Docstoc

Chico-Singleton_Linkage Modeling Presentation 072508

Document Sample
Chico-Singleton_Linkage Modeling Presentation 072508 Powered By Docstoc
					                                                                            1

Landscape Linkage Modeling




Prepared by Peter Singleton, USFS PNW Research Station for the State-wide
                       CCLC Meeting, July 28, 2008.
                                                          2

                  Introduction
Definitions of connectivity:
Merriam 1984: The degree to which absolute isolation is
  prevented by landscape elements which allow organisms
  to move among patches.
Taylor et al 1993: The degree to which the landscape
  impedes or facilitates movement among resource patches.
With et al 1997: The functional relationship among habitat
  patches owing to the spatial contagion of habitat and the
  movement responses of organisms to landscape structure.
Singleton et al 2002: The quality of a heterogeneous land
  area to provide for passage of animals (landscape
  permeability).
                                                       3


                 Introduction
• Structural Connectivity: The spatial arrangement
  of different types of habitat or other elements in
  the landscape.

• Functional Connectivity: The behavioral
  response of individuals, species, or ecological
  processes to the physical structure of the
  landscape.
  – Potential Connectivity
  – Actual Connectivity
                                                                                               4

                                Introduction
Darwin’s Finches - 1837:




     Images from Robert Rothman http://people.rit.edu/rhrsbi/GalapagosPages/DarwinFinch.html
                                                                         5

                      Introduction
Island Biography
• MacArthur & Wilson 1967 The Theory of Island Biogeography
Reserve Design
• Soule 1987 Viable Populations for Conservation
• Meffe & Carroll 1994 Conservation Biology Textbook
Conservation Corridors
• Servheen & Sandstrom 1993 Linkage Zones for Grizzly Bears… End.
   Sp. Bul. 18
• Walker & Craighead 1997 Analyzing Wildlife Movement Corridors…
   Proc. ESRI Users Conf.
• Around 2000, linkage assessment workshops start happening
• Mid-2000’s, lots of publications addressing corridors / connectivity
Landscape Processes
• Late-2000’s Maturation of landscape genetics
• Future? More empirical data relating landscape process and pattern?
                                                                                  6

                     Introduction




From: Crooks & Sanjayan. 2006. Connectivity Conservation. Cambridge Univ. Press
                                                 7

          Analysis Approaches
1. Patch Metrics
2. Graph Theory
3. Cost-distance Analysis
  •   Combining graph theory and cost-distance
4. Circuit Theory
5. Individual-based & Population Viability
   Models
      •   Patch / HexSim
                                                           8

          Analysis Approaches
                                   Simple
                                   Few Assumptions
1. Patch Metrics                   Needs Less Input Info
                                   Structural focus
2. Graph Theory
3. Cost-distance Analysis
  •   Combining graph theory and cost-distance
4. Circuit Theory
5. Individual-based & Population Viability
   Models
      •   Patch / HexSim           Complex
                                   Lots of Assumptions
                                   Needs More Input Info
                                   Process focus
                                                         9

          Analysis Approaches
1) Patch Metrics
• Quantifies Patch Characteristics or Relationships
  Between Patches (e.g. patch size, nearest neighbor)
• Emphasizes Structural Connectivity
• Generally must be summarized across a landscape unit
  (e.g. watershed or planning unit)
• Very useful for quantifying landscape patterns (e.g.
  historic range of variability, monitoring change,
  comparing landscapes)
• Structure, not process oriented
• Don’t provide a lot of information about expected
  movement patterns
Landscape Metric Example – Effective Mesh Size
                                                                                                                         10




  From: Girvetz, Thorne, & Jaeger. 2007. Integrating Habitat Fragmentation Analysis into Transportation Planning Using
  The Effective Mesh Size Landscape Metric. 2007 ICOET Proceedings.
Landscape Metric Example – Effective Mesh Size
                                                                                                                         11




