BioND — Dynamics of Biological Networks

Population dynamics in theory and experiment: An investigation of species interactions on different scales of complexity

Lars Rudolf
PhD thesis in physics, Universität Potsdam, 2008.


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Undoubtedly the growing population causes an increasing human impact on the environment. As a result, anthropogenic habitat change or destruction, overexploitation, climate change, and bio-invasions influence ecosystem functioning and cause the largest species mass extinction in the history of earth. However, we are embedded in this web of life and therefore dependent on our environment. Thus, any environmental change may cause critical economical and social problems. Furthermore, there is a feed back of the web of life to the abiotic environment and the influence of ecological systems, e.g. on the atmospheric carbon dioxide or the albedo, may cause subsequent changes. Thus, in the past decades, there has been an increasing concern about the impact upon human dependency on the ecological environment. The understanding of the processes and the underlying dynamics is one of the most pressing question faced by humanity.

The ecological environment is highly diverse and complex. Therefore understanding of its processes and dynamics is non-trivial. On large scales one can find a multitude of different populations interacting in a complex web. The population dynamics on such webs can be stationary, oscillatory or chaotic, while the interactions can be cooperative, competitive or predative. The interactions themselves are a result of the interplay between individuals and, therefore, even the understanding and description of a single interaction between two species is typically not trivial. Finally, also on the individual level the complex physiological and behavioural processes are often not fully understood and still object of ongoing research. The non-trivial nature of our ecological environment on the one hand and the necessity to understand the consequences of the environmental change, on the other hand, are motives for an increasing scientific interest, at all scales of observation. Also, the understanding of the ecological environment on different levels of abstraction will be the focus of that work.