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APPENDIX 2 - FORMULAS USED FOR THE COMPUTATION OF METRICS FOR LANDSCAPES, CLASSES, AND PATCHES IN MACHADINHO D'OESTE AND VALE DO ANARI (MCGARIGAL AND MARKS 1995).




METRICS USED FOR LANDSCAPES


  • LARGEST PATCH INDEX: percentage of landscape accounted for by largest patch

  • PATCH DENSITY: number of patches per 100 ha for a landscape

  • MEAN PATCH SIZE: average patch size for a landscape

  • PATCH SIZE STANDARD DEVIATION: population standard deviation for patch sizes of a landscape

  • PATCH SIZE COEFFICIENT OF VARIATION: population coefficient of variation in patch size relative to the mean patch size for a landscape

  • EDGE DENSITY: length of edge per hectare for a landscape

  • LANDSCAPE SHAPE INDEX: ratio of sum of edge lengths to total area for a landscape measured against a circle standard

  • AREA-WEIGHTED MEAN SHAPE INDEX: average perimeter-to-area ratio for a landscape, weighted by the size of its patches

  • TOTAL CORE AREA INDEX: core area defined by specified edge distance from the patch perimeter for the entire landscape as a percentage of total landscape area

  • MODIFIED SIMPSON’S DIVERSITY INDEX: proportional abundance of each patch type within the landscape

  • MODIFIED SIMPSON’S EVENNESS INDEX: measurement of the distribution of area among patch types within the landscape

  • INTERSPERSION AND JUXTAPOSITION INDEX: observed interspersion divided by maximum interspersion for the patch types in a landscape


METRICS USED FOR CLASSES


  • PERCENTAGE OF LANDSCAPE: percentage of landscape accounted for a class

  • LARGEST PATCH INDEX: percentage of class accounted for by largest patch

  • PATCH DENSITY: number of patches per 100 ha for a class

  • MEAN PATCH SIZE: average patch size for a class

  • PATCH SIZE STANDARD DEVIATION: population standard deviation for patch sizes of a class

  • PATCH SIZE COEFFICIENT OF VARIATION: population coefficient of variation in patch size relative to the mean patch size for a class

  • EDGE DENSITY: length of edge per hectare for a class

  • LANDSCAPE SHAPE INDEX: ratio of sum of edge lengths to total area for a class measured against a circle standard

  • AREA-WEIGHTED MEAN SHAPE INDEX: average perimeter-to-area ratio for a class, weighted by the size of its patches

  • MEAN CORE AREA INDEX: average of core areas defined by specified edge distance from the patch perimeter for the entire class as a percentage of total class area

  • INTERSPERSION AND JUXTAPOSITION INDEX: observed interspersion divided by maximum interspersion for patches in a class


METRICS USED FOR PATCHES


  • AREA: area of the patch in hectares

  • PERIMETER: perimeter of the patch, including any internal holes in the patch

  • SHAPE INDEX: ratio of sum of edge lengths to total area for a patch, measured against a circle standard

  • FRACTAL DIMENSION: degree of complexity of patches based on a perimeter-to-area ratio
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