Review of major ecosystem model classes
description
Transcript of Review of major ecosystem model classes
Review of major ecosystem model
classes
Éva PlagányiDept. of Maths & Applied Maths, University of Cape
Town
Reference: Plagányi 2007. Models for an Ecosystem Approach to Fisheries. FAO Fisheries Technical paper 477
Report of Modelling Ecosystem Interactions for Informing an Ecosystem Approach to Fisheries: Best Practices in Ecosystem Modeling, Tivoli, July 3-6, 2007
National Ecosystem Modeling Workshop (NEMoW)August 29-31 2007, NMFS Santa Cruz
With thanks to Doug Butterworth and MARAM
OUTLINE OF TALK
Ecosystem Model Objectives Ecosystem Model Types Questions for EAF* Modelling Ecosystem Model Classification Considerations in Model Building
and the Best Practice Approach Role of Management Procedures Data requirements Conclusions
Biological interactions described
Predator prey feedback
Handles the environment and lower trophic levels
Technical interaction models MSYPRMurawski 1984
Predators added to single-species models e.g. SEASTARGulland 1983; Livingston and Methot1998; Hollowed et al. 2000; Plagányi2004; Tjelmeland and Lindstrøm 2005
No
No
Yes
Yes
Handles age/size structureHandles age
structure
No Yes
Aggregate system models e.g. EwE, SKEBUB, SSEM
Spatial dynamic systems models e.g. ATLANTIS, ERSEM, SEAPODYM
Multispecies Production Models e.g. Horbowy 2005
YesNo
Dynamic multi-species models BORMICON, GADGET, MRMs,MSVPA& MSFOR, MSM, MULTSPEC, OSMOSE
No
Handles spatial structure
Yes
No
Dynamic systems models e.g. some recent EwEapplications
YesHandles spatial structureNo
Spatial aggregate systems models e.g. ECOSPACE
Yes
Ecosystem Models and Management Advice
• Conceptual/understanding: of the structure, functioning and interactions of the ecosystem, or sub-system, under consideration. May not be used explicitly in decision-making or scientific advice but forms the underlying context for any detailed management planning and decision-making
• Strategic decisions: linked to policy goals and are generally long-range, broadly-based and inherently adaptable
• Tactical decisions: aimed at the short-term (e.g. next 3-5 years), linked to an operational objective and in the form of a rigid set of instructions e.g. tactical decision to change quota
Ecosystem models generally intended to complement not replace single-species assessment models
OUTLINE OF TALK
Ecosystem Model Objectives Ecosystem Model Types Questions for EAF* Modelling Ecosystem Model Classification Considerations in Model Building
and the Best Practice Approach Role of Management Procedures Data requirements Conclusions
Model typesI. Whole ecosystem models: models that
attempt to take into account all trophic levels in the ecosystem
II. Minimum Realistic Models (MRM): limited number of species most likely to have important interactions with a target species of interest
III. Dynamic System Models (Biophysical): represent both bottom-up (physical) and top-down (biological) forces interacting in an ecosystem
IV. Extensions of single-species assessment models (ESAM): expand on current single-species assessment models taking only a few additional inter-specific interactions into account
Ecosystem ModelsI. Whole ecosystem models MODEL NAMEEwE and ECOSPACE
Ecopath with Ecosim
ATLANTIS ATLANTIS
IGBEM Integrated Generic Bay Ecosystem Model
INVITRO INVITRO
GEEM General Equilibrium Ecosystem Model
Ecosystem Models- plankton focus (NPZ-fish) MODEL NAMEERSEM II European
Regional Seas Ecosystem Model
SSEM Shallow Seas Ecological Model
Ecosystem ModelsII. Minimum Realistic Models
MODEL NAMEMRM Minimally Realistic
Models
Ecosystem ModelsII. Minimum Realistic Models MODEL NAMEGADGET Globally applicable
Area Disaggregated General Ecosystem Toolbox
BORMICON BOReal Migration and CONsumption model
MULTSPEC Multi-species model for the Barents SeaSimplified version is AGGMULT which is also connected to a ECONMULT - a model describing the economies of the fishing fleet
