Review of major ecosystem model classes

1
Review of major ecosystem model classes
National Ecosystem Modeling Workshop
(NEMoW) August 29-31 2007, NMFS Santa Cruz

• Éva Plagányi
• Dept. of Maths Applied Maths, University of
  Cape Town

With thanks to Doug Butterworth and MARAM
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
2
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

3
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
4
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

5
Model types

• Whole ecosystem models models that attempt to
  take into account all trophic levels in the
  ecosystem
• Minimum Realistic Models (MRM) limited number of
  species most likely to have important
  interactions with a target species of interest
• Dynamic System Models (Biophysical) represent
  both bottom-up (physical) and top-down
  (biological) forces interacting in an ecosystem
• Extensions of single-species assessment models
  (ESAM) expand on current single-species
  assessment models taking only a few additional
  inter-specific interactions into account

6
Ecosystem ModelsI. Whole ecosystem models
7
Ecosystem Models- plankton focus (NPZ-fish)
8
Ecosystem ModelsII. Minimum Realistic Models
9
Ecosystem ModelsII. Minimum Realistic Models
10
Ecosystem ModelsII. Minimum Realistic Models
cont.
11
Ecosystem Models- Antarctic Models
12
Ecosystem ModelsIII. Dynamic System Models
13
Ecosystem ModelsIV. Extended Single-Species
Models
14
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

15
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.

16
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?

17
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

18
(No Transcript)
19
(No Transcript)
20
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

21
Biological interactions described
Technical interaction models MSYPR Murawski 1984
No
Yes
No
Predators added to single-species models e.g.
SEASTAR Gulland 1983 Livingston and Methot 1998
Hollowed et al. 2000 Plagányi 2004 Tjelmeland
and Lindstrøm 2005
Predator prey feedback
Yes
Handles the environment and lower trophic levels
No
Yes
Handles age/size structure
Yes
No
Handles age structure
Yes
No
Handles spatial structure
Handles spatial structure
Yes
Multispecies Production Models e.g. Horbowy 2005
No
No
Yes
Spatial dynamic systems models e.g. ATLANTIS,
ERSEM, SEAPODYM
Aggregate system models e.g. EwE, SKEBUB, SSEM
Dynamic multi-species models BORMICON, GADGET,
MRMs, MSVPA MSFOR, MSM, MULTSPEC, OSMOSE
Dynamic systems models e.g. some recent EwE
applications
Spatial aggregate systems models e.g. ECOSPACE
Pg. 4
22
(No Transcript)
23
Marine mammals, sharks etc
TROPHIC LEVEL
Clupeoids, demersals etc
Zooplankton, filter-feeders
Phytoplankton, detritus
24
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

25
Strategical Model Considerations and the Best
Practice Approach(based on report from the July
2007 FAO Workshop)
26
EwE Foraging arena
27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
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
31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34
e.g. EwE, GADGET, SEPODYM
e.g. GADGET, new EwE
35
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

36
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

37
Role of OMP/MP/MSEs(MP Management procedure
MSE Management Strategy Evaluation)
Operating Model to simulate true dynamics of
resource
OPERATING MODEL
MANAGEMENT PROCEDURE
From Rademeyer et al. 2007
38
Role of OMP/MP/MSEs(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.

39
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
40
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

41
Spatial Multi-species Operating Model (SMOM) of
Krill-Predator Interactions
No feedback
Feedback
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.
42
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

43
Data Requirements
DETAILED DATA RE FEW SPECIES USUALLY SIZE/AGE
STRUCTURE DATA
MRM
MORE DATA RE MORE SPECIES e.g. ADDING AGE
STRUCTURE
ENVIRONMENT, ECONOMIC, SOCIAL, FISHING FLEET,
ANTHROPOGENIC
44
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