Weir’d Wildlife Jobs: A Summer at Hubbard Brook Experimental Forest

Larval Northern Spring Salamander

I slide what appears to be the remains of a frog between my thumb and index finger, searching for any marking that might hint at the identity of its former owner.  The egg-shell white skin is cool and smooth like ceramic and tears as easily as wet tissue paper.  It is not sticky, nor is it exactly slimy.  A pale, but distinctly yellow tinge along its edge informs me that this skin came from the rear legs of a Pickerel Frog.  I jot down my findings and gently toss the integuments onto the grassy berm before picking up the next pile of entrails a few inches away.  I don’t need to look long to know this is the back of an American Toad.  The bumpy skin is a dead giveaway, and a distinct sharp stench, like something between motor oil and pine sap, stings my nostrils as I peel the flattened body from the asphalt.  Toads don’t smell that way in life.  Just freshly dead.

This might all sound a bit grotesque, but when it's your job to tally and identify all the roadkill amphibian species after every weather event, it gets to be pretty second nature.  As a field biologist, I have amassed quite the array of inexplicably specific skills, that, as far as I can tell, have no “real world” analogue.  If I’m not out on a rainy weekday night, identifying amphibian guts on a busy on-ramp, I’m out following turtles with little radio antenna backpacks up and down thorny hillsides in 95-degree heat.  I’ve floated on my belly (donned in a full wet-suit, snorkel and all), in just over a foot of water, reaching my bite-size fingers into the dark, algae-encrusted crevices between rock slabs.  I’ve counted, measured, and cataloged thousands of random bits of my surroundings from the amount of salts in the soil, to the percentage of moisture in the air.  I’ve tallied rocks of a specific size, estimated how much sunshine is blocked by the leaves, and spun myself in circles trying to head exactly 144 degrees.

Adult Northern Spring Salamander

Learning to do field work is like training for some bizarre form of the Olympics.  It’s not just about getting faster at identifying all the mosses in a square meter frame, it’s about getting more precise and more consistent with your teammates—fellow field techs and grad students.  By the end of the field season, measuring half a dozen transects along a stream bank is so intuitive that I almost crave the opportunity to put my skills to the test in some sort of field contest.  When else in life will I have to perform minor surgery on two dozen five-inch salamanders in an afternoon, or devise a way to clip the toenails from a box turtle that is clamped tightly in its shell?

Most of my stories recounting splattered frog legs, catching snot otters, or sexing snapping turtles are met with a mix of tentative curiosity or masked repulsion from the non-wildlife oriented.  By their very nature, wildlife jobs take place off the radar of most people.  There is always the odd run in with the nearby snake-poaching property owner, or the group of campers tromping through your study site, but for better or worse, most don’t seem to know the field exists.  I’m used to the blank expressions when I declare I study reptiles and amphibians.  The classic, “what can you do with that,” is the usual retort.  Some seem to imagine that a career in wildlife means you get to play with cute and fuzzy animals all day, and while that is sometimes true (minus the fuzzy in my case) there is a lot more to jobs in wildlife and ecology than one might expect.

A wood frog found at Hubbard Brook Experimental Forest

The Hubbard Brook Experimental Forest is an epicenter for weird wildlife jobs.  I used to consider field work somewhere in the hazy divide between vacation and exile.  Once the routine kicks in, weeks and months can easily fly bye without so much as an email from our principle investigator.  Any semblance of a social life is put on relative hold as we race to collect enough data before the weather turns.  It’s tons of fun but can be pretty isolating at times. 

Hubbard Brook is something else entirely.  Imagine a neighborhood with a half dozen buildings and a large lake for a backyard.  Every morning, instead of driving to the office dressed in a suit and tie, brief case in hand, everyone here walks out the front door clad in muddy hiking boots and polyester pants, the day’s equipment tucked under each arm, and heads for the woods.  There are crews studying soils, trees, birds, water, vegetation, amphibians, you name it.  Potlucks and science talks are held every week.  During two days in July, researchers, professors, land managers, graduate students, and undergrads travel from all over the country and the world to take part in ‘The Meetings,’ a conference discussing current research and the state of the forest.  I’ve never been anywhere that felt like such a hub for environmental science.  

