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Recovery strategy for the Eastern ribbonsnake (Thamnophis sauritus), Atlantic population in Canada

3. Actions already completed or underway

In 2003, the Eastern Ribbonsnake Recovery Team was formed, and several of the recovery actions outlined in the strategy have been underway since that time. Work to date has focused primarily on filling knowledge gaps and encouraging public involvement with the species through outreach and stewardship initiatives.

Extensive surveys to expand knowledge of the range of ribbonsnakes in Nova Scotia have been underway since 2004. The majority of surveys to date have been limited to the Mersey and Medway watersheds, focusing on sites with historical or reported sightings; large areas of potential habitat, particularly to the west of the known range, remain largely unexplored. These surveys have expanded the known range in the province to a third watershed (LaHave) and have confirmed a number of new sites within the known range. They have also resulted in the confirmation of relatively high densities (>20 sightings) at five sites (Table 1). Data on area searched, date, effort, and weather conditions are collected during each survey to refine survey protocols for greater efficiency. In coordination and collaboration with the Blanding’s Turtle Recovery Team, many of the wetlands previously surveyed for the presence of ribbonsnakes have been characterized; the data will ultimately be used to try to develop models that may help predict where ribbonsnakes occur.

Researchers have been conducting intensive mark-recapture surveys in a defined area on Grafton Lake since 2004 and Molega Lake since 2007 to identify seasonal habitat use and to begin collecting long-term data on abundance, survivorship, and individual site fidelity. The first overwintering site in terrestrial habitats away from the wetland was located in November 2009 and confirmed in March 2010.

While researchers have been able to document some seasonal movement patterns, efforts to date have been hampered by a lack of a reliable long-term marking technique (especially for young snakes) and a method to track snakes. Since 2004, snakes at this site have been marked by ventral scale clipping; however, using the current techniques, these marks often wear off within a single season. Beginning in 2006, some snakes were marked by PIT tagging; long-term success of this technique will be assessed in the coming years. Attempts externally attach transmitters to adults were largely unsuccessful, with transmitters only remaining on the snake up to four days (Imlay 2009). Fluorescent powder was also used to track ribbonsnakes and was found to be useful in documenting movement paths up to 16m long but not in re-locating ribbonsnakes (Imlay 2009). In 2009 a study was initiated to examine the feasibility of using trained dogs to locate ribbonsnakes by scent. Results from the pilot year of the study were promising, showing that dogs are useful in locating ribbonsnakes and helping to track escaped snakes (Gadbois et al 2009). The study will continue in 2010.

No genetic analysis had been published on eastern ribbonsnakes anywhere in their range prior to 2004, when Harwood (2005) initiated a study to develop microsatellite primers and to conduct an initial analysis of population structure in Nova Scotia. No genetic structure was found in the initial analysis; however, both sample sizes (n=44) and number of loci (n=2) evaluated were small, and Harwood (2005) recommended the continued collection of DNA samples and the development of additional primers. A follow-up study in 2007 suggested that there is detectible structure within the Nova Scotia population, with evidence of low to moderate restriction in gene flow among concentrations (McLaughlin 2008). However both sample size (n=46) and number of loci examined (n=1) were again low and insufficient for conclusive results (McLaughlin 2008).

The Recovery Team has been engaging in outreach and in soliciting sightings from the public since 2004. People have been engaged through a variety of methods, including direct landowner contact, displays at community events, presentations at local schools and community groups, field trips, interpretive programs (KNPNHS), and media presentations. In addition, a toll-free hotline has been set up at the Mersey Tobeatic Research Institute to provide a number that people can call to report all sightings of species at risk. These efforts have already produced a number of credible sightings, mostly within the known range. Volunteers have been helping with all aspects of ribbonsnake research ranging from participating in guided surveys led by Parks Canada staff to conducting independent surveys. A number of outreach tools have been developed including an information pamphlet, a Species at Risk Identification Guide, a website (www.speciesatrisk.ca/ribbonsnake), and a Landowner Stewardship Guide. The latter, first distributed in 2009, is a collaborative effort designed to inform landowners and land users of ways to minimize the impacts of their activities on ribbonsnakes, Blanding’s turtles, and Atlantic Coastal Plain Flora.