West of the Fields

A tropical ecologist reporting from the field. Musings on life and art, botfly extractions, tropical plant identification, beer, parrots, machetes. Etc.

Tuesday, October 24, 2006

Hasta la Isla

It’s been a couple of long, exhausting months in the field, and I’m ready for a break. Fortunately, the government of Costa Rica has given me a good excuse to take a vacation: my visa expires on Thursday. As a U.S. citizen, I get an automatic 90 day tourist visa every time I come into the country. I just have to spend 72 hours outside the country and voila, another 90 days when I come back. Renewing my visa is as easy as spending three days at the beach—provided that the beach in question is not in Costa Rica. And so, dear readers, I am bound for the Isla de Ometepe in Lago Nicaragua for a few days of sun, sand, and absolutely no schedule. A heartfelt thanks to Oscar Arías and the Departamento de Inmigración.

Sunday, October 22, 2006

The cutest thing in the rain forest

What's the cutest thing at La Selva? I know many who would nominate Steven for the title, and some who would nominate Dennis, but personally I think the cutest thing here is the bats. This week I've had the good fortune to see a bunch of particularly cute ones.

On Wednesday evening, the German bat researchers caught a leaf-nosed bat about the size of my hand, with a little baby clinging to it. It was a ball of brown fluff all except for its bright pink nose and its itty bitty wings. The babies in a lot of bat species here can weigh up to a third of the mother's body weight. ("That's like giving birth to a turkey!" Erin said. For me, it would have to be an extraordinarily large turkey, like the one my family got for Thanksgiving one year from a farmer in the next town. It was so large we had to slice it in half with a crosscut saw before we could fit it in the oven. I have a whole new respect for bats.)

On Friday I got to see an even cuter bunch of bats: Ectophylla alba, the white tent-making bats. They produce their own shelters by gnawing along the midvein of a Heliconia leaf. Every few days, when the leaf wears out, they move to a new roost. I check for bats every time I see a folded-down leaf, but I've only found them twice. Erin's excellent field assistant Mauricio located these guys while he was doing a survey of understory herbs. He guided a bunch of us out there around noon. It was the best lunch break I've had in a long time.

Mauricio shows Dennis the leaf tent.
(c) 2006 S.G. Letcher

These guys are about the size of golf balls but way cuter.
(c) 2006 S.G. Letcher

Saturday, October 21, 2006

Four wheel karma

At the moment, there are slightly more than 1100 plant specimens covering the desk in my office, sorted by family, genus, and species. There’s hardly space for my computer. In the last four days, Marisol and I finished the last two inventory transects, pressed the plants, and censused half of a seedling plot. I’m tired.

The last pair of sites, Botarrama and Aceituno, were among the most remote. The sites are named after the most common tree species in each one: aceituno (“little olive”) is Simarouba amara, a gorgeous, stately tree with pinkish bark and glossy compound leaves with pale undersides; botarrama (“branch tosser”) is Vochysia ferruginea, with a lovely domed canopy that looks like a child’s idealized drawing of a tree. It really does chuck down a lot of lower branches, getting rid of all but the ones that catch the most light.

In order to get to Aceituno, the easiest road is over the hanging bridge in El Roble, constructed by the Comite Vecinario del Roble (El Roble Neighborhood Committee). It looks a bridge put together by a neighborhood committee. Two concrete pylons on either side of the river support a creaky hanging span 20 meters long and just barely wide enough for a car, constructed of wood, metal, and whatever else came to hand. The sides of the bridge sport irregular patches of chicken wire that wouldn’t keep even a chicken from falling through. The whole thing settles noticeably when a car drives onto it, even a car as light as the Silver Bullet. My faith in the hanging bridge was undermined even further when I went by underneath it on a rafting trip this past summer, and saw at least four species of epiphytic ferns taking up residence between the slats.

The hanging bridge is only the beginning of the journey to Aceituno. When I went out to visit the sites with Edwin a few weeks ago, I drew what I thought was a pretty good map and a set of directions to get out there. But when I went out to look for it on Sunday morning, we kept ending up in the middle of nowhere on dead-end, muddy roads. The GPS indicated that we were way too far north, but there didn’t seem to be any roads going southward. After a fruitless hour of exploration, I decided to go to Botarrama instead. I’d already done a plot right next to that site, so I knew I could find my way back. We turned around and headed for the next bridge, 5 km upstream, to enter Tirimbina from the other direction.

The forest at Botarrama was beautifully open. Unlike most of my sites, which were in pasture for anywhere from two to 20 years, the CATIE plots were slashed and burned once, and then left to regenerate immediately. They’re much more diverse than many of my other sites of comparable age, and much easier to work in. Despite the late start, Marisol and I finished the transect—310 individuals, 96 species—by 3:30 in the afternoon.

It would have been smart to just head back to the station, drop off Marisol in town, take a shower, and eat my rice and beans. But the challenge of finding Aceituno still rankled—it would be my last site, and I didn’t want to let something as small as a bad map stand in my way. When Edwin took me to the sites, he’d shown me a back road between Tirimbina and El Roble.

“No se puede pasar cuando llueve,” he’d said. You can’t get through when it rains. But it had been dry for three days. I had a little over a quarter tank of gas left, according to the gauge. I knew I could find the entrance to the back road, and I was pretty sure I could find my way out the other side. I’d take GPS points at every intersection for when we came back. I told Marisol about the plan. She’s a good sport; she just nodded.

