Blandings Turtles at Fort Devens, Massachusetts, USA:
A Case of Mutualism between Turtles and Tanks
BRIAN O. BUTLER
Oxbow Wetlands Associates, P.O. Box 533, Lunenburg, MA 01462, USA
ABSTRACT: The largest known northeastern metapopulation of the Blandings turtle, Emydoidea blandingii, occurs in the Nashua River Valley on lands now or formerly part of the Fort Devens Tactical Training Area (Range), Massachusetts, USA. Ongoing study in the region continues to demonstrate newly discovered adult, newly matured, and subadult animals from wetlands that range from large emergent marshland to floodplain ponds, kettleholes, and human-created wetlands. The current adult population estimate for a single, partially surveyed 300 ha former training area is 224316 animals, of which 147 are marked. Overall, more than 200 individuals have been marked in the 2,200 ha complex. Documentation of this metapopulation is far from complete, and much of the habitat remains to be evaluated. The Nashua River Valley area of Massachusetts is believed, based on available unsurveyed habitat, to support more than 400 individuals.
Military training activity over the last 50 years and more recent wildlife management practices have generated wetland and upland habitat encompassing a range of seral stages of regrowth or habitat succession within the fort. One limiting habitat parameter for E. blandingii is the presence of well-drained, sparsely vegetated, open soil for nesting. Blandings turtles have been found to nest in at least four distinct current or former military training areas where sandy glacial meltwater soils have been exposed and maintained by training activity. Radio-tagged or marked females have been found to cross the Nashua River from expansive emergent marshlands to nest in disturbed upland training areas, a distance frequently exceeding 1 km. Radio-tracking has shown that females may wander overland for up to five days in association with nesting, during which time they may visit secondary wetlands and exceed straight-line terrestrial distances of 1 km.
Abundant disturbed habitat coupled with overall low-intensity land use and lack of development are considered to be responsible for the substantial extant metapopulation of E. blandingii in the Fort Devens area. Management strategies are being developed in cooperation with Fort Devens to maintain nesting habitat in a manner compatible with military training requirements and to enhance or restore wetland habitats where E. blandingii is currently found in low numbers.
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