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Ecosystem modeling efforts at the NWFSC. A quick overview. Some basics. Major efforts focused on Salmon and their environment Mostly Pacific Northwest Groundfish and the California Current LME
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Ecosystem modeling efforts at the NWFSC A quick overview
Some basics • Major efforts focused on • Salmon and their environment • Mostly Pacific Northwest • Groundfish and the California Current LME • In addition to fisheries, a lot of effort has gone into habitat, water quality and quantity, oceans and human health, cumulative impacts
Some philosophical tenets common among NWFSC modeling groups • We define models as • mathematical or conceptual caricatures of reality, and as such are tools that allow us to project the future state of an ecosystem or guide further inquires • We develop models aimed at specific outputs and outcomes generated in collaboration with managers and stakeholders.
General types of models1 employed by the NWFSC • Statistical models • posit relationships between variables • fit to data, and thus they are specific to the location and the system under investigation • Theoretical (analytical and simulation) models • posit mechanisms and thus lead to predictions that can be tested with data • used to understand systems and predict their properties; therefore, they are intended to be general 1as influenced by Mangel et al. 2001 Theoretical and Statistical Models in Natural Resource Management and Research. In: Shenk and Franklin, Island Press
Issues that we MUST consider (we think these are somewhat different than (some) other regions) • Upwelling and how its influenced by ENSO, PDO, climate change • Huge influence of land use, land cover, water quantity (e.g., snow pack) • Salmon Salmon Salmon Salmon Salmon • ESA is huge. MSA still places a role, but less so than other centers • Weak stock management • Salmon
Generally, We use models to address the following: • Forecast effects of climate / oceanographic variability (and trends) on population dynamics and productivity, habitat, ecological community • Evaluate management strategies on target species, ecosystem indicators (and down the road, socioeconomic indicators) • Examine trade-offs between different desired ecosystem services • The potential influence of habitat restoration on freshwater and riparian ecosystems • Examine indirect effects and cumulative impacts across multiple human actions
A few examples This is not exhaustive
Generally, We use models to address the following: • Forecast effects of climate / oceanographic variability (and trends) on population dynamics and productivity, habitat, ecological community • Evaluate management strategies on target species, ecosystem indicators (and down the road, socioeconomic indicators) • Examine trade-offs between different desired ecosystem services • The potential influence of habitat restoration on freshwater and riparian ecosystems • Examine indirect effects and cumulative impacts across multiple human actions
California Current Plankton Production • Desired Outcome • Prediction of juvenile salmon production from upwelling-driven plankton production.
California Current Plankton Production mortality Z NNPPZD egestion excretion Ps Pl mortality oxidation NO3 NH4 D sinking sinking sinking upwelling diffusion mixing loss mixing loss
Fish bioenergetics • How is growth or feeding influenced by environment? • size- & temperature-dependent energy budget • potential applications: • predation impacts • climate variability • D in size distributions • link to other models R, SDA C D B, G F, U DB = CA · WCB · CVCX · e (CX · (1 – CV))· EDdiet / ED –RA · WRB· RVRX · e (RX · (1 – RV))· ACT · oxycal · ED – (SDA + U) · (C – F) – F – W · (GSImax – GSImin) Example: rockfish response to repeated ENSO events (Harvey 2005) baseline (no ENSO events) delayed maturation, lower lifetime fecundity cohort A (4 ENSOs) cohort B (7 ENSOs) Fecundity (1000s) Age (yr)
Output and Outcomes of Bioenergetic work • Output – changes in growth, size structure and reproductive output as a function of a variety of environmental parameters • Outcome – increased precision of stock and ecosystem assessment models
Generally, We use models to address the following: • Forecast effects of climate / oceanographic variability (and trends) on population dynamics and productivity, habitat, ecological community • Evaluate management strategies on target species, ecosystem indicators (and down the road, socioeconomic indicators) • Examine trade-offs between different desired ecosystem services • The potential influence of habitat restoration on freshwater and riparian ecosystems • Examine indirect effects and cumulative impacts across multiple human actions
