Wood Turtle Habitat Needs

Hibernating wood turtle, briefly taken from the bottom of a deep river pool for data collection.

A sustainable landscape includes the habitat components needed by indigenous plants and animals.  Turtles may carry their homes on their backs, but they still need suitable habitat to live in, in particular,  for hibernation, for nesting, and to sustain their food supply.

Wood Turtles (Glyptemis insculpta ) are semi-aquatic and semi-terrestrial. (See Photos above, of a torpid, hibernating wood turtle.)  They need clean, well-oxygenated rivers or large streams for hibernation, and also for feeding on stream bottom invertebrates, especially in spring and fall.

Like most other turtle species,  they need  sunny areas with well drained soil, easy to dig in, for nesting.

These large, fast-walking turtles also seem only to be found along rivers and streams with  broad, naturally vegetated buffers for terrestrial foraging at least three hundred feet wide on average, in our experience.   As  intelligent, likable turtles (reportedly the most intelligent reptile) and as large, conspicuous species, I suspect they are less vulnerable to collection if hidden in a broad thickly vegetated river valley. This species is omnivorous; while on land it eats plant matter as well as earthworms, which it can trick into emerging from the ground by tapping with its foot to cause vibrations, I have read.

Wide naturally vegetated buffers, along feeder streams as well the main stem, also maintain the species’ key habitat requirement of good water quality with high dissolved oxygen levels,  and stable in-stream habitat, without surges of high flows and spikes of warm water temperatures.  A perennial stream or river that is fit for wood turtles has rocks, sticks, and logs  free of black scum fed by excessive nutrients; it is free of large sediment bars, severe bank erosion, and scouring. It is large enough not to freeze solid in winter. Healthy instream habitat  is needed both for hibernation and also for the Wood Turtles’ invertebrate food supply during its aquatic phase.

Like E. Box Turtles, Wood Turtles (Glyptemis insculpta, formerly Clemmys insculpta) are  on the official Connecticut “NDDB” list; in fact they are even rarer.  They are absent from many suburban Connecticut towns and from Long Island, with few rivers.  (NDDB is jargon for Natural Diversity Data Base).  Spring is a good time to detect presence of a wood turtle population along a large stream or river, because their distinctive tracks will be found on sandy or muddy banks.   Like E. box Turtles , they need oxygen during hibernation.  By contrast, two common Connecticut turtle species, snappers and painted turtles,  have anaerobic metabolism to use during hibernation, usually  on the muddy bottom of a waterway or pond. Another key similarity to box turtles is the fact that both species  spend much of their time foraging on land, and are vulnerable to habitat fragmentation and roadkill.

Found in a hibernation site, a root tangle in a river bank, next to a female

Connecticut has a “Special Animal Form” to be used for reporting occurrences of animal species such as Wood Turtle, E. Box Turtle, and Bog Turtle, that are either rare, in serious decline, or dependent on rare habitats.  I can e-mail you a sample reporting form if you contact me @sigrun.gadwa@sbcglobal.net, and will provide help with records of listed turtles if you share your data with me, as these creatures are of particular scientific and conservation interest to me.  I have a DEP Scientific Collectors permit to handle turtles for collection of  data not required by the CTDEP, such as sex, age (found by counting growth rings), height, and size; please e-mail me if you would like to learn how to monitor populations of listed turtles (volunteer basis).   The Special Animal Form may or may not be downloadable from the CTDEP website, but would certainly be provided upon request via e-mail, by CTDEP Wildlife Division staff, e.g., Laurie Fortin.   An informative scientific overview of wood turtles, as well as Eastern box turtles,  may be found in Turtles of North America by Ernst, Lovich , and Barbour, 1994, published by The Smithsonian Institution.

Posted in Wildlife Habitat | Tagged , , , , | 1 Comment

Turtles are Travelling-Take Care

A sustainable landscape, even a suburban one,  has travel corridors for wildlife, to allow movement to new  food sources, nesting areas, etc. and to prevent inbreeding of isolated small populations (e.g. maintain genetic connectivity within a metapopualtion.)