Northern Dusky Salamander.

What makes Hubbard Brook such a research Mecca, are the long-term, large-scale experiments that have been ongoing here since the 60s.  Located in Central New Hampshire in the southern part of the White Mountains, this 7,800 acre valley has entire watersheds devoted to answering specific questions regarding natural and human disturbances.  In the 1960s, 70s, and 80s, several watersheds were systematically deforested to varying degrees to determine the effects on forest regeneration, stream flow, and nutrient cycling.  In 1999, another watershed had 45 tons of calcium dropped by helicopter to offset the effects of acid rain.  Other, large scale experiments have included artificial ice storms, climate change monitoring, and impacts of disease and invasive species on plant and animal communities.  The remaining water sheds have been left as controls and are intensively monitored for comparison with these landscape-scale test tubes. 

Northern Two-lined Salamander.

I was hired as an REU (Research Experience for Undergraduates) student for a project working with stream salamanders at Hubbard Brook.  Upon arrival at our field house, I was baffled to find the walls decorated by half a dozen photographs of what appeared to be outhouses.  Much to my embarrassment, it was soon made clear that these were not toilets, conveniently positioned at the top of each of our field sites, but weirs.  The ‘gage house,’ which I had mistaken for a latrine, contains a complex system of pulleys and measuring equipment used to record changes in water flow over time.  Like something out of a disaster movie, a hydrograph scratches a series of jagged lines onto a sheet of paper fed slowly through the machine as the water level rises and falls. 

Northern Spring Salamander.

While often used to describe the entire apparatus, the ‘weir’ itself actually refers to the V-notch, a V-shaped cut in the front of a large, rectangular collecting pool or ‘ponding basin’ over which water pours back into the stream.  Thanks to the design of the V-notch, the height of the water in the ponding basin translates to the amount of liquid flowing out of the watershed.  Occasionally, high flow events overtake the level of the V-notch, rendering its measurements useless.  A backup ‘flume’ which sits behind the ponding basin, is used in these cases.  It also records the flow rate, but to a less accurate degree. 

There are nine weirs in the Hubbard Brook valley, each measuring the flow of a different stream.  Thanks to the long-term data these weirs collect, scientists can test hypotheses regarding differences in stream flow rate as well as monitor water levels on an hourly basis.  Stream flashiness is of particular interest to wildlife biologists studying stream dwelling organisms.  A “flashy” stream swells rapidly during a storm before dropping back to baseline levels just hours after the precipitation has passed.  This rapid influx of water can modify habitats by overturning rocky substrate and woody debris, influencing survival of everything from macroinvertebrates to fish and amphibians. 

A large Northern Spring Salamander.

Dr. Winsor Lowe of the University of Montana has been collecting data on spring salamanders in New Hampshire for decades.  He has revealed some fascinating patterns related to their movements and dispersal, but one recent finding suggests a decline in adult salamander numbers over the past few years.  It has been hypothesized that increased stream flashiness could be to blame.  Two of his students, Maddy Cochrane and Leah Swartz, are hoping to shed some light on this mystery.

Maddy is a first year PhD student with short, brown hair, a can-do attitude, and a keen sense of adventure—she once told me about a personal bet to try every rope swing she sees.  Maddy conducted her Master’s research on wood turtles in Minnesota and is now using the closely studied hydrology of Hubbard Brook as a proxy for the impacts of climate change.  Leah Swartz did her Master's with Dr. Lowe and is now manager of his lab.  She has a tall, runner’s physique and a strict attention to detail.  Leah is helping me craft my own independent project (one of the perks of being an REU student) looking at the impacts of fish predation on salamander stress levels. 

A larval Northern Spring Salamander.

While I recuperate on the couch after a “short” eight-hour day in the field, Maddy and Leah typically head out for an afternoon run and swim, or the occasional rock-climbing session.  How they find the time and energy, I don’t know.  These two are more like ultimate rocky mountain tour guides than any biologist I’ve ever met.

