Transcript Corridor

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 – relatively
homogeneous ecological unit;
differentiated from landscape
as a whole
• Corridor – linear element that
differs from matrix on either
side; form & context
determines function (habitat,
conduit, barrier, filter)
• Matrix – element
encompassing greatest relative
area; most connected;
dominant role in landscape
dynamics
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 defined relative to
phenomenon investigated
(scale relevant)
• Patches are dynamic and
occur at a multiple scales
(space & time)
• Patch boundaries
meaningful only when
referenced to particular
scale & phenomenon;
resolution impt., gradients
or discrete boundaries?
Landscape Pattern
Corridors
• linear elements
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
Landscape Pattern
Corridors
Facilitated
Movement
Corridors
• Roads/right-ofways
• Woody strips,
windbreaks,
fencerows
• Riparian corridors
Do corridors function to facilitate movement of organisms
among patches, thereby mitigating against land use in the
matrix?
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
• Roads/right-ofways
• Riparian corridors
Do corridors function to prevent or impede movement of
organisms among patches and across the landscape (i.e.,
decrease landscape connectivity)?
Yes, but dependent on:
– Corridor type & width
– Frequency of human and other spp. activity in corridor
– Mobility & behavior of species
Landscape Pattern
Matrix
• Most abundant and
highest connectivity
• Defined relative to
phenomenon studied
• Dynamic and
variable with scale
• Influences choice of
landscape metrics for
measuring pattern
Causes of Landscape Pattern
I.
Abiotic Factors
II. Biotic Factors
III. Human Landuse
IV. Disturbance & Succession
What is the dominant force here?
Landscape Pattern
Climate & Landform
• Primary constraints
on vegetation
pattern:
– Climate….longterm, prevailing
weather affects
energy & water
dist’n
• Temperature
(elevation)
• Moisture
(exposure)
– Landform….
Geomorphology;
physical relief & soil
Merriam
Landscape Pattern
Landform Effects
• Topographic
patterns
– elevation
– aspect
– parent material
– slope
• Influencing air &
ground temps.,
moisture,
nutrients,
pollutants
Landscape Pattern
Landform Effects
• Flow of Materials
–
–
–
–
–
Organisms
Propagules
Energy
Water
DOM &
inorganics
Landscape Pattern
Landform Effects
• Disturbance
Regime
– Exogenous agents
• Frequency,
Intensity, &
Spatial Patterning
components
Landscape Pattern
Landform Effects
• Geomorphic
Processes
– Frequency &
spatial patterning
Influence of landform – spatial pattern of species distribution
Causes of Landscape Pattern
Physical Template
• Inferences about physical gradients are
confounded because:
• Each factor has specific spatial scale =
behaves at its own scale:
– Soil depth & texture
• cm and all other scales
– Topography
• 10’s to 100’s m
– Temperature
• 100’s m (elevation) or 100’s km (latitude)
– Precipitation
• 100’s m (elevation)
Historical Context
Influence of Global
Climate Change
Common N.A. trees –
contractions &
radiations in
distribution
Modeling Changes in Landscape (vegetative)
Patterns – Global Climate Change
Causes of Landscape Pattern
• Biotic Factors
– Competition
– Predation
Causes of Landscape Pattern
• Competition
– Competitive exclusion
could lead to
homogenous spatial
pattern at least at some
spatial scale
– Multiple stable states
(stochastic disturbance
patterns can mitigate
influence of
competition) (e.g.,
Allee Effect)
– Influence of
disturbance events
(abiotic and human)
Causes of Landscape Pattern
• Competition
– Species-mediated interactions (e.g., keystone sp.)
• Dominant organisms (typically impact
processes and pattern over large spatial and
temporal scales) – primarily herbivores?
– e.g., beaver, bison, elephants, other megafauna?
– Pleistocene megafauna and vegetation patterns
Causes of Landscape Pattern
• Predation
– keystone sp
– ecology of fear
– Trophic
cascades
Causes of Landscape Pattern
• Human Land Use
– Prehistoric, Historic, Present Effects
• Shift from nomadic hunter-gatherer to farming systems
Human Land Use Practices
1) Agriculture
2) Suburban Development
*Landuse / Landcover Data from
USGS sources (typically
resolution to 30 m)
Causes of Landscape Pattern
• Human Land Use
– Present Effects
• Extraction of natural resources
• Patterns of development
• Transportation networks
Roads: Formation of Barriers in Landscapes
Clearcuts and National Forest Management
Patch Clearcuts
Causes of Landscape Pattern
• Disturbance & Succession
Patch Clearcuts Simulating Natural Disturbance