Once in a great while residents of my town, Cheshire,

Colorful, active turtle, found in a Cheshire Land Trust Preserve

Connecticut, come upon an Eastern Box Turtle. This beautiful creature, whose scientific name is Terrrapene carolina carolina,  has black designs on a background of orange, yellow, or tan.  It is colorful yet surprisingly inconspicuous on a leafy forest floor or among meadow grasses.  Common less than half a century ago, Eastern box turtles are now listed by the State Dept. of Environmental Protection as a Species of Special Concern. They have disappeared from many areas where they once thrived, as suitable meadow and deciduous forested habitat has dwindled and become fragmented. These are potentially very long-lived turtles (sometimes over 100 years.)  However, population trends have been steadily downward since the advent of cars and suburban sprawl. In the 21st century there are more hazards (e.g. traffic, lawnmowers), so that adults die sooner, on average, and lay fewer nests of eggs in their life time.  Fewer eggs hatch because ironically the abundance of nest/egg predators such as skunks and raccoons is higher in suburbia relative to rural American and forestland.  A small, isolated Eastern box turtle population can, sometimes, hang on in a three to five-acre isolated woodlot. One such woodlot was found in Meriden recently, and preserved using CT DEP open space acquisition funds.

But over the long term, genetic problems from inbreeding are likely in an isolated woodlot,  unless a few new individuals can be introduced.  However, captive breeding is  something currently not allowed by the CTDEP Wildlife Division; this seems wise as a carefully designed program is needed to make sure existing populations are not depleted.  I have also read that sometimes introductions can actually cause genetic problems to a long-coevolved inbred population, though the examples  were in  the plant kingdom.

The chances of spotting a box turtle will be highest in the next few months. In the set of records I submitted last fall to CT DEP most observation dates were in May and June or early July, with  one outlier in early April.  These are the months when female turtles of several species venture out of their small, familiar home range and travel to a suitable sunny nesting site with soft, friable soil.  Males also often leave home at this time of year, searching energetically for a mate. (They have ardent red eyes and concave undershells, for better purchase on the back of a female, with brown eyes and flat undershells.)  Most box turtles can be picked up easily and safely, but a male in spring could scratch. Don’t pick up snapping turtles (dull, blackish, compared to box turtles, as you can see from on-line photos); their bite is dangerous.

Most turtle travel takes place on the day after a rain. Eastern box turtles prefer pleasant cool weather for hiking and foraging because they are very sensitive to dehydration. Physiologically they are more like aquatic turtles, than terrestrial tortoises. That’s why they like to move about in the dewy morning, soak themselves in pools and puddles on hot days, and are so often found in lush, moist microhabitats.  Favorite foods are all juicy: strawberries, mushrooms, slugs, and jewelweed. Dr. Michael Klemens, a well-known herpetologist, has New York State data showing that a preferred hibernation site is deep, moist, organic rich soils on wetland edges.

Especially during spring travel, they risk road kill, mower injury, poisoning by lawn pesticides, and kidnapping by well-meaning persons.  If they do manage to lay eggs, more often than not the nest will be predated.   A friend of mine, Tony Ianello, invented an ingenious wire cloth nest protector, with miniature exit doors for the hatchling  turtles, when working for the Quinnipiac Watershed Association (QRWA), as  coordinator of the Turtle Crossing Program, funded by the National Wildlife Foundation. Unfortunately the red tape hurdles precluded its use on this state listed species., or on wood turtle, also a Species of Special Concern.

Note that photo captions do not provide exact locations; this is per CTDEP guidance to prevent collection for the pet trade, or laboratory animal trade- there is still a market, though less than in the past, and less than down south, where they are more common.


Posted in Wildlife Habitat | Tagged , , , , , , , | 2 Comments

Bittersweet Medusa

A fat, single bittersweet vine is twining high into the crown of a tree, and there are no nearby sprouts to be seen. However, should you sever that vine and neglect to promptly paint the cut stump with an herbicide, the plant will become aggressively clonal. A plethora of bittersweet sprouts will soon be springing up, no longer inhibited by apical dominance (hormones from the top of the vine.)

Please don’t get the wrong idea:  that I condone routine herbicide use! However, cutting alone  means repeating the exercise on Medusa’s new “snakes” the following year and ad infinitum.

Even control by means of hand-pulling or with a weed wrench  will need follow-up, because the brittle roots break off, and remaining roots will sprout.  Because alternatives are absurdly difficult or time-consuming, one of the few herbicide uses that I reluctantly condone is to carefully apply  herbicide (with a window paintbrush, not a sprayer) . Several Nature Conservancy chapters recommend  triclopyr, the active ingredient in Brush-B-Gon and Garlon.