  From: Girvetz, Thorne, & Jaeger. 2007. Integrating Habitat Fragmentation Analysis into Transportation Planning Using
  The Effective Mesh Size Landscape Metric. 2007 ICOET Proceedings.
                                                            12
           Analysis Approaches
2) Graph Theory
 • Focused on quantifying relationships between patches
 • More focused on process
 • Solidly based in mathematical theory with many
   applications in other fields (e.g. geography, computer
   science, logistics)
 • Provides a language for describing relationships
   between patches
                                                                                                13
Graph Theory



 Vocabulary:

 • Patch (Node) – the points of interest
 • Link (Edge) – connections between the nodes
 • Path – a sequence of connected nodes
 • Tree – a set of paths that do not return to the same node
 • Spanning Tree – a tree that includes every node in the graph
 • Connected Graph – a graph with a path between every pair of nodes
 • Component (Subgraph) – part of the graph where every node is
   adjacent to another node in that part of the graph
 • Node-connectivity – the minimum number of nodes that must be
   removed from a connected graph before it becomes disconnected
 • Line-connectivity – the minimum number of links that must be removed
   before a graph becomes disconnected
 From: Urban & Keitt. 2001. Landscape Connectivity: A graph-theoretic approach. Ecology 82:1205-1218
                                                                                                       14
Graph Theory




 From: Urban & Keitt. 2001. Landscape Connectivity: A graph-theoretic approach. Ecology 82:1205-1218
                                                                                                   15
Graph Theory




 From: Urban & Keitt. 2001. Landscape Connectivity: A graph-theoretic approach. Ecology 82:1205-1218
                                                               16
             Analysis Approaches
3) Cost-distance Analysis
• More focus on matrix

• Can quantify isolation between patches

• Spatially explicit – can identify routes and bottlenecks

• Based on the concept of “movement cost” that has some
  foundation in ecological theory, but lacks extensive empirical
  documentation

• Several important assumptions about parameters and scale
  must be considered
Cost-distance Analysis                                                      17



 Analysis Steps:                                     Habitat Suitability:
                                 3     1    2   10
                                                     0 = Barrier
                                 1     0    2   1    1 = Poor
                                 1     1    3   3
                                                     2 = Moderate
                                                     3 = Good
   1) Identify Patches           10    3    1   2    10 = Source



                                 1     3    2   10   Travel Cost:
                                                     0 = 99
   2) Develop Friction           3

                                 3
                                       0

                                       3
                                            2

                                            1
                                                3

                                                1
                                                     1=3
                                                     2=2
      Surface                    10    1    3   2    3=1
                                                     10 = Source




   3) Evaluate                   6

                                 6
                                       5

                                      103
                                            2

                                            4
                                                10

                                                3
                                                     Cost-distance
                                                     22
                                                     16
      Landscape                  3

                                 10
                                       4

                                       1
                                            5

                                            4
                                                4

                                                6




    There are critical assumptions at each one of these steps!
Cost-distance Analysis                                                   18




 Results from cost-distance analysis:
 • Minimum cost-distance
 • Cost / Euclidean ratios
 • nth best corridor area delineations
 • Spatially explicit maps


 Many cost-distance applications have failed to take advantage of this
   information by focusing on least-cost paths or corridors
  (“Failing to see the landscape for the corridor”)
Cost-distance Analysis                                                                                            19

Step 1: Identifying source patches:
Large roadless areas and units highlighted in focal species management plans.




