habitat interspersion –
Leopold’s Law of Interspersion
Human Land Use Practices
History of Landscape Ecology
• “European School”
– roots back to those of ecology
– typing, classifying, naming
– landscape architecture, planning,
designing
• “American School”
– young = early 1980’s
– focus on natural systems
– theory & models, some field
experiments
What is Landscape Ecology?
• Meta-analysis of papers in
Landscape Ecology (Wiens
1992) – 1st 5 yrs of journal
– Most studies are large scale
(landscapes are big)
– Most studies are descriptive or
conceptual
– Experiments difficult to conduct,
thus modeling
– Emphasis on vegetation pattern /
land use pattern
– Humans = impt. part of systems
What is Landscape Ecology?
• Hobbs (1997) – 2nd 5
years of Landscape
Ecology
– Less descriptive
studies
– More “methods” and
modeling studies, no
expts.
– More quantitative /
statistical analysis
(spatial stats)
Emergence of Landscape Ecology
?
Equilibrium View
Structure
?
?
Function
?
Emergence of Landscape Ecology
Dynamic View
Structure
Function
Long
Ecological Scaling: Scale & Pattern
Speciation
Extinction
Short
Temporal Scale
Species
Migrations
Secondary
Succession
Windthrow
Fire
Treefalls
Recruitment
Fine
Spatial Scale
Coarse
• Acts in the “ecological
theatre (Hutchinson
1965) played out
across various scales
of space & time
• To understand these
dramas, one must
select appropriate
scale
Ecological Scaling: Scale & Pattern
Regional Scale
(thousands of ha)
American Redstart
American Redstart
Local Scale
(4 ha plots)
Least Flycatcher
Least Flycatcher
Ecological Scaling: Definitions
• Ecological scale & cartographic scale are exactly opposite
– Ecological scale =
– Cartographic scale =
Ecological Scaling: Components of Scale
• Grain = finest
component of
environment that can be
differentiated up close
• Extent = range at which
a relevant object can be
distinguished from a
fixed vantage point
Extent
Grain
Fine
Scale
Coarse
Ecological Scaling: Components of Scale
• )
Identifying the “Right” Scale(s)
•
•
•
•
No clear algorithm for defining
Autocorrelation & Independence
Life history correlates
Dependent on objectives and organisms
• Multiscale analysis!
• e.g., Australian leadbeater’s possum
Multiscale Analysis
• Species-specific perception of
landscape features : scale-dependent
– e.g., mesopredators in Indiana
• Modeling species distributions in
fragmented landscapes
Spatial and Temporal
Ecology of Raccoons
Gehring and Swihart. 2003.
Biological Conservation
109:283-295
Brown and Litvaitis. 1995. Canadian Journal of Zoology
73:1005-1011
Hierarchy Theory
• Lower levels
provide mechanistic
explanations
• Higher levels
provide constraints
Scale & Hierarchy Theory
• Hierarchical structure of systems =
helps us explain phenomena
–Why?
: next lower level
–So What? : next higher level
• minimum 3 hierarchical levels needed
Constraints
(significance)
Level of Focus
(level of interest)
Components
(explanation)
Landscape Pattern
I.
Landscape Components
(attributes of features or spatial elements)
landscape are comprised of:
- corridors
- patches
- matrix
Landscape Pattern
I.
Landscape Components
(attributes of features or spatial elements)
landscape are comprised of:
- corridors
- patches
- matrix
A.
B.
C.
Composition
Configuration
Connectivity
Relative to landscape spatial elements….
How much of the area is comprised of each type of spatial element?
How are spatial elements arranged in space?
How do these attributes change through time?
How does one quantify landscape pattern?
How do biotic communities interact with pattern?
Landscape Pattern
Patch-Corridor-Matrix Model
• Patch –
• Corridor
• Matrix –
Landscape Pattern
Patches
Defining patches using vector data
• Digitizing = delineating polygon patches using remotelysensed data (e.g., DOQ) based on visual interpretation of
patch boundaries; subjective, but ground truthing needed
DOQ
Vector Coverage
Landscape Pattern
Patches
Defining patches using raster data
• Satellite sensor = delineating pixel-shaped patches based on
spectral signatures; aggregating cells based on shared
attributes
DOQ
Raster Coverage
Landscape Pattern
Patches
• Patch boundaries
meaningful only when
referenced to particular
scale & phenomenon;
resolution impt., gradients
or discrete boundaries?
Landscape Pattern
Corridors
• Definition based on
function…..
• Habitat – increase
connectivity by
providing breeding
habitat…facilitate gene
flow
• Facilitated Movement
– increase connectivity
by facilitating dispersal,
migration, and/or range
shifts
• Barrier or Filter –
prohibit (barrier) or
impede differentially
(filter) movements
Facilitated
Movement
Corridors
Landscape Pattern
Corridors
Landscape Pattern
Corridors
Facilitated Movement
Corridors
• Selectivity (s): degree of
discrimination of
possible pathways
• Resistance (k): survival
cost per unit time spent
in corridor
• Velocity (v): avg rate of
movement through
• Final evaluation =
immigration rate
Landscape Pattern
Corridors
Barriers & Filters
Landscape Pattern
Matrix
• Most abundant
• Highest connectivity