With the help of telemetry, Maddy, is getting to know the day-to-day lives of spring salamanders better than just about any other scientist.  After inserting 12-millimeter PIT tags beneath the skin of three dozen spring and dusky salamanders, she has been able to record their fine scale movements and habitat preferences.  A telemetry wand, reminiscent of a metal detector, can locate these PIT tags from as much as 30 centimeters away as it is waved over the rocky substrate of the stream bed.  This is only her first year of data collection, but hopefully these intimate observations will help us understand what environmental factors contribute to reduced survival in salamanders.

A larval Northern Spring Salamander.

Before we can collect any of this data, however, we must catch the secretive salamanders.  For the first three to five years of life, northern spring salamanders are fully aquatic.  During this life stage they are called larvae, and have feathery, external gills, fish-like eyes, and a large, paddle-shaped tail.  Unlike a frog and its tadpole, these larval salamanders have two skinny pairs of legs, making them more closely resemble the adults.  Once a larva goes through metamorphosis, it absorbs its external gills, changes from a silvery gray to a dark, mottled orange, and begins to forage on land.  As basal members of the family Plethodontidae, adult spring salamanders lack lungs and respire through their permeable skin.  Unlike some of their more derived relatives, the genus Gyrinophilus is strongly tied to the water, and adults can commonly be found under rocks along stream margins or even submerged in the main channel, or thalweg. 

Leah Swartz with Tupperware full of salamanders.

Leah is adding to Dr. Lowe’s long-term mark/recapture data set by conducting 500-meter-long surveys in each of six stream reaches.  By the end of this summer, we will have conducted 54 of these surveys, flipped 27,000 rocks, and caught just shy of 1,000 salamanders.  A good day’s haul can land us with nearly 50 salamanders to process, though a few reaches consistently (and frustratingly) turn up five or less per day. 

We begin each survey staggered along the stream every 100 meters, armed with zip-lock bags, pockets full of flagging, and a tally counter.  I move along slowly, hopping from one granite boulder to the next, flipping large, rounded rocks every meter.  Two hands are essential to keep these rounded stones from spinning in their sockets and crushing anything that might be lurking below.  Any rock, no matter how inconveniently positioned, could hide a salamander.  I grip the rough, almost sharp, texture of one particularly good-looking rock, and gently lift it out of the water.  An elongate, silvery body wriggles nervously in the clear, gently flowing current.  With one hand, I cut off the salamander’s escape and usher it gently towards my open plastic bag held flush with the stream bed.  The salamander darts to one side of my trap, then to the other.  After a few moments of finessing with the stubborn amphibian, it enters the bag just far enough for me to scoop it out of the water.  I mark its rock with a piece of flagging and record the meter location and habitat. 

Inserting a PIT tag into an adult Northern Spring Salamander.

Each salamander we catch goes through the same rigorous processing.  First, I scan each salamander for a PIT tag, noting any recaptures.  New salamanders are sedated using an anesthetic called MS-222.  Once asleep, I can easily make a small, painless incision in the salamander’s flanks.  The cut is just deep enough to break the skin; they don’t even bleed.  A PIT tag is then inserted under the skin using a syringe.  Prior to the use of PIT tags, researchers injected salamanders with elastomer.  This is essentially a coded tattoo that fluoresces under a black light.  If we can catch our marked salamanders again in subsequent surveys they can help us understand population size and survival probability.

We record weight, snout-vent length, sex, and note tail condition before snipping off a small piece to be preserved for DNA analysis.  This is of little consequence to the salamander, as they can regrow the tail in a few months’ time.  After processing, we allow each salamander time to recover in a fresh water bath before returning them to the very same rock where they were found.  The whole affair takes just a few minutes for the sallies, but catching and processing 50 salamanders can take us all day. 

Northern Spring Salamander in Stream Habitat.

