Varied Habitats Key to Wood Turtle Success



Looking down into many river valleys in Northern New England you’ll see forested mountains, rolling hills comprised of hay fields and pasture, and extensive floodplain wetlands with a clear, gravel bottom stream meandering through the middle. Wood Turtles don’t necessarily need access to absolutely everything within such a view (apart from the stream), but a population of Wood Turtles would use nearly every piece of that landscape. Habitat specialists in certain respects, there are key features that need to be present in an area for a Wood Turtle population to thrive, but so long as those features are there, Wood Turtles actually use a pretty wide variety of habitat types during the summer. Really, what benefits a Wood Turtle population more than anything else, is having connectivity between and access to a wide range of habitat types to choose between. 

Every habitat type in this photo would be utilized by resident Wood Turtles.

At the forefront of a Wood Turtle’s habitat requirements is their need for clean, well-oxygenated, flowing water for them to overwinter in. Unlike Painted and Snapping Turtles, Wood Turtles are not adapted to survive oxygen depleted waters in the winter for even short periods of time, so are not typically found overwintering in lakes, ponds, or marshes. The turtles overwinter at the bottom of instream pools from November until whenever things warm up in the early spring, then spend a month or so after emergence sticking pretty close to their streams. On top of requiring oxygen rich water, they need some sort of nesting habitat close to their stream that is not prone to summer flooding. Immediately after females lay their eggs in the late spring and early summer, all bets are off and the turtles scatter. 

If you read the Wood Turtle literature or spend much time working with the species in the wild, you’ll know that they spend considerable lengths of time on land in the summer, foraging mostly in the floodplains, but also venturing up to about 1000 feet from streams into the uplands where they typically can be found in mixed hardwood forests and meadows, including man-made meadows such as pastures and hay fields. Indeed, agricultural land can actually be fairly attractive to Wood Turtles (although the risk posed from haying equipment is very great). Apart from that, attempting to classify all the different types of habitat a Wood Turtle population will use is kind of a moot point, and “varied upland habitats” can be considered a habitat requirement in itself. 

This particular Wood Turtle is hardly ever observed anywhere other than the soupy edges of muddy wetlands.

This year, as part of Orianne’s research and conservation efforts in the Great Northern Forests, we began tracking 16 Wood Turtles using radio telemetry, and have already learned some useful information about how some of the turtles in the area are using the landscape differently than their stream-mates. While most of the 16 turtles are doing what we expected, which is to say they are spending most of their time in the floodplain in thick vegetation and occasionally venturing into upland fields and forests, a few of those turtles have exhibited very consistent preferences for habitats you might not expect. 

In the spring of 2019, the turtle known as "Rocky" spent almost all of her time in habitats similar to those pictured above, and in the summer still frequented rocky outcroppings while foraging. Wear and tear on this turtle's plastron provides evidence that her affinity for rocky microhabitats began years ago.

The first of our turtles to make her unusual habitat preferences known earned the nickname, “Rocky”. She spent all of May and most of June bouncing back and forth between one steep rock slope to another, seeking refuge from the midday sun under piles of debris gathered around the few surviving shrubs on the slopes. Eventually she laid her eggs in some gravel in the middle of one such rocky slope, and since then has been seen using some upland woods as well, but seems to find the most exposed rocky areas everywhere she goes. Interestingly, while the wear and tear on a Wood Turtle’s shell (gauged by smoothness) tends to affect both the carapace (top of shell) and plastron (bottom of the shell) somewhat equally, Rocky has a very textured carapace and completely smooth plastron, which I assume is because she spends so much time dragging her shell over coarse surfaces. 

Another, nicknamed “Swamp Thing” hasn’t left a flooded willow wetland since she laid her eggs in June, and nine times out of ten we find  the turtle dubbed “McKinley Morganfield” (AKA: Muddy Waters) buried shell-deep in some sort of muck at the edge of a pond. On the few instances we’ve seen that turtle in the uplands, her shell is caked with muck. And “Stringy”, whose nickname has nothing to do with her habitat preferences, has spent the entire spring and summer on the edge of sand beaches less than a stone’s throw from the river. Sandy beaches aren’t exactly a novel habitat for Wood Turtles, but what is odd is that she hasn’t gone anywhere else the entire season. Then there are the three that seem quite fond of one upland horse pasture almost 1000 feet from the river.

As expected, many of the turtles we are tracking spend considerable time in the thickly-vegetated floodplain surrounding the river they will overwinter in.

The point is that while individual Wood Turtles might have varied, but straightforward habitat preferences, the habitat requirements of a Wood Turtle population are actually rather complex, and conserving habitat for the species can take many forms. There are certain components that are absolutely critical to the survival of Wood Turtles in an area, but once those features are restored or conserved, there are many options for conserving the surrounding habitat. Simply protecting land from development and minimizing the amount of heavy machinery (cars and tractors) used during the turtle active season within about 300 to 1000 feet of a Wood Turtle stream are key, but apart from those considerations the species can survive and thrive in landscapes with a variety of different land uses. The greater the number of different habitat types a Wood Turtle has to choose between, and the less fragmentation caused by roads and development between those different habitats, the better off a population of Wood Turtles will be.