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Developing Conceptual Models for I


Examples Who/what are the models for? ... some state-and-transition models (fire, grazing, invasive plants), driver-stressor models focused on priority vital ... – PowerPoint PPT presentation

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Title: Developing Conceptual Models for I

Developing Conceptual Models for IM Networks
  • John E. Gross
  • September 6, 2005

(SWAN monitoring plan)
National Park Service - Inventory Monitoring
  • Key background
  • Examples Who/what are the models for?
  • Strategy for getting to the finish line good,
    fast, and cheap
  • Resources

Uses of conceptual models vary with network
Phase 1
Communicate understanding about ecosystem What
are the major ecosystems? What do we know about
them? What do we need to know? Ensure selected
VS are integrative, comprehensive Communicate why
/ how VS are informative and important Inform
sampling design communication about
program Facilitate integration and synthesis of
data understanding and reporting.
Phase 2
Phase 3
Vanni et al. February 2005. Bioscience
Well designed and executed diagrams will be
useful at all stages, from selecting VS to future
publications of results. Conceptual models
frequently appear in the top ecological journals.
Refer to the monitoring plan checklist chapter
2 appendices. These are the criteria that
reviews will use to evaluate the models.
What youll likely to end up with
  • A highly aggregated, holistic model (e.g.,
  • mechanistic (process, control, etc.) models of
    key ecosystems, processes, and perhaps species,
  • some state-and-transition models (fire, grazing,
    invasive plants),
  • driver-stressor models focused on priority vital
    signs (maybe),
  • tables with important drivers, responses,
    resources, etc.,
  • detailed narratives,
  • currently (September 05), several networks are
    developing conceptual diagrams for each park in
    the network. These park-specific models have
    been very well received by park staff.

Select the model structure for the
purpose. Dont attempt to use a one size fits
all philosophy
A few observations
  • Construct need-specific models rather than
    monolithic structures
  • Hierarchically structured sets of models have
  • holistic model provides regional/global context
  • systematic means to added detail as needed,
  • makes linkages between model obvious,
  • Craft is important. Rushing the final step is
    like letting a child finish fine furniture.

  • Who and what are the models for?
  • Audiences
  • Network staff (there will be turnover)
  • Park staff interpreters, resource specialists,
    superintendents, operations staff, EPMTs, etc
  • Science partners / collaborators / researchers
  • Network committees science, technical, boards
  • For NEPA, EIA/EIS, project reviews
  • GMP / RSPs - DFC
  • WASO Monitoring Plan reviewers

NCPN modifications to Chapin model by Mark Miller
Some key information the models need to
What are the overarching, broad-scale constraints
and system drivers?
What do the models need to communicate?
General characteristics of ecosystems
Photographs are information-rich. Use them wisely.
(SECN revised Phase 1)
(IAN Newsletter 5
(Mutel and Emerick 1992)
General system characteristics
(SECN revised Phase 1 report)
Major environmental gradients are often clear on
maps. Nationwide weather gradients are available
via PRISM data.
(Hevesi et al. 2003)
Some models should communicate our understanding
of system dynamics. How do you expect the system
to change over time in response to (fire,
grazing, climate, restoration, etc)? How can we
manage lands to achieve a desired future
condition if we dont understand system dynamics?
(Knight 1992)
An aggregate, simple model can be used to put
more detailed submodels in context. Heres the
broad-scale view of the hydrological cycle. The
next slide is a more detailed consideration of
water flow.
(from http//
Hevesi et al. 2002
A good process model can clearly communicate key
links between ecosystem processes and attributes
that, together, strongly determine system drivers
and responses.
Herricks model SCPN Phase 1
(No Transcript)
What dont we know? Where are the most important
gaps in our understanding?
Forest insect and disease (Blister Rust, Pine
Atmospheric Deposition
Landbirds (Clarks Nutcracker)
Large Carnivores (Grizzly Bear)
GRYN Whitebark pine model
Emphasize the most important elements.
Forested Watersheds
Agricultural Watersheds
(Walters et al. 2000)
(Vanni et al. 2005)
Emphasize the important parts
Use line weights, colors, shapes, etc. But dont
go overboard.
What key factor(s) are primarily responsible for
the system we observe?
Ponderosa pine control model
This model is structurally correct
Seed production / persistence (pollination,
granivory, decay, etc)
Seedlings (/ha)
Seed bank
Saplings (/ha)
Snags (/ha)
Trees (ha)
Survival and growth
Survival rate
Survival and growth
Decay, combustion
Fire extent
Fire intensity
Fuel continuity(stand)
Grazing, thinning
Fuel continuity(landscape)
Fire submodel
Fire frequency (suppression, prescribed burning,
(Gross, unpublished)
Snow pack
What are the important interactions between
system components, and HOW do they affect system
Landscape Fire, veg. cover, soil properties
Runoff rate
In-channel flow
Surface flow
In-channel flow
Hyporheic flow
Ground Water
Water temperature Nutrient content
A conceptual model of the Bremer River ecosystem
has been developed that is suitable for (1)
developing a coherent overview of relevant
ecological and biogeochemical processes affecting
water quality and also for (2) design of a
relevant survey sampling program and (3)
subsequent design of a numerical simulation model
to test water quality improvement strategies.
Figure 1 Primary water column nutrient cycles in
Bremer River and inputs of phosphates, silicates,
DOC, DON and inorganic nitrogen.
From http//
A particularly nice example of a very complex,
but still understandable model.
Models vary in scale
Model Scale
What it communicates
Generalized environmental model
Stage-setting global and regional scale drivers
and responses
Landscape-scale diagrams
Environmental gradients broad-scale drivers
linkages between systems (disturbance, land use)
Dynamics broad to fine scale factors
Species, site, or habitat models
Detailed mechanisms feedbacks, stressors-VS
State and transition models see the CPN
monitoring plans and Lisa Thomas presentations
Intense crown fires
Thin and burn?
  • Dense even-aged stand
  • stand-replacing fires frequent or infrequent
  • understory vegetation sparse
  • fuel load large and continuous
  • fires intense and spatially extensive