As of today, we have just ten mark/recapture surveys remaining before we head back to our respective universities.  I have added to my repertoire of weird wildlife skills and, for the first time in my undergraduate career, I have had the opportunity to ask my own research questions and conduct my own experiments.  We are currently in the process of collecting corticosterone samples in four of our stream reaches to compare salamander stress levels with and without predation from fish.  I still have much to learn as I begin the daunting tasks of writing up our results while simultaneously entering my final year at Ohio University, but I feel more prepared for the future of my academic career than ever.  Maddy and Leah have been great friends and mentors this summer, and who knows, maybe I will even end up doing a grad project in their lab.  

These past four months at Hubbard Brook have helped me grow immensely as a young scientist.  I will miss waking up to the mournful calls of loons each morning and looking for moose in the evenings.  Hubbard Brook has been pumping out science and scientists alike for decades and I feel proud to be a part of that legacy if only in a small way. 

I know I will have to return to this amazing community of researchers and field technicians soon.

Thanks for reading!
Keep living the field life
RBW

Overwhelmed with Frogs

Lesser Treefrog (Dendropsophus minutus)

It hasn't been so much writer's block that has kept me from posting about my favorite feature from my stay in Ecuador, I just haven't been able to decide where to begin.  Ordinarily, I’ll drive for hours and make dozens of trips in search of new (to me) species.  In my home state of Ohio, there are only 80 species of native reptiles and amphibians.  Each new find feels that much closer to seeing them all (a dream I’ve had ever since I was young).  Finding all eighty might still seem like a lot of time and effort—and it is—but it’s a challenge that’s just on the periphery of reasonable.  With enough dedication, I can add a new species every few months (if I’m really lucky, multiple in a single trip!).  In the tropics, this ratio is blown way out of proportion.  Ecuador is home to 350 species of reptiles and 460 species of amphibians.  During a week long stay, you might see 80 or more species without much effort.  Add in a guide that knows what they’re doing, and your species list could easily reach the hundreds.  

So what’s the problem?  With so many species to see, the tropics can feel inaccessible to the average naturalist.  Don’t think I’m complaining, though.  As a wanna-be biologist, I value biodiversity over my own two legs.  Ecuador covers only 109,483 square miles (for comparison, the US covers 3.797 million square miles).  It’s remarkable that there are still places on earth that boast such a unique variety of species in such a small area.

Marbled Treefrog (Dendropsophus marmoratus)

But how are you supposed to build a reasonable biological picture of such a diverse area in a limited amount of time?  Even with the most recent field guides, there is always the chance of stumbling upon something no one has ever seen before (it is estimated that nearly 200 species of frogs have yet to be discovered in Ecuador).  More likely, however, is the chance of stumbling upon something no one has ever bothered to put in a field guide.  In the end, you might not know what you have.  Cryptic species complicate things further.  Two or more frog species may look indistinguishable unless you directly observe their calls (or sequence their DNA).

Dwarf Clown Treefrog (Dendropsophus bifurcus) 

When a night hike down a forested road turns up something new every five minutes, it's impractical to spend an extended amount of time observing any one animal.  While I want to see as many herps, birds, and what-have-yous as I can, I’m no life lister.  I don’t just want to check off each species and move on to the next challenge.  I want to see each creature intimately to try to understand it better.  

As I have discovered more and more of Ohio’s reptiles and amphibians, I’ve had to relearn just about everything I thought I knew about the herps of my home state.  Each discovery has allowed me to weigh everything I’ve read or assumed about a species against what I have directly observed in nature.  It’s all about subverting my expectations.  With so many tropical species, I never really know what my expectations should be in the first place.  Each find is exciting, but also a little jarring, “Oh! Didn’t realize you existed!”

Red-skirted Treefrog (Dendropsophus rhodopeplus)

To avoid this problem of “overabundance of species,” I have tried to place my discoveries into categories, namely Family or Genus.  This gives a wider context that (for me) makes tackling the superabundance of Ecuadorian frogs and toads a little more manageable.  I have done my best to ID each of the species I photographed, but many are still up for debate.  I am no expert and any suggestions are greatly appreciated.

