Including foraging arena and top-down controls improves the modeling of trophic flows and fishing impacts in aquatic food webs
Authored by M Colleter, C J Walters, P Gatti, D Gascuel
Date Published: 2015
DOI: 10.3354/meps11357
Sponsors:
Pew Charitable Trusts
French Ministries
University of British Columbia
Platforms:
R
Model Documentation:
Other Narrative
Flow charts
Mathematical description
Model Code URLs:
Model code not found
Abstract
Food web dynamics consist of processes that affect ecosystem structure
and functioning. EcoTroph (ET) is a recently developed approach and
software for modeling aquatic ecosystems, articulated entirely around
the trophic level concept. Here, we used ET to investigate impacts of 2
trophic controls (i.e. foraging arena and top-down controls) on marine
ecosystem trophic flows and associated fishing effects. A new version of
the ET model accounting for the foraging arena theory was developed.
Cross impacts of the 2 trophic controls and different fishing scenarios
were analyzed using a virtual ecosystem. Results showed that foraging
arena controls decreased the resistance and production of an ecosystem
facing increasing fishing mortality. In contrast, the inclusion of
top-down controls resulted in a more resistant ecosystem, with a
decrease in the kinetics of trophic flows at lower trophic levels (TLs)
when the abundance of higher TLs is reduced by fishing. These 2 controls
increased the interactions between TLs, and, in part, shaped fishing
impacts at the ecosystem scale. Then, we applied ET to 3 real ecosystems
which have been previously modeled using Ecopath with Ecosim (EwE).
EcoTroph and Ecosim predictions related to changes in fishing effort
were compared, and showed that accounting for trophic controls enabled
EcoTroph to mimic Ecosim models, and better reflect associated changes
in trophic flows. The 3 case studies exhibited different behaviors:
while the pelagic ecosystem had strong foraging arena controls but no
top-down controls, the other ecosystems were characterized by weaker
foraging arena controls but effective top-down controls.
Tags
Individual-based model
biomass
Community
Recruitment
Indicators
Marine ecosystems
Nw mediterranean sea
Reconstructing ecosystem dynamics
Central
pacific-ocean
Fishery
management