A multi-nutrient model for the description of stoichiometric modulation of predation in micro- and mesozooplankton

Abstract

Changes in predator behaviour when confronted with prey of disadvantageous composition have been termed stoichiometric modulation of predation (SMP; Mitra and Flynn, 2005; J. Plankton Res. 27, 393–399). Through SMP, a predator may compensate for (positive SMP) or compound (negative SMP) dietary deficiencies. While these responses are documented in experiments, albeit typically with poor parameterization, previous zooplankton models contain no explicit description of these events. A new multi-nutrient biomass-based generic zooplankton model is described, capable of handling SMP at the levels of ingestion and assimilation, for the exploration of zooplankton growth dynamics in situations where prey quality and quantity changes over time. SMP is enabled by configuring ingestion rate and assimilation efficiency descriptors as functions of food quality (indexed here to prey N:C). Sensitivity analysis of the new model shows the structure to be robust against variation in parameter (constant) values. The form of the model enables its use in population dynamic studies of different zooplankton groups; here, the model has been configured to represent micro- and mesozooplankton. It is shown that in the absence of inclusion of SMP, fits of the model to experimental data can be poor with potential for significant misrepresentation of trophic dynamics.