A warm welcome to the drift fences of SRS

Since arriving to a warm welcome at the SREL two weeks ago I have been given the opportunity to observe and participate in a number of different studies. One of the most anticipated of which was my first collection and release of marbled salamanders at Rainbow Bay (see photo to the right). Distinguishing between marked and unmarked salamanders is still a developing skill but I am becoming more familiar with the appearance of regrowth toes and what each mark means. As fall migrations continue, we have also pulled some leopard frogs, a garter snake, a bull frog, and numerous tadpoles in from the drift fence and minnow traps at the H-O2 wetlands.

My past research has taken me all over the country and the world yet I have never had the possibility of catching such diversity at one drift fence. A previous drift fence experience of mine did allow for encounters with another great amphibian though, the Siberian Salamander (Salamandrella keyserlingii) - The only salamander to brave the weather in the Amur region of Russia, it has a tolerance of -30-45⁰C and has been found 3-14m deep in permafrost, only to “wake up” and walk away once warm. Few studies have been conducted in this region of Russia and, in an effort to establish species diversity and relative abundance records for the region, we built drift fences along an Amur River basin wetland complex. Our hope is that, with this baseline information, we can start creating more robust studies in the region to learn more about the incredibly resilient Siberian Salamanders as well as many of its neighbors.

As fall ramps up here in South Carolina I look forward to seeing what will come in on the drift
fence.

Back from the long hot summer

To the few of you who were loyally following the blog I apologize for disappearing.  After a cold dry winter we had an even dryer summer which made things somewhat uninteresting in the field here.  That is of course unless you absolutely love spiders b/c we find TONS of those--like the one in the photo.  But fall is here and with or without rain the marbled salamanders dutifully return to their breeding grounds.  This year we have a much bigger study going with them.  Near the main study site, Rainbow Bay, are four other wetlands that marbleds go to: Linda's Pond, Bullfrog Pond, Pickerel Pond, and NPR pond.  One question we are interested in is how much movement is there among the ponds.  In the past David Scott has done some work on several species of Ambystomatid salamanders to estimate dispersal from Rainbow Bay to the other sites.  We're doing it again this year b/c in the Spring of 2010 we had over 10,000 marbled salamander metamorphs come out of Rainbow.  This fall would be when most of those are ready to breed so we can see which pond they show up at (they all are marked).  It was hard work but we (ie: David) opened up partial fences at the other sites and now several of us are running all the bays when it rains (rarely).  We've had about 2000 adults come back to Rainbow so far and much less than that at the partial fences, but we've definitely seen some that were born at RB and have dispersed to other sites.  Will be great to get the final numbers later.  The image shows how the wetlands are related to each other and where the fences are located.


Off to The Wildlife Society meeting in Hawaii tomorrow!!

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.

A lizard time of year

To those of you that follow this I am sorry for taking such a long hiatus.  I am hoping to get back in the swing of things and will plan on posting once a week.  Right now most of the drift fences are pretty quiet--no rain and temps in the 90's--not a great combination for amphibians.  But, this time of year we do get to see a lot of lizards.  We've had more Sceloporus than usual showing up in the pit fall traps, a handful of ground skinks, and plenty of Anolis in the buckets but also scurrying all over the fence.  This Thursday and Friday I actually had the pleasure of going out looking for lizards.  Normally I see a few opportunistically, but rarely do I go looking for them.  But, Bryan Falk, a graduate student at AMNH working with Susan Perkins (who I went to grad school with) was in town looking for Anolis and Sceloporus so I got to help him.  He is studying lizard malaria and was looking for some infected animals.  It was nice change of pace for me.  We didn't get any Sceloporus but got a good number of Anolis and saw plenty of skinks....like the broadhead skink, Eumeces laticeps, in the photo.

Other drift fence highlights this week include three ringneck snakes (as in photo) in one bucket--not surprisingly one female and two males that most likely were following the scent of the female and got stuck in the same bucket.  Also got one copperhead juvenile distinguished by it's yellow tail tip. 

