Transcript BEHAVIORAL CHARACTERISTICS OF LANDSCAPE STRUCTURE METRICS IN NEUTRAL LANDSCAPES FRAGSTATS Workshop 18, July 2003 IALE World Congress Darwin, Australia.

BEHAVIORAL CHARACTERISTICS
OF LANDSCAPE STRUCTURE METRICS
IN NEUTRAL LANDSCAPES
FRAGSTATS Workshop
18, July 2003
IALE World Congress
Darwin, Australia
Step 1: Generate binary neutral landscapes using the
computer program RULE (Gardner 1999).
0
Increasing aggregation (H)
1
5%
Increasing
area (P)
256 x 256 cell grids
Factorial Design
H (n = 21) x P (n = 19)
95%
100 replicates of each of 399
H x P combinations
Step 2: Calculate 55 applicable class-level metrics
on all 39,900 neutral landscapes using
FRAGSTATS.
FRAGSTATS Specifications:
• 30 m cell size
• 90 m edge depth
• 500 m search radius
• 8 cell neighbor rule
• No border
• No background
• Boundary not included as edge
Conceptual Metric Classification
Area/Edge/
Density
Class Area
Percent of Landscape
Patch Density
Edge Density
Landscape Shape Index
Largest Patch Index
Normalized Shape Index
Patch Area*
Radius of Gyration*
Shape
Core Area
Perimeter Area
Fractal
Perimeter Area
Ratio*
Shape Index*
Fractal Dimension
Index*
Total Core Area
Core Percent of
Landscape
# Disjunct Core Areas
Disjunct Core Area
Density
Core Area
Disjunct Core Area*
Core Area Index*
Contrast
Connectivity
Contrast Weighted Edge
Density
Total Edge Contrast Index
Edge Contrast*
Patch Cohesion Index
Isolation/
Proximity
Proximity Index*
Similarity Index*
Euclidean Nearest
Neighbor*
Contagion/
Interspersion
Percent Like Adjacencies
Clumpiness Index
Aggregation Index
Intersperson and
Juxtapostion Index
Landscape Division
Splitting Index
Effective Mesh Size
Conceptual Metric Classification
Area/Edge/
Density
CA
PLAND
PD
ED
LSI
LPI
nLSI
AREA*
GYRATE*
Shape
Core Area
PAFRAC
PARA*
SHAPE*
FRAC*
TCA
CPLAND
NDCA
DCAD
CORE*
DCORE*
CAI*
Isolation/
Proximity
PROX*
SIMI*
ENN*
Contagion/
Interspersion
Contrast
Connectivity
CWED
TECI
ECON*
COHESION
PLADJ
CLUMPY
AI
IJI
DIVISION
SPLIT
MESH
Metric Behavior
H
P
Step 4: Plot the range of the H x P space that real
landscapes occupy
• Calculate metrics in landscapes from three
geographically distinct regions in the United
States:
– Idaho (221 landscapes, 5 classes)
– Western Massachusetts (155 landscapes, 7 classes)
– Colorado (152 landscapes, 4 classes)
• Superimpose values from real landscapes onto
values from neutral landscapes.
Metric Behavior
H
P
Step 5: Evaluate patterns of class-level metric
behavior in using mean metric values for 48
metrics.
• Use cluster analysis to classify metrics based on
behavior along P and H gradients.
• Graphically compare behavior of metrics.
Primarily a Function of P
LPI
P
H
AREA_AM
AREA_SD
GYRATE_AM
GYRATE_SD
CORE_AM
CORE_SD
TCA
DCORE_AM
DCORE_SD
PROX_MN
PROX_CV
PROX_SD
DIVISION
MESH
Primarily a Function of H:
Strongly Related to H
PAFRAC
nLSI
PARA_SD
FRAC_CV
FRAC_SD
CAI_SD
CLUMPY
CLUMPY
Related to Interaction of P and H Parabolic
Response Along P
ED
LSI
PD
GYRATE_CV
FRAC_AM
SHAPE_AM
SHAPE_CV
SHAPE_SD
PROX_AM
DCORE_CV
DCAD
FRAC_AM
DCAD
SHAPE_SD
Related to Interaction of P and H
AREA_MN
GYRATE_MN
PARA_AM
CORE_MN
DCORE_MN
CAI_AM
CAI_MN
SPLIT
PLADJ
AI
COHESION
ENN_AM
ENN_MN
ENN_CV
ENN_SD
GYRATE_MN
ENN_AM
PARA_AM
COHESION
Differential Metric Sensitivity
AREA_MN
P = 95%
P = 50%
P = 5%
H=0
AREA_AM
P = 95%
P = 50%
H=1
P = 5%
**Limitations**
Main Points
• Results are based on
– binary neutral landscapes.
– at one scale.
– only one configuration gradient (H). Varying shape, interpatch distance, etc. would yield different behavior.
• Identified 7 behavioral groups with varying
relationships with P and H.
• Conceptual similarity ≠ behavioral similarity.
• Many metrics have non-linear behavior and lack of
sensitivity in at least part of the H x P space.
– Problematic conditions do not always exist in real landscapes.
• Very few metrics measure configuration independent of
area – most confound P & H.