The Commission defines "exotic invasive plants" as nonnative species
that have spread into native or minimally managed plant systems in
Nantucket, causing economic or environmental harm by developing self-sustaining
populations and becoming dominant and/or disruptive to those systems.
On Nantucket, this may include species that are native to the mainland,
but do not occur naturally on the Island. Invasive plants are those
species that spread widely beyond the location of initial establishment,
become locally abundant, or spread into natural areas. Invasive species
may cause net harm to the economy, environment and human health. While
native species may be "invasive" in certain habitats, this section
is concerned with invasive-exotic plant species, which will henceforth
be abbreviated as "invasive" plants or species. Invasive plants often
possess some of the following characteristics that increase their
ability to replace native species: rapid growth and maturation; abundant
seed set and/or asexual reproduction; rapid rates of spread; and few,
if any, natural enemies. Invasive plants are often difficult to control
and may form monocultures over large areas.