Surprisingly, we still lack a unify theory to predict disturbance role in a changing environment. In particular, disturbances of different origins (e.g. natural vs. human induced) and different characteristics (especially their level of spatial and temporal correlation) are prone to have different selective effects. This may lead to the creation of specific adaptations to disturbances as well as to a change in diversity and community structure with changes in disturbance intensity and characteristics. In a theoretical study we could prove that small unpredictable disturbances have a smaller role in governing plant traits relative to large predictable disturbances. In addition, we showed that many of the expected trade-offs between plant strategies (e.g. the competition-colonization trade-off) are not created if the model used does not pre-define the existence of such negative correlation between traits.
Our work is not limited only to the theoretical world, but is also tested in real communities. To this end, we take advantage of the natural scenery of middle Europe, where many of the areas are repeatedly disturbed by several different disturbances. In particular we use three kinds of disturbances: molehills, representing small unpredictable disturbances; natural floods and/or human-induced disturbances created due to management (e.g. mowing or grazing) are used as large scale disturbances.

Selected papers:

Seifan M., D. Schloz-Murer, T. Seifan, and K. Tielbörger (2010) Contribution of molehill disturbances to grassland community composition along a productivity gradient. Acta Oecologica 36: 569-577.

Seifan M., T. Seifan, K. F. Jeltsch and K. Tielbörger. Accepted. Combined disturbances and the role of their spatial and temporal properties in shaping community structure. Perspectives in Plant Ecology, Evolution and Systematics (PPEES). Doi:10.1016/j.ppees.2011.11003

Past and present students participating in the project:

Daniela Schloz-Murer, 2005. Effect of small scale disturbances on European grassland community dynamics along a productivity gradient: molehills as a case study. Diploma thesis (joint supervision with K. Tielbörger(TÜ) and P. Edwards (ETH, Zürich)).

Alexander Schmid, 2006-2007. Die Dynamik europäischer Wiesengemeinschaften entland eines Produktivitätsgradienten – der Einfluss individueller Wechselbeziehungen, Düngung und der Artenherkunft (Changes in species interactions along a nutrient gradient in a European grassland community). Diploma thesis (joint with K. Tielbörger (TÜ) and R. Hampp (TÜ)).

Heike Horstmann, 2007-2008. Is there facilitation in central European grasslands? A search for patterns. Diploma thesis (joint supervision with K. Tielbörger (TÜ).

Astrid Hirth, 2011- Combined disturbances and their effect on grassland diversity – effect of molehills and land management. Diploma thesis (joint supervision with K. Tielbörger (TÜ).