The shape of patches assumes a relevant importance, for the maintenance of the patch per se and as recognized habitat for a focal species.
Highly fractal patches offer more surface of contact with other patch types, and, under conditions of competition or of dominance of the neighboring patches, the shape of the border can encourage the subordinate patch to replace the invisible patch.
The fractal nature of the border can be estimated simply as the ratio between the total length of the border and internal surface of the patch. Or better still, it is possible to measure the convolution of the border applying a fractal analysis, for instance using the mass block.
The length of a patch border is not an inherent characteristic of a patch, but depends on the length of the caliber employed to measure this length.
For this reason we can measure the length of a patch using the meter to characterize the patch, but in many cases this measure is out of the range of appreciation of a species. There are good examples in the literature of employment of the species caliber to assess the length of a border. Using this method, it is possible to include also the irregularities of a border.
The convolution of the border can be perceived as important for some species like deer when they are foraging at the border between woodland and open grassland. But again the great extension of the borders facilitates the presence of edge species, of predators, and de facto the great extension of the border increases the sink character of the populations living in this system.
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