0000000000297359
AUTHOR
Hans Joachim Poethke
Modellierung der Wirkung von Chemikalien auf aquatische Ökosysteme (Fließ‐ und Stillgewässer)
Mathematische Modelle und Computersimulationen stellen heute in der aquatischen Okotoxikologie ein wesentliches Instrument zur Analyse und Prognose von Fremdstoffwirkungen im Okosystem dar. Dieser Beitrag stellt die unterschiedlichen Einsatzbereiche solcher Simulationsmodelle vor. Zunachst werden zum Vergleich heute verwendete statistische Verfahren zur Extrapolation von im Labor an einzelnen Arten gemessenen Toxizitaten auf die Okosystemebene vorgestellt. Nach einem Uberblick uber existierende Simulationsmodelle limnischer Okosysteme oder Lebensgemeinschaften zeigen die Autoren am Modell SAM beispielhaft den Aufbau und die Funktionsweise eines solchen Modells fur eine pelagische Lebensgeme…
Parameter Sensitivity and the Quality of Model Predictions
Using SIM-PEL, a comprehensive model for the pelagic compartment of lake ecosystems, we analyse synergistic toxicant effects in lake ecosystems. We show, that — even for a rather simple model — model predictions may be strongly dependent on the time horizon of the prediction and on the quality of input parameters. For longer time spans, small errors in parameter estimation may lead to qualitatively wrong prediction of toxicant effects. Monte Carlo simulations allow to take errors in parameter estimation into account, but they need rather good estimates of parameter variance.
Co-evolution between ectoparasites and their insect hosts: a simulation study of a damselfly-water mite interaction
Summary 1. A simulation model investigating the co-evolution of water mites infesting their aquatic insect hosts during emergence is presented. The model is based on field and experimental studies of the ectoparasitic water mite Arrenurus cuspidator and the damselfly Coenagrion puella. 2. Three scenarios were studied: (1) Only the host was allowed to evolve timing of emergence, while the timing of the parasites' infestation opportunity was held constant. (2) Both host and parasite were allowed to evolve. (3) Only the parasite's timing was allowed to evolve, while the host was constrained completely. 3. In the first two scenarios, parasite abundances decreased in the course of evolution and …