Ecosystem ModelsII. Minimum Realistic Models cont.MODEL NAMEMSVPA and MSFOR(and derivatives)
Multi-species Virtual Population Analysis; Multi-species Forecasting Model
MSM Multi-species Statistical Model
IBM Individual-Based Models
Bioenergetic/allometric
e.g. Koen-Alonso & Yodzis 2005
Ecosystem Models- Antarctic ModelsMODEL NAMEFOOSA Previously KPFM
(Krill- Predator-Fishery Model)
SMOM Spatial Multi-species Operating Model
EPOC Ecosystem Productivity Ocean Climate model
Other CCAMLR models e.g. Mori & Butterworth 2005, 2006
Ecosystem ModelsIII. Dynamic System ModelsMODEL NAMESEAPODYM Spatial Ecosystem
and Population Dynamics Model
OSMOSE Object-oriented Simulator of Marine ecOSystem Exploitation
SystMod System Model for the Norwegian and Barents Sea
Ecosystem ModelsIV. Extended Single-Species ModelsMODEL NAMEESAM Extended Single-Species
Models e.g. Livingston and Methot 1998; Hollowed et al. 2000; Tjelmeland and Lindstrøm 2005
SEASTAR Stock Estimation with Adjustable Survey observation model and TAg-Return dataTarget
SpeciesPredator
Catch Catch
OUTLINE OF TALK
Ecosystem Model Objectives Ecosystem Model Types Questions for EAF* Modelling Ecosystem Model Classification Considerations in Model Building
and the Best Practice Approach Role of Management Procedures Data requirements Conclusions
Questions for EAF Modelling Issues pertaining to the management of target and
related species:
• Impact of a target species on other species in the ecosystem?
• Limitations of single-species-based assessment
• Targeting of relatively unexploited species • What are the impacts of retained by-catch?• What is the effect on top predators of
removing the predators themselves and their prey?
• What is the extent of competition between fisheries and species of concern such as marine mammals, turtles, seabirds and sharks.
Questions for EAF Modelling Issues pertaining to species:
• What are the impacts of fishing on biodiversity?
• What are the impacts of commencing fishing on a previously unexploited species about which little is known.
• Effects of the introduction of non-native species.
• What are the impacts of non-retained by-catch?
Questions for EAF Modelling Environmental and unintentional impacts on
ecosystems
• Effects of physical/environmental factors on the resources on which fisheries depend.
• Changes in ecosystem state, e.g. regime shift, change to a less productive/less desirable state.
• Anthropogenic effects.• Effects of habitat modification e.g.
trawling damaging benthic habitats
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RESEARCH QUESTION/
MODEL
Ecopath with Ecosim and ECOSPACE IGBEM ATLANTIS INVITRO ERSEM II SSEM KPFM*
MRM e.g. Punt and Butterworth (1995)
MSVPA and MSFOR MSM
1a. Understanding - subset of ecosystem
1b. Understanding - complete ecosystem
2. Impact of target species
3. Effect of top predators
4. Competition: marine mammals - fisheries
5. Rebuilding depleted fish stocks
6. Biases in single-species assessment
7. Ways to distribute fishing effort among fisheries
8. Under-exploited species
9. Change in ecosystem state
10. Spatial concentration of fishing
11. Environmental/physical effects
12. Effects of habitat modification
13. Effects of by-catch
14. Introduction of non-native species* Still being developed
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MULTSPEC GADGET
Bioenergetic/allometric models OSMOSE SEAPODYM
CCAMLR models EPOC* SMOM* ESAM SEASTAR
1a. Understanding - subset of ecosystem
1b. Understanding - complete ecosystem
2. Impact of target species
3. Effect of top predators
4. Competition: marine mammals - fisheries
5. Rebuilding depleted fish stocks
6. Biases in single-species assessment
7. Ways to distribute fishing effort among fisheries
8. Under-exploited species
9. Change in ecosystem state
10. Spatial concentration of fishing
11. Environmental/physical effects
12. Effects of habitat modification
13. Effects of by-catch
