landscape pattern i.landscape components (attributes of features or spatial elements) landscape are...

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


Facilitated Movement Corridors

• Roads/right-of-ways

• Woody strips, windbreaks, fencerows

• Riparian 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


Barriers & Filters• Roads/right-of-

ways• 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

• 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


• Disturbance Regime– Exogenous agents

• Frequency, Intensity, & Spatial Patterning components


• Geomorphic Processes– Frequency &

spatial patterning


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

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