Table 1 Description of landscape metrics used in this study [11]

frac_mn_*

Mean fractal dimension index

Shape

Fractal dimension based on the patch perimeter and patch area: value (x) approaches 1 if all patches are squared and 2 if all patches are irregular

frac_sd_*

Standard deviation of fractal dimension index

Shape

Standard deviation of the fractal dimension index, where x = 0 if the fractal dimension index is identical for all patches and increases without limit as the variation of the fractal dimension indices increases

para_mn_*

Mean perimeter to area ratio

Shape

A patch complexity metric that approaches 0 if the perimeter-to-area ratio for each patch approaches 0 (i.e. the form approaches a rather small square) and increases without limit, as perimeter-to-area ratio increases (patches become more complex)

para_cv_*

Coefficient of variation of perimeter to area ratio

Shape

Coefficient of variation of perimeter-area ratio where x = 0 if the perimeter-area ratio is identical for all patches and increases without limit as the variation of the perimeter-area ratio increases

para_sd_*

Standard deviation of perimeter to area ratio

Shape

Standard deviation of perimeter-area ratio where x = 0 if perimeter-to-area ratio is identical for all patches and increases without limit as the variation of the perimeter-area ratio increases. This is scale dependent

area_cv_*

Coefficient of variation of patch area

Area and edge

Summarizes variation in patch area where x = 0 if all the patches are identical in size and increases without limit as the variation of patch area increases in the landscape

area_mn_*

Mean patch area

Area and edge

This is the simplest metrics—mean patch area of a given class. If all patches are small, x = 0 and increases without limit as the patch areas increases

pland_*

Percentage of landscape

Area and edge

Characterizes the composition of the landscape as percentage of class *. When the proportional class area is decreasing, the value approaches 0. The metric is equal to 100 when only one patch is present on the landscape

pd_*

Patch density

Aggregation

Describes the fragmentation of the class as patch density where x approaches 0 as the proportional class area decreases. It is equal to 100 when only one patch is present. It is standardized to 100 hectares area

dcore_mn_*

Mean number of disjunct core area

Core area

This counts the disjunct core areas, whereby a core area is a patch within the patch containing only core cells. If ncore = 0 for all patches, x = 0 and increases without limit as the number of disjunct core area increases

dcad_*

Disjunct core area density

Core area

This is the number of disjunct core areas per ha relative to the total area. When no patch of class * contains a disjunct core area, x = 0, and increases without limit as disjunct core areas become more present (i.e. patches becoming larger and less complex)

ed_*

Edge density

Area and edge

Describes the configuration of the landscape as the sum of all edges of class * in relation to the landscape area. If only one patch is present, x = 0, and increases without limit as the landscape becomes more patchy

lsi_*

Landscape shape index

Aggregation

Metric based on actual edges and minimum hypothetical edges. When only one squared patch is present or all patches are maximally aggregated, x = 1, and increases without limit as the length of the actual edges increases (i.e. the patches become less compact)