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Landscape Pattern. Landscape Components (attributes of features or spatial elements) landscape are comprised of: - corridors - patches - matrix. Landscape Pattern. Landscape Components (attributes of features or spatial elements) landscape are comprised of: - PowerPoint PPT Presentation
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Landscape PatternI. Landscape Components
(attributes of features or spatial elements)
landscape are comprised of:
- corridors
- patches
- matrix
Landscape PatternI. Landscape Components
(attributes of features or spatial elements)landscape are comprised of:
- corridors- patches- matrix
A. CompositionB. ConfigurationC. 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?
• 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 Patch-Corridor-Matrix Model
Landscape PatternPatches
Defining patches using vector data• Digitizing = delineating polygon patches using remotely-
sensed data (e.g., DOQ) based on visual interpretation of patch boundaries; subjective, but ground truthing needed
DOQ Vector Coverage
Landscape PatternPatches
Defining patches using raster data• Satellite sensor = delineating pixel-shaped patches based on
spectral signatures; aggregating cells based on shared attributes
DOQ Raster Coverage
• 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 Patches
• 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-of-ways
• Woody strips, windbreaks, fencerows
• Riparian corridors
Landscape Pattern Corridors
Do corridors function to facilitate movement of organisms among patches, thereby mitigating against land use in the matrix?
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-of-
ways• Riparian corridors
Landscape Pattern 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
• Most abundant and highest connectivity
• Defined relative to phenomenon studied
• Dynamic and variable with scale
• Influences choice of landscape metrics for measuring pattern
Landscape Pattern Matrix
Causes of Landscape PatternI. Abiotic Factors
II. Biotic FactorsIII. Human LanduseIV. Disturbance & Succession
What is the dominant force here?
• Primary constraints on vegetation pattern:
– Climate….long-term, prevailing weather affects energy & water dist’n
• Temperature (elevation)
• Moisture (exposure)
– Landform…. Geomorphology; physical relief & soil
Landscape Pattern Climate & Landform
Merriam
• 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
Landscape Pattern Landform Effects
Influence of landform – spatial pattern of species
distribution
Causes of Landscape PatternPhysical 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) Agriculture2) 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