title: Food-dependent growth leads to overcompensation in stage-specific biomass when mortality increases: the influence of maturation versus reproduction regulation.
abstract: We analyze a stage-structured biomass model for size-structured consumer-resource interactions. Maturation of juvenile consumers is modeled with a food-dependent function that consistently translates individual-level assumptions about growth in body size to the population level. Furthermore, the model accounts for stage-specific differences in resource use and mortality between juvenile and adult consumers. Without such differences, the model reduces to the Yodzis and Innes (1992) bioenergetics model, for which we show that model equilibria are characterized by a symmetry property that reproduction and maturation are equally limited by food density. As a consequence, biomass production rate exactly equals loss rate through maintenance and mortality in each consumer stage. Stage-specific differences break up this symmetry and turn specific stages into net producers and others into net losers of biomass. As a consequence, the population in equilibrium can be regulated in two distinct ways: either through total population reproduction or through total population maturation as limiting process. In the case of reproduction regulation, increases in mortality may lead to an increase of juvenile biomass. In the case of maturation regulation, increases in mortality may increase adult biomass. This overcompensation in biomass occurs with increases in both stage-independent and stage-specific mortality, even when the latter targets the stage exhibiting overcompensation.
authors: Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94084, NL-1090 GB Amsterdam, The Netherlands. a.m.deroos@uva.nl
authors: Andre M
authors: AM
authors: De Roos
authors: Tim
authors: T
authors: Schellekens
authors: Tobias
authors: T
authors: van Kooten
authors: Karen
authors: K
authors: van de Wolfshaar
authors: David
authors: D
authors: Claessen
authors: Lennart
authors: L
authors: Persson
mesh_terms: D018533:Biomass; D049628:Body Size; D005502:Food; D008954:Models, Biological; D009026:Mortality; D011157:Population Dynamics; D012098:Reproduction