Emergence of Holling type III zooplankton functional response: Bringing together field evidence and mathematical modelling

Abstract

Food-web population models are rather sensitive to parameterization of functional response in predation terms. Theoretical studies would predict enhancing of ecosystems' stability for a functional response of sigmoid type (Holling type III). The choice of a correct type of response is especially important for modelling outcome of grazing control of algal blooms by zooplankton in nutrient-rich ecosystems. Extensive experiments on zooplankton feeding in laboratories show non-sigmoid nature of response for most herbivorous zooplankton species.As a consequence, there is a strong opinion in the literature that the implementation of Holling III type grazing in plankton models is biologically meaningless. I argue, however, that such an 'evident' claim might be wrong and sigmoid functional responses in real plankton communities would emerge more often than it was suggested earlier. Especially, this concerns plankton models without vertical resolution, which ignore heterogeneity in species vertical distribution. By having conducted extensive literature search of data on zooplankton feeding in situ, I show that vertical heterogeneity in food distribution as well as active food searching behaviour of zooplankton can modify the type of functional response. A c c e p t e d m a n u s c r i p t 2In particular, the rate of food intake by the whole zooplankton population in the column, as a function of total amount of food, often exhibits a sigmoid behaviour, instead of a nonsigmoid one postulated previously based upon laboratory experiments. This conceptual discrepancy is due to the ability of zooplankton to feed mostly in layers with high algal density. I propose a generic model explaining the observed alteration of type between the overall and the local functional responses. I show that emergence of Holling type III in plankton systems is due to mechanisms different from those well known in the ecological literature (e.g. food search learning, existence of alternative food, refuge for prey).

California Coastal Upwelling Onset Variability: Cross-Shore and Bottom-Up Propagation in the Planktonic Ecosystem

“…The zooplankton parameters were designed for the CCS by comparison with other planktonic model studies [29], [33], [34], [35]. We also used a Holling type III formulation for grazing, which is numerically more stable than the default Ivlev formulation used commonly in NEMURO ([36], [37], and references therein). Note that Li et al [32] compared Ivlev and Holling type III grazing formulations in the CCS and showed that they gave statistically indistinguishable results.…”

Variations in the elemental ratio of organic matter in the central Baltic Sea: Part I—Linking primary production to remineralization

“…According to Real (1977), we use a modified Michaelis-Menten equation to describe the feeding response (ingestion) to food availability. Given opposed perspectives about the correct form for the functional response applied to zooplankton as summarized in Morozov (2010), we adopted the sigmoidal shape (Holling type III, Holling, 1959). In context of multiple prey resources, the review of Gentleman et al (2003) showed that some commonly used formulations exhibit anomalous dynamics such as negative switching and sub-optimal feeding.…”

Plankton blooms and patchiness generated by heterogeneous physical environments

“…A turbulent environment would disturb the predator, making it harder or even unnecessary to behave like this because the turbulent medium force the plankton to some random motion. Morozov (2010) showed that the sigmoid grazing function (Holling-type III) is realistic for heterogeneous prey distributions while in a well mixed homogeneous environment the predators' behavior has to be described less sigmoid (Holling-type I or II). Therefore we model the change in the predators behavior by changing from a Holling-type III functional response in a nonturbulent environment, to Holling-type II in a strongly turbulent, and therefore well mixed, environment.…”