occurrence of a protected species.

We have developed Animal-Aided Design® as a methodology for the design of open spaces that can help to overcome this difference between landscape architecture and conservation. The basic idea of Animal-Aided Design® (in short, AAD) is to include the presence of animals in the planning process, such that they are an integral part of the design. For AAD, the desired species are chosen at the beginning of a project. The requirements of the target species, i.e. their life-cycles, then set boundary conditions and serve as an inspiration for the design.
Download booklet that describes Animal-Aided Design (only in German). Please use the two-pages view in Adobe Acrobat!

Animal-Aided Design is a cooperation project with Dr. Thomas Hauck, Universität Kassel Link to Polinna Hauck Landscape+Urbanism

and a subproject of the Centre for Urban Ecology and Climate Adaptation (ZSK).

In the past two decades, an increasing number of studies has been performed to analyze the relationship between biodiversity and ecosystem functioning. We contribute to the search for ecosystem consequences of biodiversity loss in the DFG-funded Jena Experiment, a grassland biodiversity experiment coordinated by our research group, and in the BMBF-funded BIOLOG DIVA-Jena project (completed at the end of 2010), a study in semi-natural grasslands along a plant species richness gradient. A major conclusion that can be drawn from this research is that a low diversity in an assemblage is often associated with a lowered mean (and an increase in the variance) in many of the ecosystem variables investigated. In the Jena Experiment, for example, about 40% of ecosystem variables are affected by plant species richness. One major shortcoming of the current state of knowledge is, however, that for many of the observed biodiversity effects we do not know the underlying mechanism. We are interested in how species interaction change with increasing plant species richness and how these changes underlie the observed biodiversity effects on ecosystem variables. See the descriptions of the Jena Experiment and BIOLOG Diva-Jena for more detail.

In an ecological community, species interactions structure local populations and influence species coexistence. Two different, yet complementary, approaches to studying species interactions are community genetics, which recognises that within-species genetic variation can alter the interactions between different species; and, metacommunity ecology, which emphasizes the role dispersal plays in structuring local communities.

We investigate how community genetic interactions influence metacommunity dynamics, using a model tansy (Tanacetum vulgare) plant – aphid system. Individual tansy plants act as 'islands of resource' and, on this plant, classical metapopulation structuring is exhibited by competing specialist aphids and their parasitoids (e.g. We study this system using field, common garden and greenhouse experiments to uncover the mechanisms driving metapopulation and metacommunity dynamics. We also examine aphid population genetic structure and the effect of plant genetic variation.

One focus has been for several years the role of predation for prey population ecology and genetics. In 1999, we demonstrated that pea aphids, Acyrthosiphon pisum, produce winged offspring when exposed to predatory ladybirds, the first example of an enemy-induced morphological change facilitating dispersal (Weisser et al. 1999). We continue investigating the role of natural enemies for aphid wing induction, and have found wing-inducing effects of e.g. aphid parasitoids (Sloggett & Weisser 2002), lacewing larvae (Kunert & Weisser 2003) and aphid entomopathogenic fungi (Hatano et al. 2012). We also investigate the underlying mechanism of this response to the presence of natural enemies. Particular attention is paid to the role of (E)-ß-Farnesene (EBF), the main component of aphid alarm pheromone. We have shown (Kunert et al. 2005) that wing induction in the presence of natural enemies is mediated by EBF. Currently, we focus on the role that EBF plays in the network of ecological interactions between plants, aphids, ants and the natural enemies of aphids using e.g. rapid gas chromatography for real-time analysis of volatile communication (Joachim et al. 2013, 2014).

In our current DFG-funded project on tansy aphids metacommunity genetics we cooperate closely with the Helmholtz Zentrum München, who study the plant chemical ecology, and investigate the effect of expression of mono- and sesquiterpenes on metacommunity dynamics.