Individual-based population models (IBMs)
In most aquatic simulation models, populations or communities are treated as homogeneous units (compartment models, state variable models) without further internal differentiation into age groups or individuals. In individual-based models (IBMs), however, the organisms are represented as individual entities with specific life cycles. An individual-based population dynamics emerge therefore from either direct or indirect interactions of the individuals amongst themselves (e.g. by competition, predation) and with their environment. The IBM approach is based on a probabilistic structure, where individual differences lead to natural variability on the population level.
gaiac develops individual-based models, partially in cooperation with the Institute of Environmental Research (RWTH Aachen University).
Currently the following numeric models are available:
- IBM Chaoborus: Population model for the phantom midge (Chaoborus crystallinus, Diptera)
- IDamP: Water flea (Daphnia magna) population model (Dr. T. Preuss, RWTH Aachen University)
- Modelling aquatic populations in outdoor mesocosms: A hybrid model, which combines a compartment lake model (StoLaM) and individual-based population models under field conditions (e.g. IDamP)
gaiac is involved as an associated partner in the EU project "Mechanistic Effect Models for Ecological Risk Assessment of Chemicals (CREAM)".
Concerning the question of which environmental factors should be considered in protective population modelling see also:
Preuss T.G., Strauss, T., Ratte, H.T. (2008): How detailed do we have to model populations to predict extinction probabilities and recovery time? Poster presentation, 18th SETAC-Europe Annual Meeting, Warschau, Polen.