Ecological Theory and Concepts

A central element of the department’s research is the development and testing of ecological theories and concepts. Stability concepts are underlying most of our projects, for example the viability of small populations, the sustainability of harvesting regimes in rain forests, or the resilience of ecological and socio-ecological systems. Another main focus are the ecological consequences of disturbance events and multiple stressors.

Originally starting from population ecology, the department now has also a strong focus on theories and concepts related to communities and ecosystems. In particular, the relationship between biodiversity, ecosystem functions, and stability properties is addressed using both conceptual and structurally realistic models. Questions addressed include the role of stochasticity for species coexistence (sNiche workshop), ecosystem responses to environmental change (Singer et al. 2016), their predictability and the resulting challenges to modeling (Grimm and Berger 2016, Grimm et al. 2017), the effects of stressors on biodiversity and ecosystem functions (Radchuk et al. 2016), or global patterns of forest fragmentation (Taubert et al. 2018).

successional stages of benthic communities
Biodiversity-ecosystem functioning relationships in microcosm experiments depend on the environmental context. From environment 1-3, the environment is getting harsher in terms of stress. Communities of up to 12 bacterial species were exposed to these different environments, which strongly influenced species‘ roles and functional redundancy. Insets show estimated species interactions, indicating context-dependent changes and, particularly, complex potential interactions in one of the three environments (Fetzer et al. 2015).

We are also increasingly integrating modelling and analyses of data from experiments or observations to test theories. For example, using experiments with microbial communities, the role of seemingly redundant species in species-rich communities could be elucidated: they can become key species when environmental conditions are getting harsher (Fetzer et al. 2015; see Figure).

An underlying theme of virtually all theories and concepts in the department’s research are multiple patterns, or regularities, generated by ecological systems at different scales and hierarchical level. These patterns are key to decoding the internal organization of ecological systems (“pattern-oriented modelling”, Grimm et al. 2005).

Selected Publications