14. Introduction of non-native species* Still being developed
OUTLINE OF TALK
Ecosystem Model Objectives Ecosystem Model Types Questions for EAF* Modelling Ecosystem Model Classification Considerations in Model Building
and the Best Practice Approach Role of Management Procedures Data requirements Conclusions
Pg. 4
NO
EN
VIR
ON
ME
NT
ENVIRONMENT
AGE STRUCTUREAGE STRUCTURE
Biological interactions described
Predator prey feedback
Handles the environment and lower trophic levels
Technical interaction models MSYPRMurawski 1984
Predators added to single-species models e.g. SEASTARGulland 1983; Livingston and Methot 1998; Hollowed et al. 2000; Plagányi 2004; Tjelmeland and Lindstrøm 2005
No
No
Yes
Yes
Handles age/size structureHandles age
structure
No Yes
Aggregate system models e.g. EwE, SKEBUB, SSEM
Spatial dynamic systems models e.g. ATLANTIS, ERSEM, SEAPODYM
Multispecies Production Models e.g. Horbowy 2005
YesNo
Dynamic multi-species models BORMICON, GADGET, MRMs, MSVPA& MSFOR, MSM, MULTSPEC, OSMOSE
No
Handles spatial structure
Yes
No
Dynamic systems models e.g. some recent EwE applications S
PA
TIA
L S
TR
UC
TU
REYes
Handles spatial structureNo
Spatial aggregate systems models e.g. ECOSPACE
Yes
Ew
E
NO
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PE
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S /
CO
MP
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20
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RM
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EA
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ype
EwE, ATLANTIS, INVITRO
External forcing
Phytoplankton, detritus
Zooplankton, filter-feeders
Clupeoids, demersals etc
Marine mammals, sharks etc
TR
OP
HIC
LE
VE
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ERSEM SSEM
MRM, MSVPA, GADGET, SEASTAR, SEAPODYM, IBM, MSM, Bioenergetic
OS
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OUTLINE OF TALK
Ecosystem Model Objectives Ecosystem Model Types Questions for EAF* Modelling Ecosystem Model Classification Considerations in Model Building
and the Best Practice Approach Role of Management Procedures Data requirements Conclusions
Strategical Model Considerations Strategical Model Considerations and the Best Practice Approachand the Best Practice Approach
(based on report from the July 2007 FAO Workshop)(based on report from the July 2007 FAO Workshop)
Consideration in Model Development
Best practice approach : ‘ideal’ practices, i.e. considerations when developing models. Not anticipated that these practices are always achievable or required.
Setting up a model
How many species or groups?
Aggregate based on shared characteristics of the species and omit the least important to keep web tractable
Include age, size or stage structure of the species of interest?
Include if there are major shifts over the course of the life history
Modelling predator-prey interactions:
How much detail in representing predator-prey interactions?
Represent as bi-directional unless it can be motivated sufficiently strongly that it is adequate to include a one-way interaction only in which the predator ration is fixed and changes in prey abundance have no effect on predator populations
Which functional response?
Test sensitivity and robustness to alternative functional relationships
PREY DENSITY
PR
EY
KIL
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PE
R P
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DA
TO
R P
ER
UN
IT T
IME
a) Type I
b) Type II
c) Type III
Predator abundance Bj
To
tal c
on
sum
ptio
n r
ate
Qij
(fo
r fix
ed
pre
y a
bu
nd
an
ce B
i)
Bj (Input)
Default assumption is that thisis the present (input) situation
limit
limit/2
EwE Foraging arena
Spatial considerations Spatial considerations Best Practice ApproachBest Practice Approach
Include spatial structure?
Include where there are major shifts in the location of the species of interest over the course of its life history
Include seasonal and temporal structure?
