One of the most critically imperiled turtles
to be found in North America is the Blanding’s Turtle (Emydoidea blandingii), named for William Blanding, a Philadelphia naturalist
who first described it. They are found from Ontario, Canada; south to Iowa and
back east as far as New York. There is a small population of about 300 found in
Nova Scotia. The highest population densities are found in the Great Lakes region.
They are listed as state endangered or a species of special concern in nearly
every state they are found in. The biggest threat these turtles face is the loss
of habitat due to agriculture and from major modifications to streams and
rivers, such as dam building. Blanding’s turtles have very specific habitat
requirements that include marshes, sloughs, ponds, lakes, streams, creeks, and
vernal pools with shallow water, soft bottoms and large amounts of aquatic
vegetation.
With the draining of these wetlands for
agriculture and other human endeavors the turtle finds it harder and harder to
survive. Added problems this turtle face are cars, predators such as raccoons,
foxes, skunks, and even ants.
Then we must consider that this species reaches
sexual maturity later than most turtles with females reaching sexual maturity
between the ages of 14 to 20 years of age and males at about 12 years of age.
With all these things combined we can begin to understand how this turtle has
suffered such dramatic population declines.
Blanding’s turtles are semi-aquatic basking
turtles that can be found either in their watery habitats or on land. Typically
they will leave water when seeking new areas to inhabit or when looking for
places to lay their eggs. In the water they are actually poor to average
swimmers and will use the dense aquatic vegetation to support themselves as the
move through the water. They are often found floating among the aquatic plants
or basking on logs, muskrat mounds and other objects within the water.
Their carapace is dark in color and may vary
from dark gray to black with small light color spots or small lines in a highly
variable pattern, although some specimens lack any markings at all. The
plastron is yellow with dark blotches on each scute.
The most distinctive characteristic of this
species is the yellow chin and neck. This feature makes identifying them easy
as no other turtle in North America has this bright yellow neck and chin. They
often look as if they are smiling, which in my opinion gives them an adorable,
charming appearance.
This species also has an extremely long neck
and are often referred to as long-neck turtles and are lumped in with another long-neck
turtle called the Chicken Turtle which is also critically endangered in much of
their range. Blanding’s turtles are the only species in the genus Emydoidea even though they share the
same long-necked characteristic as the chicken turtle they are not particularly
closely related.
The young will leave the nest and move towards the nearest
water source. In some areas it has been reported (although rare) that they
spend the entire winter in the nest and emerge the following spring. It can be
assumed they have special adaptations within their blood that allows them to
survive the freezing temperatures of winter. Many turtles, like painted turtles
have blood that contains a chemical much like anti-freeze and will spend the
winter encased in the underground nest.
The biggest threat to these turtle eggs
is predators such as raccoons, and foxes. As many as 84% of the eggs laid by
the Blanding’s turtles may fall victim to predation. Ants can also destroy a
batch of newly laid eggs, as well small burrowing rodents like chipmunks. Once
the eggs hatch they are still not out of danger from predation, as foxes,
raccoons, skunks, opossums, and large birds like herons and crows all savor
baby turtles. Females traveling on land often cross roadways to seek suitable nesting sites and are hit by careless drivers.
This takes a devastating toll on the future success of this species. Even a
loss of 1 to 2 percent of adult turtles can have long lasting impacts on future
generations.
It is common for this species to live more
than 50 years and there are reports of specimens exceeding 70 plus years. Their
reproductive cycle does not slow down with age; in fact quite the opposite is
true. The older, more mature females produce larger litters and are likely to
mate more frequently. The ability of this turtle to live to a ripe old age and
to continue to reproduce throughout its life may be the only saving grace for
this species.
In Missouri where I live there are only a few
populations in three counties reported in the entire state. One of those
locations is Squaw Creek NWR in Holt County. In June a female was found
crossing the roadway near one of the wetlands. It was captured, and had a
transmitter secured to its shell. This is the first Blanding’s to be tagged in
over 20 years on the refuge. This species is rarely encountered on the refuge,
so this particular turtle caused much excitement among the refuge biologist,
Darrin Welchert, and our local herpetologist Dr. Mills and the rest of us who
were privy to the situation.
The next day after it was tagged it was found
within 25 yards of where it was released. Two days after being released it was
300 yards away!!!
This illustrates this species ability to
travel great distances. Skipping even one day of searching for this tagged
turtle could result in losing it and the transmitter for good.
(Dr. Mills using transmitter to locate turtle)
Over the course of several weeks numerous
trips were made to the refuge to locate the turtle. It was found within a 300
yard radius of its original release location each time. Several weeks ago,
Dr.
Mills picked up the signal of the turtle and discovered that the transmitter
had somehow fallen off the shell. To say everyone was disappointed would be an
understatement as much knowledge stood to be gained about this species and
their habits on the refuge by following the day to day activities of this
single turtle. Hopefully next spring will yield an additional turtle and
barring any problems we will be able to start the study anew.
Blanding’s, like all turtles that occur in
colder climates hibernate during the winter and will submerge themselves in the
water and lay dormant on the bottom in the mud and silt. Their heart rate slows
down and their bodies become inactive as they wait out the cold weather.
However they seem to tolerate cold weather better than many water turtles and
have often been found swimming below the ice along the shoreline of their
watery homes. In Missouri they may become active again with the first thaw as
early as March. Further north it may be the end of April before they begin
showing signs of activity. During the hottest days of summer they typically
stop feeding and once again go dormant in a form of summer-time hibernation
known as aestivation. This heat induced inactivity may last a month or more,
but will usually end when cooler temperatures return in the early fall. They
will start eating again to put on fat reserves that will see them through their
long winter hibernation.
Much consideration should be given before
land development takes place in areas where known populations of these turtles
are located. Some areas have had success with artificial habitats in helping
secure areas for this turtle to reproduce and live. As nearly all states
provide some sort of protection for this species, anyone planning to alter
these habitats should be made responsible for creating alternate areas for
these turtles to live.