Ponderosa pine state and transition model
Model strengths and weaknesses
  • Control models
  • accurately represent feedbacks and interactions
  • usually most realistic structure
  • insights from construction
  • often complicated and hard to communicate
  • state dynamics may not be apparent
  • State and transition
  • clear representation of alternative states
  • can be simple
  • excellent communication with most audiences
  • generally lack mechanism
  • usually too general to directly link to vital
  • Driver-stressor models (but be careful of
    driver/stressor distinction)
  • provide clear link between agent of change and
  • simple and easy to communicate
  • no feedbacks
  • few or no mechanisms
  • frequently inaccurate and incomplete

A bit on the craft it makes a BIG
difference!!! Some very basic elements
  • align boxes, both horizontally and vertically
  • emphasize key linkages by line weight, style, or
  • minimize use of colors and shapes
  • aggregate lines when possible
  • maximize content ink
  • See Tufte The visual display of quantitative

Likely a major move to using IAN toolkit or
similar for conceptual diagrams, particularly for
diagrams of parks
Simplify where possible
As published
Same content, with 20 minutes of editing
(Schiller et al. 2001. Cons. Ecol 5(1)19)
Same content, simplied
Lithosphere Hydrosphere Biosphere
Atmosphere Cryosphere
(from landscape workshop, January 2003)
Global change
Extensive land use
Disturbance regime
Intensive land use
Ecosystem condition
Values Wilderness Viewshed Night sky Soundscape
Ecological flows
Changes in effective reserve size
Ecosystem resilience
Crucial habitat
Edge effects
Some aspects may be non-spatial
  • Mechanistically correct models
  • Begin by identifying state variables (population
    size, N, C, etc)
  • Rates connect state variables
  • Feedbacks are from state variables to rates, not
    rates to rates
  • Consider flows of information, energy/material
  • Separate external drivers, sources, sinks from
    internal variables
  • Think about functional form of relationships
  • Simplicity is a virtue, and a serious challenge

Contents of Chapter 2 (and/or appendix)
  • Introduction. Short justification, goals, and
    philosophy that guided model development (NCPN).
  • Clear table listing all models, w/ figure and
    page numbers (revised ROMN)
  • Overall description of models and chapter
    structure (by ecosystem, park, discipline, or ??)
  • Detailed narratives with pertinent, and complete,
    citations that closely match and that
    explain/embellish figures
  • Pertinent citations, all in the bibliography
  • and, of course, models that meet all the criteria
    in the checklist

There must be a clear connection between the
models and vital signs. If theres not, are the
models or VS inadequate?
Resources Dont reinvent the wheel
Other Networks reports see esp. CPNs, UCBN,
ROMN, SECN, GRYN Conceptual model web page
lModels.htm Mike Scott Riparian models for
CPN. Great report. Landscape effects Hansen and
Gryskiewicz report Faculty at nearby
colleges/universities Alpine for start, see
Niwot ridge LTER site http//
WT/research/research.html Simple models for
various systems GRYN Integration and
Application (IAN) http// -
symbols toolkit, handbook, professional
support Maddox et al. 1999 best single
paper Call or email John Gross, 970 267-2111,