Towards Ecosystem-Based Management Modelling Techniques 2. Whole Ecosystem Models

Transcription

1 Towards Ecosystem-Based Management Modelling Techniques 2 Ecopath with Ecosim: : Mass-Balance and Dynamic Whole Ecosystem Models Ecospace spatial ecosystem simulation tool predicting spatial patterns of biomass 1

2 Using Ecospace Ecospace builds on Ecopath and Ecosim First step Construct Ecopath model Mass-balance and trophodynamic constraints ensure parameters compatible & realistic Run diagnostics and adjust - Next Set up Ecosim Run diagnostics and adjust - Then Set up and run Ecospace enter map & habitat-related parameters - Ecospace: spatial ecosystem simulation Replicates Ecosim dynamics Links cells over spatial grid of homogeneous cells through dispersal of organisms, and fishing effort movement/allocation Accounts for spatial variation in productivity Represents habitat preferences by differential dispersal, feeding and predation rates a spatial, meso-scale scale version of Ecopath 2

3 Ecospace dispersal dynamics B ij m i,j+1 B ij Equal m s m s means symmetrical mixing, toward preferred habitats (except at shores) Ecospace computation Huge equation system e.g. 20x20 grid for 10 pool model requires 4000 differential equations So needs Numerical approximation by linearization, and matrix exponential solution method generate projections toward spatial equilibrium NOTE: approximations mean you should always test for step size effects 3

4 Data requirements for Ecospace Habitat definitions Habitat preferences Dispersal rates MPAs Max 100+ Ecopath groups Fishing fleets km year-1 One or several types Regulations by fishery sector Compliance 100% Define habitats 4

5 Habitat preferences Ecospace movement rates Baseline dispersal rate km/yr Relative movement in bad habitat Relative vulnerability Adjust default in bad habitat values Relative feeding in bad habitat Uses same behavioural ecology as Ecosim arena foraging 5

6 Ecospace: fishing by habitat Enter fisheries by defined habitats Ecospace basemap Spatial grid defined at start 6

7 Ecospace basemap Draw coastline, MPAs Ecospace basemap Draw habitats 7

8 Ecospace simulations You can hide/show group panels Simulations by group Time plot of adundances (like Ecosim) Colour scale shows abundance relative to start Advection Computes resulting transports Sketch current directions You can enter MLD Sketch upwelling 8

9 Ecospace predictions Spatial distributions by group shows impact of protected areas & habitats Once OK.. speed up by increasing time step Time plot of adundances (like Ecosim) An Alternative Modelling System Atlantis biogeochemical spatial ecosystem model CSIRO, Hobart, Tasmania, Australia Their slides (with thanks!) Fulton, F.A., Parslow, J.S., Smith, A.D.M. and Johnson, C.R. (2003) Biogeochemical Marine Ecosystem Models I: the generic behaviour of a biogeochemical ecosystem model. Ecol. Modelling 174(3):

10 Atlantis - Outline Operating model structure fleets mangement options data output Sampling model Atlantis - Physical structure Each box has physical characteristics depth seabed type canyon coverage porosity stress erosion rate temperature salinity light Transport vectors cover flows between boxes 10

11 Atlantis - Physical structure Within each box there can be multiple layers Atlantis - Biological Structure Inanimate Nutrients Detritus Biological Primary producers Bacteria Invertebrate s Vertebrates Anthropogenic Pollution Fisheries Management 11

12 Atlantis - Biological Structure Nutrients Nitrate Ammonia Silica Oxygen Atlantis - Biological Structure Detritus Labile detritus Refractory detritus Carrion 12

13 Atlantis - Biological Structure Primary producers Small phytoplankton Large phytoplankton Macroalgae Seagrass Atlantis - Biological Structure Bacteria Pelagic (attached) Sediment 13

14 Atlantis - Biological Structure Invertebrates Pelagic Microzooplankton Mesozooplankton Large zooplankton (e.g. krill) Gelatinous zooplankton Cephalopods (juveniles & adults) Meiobenthos Benthic Deposit feeders Carnivorous infauna Benthic grazers Filter feeders (deep & shallow) Macrozoobenthos (deep & shallow) Atlantis - Biological Structure Vertebrates Functional Groups Planktivores (small & large) Piscivores (deep, shallow & tropical) Mesopelagics (migratory & nonmigratory) Demersal fish (deep & shallow) Sharks (pelagic & demersal) Seabirds Whales (baleen & toothed) Flathead Ling Species Orange roughy Southern bluefin tuna Gummy shark 14

15 Atlantis - Biological Structure Pollution Change in nutrients Atlantis - Biological Structure Fisheries Bottom trawl (cephalopods, deep demersals, shallow demersal fish, benthos, orange roughy) Danish seine (shallow demersals) Demersal line (deep demersal fish, shallow piscivores, demersal sharks) Dive (herbivorous benthos) Dredge (shallow filter feeders) Gillnet (deep demersal fish, shallow demersal fish, demersal sharks) Jig (cephalopods) Midwater trawl (cephalopods, deepwater fish, planktivores) Pelagic line (tunas) Purse seine (planktivores, tunas) Trap (benthos, deep demersal fish) 15

16 Atlantis - Biological Structure Management Pre-specified effort profiles (mimic timeseries of effort) Dynamic Effort (ports, explore, effort displacement) Dynamic Effort management (based on stock size of target or vulnerable species) Quotas Area closures Temporal closures Incidental mortality mitigation Size based discarding Changing discarding practices Changing gear (selectivity) Atlantis - Biophysical structure Management has knowledge about entire area & effects entire area 16

17 Atlantis - Sampling Model Sampling Indicators AN indicator And another And yet anotehr Wow another One more Amazingly anotehr Number lots Last of all vs Attributes Production Trophic structure Biomass Diversity Composition Habitat Oxygen Pretty Atlantis Case Studies To Date 17

18 Comparison of Atlantis with Ecosim Fulton, E.A. and Smith, A.D.M. (2004) Lessons Learnt From A Comparison Of Three Ecosystem Models For Port Phillip Bay, Australia. African Journal of Marine Science 26(1):