Thursday, October 18, 2012

Timber Rattlesnakes & Fire

A black timber rattlesnake. JCM

Timber rattlesnakes (Crotalus horridus) are relatively widespread in the eastern US, and associated with forests. Beaupre and Douglas (2012) suggest they make excellent model organisms for understanding the effects of large scale habitat manipulations due to their low energy lifestyle, rapid response to changes in resources in the environment, and their uniform diet  of small mammals. They present two case studies that illustrate interactions between timber rattlesnakes and fire in a single large population in Madison County, Arkansas. The first case describes the decimation and subsequent 11 year recovery of a timber rattlesnake subpopulation associated with a fire during a particularly vulnerable time of year. In the second case four
control plots, three cut (thinned) plots, three burned plots, and three plots that were both cut and burned were studied. The primary goals were to monitor responses of the food chain to the above four treatments and to assess timber rattlesnake responses as potential indicators for the relative success of manipulations. Although plant communities did not initially differ among treatment plots, manipulated sites experienced increases in early-successional annual vegetation after thinning and burning. Biannual live-trapping  indicated an increase in abundance of principal prey species after manipulations, although this increase was not uniform among treatments. Timber rattlesnakes that utilized manipulated sites exhibited enhanced growth and body condition relative to snakes that foraged solely in control areas. Snake physiological responses were more
rapid and well-defined than measurable small mammal population responses suggesting that these top predators may potentially serve a role as indicator species for restoration ecology. The two case studies illustrate both direct and indirect effects, as well as dramatically divergent outcomes resulting from minor changes in the timing of fire application.  The entire article can be found on-line.

LESSONS FROM TWO PRESCRIBED BURNS. Proceedings of the 4th Fire in Eastern Oak Forests Conference pages 192-204.

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