|Project:||Structured population dynamics|
In classical models of population dynamics, all individuals within a population are treated as if they are identical objects. However, usually the individuals are far from the same. For example, food intake rate and reproduction of the waterflea Daphnia magna strongly depends on its size. These differences between individuals will have an important influence on the dynamic behavior of the system.
Structured population models do not only take into account the size of a population, but also its structure, where structure refers to any subdivision on the basis of one or more traits of the individuals.
The primary aim is to illuminate the influence of population structure on the dynamics of predator-prey systems.
A secondary aim is to gain insight in the dynamic behavior of food chains. An important question in ecology is why chains in nature are short.
A relatively simple model for a size-structured predator, feeding on an unstructured prey population is used. With numerical simulation we have shown that complex dynamic behavior can occur in this structured population model. However, for most parameter values the dynamics are predicted well by the classical models.
Further we are investigating the dynamic behavior of a tri-trophic food chain constisting of resources, prey, predator and top-predator. For this model a rich set of dynamical behaviors has been found. One of the most remarkable results is that increasing the nutrient input to the system can cause the extinction of the top-predator.