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The Invasive Species Working Group (ISWG)
is composed of 13 representatives from 9 Florida state
agencies and 1 Florida university. Their objective is to
develop a statewide strategic plan for managing and
preventing invasive species in Florida.
The ISWG defines an invasive species as a
non-indigenous species that has the ability to establish
self-sustaining, expanding, free-living populations, and may
cause economic and/or environmental harm as measured by risk
assessment(s) accepted by the ISWG.
Similarly, the
National Invasive Species
Information Center (NISIC) defines an invasive species as
1) nonnative to the ecosystem under consideration and
2) whose introduction causes or is likely to cause economic
or environmental harm or harm to human health.
The NISIC states that invasive species can
be plants, animals, and other organisms (such as microbes),
and that human actions are the primary means of invasive
species introductions. |
Cuban treefrog photo by Kevin
Enge/FWC |
A nonnative species could become invasive soon after becoming established,
like the Cuban tree frog. It was introduced a century
ago through packing materials, and has invaded Florida's
natural areas, preying on our native tree frogs. Cuban tree
frogs rapidly spread in south Florida and were common
throughout most of the state by the 1970's.
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Iguana photo
by Kevin Enge/FWC |
On the other
hand, it might take years for the right factors to fall into
place to allow a species to expand its range and cause
ecological problems. For example, green iguanas have resided
in Florida since the 1960's, but their population has
increased greatly since Hurricane Andrew. Although
green iguanas have not had ecological impacts, this Central
and South American lizard causes significant economic damage
to landscape plants, primarily in Miami-Dade and Broward
Counties. On Florida's west coast, black spinytail
iguanas have reached such abundance that many residents view
them as a nuisance, and the town of Boca Grande has
considered hiring trappers to remove them.
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Nutria photo by
US Fish and Wildlife Service |
Some invasive animals do not cause problems in all areas.
The nutria, a large rodent from South America, lives in
warm, marshy areas. It is abundant in the lowlands of
Louisiana and Mississippi, but Florida populations have not
been very successful even though Florida has similar
habitats to other Gulf Coast states.
