Landscape Pattern I Landscape Components attributes of features

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