Flamingo Bay critters continued

It's been some time since my grand visit to Flamingo Bay but in addition to the southern leopard frog eggs, and the sea of toads we came across two nice cottonmouths within a short distance.  This is a gorgeous snake that gets a really bad rap.  I admit I have had "snake issues" in the past.  Working in the rainforest in Panama helped but I still wasn't exactly cured.  Before I moved to SC from New England everyone warned me about the aggressive cottonmouths that were everywhere and would attack for no reason.  I wasn't exactly feeling confident when I first was doing field work here.  What I quickly learned is that, like many wildlife stories, it was way off base.  That they are quite common here is certainly true, that you can expect them to be aggressive and attack you is utterly ridiculous.  Take these two snakes for instance.  The one with the tell-tale open mouth posture (the cotton mouth) sat like that for about 5 min or more while several of us took photos and video.  That's my experience so far with all of them (as long as you're not stepping on them or some such thing).  We get them in our box traps and pit fall traps and they give you the open mouth posture, you move them out of the trap in a safe manner, and they go about their business.  Hate to admit with this one we even moved it into better light for the sake of the videographer we had with us and it still did nothing aggressive. Just sat there and posed for the camera.  The second one was pretty much the same, it finally closed its mouth so I could get a head shot.  I've come a long way with my "snake issues."  I even have a pet snake (thanks to a grad student that couldn't have it in his apartment) that I took to help with my issues.  But one thing I am absolutely convinced of is that cottonouths are gorgeous animals that have a really bad rep.

Flamingo Bay-part 2

The most amazing thing at Flamingo Bay the other day was the the number of southern toad tadpoles.  All along the edges and at islands of vegetation it was just a river of toads.  Given the size of the bay the number of toads was pretty ridiculous.  We looked closely at one little area and figured there had to be 50,000 or so in the one little section.  I'll have to go back soon because in addition to the southern toad tadpoles there were huge amounts of spadefoot toad eggs.  By now they've also hatched so it must be even more impressive.  Guess it will be a good year for toads there.  The bay filled so late that there are next to no salamander larvae in there to be feasting away on toad tadpoles.  The pictures I took really didn't do it justice but hope the video I put on you tube will help give the sense of the  non-stop flow of tadpoles.  In the photo on top every single black speck is a tadpole then below it is zoomed in and you can see the spadefoot toad eggs---the grayish mass.

Flamingo Bay-part 1

We got quite a bit of rain last week, there actually wasn't a lot of amphibian movement because it was pretty cold, but it warmed back up this weekend and one bay in particular--Flamingo Bay-- just had a ton going on.  The number of toad tadpoles was absolutely unbelievable, I'll talk more about those later b/c I want to look at my photos/videos more.  There was a great combination of southern toad tadpoles, some very recently hatched and some that clearly hatched a couple of weeks ago.  There was a whole slew of spadefoot toad eggs, a new round of leopard frog eggs, leopard frogs were still calling, and spotted several snakes, one of last year's yellow bellied slider babies, and a green treefrog.  Definitely will be back to Flamingo this week.  Supposed to be 88 tomorrow and more storms coming so with some warm rainy nights it could get even better.  Here we've got a photo of the bay, sorry for the water droplets on my underwater casing, a cluster of leopard frog egg masses, a single mass and then a close-up of one.  These are fairly fresh, you can see the developing embryos are still very spherical.  I'll try to post more later as they develop.

Hogs: not the typical trap finding!

