A semi-regular description of what’s going on at the drift fences on the Savannah River Site. Most will refer to Rainbow Bay--an isolated wetland completely encircled by a drift fence with pitfall traps. The Rainbow Bay fence has been “run” every day since September of 1978! We'll also talk about all types of fieldwork occurring at the Carolina Bays and other wetlands on site.
"The last word in ignorance is the man who says of an animal or plant: ‘What good is it?’”--Aldo Leopold
“No matter how intently one studies the hundred little dramas of the woods and meadows, one can never learn all the salient facts about any one of them”--Aldo Leopold
Sunday, June 19, 2011
H-02 wetland metamorphs
Quite a while back I did a several post series on the ecotoxicology studies we are doing at the H-02 wetlands (starting Jan 24, 2011). Those continue and are mostly focused on some lab and mesocosm studies of southern toads right now (more on that next week), but we continue to do some field work in the wetlands. part of the goal is to keep track of which species have been able to not only colonize the wetlands, but successfully reproduce in them. The way our drift fence is set up we can't tell which wetland cell the metamorphs come from, but at least we know there is somewhere in the wetlands where they can make it. The last couple of weeks we are getting a good number of metamorphs for green frogs, bullfrogs, and southern leopard frogs. The fact that those three species are doing well there is somewhat surprising since they have a very long larval period and have to spend all of that time in the contaminated water. Hopefully we can start determining if they are only making it in the effluent ends (where the copper, zinc and pH are lower) of the treatment cells. we do catch a lot more of them in minnow traps put at those ends. One of the most frustrating research we've tried is rearing amphibians from the freshly hatched stage to metamorphosis in some bucket style cages in the wetlands. Goal is to compare success in the retention pond, the influent end and effluent ends of the treatment cells. sounds easy enough but between storms and vertebrate predators flipping buckets and invertebrate predators getting in the buckets no matter how hard we try to keep them out it has been ridiculously hard. Gonna try again this fall with some new designs. Never thought the gene expression work would be easier than rearing amphibians in buckets. crazy stuff. Anyway, we at least know these three ranids are reproducing in there. In the photo you've got recent metamorphs of a bullfrog on top, southern leopard frog on right and green frog on left. Last week had probably a 100 or so combined coming out of the wetland.
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