Seedlings can be identified by veiny, alternate, sharp-tipped leaves and orange roots

Apply to the cut surface and adjacent bark of a vine cut  less than ten minutes ago. This is possible when one works with a partner, one person cutting the vines, the other painting them (the “snip and paint” technique.)  In dense vegetation, it also may help to scout ahead of time and tie colored flagging  to the vines to be controlled.

Use a substantial container that will not tip over easily, and wear gloves, long sleeves, and goggles.   Based on my research, the only human health risk is eye-damage, if it splashes in your eyes.  As for the rest of the environment, available  data is too scanty to be confident of lack of harm;  therefore careful application is important.  However, we know an  invasive woody plant infestation will shade out native plants, and reduce the food supply for wildlife.  Therefore control by means of cut stump painting (within minutes after cutting) seems like the lesser of two evils.

A better solution would be to keep sheep, for whom the Medusa sprouts of bittersweet are a delicacy, but zoning forbids this on most smaller properties.

Note: I recommend that you check the product label and the active ingredient of any herbicide, insecticide, or fungicide you are considering using.  Google the name of the ingredient, and databases like Extoxnet will come up.   Look for the skull and crossbones symbol, the term “potential carcinogen”, and the list of types of organisms to which it is toxic, as a basis for your decision to use a product or not.

Additional photos of bittersweet have been posted on a blog dated 5-23-2010.

Posted in Invasive Species | Tagged , , , , , , , , , , , | Leave a comment

Beech parents

Beech grove on hillside in Newtown, Connecticut, fall 2008

As it’s just a few days past Mother’s day, this blog has a parenting theme. Corny as it sounds, beech parents care for their children, and grow old surrounded by their families. American beech is one of our few full-size clonal forest trees, a good thing because beech nuts are so sought after by wildlife that very few ever germinate. In Connecticut one often comes upon a stately mature beech tree surrounded by young trees and saplings, all growing well despite the deep forest shade. The young beeches can’t make much food (photosynthate) , but their “mother” feeds them via root connections, until they are tall enough to get ample sunlight themselves. The network of shallow beech roots also excludes weedy competitors.

Seedlings from oak acorns have no such parental food source. If growing in a dark forest, they must remain stunted, barely growing, maybe for decades, until a sunny gap is created when a tree dies or tips over. Only then can they take off and become a sapling and then a tree.

The practical lesson here: plant seedlings of native forest trees like oaks, hickories, ashes and beeches in well-lit areas, not in deep forest shade.

Posted in Native Landscaping | Tagged , , , | 2 Comments

Clonal Woody Plants

Likely as not, a large thicket of many plants that all look alike is in fact a multitude of clones from just a few plants, thaSweet pepperbush (Clethra alnifolia), a clonal native shrubt have sent out root suckers. If one is willing to wait five to ten years, a low budget planting plan with clonal species can yield impressive coverage. Sumac clones can be twenty to thirty feet tall, and make a fine hedge. Scattered aromatic sweet fern (Comptonia) will coalesce to form a low spreading cover on a sandy slope. A few sweet pepper bush (Clethra) shrubs will become a a mass of white fragrant flowers in early summer. Patch-forming native woody species, that form large, even homogeneous masses are actually very well suited to formal landscaping,  contrasting with isolated specimen plants. Other excellent clonal shrubs for use in landscaping are gray dogwoods,  chokeberries (Aronia spp.) ,  and bayberries.

A knee-jerk reaction might be that with a few large clones,  we have few species and low genetic diversity, not a desirable situation, ecologically.  In fact these species form clones wherever they grow in the wild or human designed landscapes.  From the perspective of insects, tree frogs,  and birds,  larger patches make for more energy efficient foraging. A flock of cedar wax wings will settle down to feed for an afternoon on a sizable patch of  chokeberry or gray dogwood  and the nectar from a Clethra colony is a  significant food source for a bee colony.  Its easier than hunting for widely scattered fruiting or blooming shrubs!  Of course, taken to an extreme, a large monoculture or plantation often leads to pest infestations.  Landscaping with clonal native woody shrubs is not only economical for us, it is energy efficient for the creatures further up the food chain.

Posted in Native Landscaping | Tagged , , , , , , , , , , , , , | 2 Comments