Last time I mentioned that while releasing the raccoon we came across some hogs.  Well here are some photos. It was quite surprising--not seeing the hogs--but seeing them in a very large trap.  We have a lot of wild hogs on the SRS and they've been studied quite a bit.  Before the SRS was established there were many farmers living in the towns that used to be there.  When the towns and the people were move off site some farmers left some hogs behind and there were also already some feral hogs in the area.  They reproduced like crazy and did so well that by the mid 1960's DOE started allowing controlled hunts on site--along with hunts of deer.  Any animals being hunted from the SRS need to be monitored for environmental contamination and for that reason and others, like being omnivores that can be a part of multiple trophic levels and get exposed to contaminants through numerous pathways, the wild hogs have been studied extensively.   There are still a lot of them and sometimes I have the fun of coming across a big group of them with lots of little piglets.  This was the first time I'd seen them in a trap--turns out some folks are radio-collaring and tagging some to further study their movements and group behavior.  You can see the lead hog has a radio collar, but monitoring her they can keep track of the group which is likely a group of females and their offspring.  It was fun to watch their behavior, they all turned toward us immediately, backed up, the dominant female stayed in front of the rest and the piglets all took off.  They could fit through the fence so they ran away, I'm sure they came right back when we left.  Most often I just get to see the wallows of hogs or see a group running away so it really was fun to get to watch them for a bit when they couldn't run. 

Drift fence predator!

Usually I am very excited to find mammals visiting our drift fences.  We frequently deer mice and shrews in our pit fall traps and it's always fun to have something other than the expected amphibian.  A few weeks ago we even had a flying squirrel in a bucket.  Very cool.  I also like finding mammal tracks in the area, having studied gray foxes and fox squirrels for several years I especially like getting to see those, or signs of those.  But, unfortunately, the most common mammal experience we have at the drift fence is when we find toads and salamanders that have been killed by raccoons.  I love and respect raccoons, but their behavior at the drift fence just drives me nuts.  They go from bucket to bucket and bite the heads off of marbled salamanders, but don't eat them--presumably because their skins secretions make them distasteful.  Same goes for southern toads, they puncture them and maybe take some eggs out if it's a gravid female, but for the most part they just kill them.  I wouldn't mind so much (it is just part of the normalcy of nature) but they just don't seem to learn that they don't like the taste so they just keep killing a few per bucket.  So when we find that we have a raccoon "running the fence" we set traps.  Got a coon last week, and took some photos when we released it.  We just take them away from our sites and let them go in suitable coon habitat. This one was fun to watch, it ran quickly then went right up a tree, almost to the top, and just watched us for a while.  Then while leaving that area we came across a bunch of wild pigs so I'll share some photos of those next time.

Toad time

Well, the toads have been more cooperative than the leopard frogs so far.  I wouldn't exactly say they are doing just what we want, but they are at least laying eggs.  We have two separate groups doing ecotoxicology projects on southern toads right now.  A few of us are setting up a huge experiment to look at copper as I've talked about before.  Brian Metts is setting up some studies to look at coal fly ash.  Brian is wrapping up his PhD examining the effects of fly ash on amphibians and this will make the final chapter.  With the work we all are doing right now I could really relate to an article I read yesterday about being a scientist.  One quote: "My job, in essence, is to move small amounts of liquid from one place to another. That's it"can ring true when I'm doing a ton of lab work.  It's odd that I can convince myself it is more interesting to move liquid when it's DNA from a really cool species, or even more when it's RNA, but the truth is it all looks like water and I move tiny amounts of it from tube to tube.  That actually may be more exciting than what Brian gets to do right now.  For his work one of the things he needs to measure is clutch size (number of eggs a female lays) of toads.  Clutch size is one thing that can be strongly affected by exposure to contaminants so it's an important variable to measure. But measuring it really sucks.  Toads lay a lot of eggs, seriously, a lot of eggs.  Trying to count them all in one sitting you'd never keep track so he separates the clutch into 5 of more bins and takes pictures.  Toads lay their eggs in long strings so in a bin you can kind of spread them out in a way that there is just one layer of eggs, then with a photo you can count at your leisure and keep track of which you've counted.  He has to measure a lot of clutches so this will take some time.  The two pictures show two such bins.  The top one is pretty good, but counting the bottom one will be annoying b/c their not spread out into one even layer.  So, sometimes being a scientist means counting all day long for many days.  I only had to count eggs from 78 small containers today, with only about 20-30 eggs per container so no so bad!

