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ENV510 Landscape Ecology and GIS
Definitions
& descriptions |
Structure & pattern |
Function
& process | Change
& dynamics | Management
implications
Structure
| Features
| Patches
| Matrix
| Corridors
| Measurements
| Indices
| Measures
| Metrics
| Inadequacies | Quantification
| Appearance | Complexity
Redundancy
Transfer of indices
Indeterminate boundaries
Many indices
may be necessary to cope with the different data types and formats that are
commonly used in landscape studies but there are still inadequacies.
Riitters
et al. (1995) show that a lot of the indices are highly intercorrelated.
This is because there are basically only a few measures that can be made from
land cover maps,
so what we end up with is redundancy
and replication in some landscape indices.
Most of
the indices widely used today were developed on, and applied to data sets in
North America and there are problems in applying them to other areas.
Hulsoff
(1995) looked at pattern indices such as land use type, patch number, mean
patch size, patch shape and dominance, and change indices. She found that not
all the indices widely used in North America were suitable for application in
Dutch landscapes.
This means that different indices or measures may be necessary for different landscape types.
Most of
the indices so far are assessments of patch geometry. These are useful metrics
of landscape structure provided boundaries between landscape elements can be
clearly identified, like Kellerberrin. Problems arise however, when the landscape
takes the form of a continuum
with landscape features grading into one another, eg in the New
England tablelands.
Defining
objects in this situation is difficult. One solution is to treat the landscape
as a series of gradients
rather than discrete objects and to apply a range of texture
measures derived from image processing. These can be used with remotely sensed
data or data that exists as surfaces. This constitutes a move away from patch
theory and could be a good way of measuring landscape structure in landscapes,
such as those found in Northern
Australia.
Texture
refers to 'the spatial variation in brightness values within a region of an
image' (Haines-Young
and Chopping, 1996). Descriptors of texture include properties such as:
Other measures that could be used are ones based on spatial statistical analysis, for example spatial autocorrelation (Pearson, 1998).
Do this - Identify appropriate measures - Why?
Would the same measures be appropriate in studying Kellerberrin and New England? Identify what would be best in each location.More?
A good article providing more information on indices is Reading 1.5 written by Haines-Young and Chopping.
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