Study

Manipulation of basking sites for endangered eastern massasauga rattlesnakes

  • Published source details Johnson B.D., Gibbs J.P., Bell T.A. & Shoemaker K.T. (2016) Manipulation of basking sites for endangered eastern massasauga rattlesnakes. Journal of Wildlife Management, 80, 803-811.

Actions

This study is summarised as evidence for the following.

Action Category

Clear or open patches in forests

Action Link
Reptile Conservation

Manage vegetation by cutting or mowing

Action Link
Reptile Conservation
  1. Clear or open patches in forests

    A replicated, controlled study in 2008–2012 in swamp forest and shrubland in New York State, USA (Johnson et al. 2016) found that where canopy cover and shrubs were reduced, densities of eastern Massassauga rattlesnakes Sistrurus catenatus were higher in the first three years after cutting, but similar to uncut plots after four years. The effect of removing canopy or shrubs cannot be separated. Estimated rattlesnake densities were greater in 0-year-old (0.072–0.141 snakes/100 m2), 1-year-old (0.045 snakes/100 m2) and 3-year-old (0.133 snakes/100 m2) cut plots than uncut plots (0.003–0.009 snakes/100 m2). Rattlesnake densities in 4-year-old cut plots (0.013 snakes/100 m2) were similar to uncut plots. Canopy was reduced by cutting shrubs to <0.25 m high in 50 plots in two known rattlesnake breeding areas in 2008 (six 28 m2 plots), 2011 (thirty-two 100 m2 plots) and 2012 (twelve 28 m2 plots). In addition, 4 ha of adjacent forest was mechanically cleared in 2011. Snakes were monitored using visual encounter surveys in 66 plots with canopy removal (50 plots of cut vegetation in breeding areas and sixteen 36 m2 plots within the forest areas cleared ion 2011), and 44 areas with no vegetation removal (twenty-eight 28 m2 plots of uncut vegetation in breeding areas and sixteen 36 m2 plots in uncut forest). In 2011 and 2012, the number of snakes caught in canopy removal areas (removal having occurred 0–4 years previously) was compared to the number of snakes in uncut plots. It is unclear whether the results reported are based on the breeding areas only or include the cut and uncut forest plots. Surveys were carried out once a week in June–August 2011 and May–August 2012. Snakes were captured, sexed and individually marked with PIT tags.

    (Summarised by: Katie Sainsbury)

  2. Manage vegetation by cutting or mowing

    A replicated, controlled study in 2008–2012 in swamp forest and shrubland in New York State, USA (Johnson et al. 2016) found that where shrubs and canopy cover were reduced, densities of eastern Massassauga rattlesnakes Sistrurus catenatus were higher in the first three years after cutting, but densities in cut and uncut plots were similar after four years. The effect of removing canopy or shrubs cannot be separated. Estimated rattlesnake densities were greater in 0-year-old (0.072–0.141 snakes/100 m2), 1-year-old (0.045 snakes/100 m2) and 3-year-old (0.133 snakes/100 m2) cut plots than uncut plots (0.003–0.009 snakes/100 m2). Rattlesnake densities in 4-year-old cut plots (0.013 snakes/100 m2) were similar to uncut plots. Canopy was reduced by cutting shrubs to <0.25 m high in 50 plots in two known rattlesnake breeding areas in 2008 (six 28 m2 plots), 2011 (thirty-two 100 m2 plots) and 2012 (twelve 28 m2 plots). In addition, 4 ha of adjacent forest was mechanically cleared in 2011. Snakes were monitored using visual encounter surveys in 66 locations with canopy removal (50 plots of cut vegetation in breeding areas and sixteen 36 m2 plots within the forest areas cleared in 2011), and 44 areas with no vegetation removal (twenty-eight 28 m2 plots of uncut vegetation in breeding areas and sixteen 36 m2 plots in uncut forest). In 2011 and 2012, the number of snakes caught in canopy removal areas (removal having occurred 0–4 years previously) was compared to the number of snakes in uncut plots. It is unclear whether the results reported are based on the breeding areas only or include the cut and uncut forest plots. Surveys were carried out once a week in June–August 2011 and May–August 2012. Snakes were captured, sexed and individually marked with PIT tags.

    (Summarised by: Katie Sainsbury)

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