Leopard frogs are stubborn!

Sorry for the incredibly long delay in posting.  After blogging about doing ecotox studies on amphibians the ecotox project we were trying to get started kind of took over our lives.  Thought I'd explain today how some of the best laid plans can still completely backfire.  Our goal was to set up an enormous study on southern leopard frogs.  We would have experiments in the field (the H02 constructed wetlands), nearly 400 tadpoles being reared in the lab, and 42 outdoor mesocosms too.  It's incredibly ambitious, but also a pretty cool study.  Anyway, to make this work it was critical to be able to pair a male and female together, get them to breed, and collect some of their eggs for the study.  We needed several pairs from two different locations to breed and they needed to all breed on the same night so we could start the experiments at the same time.  With many species this isn't so hard.  With leopard frogs it is a royal pain in the arse.  We knew from experience that leopard frogs could be a bit stubborn so this year we tried setting up 20 bins (each with a pair) right on the banks of one wetland where they could hear the large chorus of calling male frogs to get in the mood.  This was a pretty big undertaking, measured all of our frogs, injected them with some hormones to enhance the chance of egg laying, and got them into pairs.  then we lugged 4 50L carboys of "lab water" down to Ellenton bay, filled the bins, put the pairs in, carried them to the bank, duct taped and bungee corded the lids down to prevent raccoon predation, covered them with shade cloth and hoped for the best (the bins are pictured here).  Well, the next morning we got skunked: 0 for 20.  Gave them another night and got skunked again.  Had to make an on the fly decision and we decided to punt on the main plan, grab some fresh egg masses from the wetland at large, do a small scale study on the leopard frogs and regroup for the southern toad season.  We finished the leopard frog egg study and now we are just waiting for a big toad movement.  We've had a couple of rainy nights but so far the toads are holding out--not sure what they are waiting for, but we hope they behave better.  They usually do---I guess they aren't so finicky about their mating partners!  So, things are hopefully returning to normal and blog posts will be more regular again!

Water and eggs!!

Some bays are finally filling.  Rainbow Bay is still completely dry but some of the bays that tend to hold water for much longer than Rainbow are filling up.  We've started to see and/or hear evidence of breeding for leopard frogs, spring peepers, tiger salamanders, spotted salamanders, and ornate chorus frogs.  At the H02 wetlands we have seen a good number of leopard frog egg masses and as a result we have started our next big ecotox experiment looking at the effects of copper and zinc on leopard frogs.  Set up 234 containers with ~25 eggs each yesterday.  Was a crazy day but the experiment is underway!

The photos are of southern leopard frog egg masses (top photo) and tiger salamander egg masses (middle photo) in Ellenton Bay (bottom photo). Unfortunately the tiger salamander egg masses seem to have been nailed by some very cold weather and don't look very good.  Hopefully there are more females left to enter the bays and breed now that we are having nice nighttime weather (heat is off and windows are open!).

Skunk season

Still not seeing that many amphibians at the fences, but we do have some bays filling and we've opened up part of the drift fence at Ellenton Bay to get some leopard frog pairs for breeding.  Ellenton Bay is a site we use as a reference site to compare to the H-02 Constructed Wetlands and to some coal fly ash studies we do.  Ellenton Bay is now holding water and a decent number of leopard frogs and mole salamanders have gone in.  No egg masses yet but that should come soon. Anyway, we have had some rain and that caused most of the remaining marbled salamanders to leave Rainbow Bay and a bunch more mole salamanders enter the bay.  Unfortunately we also had a predation event.  Sometimes raccoons, possums and/or skunks hone in on the good nights for amphibian to move and they go feast.  The marbled salamanders are distasteful and it looked like something had "sampled" a handful of marbleds and then didn't like what they found and didn't actually eat them.  But they did kill them in the process.  We weren't sure who the culprit was but then we did smell skunk.  Tis the season to see more skunks around as their mating season gets underway.  Today we saw a skunk and I managed to get a few photos with my cell phone.  This one was fairly close to Rainbow Bay and could have been the culprit.  I actually like skunks and even their smell in moderation.  I'd like them even more if they would learn to avoid the distasteful salamanders rather than sampling them again and again. This one has really faint stripes.  We only have two types of skunks in SC: striped skunks, Mephitis mephitis, and spotted skunks, Spilogale putorius.

