Table 2.

Landscape indices of NTL footprints.

Indicator	Calculation	Significance
Number of patches, NP	Total number of patches of NTL’s footprints	NP reflects the spatial pattern and heterogeneity of NTL’s footprints; it is positively correlated with fragmentation of NTL’s footprints.
Class area, CA	Total class area of NTL’s footprints	CA determines the range of NTL’s footprints; It indicates the scope of human activity.
Patch density, PD	The NP/CA ratio of NTL’s footprints	PD is the number of patches per unit area; it reflects the dispersion of footprints of NTL.
Mean patch size, MPS	The CA/NP ratio of NTL’s footprints	MPS indicates the fragmentation of NTL’s footprints; it also reflects NTL’s footprints heterogeneity.