title: Intraguild Predation Dynamics in a Lake Ecosystem Based on a Coupled Hydrodynamic-Ecological Model: The Example of Lake Kinneret (Israel).
abstract: The food web of Lake Kinneret contains intraguild predation (IGP). Predatory invertebrates and planktivorous fish both feed on herbivorous zooplankton, while the planktivorous fish also feed on the predatory invertebrates. In this study, a complex mechanistic hydrodynamic-ecological model, coupled to a bioenergetics-based fish population model (DYCD-FISH), was employed with the aim of revealing IGP dynamics. The results indicate that the predation pressure of predatory zooplankton on herbivorous zooplankton varies widely, depending on the season. At the time of its annual peak, it is 10-20 times higher than the fish predation pressure. When the number of fish was significantly higher, as occurs in the lake after atypical meteorological years, the effect was a shift from a bottom-up controlled ecosystem, to the top-down control of planktivorous fish and a significant reduction of predatory and herbivorous zooplankton biomass. Yet, seasonally, the decrease in predatory-zooplankton biomass was followed by a decrease in their predation pressure on herbivorous zooplankton, leading to an increase of herbivorous zooplankton biomass to an extent similar to the base level. The analysis demonstrates the emergence of non-equilibrium IGP dynamics due to intra-annual and inter-annual changes in the physico-chemical characteristics of the lake, and suggests that IGP dynamics should be considered in food web models in order to more accurately capture mass transfer and trophic interactions.
authors.affiliation: Oranim Academic College of Education, Kiryat Tivon 36006, Israel. vardit@oranim.ac.il.
authors.forename: Vardit
authors.initials: V
authors.lastname: Makler-Pick
authors.affiliation: Aquatic Ecodynamics, UWA School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia. matt.hipsey@uwa.edu.au.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hipsey
authors.affiliation: Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal 1495001, Israel. tamarz@ocean.org.il.
authors.forename: Tamar
authors.initials: T
authors.lastname: Zohary
authors.affiliation: Faculty of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel. gal@ocean.org.il.
authors.forename: Yohay
authors.initials: Y
authors.lastname: Carmel
authors.affiliation: Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal 1495001, Israel. yohay@technion.ac.il.
authors.forename: Gideon
authors.initials: G
authors.lastname: Gal
keywords: DYCD-FISH; Mirogrex terraesanctae; ecosystem modeling; intraguild predation (IGP); lake Kinneret; sustainable management