Journal Article

Omnivory by Planktivores Stabilizes Plankton Dynamics, but May Either Promote or Reduce Algal Biomass

Corso, Gilberto, Scheffer, Marten, van Nes, Egbert H., Attayde, José Luiz, Araujo, Aderaldo I. L.

2010

Overview

Classical models of phytoplankton-zooplankton interaction show that with nutrient enrichment such systems may abruptly shift from limit cycles to stable phytoplankton domination due to zooplankton predation by planktivorous fish. Such models assume that planktivorous fish eat only zooplankton, but there are various species of filter-feeding fish that may also feed on phytoplankton. Here, we extend these classical models to systematically explore the effects of omnivory by planktivorous fish. Our analysis indicates that if fish forage on phytoplankton in addition to zooplankton, the alternative attractors predicted by the classical models disappear for all realistic parameter settings, even if omnivorous fish have a strong preference for zooplankton. Our model also shows that the level of fish biomass above which zooplankton collapse should be higher when fish are omnivorous than when fish are zooplanktivorous. We also used the model to explore the potential effects of the now increasingly common practice of stocking lakes with filter-feeding fish to control cyanobacteria. Because omnivorous filter-feeding fish forage on phytoplankton as well as on the main grazers of phytoplankton, the net effect of such fish on the phytoplankton biomass is not obvious. Our model suggests that there may be a unimodal relationship between the biomass of omnivorous filter-feeding fish and the biomass of phytoplankton. This implies that to manage for reductions in phytoplankton biomass, heavy stocking or strong reduction of such fish is best.

• Publisher: New York : Springer-Verlag,Springer Science+Business Media,Springer-Verlag,Springer,Springer Nature B.V
• Subject: Agnatha. Pisces / Algae / alternative stable states / Analysis / Animal and plant ecology / Animal, plant and microbial ecology / Aquatic ecosystems / Biological and medical sciences / Biomass / Biomedical and Life Sciences / Ecology / enclosure experiment / Environmental Management / eutrophication / filter-feeding fish / Fish / Fish feeding / Fish stocking / Fishes / food webs / Forage / Freshwater fishes / Fundamental and applied biological sciences. Psychology / General aspects / Geoecology/Natural Processes / Hydrology/Water Resources / hypophthalmichthys-molitrix / intraguild predation / lakes / Life Sciences / nile tilapia / Omnivores / Oreochromis / Phytoplankton / Plankton / Plant Sciences / Predation / shallow lakes / silver carp / Synecology / Tilapia / tilapia (common name) / tilapia oreochromis-niloticus / top-down control / trophic cascade / trophic dynamics / Tropical fishes / Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution / Zoology / Zooplankton