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From inducible defences to population dynamics: modelling refuge use and life history changes in Daphnia

Vos, M. and Flik, B.J.G. and Vijverberg, J. and Ringelberg, J. and Mooij, W.M. (2002) From inducible defences to population dynamics: modelling refuge use and life history changes in Daphnia. Oikos, 99, 386-396. ISSN 0030-1299.

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Official URL: http://dx.doi.org/10.1034/j.1600-0706.2002.990221.x

Abstract

We investigated the relative importance of a behavioural defence (refuge use through diel vertical migration) and a life history change (a reduced size at first reproduction) that are used by daphnids to decrease the risk of predation by visually hunting fish. We used an individual based model of a Daphnia population in a stratified lake to quantify the effects of these inducible defences on Daphnia predation-mortality and the resulting Daphnia population dynamics. Our analysis shows that diel vertical migration (DVM) confers a much stronger protection against fish predation than a reduced size at first reproduction (SFR). DVM allows daphnids to withstand a higher predation pressure in the epilimnion and it decelerates a Daphnia population decline more strongly than a reduced SFR. DVM effectively reduces the (P/B) flow of carbon from daphnids to fish. Many theoretical studies have only considered the fitness benefits of DVM above ‘staying up’ in the epilimnion of a lake. Our results suggest that ‘staying down’ in the hypolimnion would confer an even stronger fitness benefit to Daphnia than DVM at times of peak predation risk. Daphnids that remain in the hypolimnion avoid the predation suffered by migrating daphnids around dusk and dawn. Staying down could prevent a Daphnia population decline, while DVM and a reduced SFR can only decelerate th

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:11250
Deposited On:24 Nov 2011 01:00
Last Modified:31 Mar 2014 11:04

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