1. Defining Landscapes Forman and Godron (1986): A
heterogeneous land area composed
of a cluster of interacting ecosystems that is repeated in similar form throughout.
Turner at al. (2001): An area that is spatially heterogeneous in at least one factor of interest.
Both stress the presence of patches or elements and interactions between systems.

2. Defining Landscapes
A landscape has no absolute size; size may differ among organisms depending on the question or problem.
Functional landscapes occur at multiple spatial scales that may not correspond to human
perceptions of the environment.
Therefore, the manager or investigator must define the landscape appropriately.
4m2
16m2 plots
1km2
100s of km2

3. Patches: definitions
Vector Data = polygons. In ArcGIS, these are shape files.
Grid Cells = homogenous rectangles, typically squares. Also called lattice data, pixels. In ArcGIS, these are grids files.

4. Models of Landscape Cover
Patch-Corridor-Matrix
model:
The extent, shape, and
configuration of landscape
elements defines landscape
pattern.
Landscape continuum model:
Rather than solely patches and corridors, landscapes are composed of a gradient of vegetative (or habitat) cover.

5. Defining a Patch
Patch = relatively discrete areas or periods of relatively homogeneous environmental conditions, with boundaries distinguishable or relevant to the object of interest.
Humans
/Natural Disturbance
Environmental
Fragments
Introduced
????

6. Defining a Patch
Digitizing: Using remotely-sensed data, one can subjectively delineate polygons (patches) using visual determination of boundaries.
Aerial Photo
Vector Coverage

7. Defining a Patch
Simple aggregation: Combine all adjacent areas that have the
same (or similar) value for the
attribute of interest, usually in a GIS.
Moving/split window:
Local variance methods – variance is computed within a moving window; boundaries have high local variance.
Local rate-of-change methods –
calculate a local regression and
examine the slope; steep slopes
indicate boundaries.

8. Defining a Patch
Global zonation: Hierarchical, divisive partitioning based on the
ratio of between- to within-patch variance.
Spatially-constrained clustering:
multivariate clustering that joins groups only if they are spatially adjacent.

9. Patch Characteristics
AREA
- sensitive to your unit of measurement
PERIMETER
- actual length dependent upon the smallest distance unit
SHAPE COMPLEXITY
- many methods available for measurement

10. Corridors and Edges
Corridor = narrow, linear elements of a type that differs from that on either side.

11. Defining Corridors and Edges
Corridor definition can be defined on structural attributes
Structural attributes:
Length and Width of corridor
Shape or Curvilinearity
Contrast from the matrix or other patches
Is there an environmental gradient included across the corridor? If so, is it an edge?
Presence of separate internal conditions?
Connectivity or presence of gaps along the corridor
Patch
type B
type A
type A
Corridor
Matrix
(Patch type C)

12. Defining Corridors and Edges
Corridor definitions based on functional attributes
Habitat corridors:
Increase connectivity by providing
breeding habitat that facilitates
gene flow across the landscape.
Facilitated movement corridors:
Increase connectivity by facilitating movement during dispersal, migrations, and/or range shifts.

13. Facilitated Organism Movement Corridors
May include:
Roads and powerlines
Woody strips, windbreaks, and hedgerows
Riparian corridors
Selectivity – Degree to which an organism can discriminate between habitat patches so as to maximize its likelihood of successful dispersal.
Resistance – Survival costs per unit of time spent in a given corridor.
Velocity – Average rate of organism movement in a given corridor.
NOTES:
Corridors may/may not facilitate movement and alleviate a loss of connectivity in the matrix.
Ultimate test of corridors: does the rate of immigration increase? Migration of more than desirable species may be enhanced!

14. Defining Corridors and Edges
Corridor definitions based on functional attributes
Barrier or filter corridors:
Prohibit or differentially impede (filter) the movement of organisms across the landscape.
Modifying corridors:
Alter the abiotic or biotic connection between patches or matrix.

15. Barrier and Filter Corridors
May include:
Roads and powerlines
Rivers and streams
Corridor/Edge may function to prevent or filter movement of organisms across landscapes, thereby decreasing connectivity, depending on:
Corridor width
Frequency of human or other disruptive activities in the corridor
Mobility and behavior of the species

16. The Matrix
Matrix = the most common or connected landscape element type that
generally plays the dominant role in landscape function.
The matrix is defined based on the object of interest
The matrix is dynamic and a function of time and space
The definition of a matrix will influence the interpretation of landscapes as well as landscape metrics - because of its large extent, the matrix may dominate certain metrics.

17. The Landscape Continuum Model
In many landscapes, patches and corridors are too difficult to define, at least from a human perspective.
Small or isolated elements may not serve as habitat alone, but may do so collectively, such that they should not be considered part of the background matrix.

18. The Landscape Continuum Model
Habitat
Destroyed
Intact
Variegated
Fragmented
Relictual
Decreasing connectivity, increasing edge effects