These metrics usually are best considered as representing landscape configuration, In addition to these primary metrics, FRAGSTATS also summarizes the. There is a wide variety of landscape metrics that have been developed and applied for many years. These metrics help us to quantify physical characteristics on. every patch is counted; FRAGSTATS does not sample patches from the . For a categorized list of FRAGSTATS output metrics see the FRAGSTATS Metrics.
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Example metrics are shown here. Because these measures are not wholly redundant, it may be meaningful to interpret both measures in some fragdtats. Ultimately, the choice of standard deviation or coefficient of variation will depend on whether absolute or relative variation is more meaningful in a particular application. An excellent source for information on landscape metrics are the Fragstats webpages and their associated documentation.
As noted above, the area AREA of each patch comprising a landscape mosaic is perhaps the single most important and useful piece of information contained in the landscape. metricx
Fragstats and Landscape Metrics
The minimum value of LSI is always equal feagstats 1 when either the class is maximally compact at the class level or the landscape consists of a single patch at the landscape level. The number or density of patches also can alter the stability of species interactions and opportunities for coexistence in both predator-prey and competitive systems Kareiva Furthermore, mean patch size represents the average condition.
A mean patch size of 10 ha could represent 1 or patches and the difference could have profound ecological implications. Typically metrics fragsfats calculated for data classed within a specified landscape your extent. The radius of gyration can be considered a measure of the average distance an organism can move within metrkcs patch before encountering the patch boundary from a random starting point.
Fragstats and Landscape Metrics | GEOG Conservation GIS
Similarly, holding area constant, the more extensive the patch i. There is a wide variety of landscape metrics that have been developed and applied for many years. Variability in patch size measures a key aspect of landscape heterogeneity that is not captured feagstats mean patch size and other first-order statistics.
Total edge TE is an absolute measure of total edge length of a particular patch type class level or of all patch types landscape level. A landscape with a greater number or density of patches has a finer grain; that is, the spatial heterogeneity occurs at a finer resolution. FRAGSTATS computes several simple statistics representing the number or density of patches, the average size or radius of gyration of patches, and the variation in patch size or radius of gyration at the class and landscape levels.
Edge density ED standardizes edge to a per unit area basis that facilitates comparisons among landscapes of varying size. In this case, the interpretations of landscape pattern would be very different, even though absolute variation is the same. Mean patch size at the class level is a function of the number of patches in the class and total fragstas area. These metrics help us to quantify metricss characteristics on the ground and connect them to ecological processes.
In contrast to the class level, these indices are completely redundant assuming there is no internal background. In applications that involve comparing landscapes of varying size, this index may not be useful.
However, when comparing classes or landscapes of identical size, total edge and edge density are completely redundant. Edge metrics usually are best considered as representing landscape configuration, even though they are not spatially explicit at all.
In addition, although mean patch size is derived from the number of patches, it does not convey any information about how many patches are present.
Note, shape complexity and aggregation or contagion are closely related concepts. Patch size coefficient of variation measures relative variability about the mean i. At the class and landscape levels, edge can be quantified in other ways. For example, two landscapes may have the same patch size standard deviation, e.
It is important to keep in mind that both standard deviation and coefficient of variation assume a normal distribution about the mean.
The number of subpopulations could influence the dynamics and persistence of the metapopulation Gilpin and Hanski Fragstats and Landscape Metrics Print There is a wide variety of landscape metrics that have been developed and applied for many years.
There are metrics that have been identified that inform about the landscape in its entirety as well as metrics that break down each land cover class within the defined landscape. Thus, mean patch size can serve as a habitat fragmentation index, although the limitations discussed below may reduce its utility in this metricx. In addition to its direct interpretive value, class area in absolute or relative terms is used in the computations for many of the class and landscape metrics.
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