page of "introduced species" covers several different types
of introductions. There are three main distinctions
that people should be aware of when looking at introduced
species in this region:
Some "introduced species" never historically occurred
in our region, like the Italian Wall Lizard. When
these individuals are released they are truly "invading"
an area that they never historically inhabited.
Other "introduced species" like the wood turtle, may have
occurred in our area historically but are now extinct throughout
the region. Scattered individuals may be frequently
released by people who find them in neighboring regions
(upstate NY, northern NJ) where they still occur naturally.
This may happen during a vacation or wilderness trip.
When the person or persons return home to the Long Island,
Staten Island and Manhattan area they may release the captured
animals where they are now extinct.
Some of our "introduced" reptiles and amphibians are so
similar to our normal native species that they are called
subspecies. The term subspecies refers to animals
that are identical in their genus and species status, yet
have evolved slight differences due geographic isolation,
climatic differences or other environmental factors.
Although different subspecies can interbreed in captivity,
they are usually isolated from each other in the wild and
do not interbreed. Subspecies differences may be minute
or may be easily observable. The diamondback terrapin
for example has seven subspecies that are found along the
Atlantic and Gulf coasts. The native New York subspecies
is the Northern diamondback terrapin, Malaclemys terrapin
terrapin. Yet the other six subspecies are sometimes
released in the NY. The danger of subspecies mixing
is that individuals can interbreed when mixed, while they
would normally never meet in the wild. This can lead
to genetic mixing and destruction of biodiversity.
you read each individual species description you can learn
for yourself which of the following situations occurred
for each of the region's introductions.
Turtle - Chrysemys picta ssp.7
Eared Slider - Trachemys scripta elegans7
Turtle - Pseudemys rubriventris7
Turtle - Trachemys scripta scripta7
Turtle - Clemmys insculpta5,
Garter Snake - Thamnophis sirtalis ssp7
Snake - Thamnophis sauritus ssp.7
Wall Lizard - Podarcis sicula7
Fence Lizard - Sceloporus undulatus7
Terrapin - Malaclemys terrapin ssp5
1 = Federally Endangered Species
2 = Federally Threatened Species
3 = New York State Endangered Species
4 = New York State Threatened Species
5 = New York State Special Concern Species
6 = Species Extinct in our area
7 = Species Introduced to our area