Where there are large differences in the seasonal dynamics in species movement or production
Defining boundary conditions
Basing boundaries on biological rather than anthropogenic considerations such as national boundaries
Is fishery harvesting more than one stock of a particular species?
Model needs to distinguish such different stocks when the harvesting practice is such as might impact these stocks to different extents; this will necessitate spatially structured models
Distinguish different fleets?
If for the same mass of catch, they make substantially different impacts on target and bycatch species or on the habitat
Model componentsModel components Best Practice ApproachBest Practice Approach
Explicitly represent primary productivity and nutrient cycling
May only be necessary when bottom-up forces or lower trophic levels are of key concern. Can be highly informative for some strategic modelling exercises.
Include environmental forcing?
Only if it is an absolute requirement for capturing system dynamics. When it is included there must be some means of generating future forcing for use in predictions and closed loop simulations.
Model Model componentscomponents
Best Practice ApproachBest Practice Approach
How to model recruitment?
Recruitment may be included either as an emergent property or as a derived relationship Likely important for tactical and risk analyses, but not strict requirement for strategic models.
Mainly emergent recruitment
Mainly derived property
e.g. EwE, Atlantis, OSMOSE, GADGET
e.g. MSVPA, SEAPODYM, MSM
Model componentsModel components Best Practice ApproachBest Practice Approach
How to model movement?
Testing sensitivity to a range of movement hypotheses. Parameterising movement matrices by fitting to these data. Decision rules check if resultant changes in distribution are sensible
EXAMPLES:
OSMOSE: Spatially explicit with fish schools moving to areas with highest potential prey biomass
GADGET: migration matrices specifying movement between areas; can parameterise by fitting to data
SEAPODYM: Movement model linked to habitat quality
External forcingExternal forcing Best Practice ApproachBest Practice Approach
Other process error considerations
Other process error, arising from natural variation in model parameters, needs to be included when variation contributes substantially to uncertainty
Other anthropogenic forcing?
Their influence on shallow coastal and estuarine systems should be considered in conceptual models ; should be empirically included
Alternative stable states?
Strategic models in particular need to ensure forecasting the consequences of environmental change…
Explicitly consider fleet dynamics?
Important to consider if substantial changes to the spatial distribution of fishing may result from, for example, the declaration of an MPA.
Technical and non-Technical and non-trophic:trophic:
Best Practice ApproachBest Practice Approach
Technical interactions(e.g. multi-stock fisheries; by-catch)
If the bycaught species are themselves also subject to management, including stock rebuilding, or if the model aims to inform the level of bycatch of a threatened species.
Non-trophic interactions(e.g. habitat dependency and habitat mediated interactions and processes)
If a critical determinant of the dynamic of interest (e.g. biomass or abundance of a target group), or if management could be based around this interaction
Dealing with Dealing with uncertaintyuncertainty
Best Practice ApproachBest Practice Approach
Should the model be fit to data?
Fitting to data is best practice, and this requires careful specification of likelihoods.
Taking account of parameter uncertainty
Include clear statements about uncertainties in model parameters; Bayesian methods and bootstrapping in ESAM and MRMs; …..
Model structure uncertainty
Identify alternative qualitative hypotheses for all of the processes considered likely to have an important impact on model outputs
What features to include in closed loop simulations?