Management submodel Assessment and policy decisions Fisheries submodel a b c g f e d c b a d 0 m e f 50 g 100 Community submodel 150 200 Habitat 550 1200 2400 3-dimensional structure of model Daily oceanographic fluxes (water, heat, salt) into and out of each box are controlled by a 10 km x 10 km oceanographic model Biogeochemistry Hydrographic submodel Climate and oceanography
Outputs and Outcomes • Output – dynamics of ecosystem indicators under a variety of scenarios • Outcome – ability to evaluate a variety of monitoring programs, ecosystem indicators and management strategies in the face of environmental variability/uncertainty/change
We use models to address the following: • Forecast effects of climate / oceanographic variability (and trends) on population dynamics and productivity, habitat, ecological community • Evaluate management strategies on target species, ecosystem indicators (and down the road, socioeconomic indicators) • Examine trade-offs between different desired ecosystem services • The potential influence of habitat restoration on freshwater and riparian ecosystems • Examine indirect effects and cumulative impacts across multiple human actions
Yield:ecosystem trade-off with increasing MPA % coverage Coos Bay area 20% shelf/slope MPA total fishery yield Eureka area piscivore biomass Ecospace model of N. California Current • How does MPA size affect the trade-offs between fishery yield and ecosystem well-being? • Based on John Field’s NCC Ecopath/Ecosim model • Each grid square (75 km2) has a “leaky” Ecosim model and a habitat type • Other spatial components: primary production, dispersal, migrations, fishing fleets, hypothetical MPAs • 64 food web groups, 7 fleets Habitats, based on depth and substrate Juan de Fuca Colu mbia River Blanco Mendocino
We use models to address the following: • Forecast effects of climate / oceanographic variability (and trends) on population dynamics and productivity, habitat, ecological community • Evaluate management strategies on target species, ecosystem indicators (and down the road, socioeconomic indicators) • Examine trade-offs between different desired ecosystem services • The potential influence of habitat restoration on freshwater and riparian ecosystems • Examine indirect effects and cumulative impacts across multiple human actions
Designing and evaluating recovery strategies with uncertain futures
Hadley model GFDL model Global climate impacts on stream flows in the Snohomish watershed Peak flows Low flows Pre-spawning temperature Battin et al. 2007
Modeling cumulative effects Spawning Capacity stream gradient stream width riparian condition Egg-to-juv Survival peak flows temperature Egg Juvenile Juv. Rearing Capacity stream gradient stream width riparian condition estuarine channel form connectivity of nearshore patches Pre-spawning Survival temperature low flows Adult Stochastic Variation in Ocean Survival Bartz et al. 2006 Scheuerell et al. 2006
Chinook Population Impacts GFDL Hadley Battin et al. 2007
Scoping Identify goals of EBM and threats to achieving goals Develop ecosystem indicators and targets Risk Analysis Characterization of Characterization of susceptibility to resiliency to perturbation perturbation Data Acquisition Monitoring of Ecosystem Indicators Assessment of ecosystem status relative to EBM goals Management Actions
Summary Diversity of NWFSC modeling efforts reflects diversity of ecosystems we must consider – seas to summits Models address response variables ranging from habitat (e.g. water flow) through single species (salmon, groundfish) to ecosystem indicators. Objectives also vary, but typically are management driven Data availability / quality ranges from incredible to horrible
Key contacts • Ecosystem simulations and bioenergetic models • Chris Harvey, Isaac Kaplan, Tom Wainwright • Multi-species models • Mark Scheuerell, Chris Harvey • Climate-related models • Mary Ruckelshaus, Mark Scheuerell, Chris Harvey, Tom Wainwright • Habitat and water quality related models • Tim Beechie, Mary Ruckelshaus, Mark Scheuerell
100 100 100 100 94 97 96 95 100 100 98 99 100 100 100 100 100 100 101 Identifying peak-flow impaired sub-basins 100 Impaired: >10% impervious area Functioning: <3% impervious area
Multispecies age-structured population models • What is the relative importance of juvenile predation vs. adult bycatch? • Adaptation of Lotka-Volterra models • Predation and bycatch connect populations • Rockfish species is overfished • Predation slows rockfish rebuilding modestly • BUT, bycatch is major mortality source • Effective bycatch control offsets predation Adult rockfish − + bycatch in hake fishery + + Pacific hake = predation − Juvenile rockfish (Harvey et al., accepted)
Nutrient mass-balance models Historical: P ≈ 80 000 kg Scheuerell et al. (2005) CJFAS
Forecasting climate impacts on salmon Atmosphere Adults Adults Eggs Smolts Smolts Parr Ocean Freshwater
We don’t know • At what level of complexity do we get the answer we need? • No single answer