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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In addition, although many metrrics species that specialize on a particular habitat have minimum area requirements e. Class area CA and percentage of landscape PLAND are measures of landscape composition; specifically, how much of the landscape is comprised of a particular patch type.
Therefore, at the class level, these two indices represent slightly different aspects of class structure.
Fragstats and Landscape Metrics
Total edge TE is an absolute measure of total edge length of a particular patch fragstatts class level or of all patch types landscape level. Patch size coefficient of variation measures relative variability about the mean i.
In applications that involve comparing landscapes of varying size, this index may not be useful. 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.
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 metrrics the landscape. Variation in patch size may convey more useful information. The Patch Analystan Esri extension, contains many of the Fragstat metrics.
For this species, late-seral forest area might be a good index of habitat suitability within landscapes the size of spotted owl home ranges Lehmkuhl and Raphael Riparia, a research Center at Penn State, has been assessing landscape conditions around its more than reference wetland sites. fragststs
Go to the Fragstats webpage. Meyrics contrast to the class level, these indices are completely redundant assuming there is no internal background. Greater variability indicates less uniformity in pattern either at the class level or landscape level and may reflect differences in underlying processes affecting the landscapes. These metrics help us to quantify physical characteristics on the ground and connect them to ecological processes.
Note, shape complexity and aggregation or contagion are closely related concepts. These metrics usually are best considered as representing landscape configuration, even though they are not spatially explicit measures.
Number or density of patches is probably most valuable, however, as the basis for computing other, mefrics interpretable, metrics. I encourage you to explore it! 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.
There is a wide metrucs 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.
Fragstats and Landscape Metrics | GEOG Conservation GIS
Mean patch size at the class level is a function of the number of patches in the class and total class area. Because these measures are not wholly redundant, it may be meaningful to interpret both measures in some applications.
For example, progressive reduction in the size of habitat fragments is a key component of habitat fragmentation. Thus, it is not necessary to know mean patch size to interpret the coefficient of variation. An excellent source for information on landscape metrics are the Fragstats webpages and their associated documentation.
This is an important characteristic in a number of ecological applications. In many ecological applications, second-order statistics, such as the variation in patch size, may convey more useful information than first-order statistics, such as mean patch size.
In a real landscape, the distribution of patch sizes may be highly irregular. In addition to these primary metrics, FRAGSTATS also summarizes the distribution of patch area and extent radius of gyration across all patches at the class and landscape levels.
For example, the number or density of patches may determine the number of subpopulations in a spatially-dispersed population, or metapopulation, for species exclusively associated with that habitat type.
In the study of forest fragmentation, therefore, it is important to know how much of the target patch type habitat exists within the landscape. In both cases, there is no variability in patch size, yet the ecological interpretations could be different. It may be more informative to inspect the actual distribution itself, rather than relying on summary statistics such as these that make assumptions about the distribution and therefore can be misleading.