Wednesday, August 22, 2012

Juvenile Amphibian Dispersal in Small Ponds of Southern Virginia

(Trevor was one of two students who worked on the Habitat Use and Activity Patterns of Reptiles and Amphibians in Relation to Temperature and Humidity project with faculty mentor Dr. Todd Fredericksen during the inaugural Freshman Scholars Program in summer 2012.)

by Trevor L., Freshman Scholar and Guest Blogger

For part of our Freshman Scholars project, we studied the dispersal of common pond amphibians at Chapman Pond on the campus of Ferrum College. We were trying to find out the timing of the juvenile dispersal of pond-breeding amphibians. We were also trying to find out the time of year and duration of juvenile dispersal of different species of frogs, toads, and red-spotted newts. Finally, we were evaluating whether the dispersal of juvenile amphibians was linked to temperature, humidity, and rainfall.

In order to record information on the juvenile amphibians, we used pitfall traps to catch them as they exited the pond. Pitfall traps are buckets dug into the ground so that the open top of the bucket is at ground level and the cover is placed several inches from the opening of the bucket to allow shade for the amphibians. A fencing material is used to stop the amphibians from getting to the forest, and the fencing helps to guide the amphibians - leaving or entering the pond - into the open pitfall traps.

The traps were by far the most exciting part of the study because we didn't know what to expect. Using the traps, we could have found the amphibians we were looking for to do the study, or we could have found reptiles or invertebrates. During the study, we found that the red-spotted newt was the most commonly trapped amphibian. Also, the majority of juveniles captured were caught in the late summer months instead of the early summer months because the juvenile amphibians needed time to hatch and mature after the mating season. Pickerel frog juvenile dispersal spiked in early June while the red-spotted newt juvenile dispersal spiked in early July. The timing of juvenile amphibian dispersal varied among species. It was also evident that there was a significant positive correlation between rainfall in the previous 24 hours and the total number of captures.

I have really enjoyed this experience, and I think it will help me with the rest of my education.

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