Dynamic and spatial models of kelp forest of Macrocystis integrifolia and Lessonia trabeculata (SE Pacific) for assessment harvest scenarios: short‐term responses

Abstract

Abstract1. Dynamic and spatial models of the kelp forest off northern Chile (SE Pacific coast) were constructed using the Ecosim and Ecospace theoretical frameworks based on a previously mass‐balanced trophic model using Ecopath II software.2. The biomass of Macrocystis integrifolia and Lessonia trabeculata blades constituted the most relevant compartments or variables of the ecosystem studied.3. The relative ascendency (A/C) of 35.5% suggests that this ecosystem is immature, but resistant to disturbances (e.g. fisheries).4. The results obtained using mixed trophic impacts (MTI) show that both brown macroalgae produced relatively similar quantitative and qualitative effects, however, the predictions based on Ecosim clearly show that L. trabeculata experienced the most relevant direct and indirect effects.5. The highest values of system recovery time obtained by Pinguipes chilensis and the other seastar group suggest that both compartments could be considered to be top predator species with strong top‐down control.6. The exploitation of kelp blades as a new harvest strategy appears to be ecologically sustainable.7. The Ecospace trophic‐spatially explicit model shows that exploitation exerted separately by habitat generates a similar pattern of direct and indirect effects. These results suggest that a habitat rotation of fisheries would not be justified.Copyright © 2010 John Wiley & Sons, Ltd.