Spotted Turtle Population Monitoring

The spotted turtle is a semi-aquatic, freshwater reptile that inhabits vernal pools, bogs, freshwater swamps and small ponds on Nantucket. Throughout most of its range, spotted turtles are considered threatened, endangered or vulnerable. We have several ongoing projects investigating the habitat use and movement patterns of spotted turtles on Nantucket.

Between 2005 and 2014, we trapped and used radio telemetry to track spotted turtles at the Foundation’s Squam Farm and Medouie Creek properties. At Squam Farm, the goal of our work was to gain a better understanding about how and when this species uses wetland and upland habitat on the property and the management implications for mowing upland areas that may be used by spotted turtles, particularly during spring movement and nesting periods. Understanding when and where turtles were moving, allowed us to adapt our property management plans in order to avoid impacting turtle populations.

At Medouie Creek, our research documented the habitat preferences of turtles using wetlands on the property prior to increased salinity conditions that occurred in portions of the marsh immediately following our salt marsh restoration project. We radio-tracked turtles at this site in 2007-2008 (just prior to restoration), 2009-2010 (immediately following restoration) and 2013-2014 (several years post-restoration) to document their long-term response. The results of this research have been published in the journal Wetlands Ecology and Management (see below for more information).

In 2018, we revisited spotted turtle trapping sites monitored at Squam Farm during 2005-2008 when we uniquely marked almost 100 turtles and recaptured several old turtles that were marked by a previous researcher in the early 1990’s. Ten years later, we captured 56 individuals, including 28 recaptures - 3 of which were first marked in the 1990’s and recaptured during 2005-2008. We plan to do similar re-monitoring at Medouie Creek in the coming years as well.

In 2019, we initiated a spotted turtle trapping and tracking project at Windswept Bog to obtain information about turtle populations present at this site, in preparation for a planned wetland restoration project that will be taking place here in the near future. The ditches in the cranberry bogs provide habitat for spotted turtles in the spring and early summer. During the hotter, drier months of late summer and fall, spotted turtles generally move out of the bogs and into the surrounding forests and wetlands where they tend to stay and hibernate for the winter. To date, we have only documented one turtle hibernating within the former cranberry bogs. This is good news as any physical work that would need to be conducted for the restoration project would likely happen during the winter, at a time when turtles are hibernating and would be unable to respond to disturbance. 

This work is also contributing information about spotted turtle longevity and is part of a statewide survey to inform re-consideration of this species for federal “threatened” protection status. State biologists believe that Nantucket’s spotted turtle population may be one of the most robust in Massachusetts.