The Lizard Log

The Langkilde Lab in Action

Rattlesnakes and Vernal Pools

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Image 2Another field season is underway and things are getting crazy!  This summer, I will be conducting three big projects, but luckily I will have the assistance of a small army of technicians.  The first project will focus on the habitat use and thermal biology of the timber rattlesnake and how prescribed fire may affect the availability of these preferred habitat characteristics.  This summer we will radio-track rattlesnakes to determine thermal and habitat preferences.  Next year, the study sites will be burned, and I will determine if these post-burn landscapes provide more or less habitat fitting these preferences.  So far we are off to a great start! We have captured 21 rattlesnakes and we are radio tracking 5 males and 4 females (we hope to get a few more females).  Next week we will begin to characterize the available habitat surrounding the rattlesnakes as we will begin vegetation surveys, measuring operative temperatures, and small mammal trapping.

Image 5In addition to investigating the effects of fire on timber rattlesnakes, I am also looking at the effects of prescribed burning on vernal pool amphibians.  From time-to-time, prescribed burns are conducted right next to a vernal pool.  This disturbance may reduce canopy cover over the vernal pool, raise temperatures within the vernal pool, and change water chemistry.  Long-term effects may also include changes in soil composition surrounding the vernal pool which may lead to more run-off into the vernal pool.  To determine these effects more clearly, I am measuring the physio-chemical characteristics of 4 vernal pools (2 that will be burned over next spring and 2 that will remain untouched).  I have deployed weather stations in each vernal pool that will track water temperatures, air temperatures, relative humidity, wind speeds, rain fall, and amount of solar radiation reaching the vernal pool.  I am also measuring DO, pH, and conductivity each time I visit the vernal pool, in addition to surface area and depth of the vernal pools.  During these visits, I am surveying for larval amphibians, egg masses, and invertebrates.  So far we have seen many wood frogs, Jefferson’s salamanders, and spotted salamanders.  However, we seemed to skip “spring” this year and things warmed up very quickly.  Two vernal pools completely dried up! And the other two are getting very shallow!  We were able to add on another vernal pool to replace one that dried up, but things aren’t looking good for this year’s tadpoles and larval salamanders…  Next year, we will burn over the vernal pools and investigate changes in water chemistry and physical characteristics of each pool.

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A spotted salamander (Ambystoma maculatum) eggmass in one of the vernal ponds.

 

These salamander eggs are definitely ready for their close-up.

 

Working with one of the weather stations in a vernal pool (prior to the dramatic dry-down!)

Lastly, Mark Herr and I will begin a project looking at ecological trade-offs between thermal resource acquisition and predation at gestation sites of various sizes.  We will be deploying operative temperature models and foam predation models at 6 gestation sites (3 small and 3 large sites).  We will also radio track a couple gravid females at each site to determine body temperatures, survival, and lay dates.  For more on this project, see Herr’s post!  And for more on all of these projects, stay tuned to future posts!

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One thought on “Rattlesnakes and Vernal Pools

  1. Pingback: Don’t Prey on Me: Part 2 | The Lizard Log

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