Forschungsprojekte

Binzer, A. et al. 2016. Interactive effects of warming, eutrophication and size structure: impacts on biodiversity and food-web structure. – Glob. Change Biol. 22: 220–227.

Fussmann, K. E. et al. 2014. Ecological stability in response to warming. – Nat. Clim. Change 4: 206–210.

Heckmann, L. et al. 2012. Interactive effects of body-size structure and adaptive foraging on   food-web stability. – Ecol. Lett. 15: 243–250.

Kalinkat, G. et al. 2013. Body masses, functional responses and predator–prey stability. – Ecol. Lett. 16: 1126–1134.

Lang, B. et al. 2012. Warming effects on consumption and intraspecific interference   competition depend on predator metabolism. – J. Anim. Ecol. 81: 516–523.

Rall, B. C. et al. 2012. Universal temperature and body-mass scaling of feeding rates. – Philos. Trans. R. Soc. B Biol. Sci. 367: 2923–2934.

Vucic-Pestic, O. et al. 2011. Warming up the system: higher predator feeding rates but lower energetic efficiencies. – Glob. Change Biol. 17: 1301–1310.

Many natural landscapes are characterized by a patchy distribution of habitats that are separated by a less-inhabitable landscape matrix. Examples of these spatial structures include (1) agricultural landscapes with forest fragments, ponds and small grasslands as patches within large areas that are dominated by intensively used fields or plantations; (2) lakes that are are surrounded by terrestrial ecosystems and (3) islands in the ocean. The local communities of these patches are not isolated but coupled by species dispersal. This yields metacommunities composed of the species across all habitat patches. Moreover, the habitat patches are linked by species movement creating spatial habitat networks.

What constrains the movement of species?

Movement is one of the most fundamental processes of life linking individuals with their resources, mating partners and resting sites. Why are the movement rates so different between species? We analyze how this variance is explained by movement modes (running, flying, swimming) and species‘ body masses and how this yields systematic patterns in spatial networks.  The movement theory is linked to natural movement trajectories by fitting Bayesian state-space models to unravel the importance of landscape characteristics for individual movement. Currently, the vast majority of movement trajectories is available for vertebrates. We aim at complementing this with data on invertebrate movement by employing camera systems in the laboratory (Dell et al. 2014) as well as passive sensor techniques in the field.

Dell, A. I. et al. 2014. Automated image-based tracking and its application in ecology. – Trends Ecol. Evol. 29: 417–428.

A big challenge in ecology is to link theory predictions obtained under simplifying assumptions to the complex patterns and processes found in natural ecosystems. For instance, natural communities are not only characterized by an entangled structure of inter- and intraspecific interactions between species but also by heterogeneous spatial distributions of habitat patches linked by species dispersal. The structure of these trophic and spatial networks constrains the diversity, dynamics and functioning of the communities. Therefore, experimental systems need to establish these types of networks under controlled and replicable conditions.

How can microbial networks help us to understand theory predictions?

Microbial networks comprising protists and bacteria have a long history in ecology. They have the big advantage that they are easy to manipulate, highly flexible and represent a great tool to test theoretical predictions in relatively short time. For example, it was generally assumed that global warming destabilizes natural systems due to an increased speed of life and accelerated oscillations. However, our microcosm experiments revealed that predator-prey (protozoa-bacteria) interactions are stabilized by warming due to dampened oscillations in population cycles, whereas extinctions due to predator starvation become more likely (Fussmann et al. 2014). Our current research investigates the processes driving coexistence in microbial networks comprising protists and bacteria on sugar resources.

Fussmann, K. E. et al. 2014. Ecological stability in response to warming. – Nat. Clim. Change 4: 206–210.