    From: Singleton et al. 2002. Landscape Permeability for Large Carnivores in Washington: A Weighted-Distance
                  and Least-Cost Corridor Assessment. USFS PNW Research Station PNW-RP-549
Cost-distance Analysis                                                                                              20
Step 2: Develop friction surface
                                                                    Cost Model Parameters:
                         Road Density
                                                                    Population Density
                                                                         0 - 10 people/mi2                 1.0
                                                                         10 - 25 people/mi2                0.8
                                                                         25 - 50 people/mi2                0.5
                                                                         50 - 100 people/mi2               0.3
                                                                         >100 people/mi2                   0.1

                                                                    Road Density
                                                                         < 1mi/mi2                         1.0
                                                                         1 - 2 mi/mi2                      0.8
                                                                         2 - 6 mi/mi2                      0.5
                                                                         6 - 10 mi/mi2                     0.2
                                                                         >10 mi/mi2                        0.1
                         Land Cover
                                                                    Land Cover
                                                                         All Forest & Wetlands             1.0
                                                                         Alpine, shrub,                    0.8
                                                                                grasslands
                                                                         Agriculture, bare                 0.3
                                                                         Water, urban, ice                 0.1

                                                                    Slope
                                                                         0 - 20%                           1.0
                                                                         20 - 40%                          0.8
                                                                         >40%                              0.6



      From: Singleton et al. 2002. Landscape Permeability for Large Carnivores in Washington: A Weighted-Distance
                    and Least-Cost Corridor Assessment. USFS PNW Research Station PNW-RP-549
                                                                                                                  21
Cost-distance Analysis
Step 2: Develop friction surface




    From: Singleton et al. 2002. Landscape Permeability for Large Carnivores in Washington: A Weighted-Distance
                  and Least-Cost Corridor Assessment. USFS PNW Research Station PNW-RP-549
                                                                                                                                                      22
Cost-distance Analysis                                                                        9000
                                                                                              8100




                                                                 Cell Weighted Distance (m)
Step 2: Develop friction surface                                                              7200
                                                                                              6300
                                                                                              5400
                                                                                              4500
                                                                                              3600
                                                                                              2700
                                                                                              1800
                                                                                               900
                                                                                                90
                                                                                                 0
                                                                                                     0.01 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00
                                                                                                                   Dispersal Habitat Suitability




    From: Singleton et al. 2002. Landscape Permeability for Large Carnivores in Washington: A Weighted-Distance
                  and Least-Cost Corridor Assessment. USFS PNW Research Station PNW-RP-549
Cost-distance Analysis                                                                                            23

Step 3: Evaluate the landscape




    From: Singleton et al. 2002. Landscape Permeability for Large Carnivores in Washington: A Weighted-Distance
                  and Least-Cost Corridor Assessment. USFS PNW Research Station PNW-RP-549
Cost-distance Analysis                                                                                            24
Step 3: Evaluate the landscape




    From: Singleton et al. 2002. Landscape Permeability for Large Carnivores in Washington: A Weighted-Distance
                  and Least-Cost Corridor Assessment. USFS PNW Research Station PNW-RP-549
Cost-distance Analysis                                                                                            25

Step 3: Evaluate the landscape


                                                                                          Cost Distance /
                                   Minimum Cost                Actual Linear
     Fracture Zone                                                                        Linear Distance
                                   Distance (km)               Distance (km)
                                                                                               Ratio

   Fraser River                          288.1                        27.9                        10.3
   Canyon
   Upper Columbia                        423.5                        46.3                        9.1
   River
   I-90 Snoqualmie                       630.4                        33.5                        18.8
   Pass
   Okanogan Valley                       633.5                        80.8                        7.8


   Southwestern                         6943.8                       116.2                        82.6
   Washington


        Pretty easy to understand with a simple patch – linkage structure,
                       but when things get more complex…

    From: Singleton et al. 2002. Landscape Permeability for Large Carnivores in Washington: A Weighted-Distance
                  and Least-Cost Corridor Assessment. USFS PNW Research Station PNW-RP-549
                                                                                                    26
A Digression: Integrating Cost-Distance Analysis
               and Graph Theory




  From: O’Brien et al 2006. Testing the importance of spatial configuration of winter habitat for
     woodland Caribou: an application of graph theory. Biological Conservation 130:70-83.
                                                                                                                            27
       A Digression: Integrating Cost-Distance Analysis
                      and Graph Theory
            FunConn ArcGIS Toolbox: http://www.nrel.colostate.edu/projects/starmap/