Evaluation of feedback control harvest strategies should involve simulating the scheme that is likely to be actually used to determine management actions
Implementation uncertainty
Implementation uncertainty needs to be linked to consideration of fleet dynamics and is largely driven by, and must be included in, economic considerations…
Use and outputsUse and outputs Best Practice ApproachBest Practice Approach
Should code be freely available
Documentation and source code must be freely available to allow for review and understanding of the model. Using existing models can be of great help in learning, but careful thought is required when using a pre-existing model so that the tool is not misused
Social and economic outputs
Have economic experts collaborating with fisheries ecologists when designing a model implementation of economic factors
Ease of modularization
Best is object-oriented design
e.g. EwE, GADGET, SEPODYM
e.g. GADGET, new EwE
Recent trends in model development• Modularisation – e.g. substitute different
growth, functional response modules• Fitting to time series data• Computing constraints – e.g. running on
multiple computers in parallel using PVM
• Spatial considerations• Representation of socio-economic
factors and human behavioural drivers• Multiple sector dynamics and
management • Representation of biodiversity • Multi-species/ecosystem MSEs
OUTLINE OF TALK
Ecosystem Model Objectives Ecosystem Model Types Questions for EAF* Modelling Ecosystem Model Classification Considerations in Model Building
and the Best Practice Approach Role of Management Procedures Data requirements Conclusions
Operating Model to simulate “true dynamics of resource
OP
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AT
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M
OD
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Sim
ulatio
n testin
g
Explore uncertainties re model specification and fit to data
Methods and rules to compute Catch per ssmu
Use “future” data to compute Catch per ssmu
MA
NA
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ME
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P
RO
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DU
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Role of OMP/MP/MSE’s(MP = Management procedure; MSE = Management Strategy Evaluation)
From Rademeyer et al. 2007
Role of OMP/MP/MSE’s(MP = Management procedure; MSE = Management Strategy Evaluation)
• Approach involves an evaluation of the implications of alternative combinations of monitoring data, analytical procedures, and decision rules to provide advice on management measures that are robust to inherent uncertainties in all inputs and assumptions used.
• MSE or MP frameworks are used to identify and model uncertainties and to balance different resource dynamics representations.
• They provide key examples of formal methods for addressing uncertainty issues.
More re Dealing with Uncertainty
• Few ecosystem models with applications to practical fisheries management
• Management Procedure testing procedures can use changes in single species parameters (such as carrying capacity K) as a surrogate for ecological ecosystem effects e.g. climate change that are difficult to incorporate explicitly in operating models
• Technical ecosystem effects such as bycatch concerns can also be included as Robustness tests in the MP testing process
• These additions constitute a first step towards incorporating ecosystem aspects into practical fisheries management advice
• Multi-species/Ecosystem MPs being developed
Pg. 52
Multi-species/Ecosystem MPs• ATLANTIS used to evaluate the
performance of ecological indicators • ATLANTIS used to test ecosystem
models such as EwE by generating simulated data with known parameters
• South African Pelagic OMP - food requirements of predators such as penguins need to be accounted for in the management process
• CCAMLR: FOOSA and SMOM – spatially explicit multi-species MP frameworks
Spatial Multi-species Operating Model (SMOM) of Krill-Predator Interactions
Area 3 Feedback comparison
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SMOM-predicted change in predator abundance with a) no feedback in spatial catch allocations and b) using a feedback control rule based on a moderate amount monitoring information available for all SSMUs.
No feedback
Feedback
OUTLINE OF TALK
Ecosystem Model Objectives Ecosystem Model Types Questions for EAF* Modelling Ecosystem Model Classification Considerations in Model Building
and the Best Practice Approach Role of Management Procedures Data requirements Conclusions
Data Requirements
MRM DETAILED DATA RE FEW SPECIES – USUALLY SIZE/AGE STRUCTURE DATA
WHOLE ECO-
SYSTEM
LESS DATA RE MORE SPECIES
MORE DATA RE MORE SPECIES e.g. ADDING AGE STRUCTURE
SPATIAL
DATA RE MOVEMENT / DISTRIBUTIONS
ENVIRONMENT, ECONOMIC, SOCIAL, FISHING FLEET, ANTHROPOGENIC
Some conclusions• A good range of models have been developed
for the task of EAF, but greater focus is needed on strengthening these approaches and conducting the necessary data collection and experimentation to underpin confidence in these approaches
• Management decisions will be enhanced by exploring the same issue with different models; confidence in the decisions will increase when the models independently converge on the same management decisions and when uncertainties in the results have been adequately considered.
• MSE/MP approach is best practice• Strategical modelling will mainly be used to
inform and evaluate the Ecosystem Approach to Fisheries, with use in tactical decisions rare