Pitfall trapping underway

With the help of 16 SUNY-ESF undergraduate volunteers, 18 drift fence/pitfall trap arrays were installed at Heiberg over the Labor Day weekend. Each array consists of a 5-meter section of polyethylene tarp (the fence) and six 5-gallon buckets (the pitfalls) buried in the ground adjacent to the fence.

Half of the pitfall trap arrays are located in close proximity to the 39 pools that consititute the Hexagon Array, and half are distributed elsewhere throughout the forest, several hundred meters from recently constructed pools. The latter group will serve as controls with which to compare the amphibian population impacted by pool construction. Traps were opened on 9 September and undergraduate interns have been diligently checking them since, recording species ID and length of each animal. So far we have encountered robust numbers of seven species: American toads, green frogs, pickerel frogs, wood frogs, red-backed salamanders, red efts of eastern newts, and spotted salamanders.

We intend to repeat the effort next year and in 2012. Since the hexagon pools were constructed in early June, no wood frog or spotted salamander breeding occured in them. Green frogs have bred in approximately a quarter of these pools, but their tadpoles require a year to develop before metamorphosing, so we will not expect to see recruited froglets until next year. One single pool did have a late pair of American toads breed soon after it was created, and these have completed larval development. With the exception of this single clutch of toads, this year's trapping should represent Time Zero -- essentially a perspective of the landscape before being impacted by amphibian production associated with the pools. If the pools are functioning as breeding habitats for vernal pool-associated species, we expect to see a relative increase in metamorph wood frogs and spotted salamanders next autumn, and as we catch up with demographic lag times, increases in relative abundance of adults of these two species.

More images of the trap construction process can be viewed by clicking here.

-Jim Arrigoni, SUNY-ESF