Constructed wetlands....part 6

The other day we talked about copper as an environmental contaminant.  We have been researching the effects of copper on amphibian development.  As I've said, 13 species have colonized the wetlands.  So far we've done some studies on southern leopard frogs, southern toads, and eastern narrowmouth toads.  We look at how the eggs develop and hatch under different levels of copper and then how well larvae survive to metamorphosis--such as the southern toad on it's way to terrestrial life with back legs out, but still a tail and no front legs yet.  We do this in a lab facility where we can control everything and just vary copper exposure in the water but then also do experiments in the actual constructed wetlands where they are exposed to copper in the water but also through the food they eat.  In the wetland they also have exposure to elevated zinc and elevated pH.  We have a lot of interesting results and are working to write up some papers, but one of the most important things we've seen is that each species responds very differently to copper with leopard frogs being the most tolerant and the eastern narrowmouth toads the most sensitive.  Really emphasizes how doing an ecotox study on one species isn't good enough for setting regulations.  right now we are setting up a really large study with leopard frogs that will start looking at how the route of exposure (food or water) of copper affects them and how exposure to both copper and zinc interacts.  Crazy time now trying to get it all set up, but will be a fun and hopefully interesting study.

Constructed wetlands....part 5

Eastern narrowmouth toad eggs

Southern toad eggs

The other day I mentioned that the H-02 wetlands were constructed to take help remove copper and zinc from the water leaving an industrial facility before it enters the watershed.  Thought I should discuss the fact that this is not a pollution problem restricted to DOE sites like the Savannah River Site.  Metal contamination is actually a huge problem over a large percentage of the world and copper is a really widespread contaminant.  Like many things, copper and zinc are essential elements and are critical to many of our (and most species') biochemical pathways, but in excess they become toxic.  Copper occurs naturally in the environment but in many places it's concentrations are quite elevated.  Copper is used in the production of many things including kitchen tools, paintings, water pipes, building siding and it's used as a fungicide and algaecide.   As a result it can be really high in water passing through corroding pipes, in all the stormwater runoff from parking lots, roads, and roofs, and from runoff from agricultural areas and mines.  On roads it actually is released from brake abrasion.  In some places it is used very heavily (as copper sulfate) to kill algae in ponds or aquaculture systems or as a pesticide on crops. Unfortunately aquatic environments are always the final receptor of urban wastewater, runoff from mines and agriculture, and industrial effluents--plus some aquatic environments have copper sulfate directly applied to control algae.  It is estimated that 15 million tons of copper are used annually so it's not surprising that many aquatic environments have a lot more copper than would be found there naturally.  As a result, there has been a lot of research on the effect of elevated copper on fish and it can be extremely toxic (and often fatal) to fish.  The EPA has set regulations for how much copper can be allowed in water and in industrial effluent.  The industrial facility on site where the H-02 wetlands exceeded that value and that's the reason the wetlands were constructed---and they do a great job of reducing the copper level to a "natural" level before the water enters Upper Three Runs Creek which runs to the Savannah  River.  Though we know copper is highly toxic to fish there is a lot less known about it's effect on amphibians and that's what we've been studying and will talk about next.  Two of the species we've studied are Southern toads and Eastern narrowmouth toads and their eggs are shown in the photos.