At most sites the extent of contiguous habitat is small, both increasing the vulnerability of large populations to collection due to their density, and of small populations due to the potential of extirpation by removal of only a few plants (22).
(the extent of contiguous habitat; is; small; L:At most sites) (both; increasing; the vulnerability of large populations to collection due to their density)
the extent of contiguous habitat both
is increasing
small L:At most sites
the vulnerability of large populations to collection due to their density