Crested forest toad (Bufo margaritifer)

I will begin with the family Bufonidae.  I was on such a high that first night at the research station that you might have assumed I was running around licking toads instead of photographing them.  It was thrilling to watch my fellow biology students join in with equal levels of enthusiasm, referring amusingly to our group herping as “The Hunt.”

Crested forest toad (Bufo margaritifer)

The Bufonids are the true toads, locally represented in Ohio by the ubiquitous American toad (Anaxyrus americanus).  Tropical bufonids share the warty skin and earth tones, but many species are much more regal in their head adornments.  The Crested Forest Toad (Bufo margaritifer) is commonly encountered hopping across the forested trails.  These toads are extremely variable; some express slight ridges along their craniums, while others show exuberant crests extending above their eyes and nostrils.

The toads don’t just get fancy in the tropics, they get big too.  The Marine or Cane toad (Rhinella marina) can grow over eight inches in length and weigh nearly four pounds.  We discovered one of these behemoths the very first night, hopping confidently across the pavement beneath our dorms.  They have been introduced to many parts of the world and are driving native amphibian populations extinct by outcompeting and eating local frogs.  It was refreshing to see them in their natural habitat where they belong.

Marine Toad (Rhinella marina)

Then, of course, there are the treefrogs.  Treefrogs belong to the family Hylidae, the largest group of Amazon frogs.  Most of these frogs are distinguished by their enlarged toepads which allow them to scale foliage and buildings with ease.  Their shear diversity makes them challenging to identify.  This is complicated further by the fact that many species change color pattern from day to night.

Three hundred species represent the genus Hyla worldwide (of which, the gray treefrog of Ohio (Hyla versicolor) is a member).  Most species in this genus are arboreal, nocturnal, and posses webbed feet.  In 2005, many common Amazon treefrog species were split off from Hyla and placed in their own genus Dendropsophus based on their number of chromosomes (many of these species are pictured in the intro to this post).

Giant Broad-headed Treefrog (Osteocephalus taurinus)

There is the bizarre treefrog genus Osteocephalus: the Bromeliad or Broad-headed Treefrogs.  The skin on the head of these frogs is actually fuzed to the roof of the skull, giving them a distinct, flat-headed appearance.  They are a wary group, leaping away from the slightest disturbance.  They breed in the shallow pools that collect in the flower cup of bromeliads.  The radiated irises of the Giant Broad-headed Treefrog (Osteocephalus taurinus) are mesmerizing.  

White-lined Leaf Frog (Phyllomedusa vaillantii)

My favorite treefrogs belong to the genus Phyllomedusa: the Monkey frogs.  Elongate limbs that bend at sharp angles and opposable thumbs allow these frogs to spread waxy secretions across every inch of their bodies.  These secretions act as a kind of sunscreen, helping to prevent desiccation. Their movements are slow and methodical, very unlike many of the other rapid, nervous frog species.  The eery stillness of these frogs is almost ghostly when illuminated in the light of a headlamp.

Veined Treefrog (Trachycephalus typhonius)

While photographing one particularly bizarre species of Caque-headed Treefrog in the genus Trachycephalus, the veined treefrog (Trachycephalus typhonius), I noticed something sitting along the branch a mere inch from the frog's enlarged toepads. Shining the branch with my flashlight, I was baffled to find a salamander.  Amazon climbing salamanders (Bolitoglossa altamazonica) belong to the family Plethodontidae (many of our North American species belong to this family too).  Unlike North American species, on humid nights, these salamanders scale vegetation up to six feet high.  They sit motionless, apparently doing nothing for hours before returning to the leaf litter by morning.  

Amazon climbing salamander (Bolitoglossa altamazonica)

The family Leptodactylidea was a mixed bag.  A few species, like the enormous Smoky Jungle Frog, struck me as very familiar.  It could practically have been a leaf-colored bullfrog.  Later, I was shocked to learn it is one of the more toxic species in its range.  These jungle frogs belong to Leptodactylus, a genus containing around 55 species, most of which are moderate to large frogs.  Some species are so toxic that just holding them can cause a burning sensation on the skin (which was duly noted when I caught a large Smoky Jungle Frog the first night).  

