1. 1.Causeways and other roads bisecting wetlands.
   

Where causeways bisect wetlands of high ecological integrity, turtle roadkills are often found throughout the spring, summer, and fall, with peaks in May and June.

The species of turtle found in these systems varies depending on the adjacent wetland communities and season, but typically includes large numbers of painted turtles (Chrysemys picta) and snapping turtles (Chelydra serpentina). Where roads bisect shallow marshes, flooded fields, cranberry bogs, or vernal pools, spotted turtles (Clemmys guttata) are often present. Where roads bisect deep marshes, or separate riverine or lacustrine shrub wetlands from vernal pools in eastern Massachusetts, Blanding’s turtles (Emydoidea blandingii) may be found. Wood turtles (Glyptemys insculpta) are typically found on roads that parallel or cross high-quality coldwater trout streams in central and western Massachusetts. Eastern box turtles (Terrapene carolina) are not typically found in these wetland contexts: they are most often found crossing roads in upland mosaics of hardwood forest, pastures, and old fields. Because box turtles move along powerlines or rights-of-way, they may be found where these features cross roads in the Connecticut Valley, southeastern Mass., Cape Cod, and Martha’s Vineyard.

<<<  Assawompset Causeways, Bristol County (left)

The large ponds between Freetown and Lakeville comprise the largest naturally-occurring lakes in the state. Numerous causeways and culverted streams occur throughout this system. At these sites, dozens of painted turtles, snapping turtles, and musk turtles are killed annually. Spotted turtles and an occasional redbelly cooter are also present in these areas.

2. Roads with undersized or improperly placed culverts

Because marsh-dwelling turtles often move along watercourses, problem sites occur where culverts are improperly placed or undersized. At these locations, turtles emerge from the wetland and cross the road to continue their trajectory. Painted turtles (Chrysemys picta) and snapping turtles (Chelydra serpentina) are the most commonly encountered species in these areas, although eastern musk turtle (Sternotherus odoratus) are occasionally encountered. Spotted turtles (Clemmys guttata) and Blanding’s turtles (Emydoidea blandingii) may be found in low numbers at certain high-quality sites. Wood turtles (Glyptemys insculpta) are rarely found in association with large marshes, as they prefer free-flowing, clear streams, but where small streams are culverted, wood turtles may be found on the road.

>>>  Beaver Brook wetlands, Middlesex County

The extensive marshes and shrub wetlands associated with the Nashua and Squanicook Rivers and their tributaries comprise a large number of key crossing sites. Painted turtles (Chrysemys picta), snapping turtles (Chelydra serpentina) and eastern musk turtle (Sternotherus odoratus) are occasionally encountered. Spotted turtles (Clemmys guttata) and Blanding’s turtles (Emydoidea blandingii) may be found in large numbers at some sites throughout northern Middlesex County and the Nashua River watershed.

3. Roads bisecting wetland habitat from nesting habitat

A problematic context for all freshwater turtles is the situation in which nesting habitats, which typically is comprised of open, sandy, well-drained upland, are bisected from typical spring or summer habitat (which, again, varies from species to species). A related phenomenon occurs where causeway construction, or road maintenance, has created nesting habitat immediately adjacent to the road shoulder. In these areas, turtles may be killed after incidentally ending up on the road surface while searching for a nest site.

As is the case in all areas, painted turtles (Chrysemys picta) and snapping turtles (Chelydra serpentina) are the most commonly encountered species in these areas, occurring where gravel pits, playing fields, and recently cleared sites occur across the road from ponds, marshes, rivers, or vernal pools. Because eastern musk turtles (Sternotherus odoratus) nest very close to water, they may may present in large numbers where roadside nesting habitat occurs immediately adjacent to a pond or riverine backwater. Spotted turtles (Clemmys guttata) and Blanding’s turtles (Emydoidea blandingii) may be found in association with the above-listed species in appropriate habitat. Wood turtles (Glyptemys insculpta) (more than any other species listed here) prefer sandy nest sites, and may be found where roads bisect clear, low-gradient streams from gravel pits.

<<< Forest Lake, Palmer

The causeway through Forest Lake provides nesting habitat for three species of turtle. Dozens of turtles are killed annually as they move from one side of the pond to the other, or when they are searching for nest sites along the sandy road shoulder. In August and September, hatchlings are killed as they emerge from roadside nests.