MBI Videos
Gregor Fussmann
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Gregor FussmannI will present three examples of eco-evolutionary dynamics. The studies vary in the degree to which they utilize mathematical models, the degree of empiricism, and the degree to which models and empirical findings are linked. Study 1 is concerned with a relatively artificial laboratory predator-prey system. This is the first system, for which a complete feedback cycle between ecological and evolutionary dynamics could be demonstrated. Study 2 reports evolution of resistance in a guppy-monogenean parasite-host system in a field experiment in tropical streams. Surprisingly, relaxed selection (absence of parasites) leads to increased resistance in this complex field situation. Study 3 analyzes a mathematical model of evolutionary rescue in a community context. The idea that species may be able to avoid extirpation due to rapid environmental change through equally rapid adaptation has only been tested for single-population systems. I will show that evolutionary rescue can also occur in complex communities and that it has a distinctive dynamic signature.
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Gregor FussmannFood webs are interaction networks that link predator and prey populations. The so-called functional response is the linking function that determines the uptake of prey by the predator. While it is clear that this function should be nonlinear and saturating with increasing prey densities, there is no single “right� function that describes the predator-prey interaction. A number of functions with vastly different mathematical properties (e.g., polynomial, exponential, trigonometric) are used in food web models. It has been shown previously that, already for two-species models, predictions about predator-prey dynamics and stability strongly depend on the choice of functional response. In this talk, I show the consequences of multiplying the sources of uncertainty by varying functional responses for the large number of predator-prey interactions that occur in complex food webs.