 Smoky Jungle Frog (Leptodactylus pentadactylus)

Other frogs in this family, such as the Painted Forest Toadlet (Physalaemus petersi) were like nothing I had ever seen.  These toadlets were speckled with little red lesions that almost made them look diseased.  Otherwise, they were cute, little frogs that held their heads erect, giving the impression of an opposable neck.  

Painted forest toadlet (Physalaemus petersi)

Another member of Leptodactylidae and the only member of its genus, the Painted Antnest frog (Lithodytes lineatus), is a poison-arrow frog mimic.  Their pattern of brown with light yellow stripes is almost identical to Allobates femoralis.  This is a case of Mullerian mimicry.  Both species have converged on a similar coloration because it turns out the Painted Ant-nest frog is also toxic.  They live in the mounds of leaf-cutter ants, fending off attack with noxious skin secretions.  

Painted Antnest frog (Lithodytes lineatus)

The Microhylids, or narrow-mouthed toads are represented in the tropics by a handful of species.  Here they are commonly referred to as "sheep frogs."  These small frogs grow scarcely longer than an inch.  

Sheep Frog Species (Elachistocleis sp.)

If you’re a herper, you might be wondering, “did he see any dendrobatids?”  Dendrobatidae is the family that includes the poison-arrow frogs.  The short answer is yes.  For a while, however, I thought I was going to have to pretend I hadn’t to save face as a photographer.  

I actually saw three poison arrow frogs.  All were the same species: the Ecuadorian Poison Frog (Ameerega billinguis). These frogs are tiny.  The tropics are home to a lot of tiny frogs, but these frogs are really tiny.  I mean fit-on-your-fingernail tiny.  To escape, all these frogs have to do is hop once.  Their red back and yellow-spotted legs allow them to instantaneously disappear among the decaying red and yellow leaf litter.  I could be staring directly at the frog, ready to snap a photograph, and a single spring would mean I had to find it all over again.  This was the one frog family I felt I needed to photograph (I was even presenting a talk for the class on their family) but for most of the trip, it looked like I was going home empty handed.  It wasn't until our group teamed up with the local Wairani guides that my moment finally came.  

Ecuadorian Poison Frog (Ameerega billinguis)

Nange (pronounced Nahn-gey), the village chief, spotted the frog.  He spoke no English, and I no spanish (or Wairani for that matter) but he knew I wanted to see the frogs.  He beckoned for me to come over and pointed out the minute frog sitting innocently among the leaf litter, its throat fanning rapidly.  We positioned ourselves to make the capture.  The frog hopped and was instantly gone.  I groaned, certain the little amphibian would not reappear.  A moment later, the frog hopped back into view and I was able to grab it (and a decent amount of the surrounding leaf litter) and hand it to Nange.  

Ecuadorian Poison Frog (Ameerega billinguis)

Nange placed the frog in the middle of the trail for me to photograph.  I got some delightful shots, emphasizing the little amphibians gorgeous color pattern and texture.  When I returned home after our two weeks, I immediately downloaded my 5,000+ photos.  I had taken so many images that my computer’s hard drive filled up.  To make room as quickly as I could, I deleted the photos I had already imported from my chip.  Once that was finished I started scrolling back through the two weeks and that’s when DISASTER struck.  My computer had glitched when the hard drive had filled up, and the images of my poison arrow frog (and only my poison arrow frog) had been deleted.  

I was horrified to say the least.  Months passed and I couldn't bring myself to write anything about the amphibians without my crown jewel.  “You’ll just have to go back one day and photograph another,” I tried to tell myself.  Inexplicably, when going back through my photos last week—wallah! Unharmed on the screen in front of me: my poison arrow frogs.  I don’t know what cosmic force took pity on me, but I’ve never been so relieved.  

Even though my poison frog photos turned up, I am still certain I need to return to Ecuador and the Amazon Rainforest.  There are so many more frogs to see after all.