title: Biological ensemble modeling to evaluate potential futures of living marine resources.
abstract: Natural resource management requires approaches to understand and handle sources of uncertainty in future responses of complex systems to human activities. Here we present one such approach, the "biological ensemble modeling approach," using the Eastern Baltic cod (Gadus morhua callarias) as an example. The core of the approach is to expose an ensemble of models with different ecological assumptions to climate forcing, using multiple realizations of each climate scenario. We simulated the long-term response of cod to future fishing and climate change in seven ecological models ranging from single-species to food web models. These models were analyzed using the "biological ensemble modeling approach" by which we (1) identified a key ecological mechanism explaining the differences in simulated cod responses between models, (2) disentangled the uncertainty caused by differences in ecological model assumptions from the statistical uncertainty of future climate, and (3) identified results common for the whole model ensemble. Species interactions greatly influenced the simulated response of cod to fishing and climate, as well as the degree to which the statistical uncertainty of climate trajectories carried through to uncertainty of cod responses. Models ignoring the feedback from prey on cod showed large interannual fluctuations in cod dynamics and were more sensitive to the underlying uncertainty of climate forcing than models accounting for such stabilizing predator-prey feedbacks. Yet in all models, intense fishing prevented recovery, and climate change further decreased the cod population. Our study demonstrates how the biological ensemble modeling approach makes it possible to evaluate the relative importance of different sources of uncertainty in future species responses, as well as to seek scientific conclusions and sustainable management solutions robust to uncertainty of food web processes in the face of climate change.
authors.affiliation: Swedish University of Agricultural Sciences, Department of Aquatic Resources, Institute of Coastal Research, Skolgatan 6, SE-742 42 Oregrund, Sweden. anna.gardmark@slu.se
authors.forename: Anna
authors.initials: A
authors.lastname: Gårdmark
authors.forename: Martin
authors.initials: M
authors.lastname: Lindegren
authors.forename: Stefan
authors.initials: S
authors.lastname: Neuenfeldt
authors.forename: Thorsten
authors.initials: T
authors.lastname: Blenckner
authors.forename: Outi
authors.initials: O
authors.lastname: Heikinheimo
authors.forename: Bärbel
authors.initials: B
authors.lastname: Müller-Karulis
authors.forename: Susa
authors.initials: S
authors.lastname: Niiranen
authors.forename: Maciej T
authors.initials: MT
authors.lastname: Tomczak
authors.forename: Eero
authors.initials: E
authors.lastname: Aro
authors.forename: Anders
authors.initials: A
authors.lastname: Wikström
authors.forename: Christian
authors.initials: C
authors.lastname: Möllmann
mesh_terms: D000818:Animals; D018533:Biomass; D057231:Climate Change; D003247:Conservation of Natural Resources; D004784:Environmental Monitoring; D005398:Fisheries; D048389:Gadus morhua / Q000502:physiology*; D008954:Models, Biological; D009792:Oceans and Seas; D011157:Population Dynamics; D013696:Temperature; D013997:Time Factors