From: Theobald et al. 2006. FunConn v1 User’s Manual: ArcGIS tools for Functional Connectivity Modeling. Colorado State University.
                                                                                 28
                 Analysis Approaches
4) Circuit Theory
• Based on electrical
  engineering theory
• Generates a measure of
  “flow” through each cell in a
  landscape
• Integrates all possible
  pathways into calculations
• Corresponds well with
  random-walk models
• Resistance measures can be
  used in graph-theory
  applications
From: McRae et al. in press. Using Circuit Theory to Model Connectivity in Ecology,
Evolution, and Conservation. Ecology (expected publication fall 2008).
Simple landscapes                                             29


A        B




                    Least-cost path distance




                                                               Resistance distance
C        D




E        F




                                               Slide by Brad McRae
                                                   30
A more realistic landscape

                    High



                    Low


Circuit theory:            Least-cost path:




                                              Slide by
                                              Brad
                                              McRae
                                                                       31
              Analysis Approaches
5) Individual Based Models & Other Approaches
• Individual-based movement models (IBM)
   – Simulates movement of an individual through the landscape (e.g.
     PATH)
   – Many scales, from dispersal (coarse) to foraging (fine)

• Population viability models (PVA)
   – Uses demographic information to project population persistence (e.g.
     Vortex)

• Spatially explicit population models (SEPMs)
   – Integrates PVA with a heterogeneous landscape where vital rates vary
     (e.g. Ramas GIS)
Individual-based model example: Patch / HexSim
                                                          32



    HexSim (updated version of Patch):
    • IBM & SEPM
    • Each cell represents a female home range
    • Survival / reproduction / dispersal probabilities
      are related to the habitat characteristics of the
      cell
    • Models individual dispersal movements through
      the landscape
    • Assumes territorial, non-social behavior
      (originally developed for spotted owl PVA)
    • Developed by Nathan Schumacher, EPA,
      Corvallis OR (http://www.epa.gov/hexsim/)
Individual-based model example: Patch / HexSim
                                                               33




                                  From: USFWS 2008. Final
                                  Recovery Plan for the Northern
                                  Spotted Owl. May 2008. USFWS
                                  Region 1, Portland OR.
                                  Analysis by Marcot & Raphael
                                  Images by Bruce Marcot
Individual-based model example: Patch / HexSim
                                                                                                                            34




 From: Carroll 2005. Carnivore Restoration in the Northeastern U.S. and Southeastern Canada: A Regional-Scale Analysis of
 Habitat and Population Viability for Wolf, Lynx, and Marten. Wildlands Project – Special Paper No. 2. Richmond VA
                     Discussion                                 35



Different approaches provide different information
  and require different inputs and assumptions

                    Information   Data Model
                    Provided      Inputs Assumptions Focus
Landscape Metrics   Less          Less Fewer (implicit) Structure
Graphs
Cost-distance
Circuit Theory
IBM / SEPM          More          More   More (explicit) Function
                                                   36

                 Discussion
All of these modeling approaches involve major
  assumptions about:
• Habitat associations
  – Parameterizing source areas or habitat patch
    characteristics
• Dispersal behavior
  – Resistance to movement


Some projects have addressed some of these
  issues by using parameters based on empirical
  RSFs, but assumptions about dispersal habitat
  selection remain difficult.
                                                  37


               Discussion
The future of linkage modeling
• Better empirical techniques:
  – Integration of detection probability and
    movement probabilty into resource selection
    analysis
• Model validation:
  – Landscape genetics
  – GPS telemetry studies
                                                     38
                    Closing
Pete’s cornball philosophy of landscape modeling:
• Know your question
• Know your data
• Keep it simple
• Own your assumptions
• Be open to surprises, but always check twice
• All models are wrong, but some models are useful
• Validate, validate, validate …

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:6
posted:1/28/2011
language:English
pages:38