The back road was worse than I remembered. With Edwin driving, I hadn’t really noticed quite how deep the mudholes were, or how many steep ruts cut across the downhills. The drive was fairly hair-raising. Of all the unlikely skills I have picked up en route to my doctorate, four-wheeling in a Suzuki Samurai is among the most complex and subtly nuanced. You’ve got to judge which side of a rut to take, and where to position the wheels for maximum traction in a mudhole; when to gun it and when to ease ahead. My hands are still bruised from rattling against the wheel.

At the bottom of the longest hill, we came across an obstacle that not even the Silver Bullet could surmount: a fence of stout poles and barbed wire placed solidly in the middle of the road.

“Oh,” Marisol said. “Yo pensaba que el rótulo era por pertinencia, que hay que pedir permiso del dueño...” I thought the sign was there for property rights, that you’ve got to ask permission...

“¿Cúal rótulo? Marisol, de que habla?” What sign? What are you talking about?

“El rótulo arriba. Lo que dijo ‘prohibido el paso.’” The one back there that said ‘no entry.’”

With my eyes firmly fixed on the obstacles of the road, I hadn’t even seen the sign. “Oh.” I parked the Silver Bullet and took a GPS reading. We were fractions of a decimal degree from the point I’d taken at the plot three weeks earlier. It had to be just there, just down the road... but the fence blocked the way. And it was no lily-livered fence, either; it was a solid row of poles as thick as my waist and nearly head-high, set deep into the ground. On either side of the road there were deep ditches and barbed-wire fences, precluding a detour. I sighed and turned the car around.

“Bueno, al menos ya sabemos donde queda la parcela,” I said. Well, at least we know where the plot is. And this was when the engine coughed a few times and quit. “Vamos, Bala Plateada,” I said (come on, Silver Bullet), trying to keep the fear out of my voice. The sun was skimming the deserted pejibaye plantations to the west of us. I let the engine sit for a few minutes, and tried again. It sputtered out almost immediately. The gas gauge still read a quarter tank, but it sure seemed like we were out of gas. I didn’t want to think about what else it might be, and how much time, effort, and money it would take to get the car out of there otherwise.

“¿Caminamos?” Marisol asked. Shall we walk?

I didn’t see any other option, so I took my backpack with the last half-empty water bottle, my headlamp, and the Ziploc with my license, collecting permit, and money. Walking back through the mud pits, I was amazed the little car had made it through. I could see why they wanted to close the road. I couldn’t quite see how we would get out.

The sun had taken on a red tinge and dropped a few more degrees by the time we reached the main road. I stopped at a field station nearby, where I’d hoped to find someone who could help out, but the place was deserted. The whole countryside seemed to be deserted as evening settled. It was beautiful out there; pastures and fence lines and patches of forest and little streams, all lush green and glowing with evening. (Watching Fellowship of the Ring yesterday evening, at least as much as I could before I fell asleep, I was amazed by how much the Shire looked like Tirimbina). But with night creeping up behind us, and the road empty, it seemed like a desolate kind of beauty.

We walked probably four or five km, all the way to the pulperia next to the Sketchy Bridge. Pulperias are a universal feature of the Costa Rican countryside: little stores, often attached to somebody’s house, selling cold beer, fruit juice, bread, and a host of other items ranging from disposable razors to chicken feed. I hoped that the stock of this one would extend to gasoline.

“¿Gasolina?” said the old man at the counter. “Ay, ya no tenemos, niña. Ayer la vendemos todita la gasolina.” We don’t have any right now, kid. We sold it all yesterday.

“Pero Beto tiene un galón en su casa, ¿verdad, amigo?” This was a man at the little table that served as a bar, elbowing a friend. You’ve got a gallon at home, don’t you, Beto?

Beto was a stocky, short man with a mop of curls. He took a look at me and Marisol. We’d been in the field since seven in the morning. I was sunburned, hungry, thirsty, and at my wit’s end. It didn’t take much to work up a damsel-in-distress look. “Ya vengo,” he said. “Vivo aquí cerca.” I’m on my way. I live close by.

I bought a beer for Marisol and drank a Fanta while we waited for Beto to return with the gas. Santiago, the man who’d nominated Beto for the gas run, chatted with us. He told us about growing up in the neighborhood, and I told him about the little town in Maine where I’d grown up. Small towns are the same everywhere, it seems—whether your neighbors are helping you rescue your cattle from an oncoming flood, or whether they’re helping you shovel three feet of snow off your grandmother’s sidewalk. Or whether they drive halfway out to La Virgen to bring you the last gallon of gas in town.

When Beto returned, evening was painting the hills purple. He and Santiago insisted on driving down to where the Silver Bullet was foundered, even though I warned them about the mud. (On the way in, I finally spotted the Prohibiod el Paso sign, tacked to a tree at the edge of the road.) Beto’s Toyota, only a little heavier than the Samurai but a lot more comfortable, floated through the worst of the mud with barely a protest. In the last light, we reached the clearing where the Silver Bullet was parked in the abandoned pejibay plantation. We improvised a funnel from a plastic water bottle and cut a stick to hold the intake open—Beto’s gallon of gas was in a milk jug, and we didn’t have a hose.

I insisted on paying for the gas. “Mil gracias,” I said. Any words of thanks seemed insufficient—without his help, we’d be stuck there overnight, and if the rain clouds now descending from the volcanoes made good on their promise, we might be stuck there a lot longer. “Voy a decir al mundo que hay muy buena gente en La Virgen.” I’ll tell the world there are wonderful people in La Virgen.

Beto waved away my thanks, grinning. “Todos somos ticos. Quizá mañana ustedes ayudan a otra persona.” We’re all ticos. Maybe tomorrow you guys will help somebody else out.

I told him about the family in El Hueco.

“Eso,” he said. It’s an untranslatable tiquismo, literally meaning “that.” Figuratively, it expresses the utter rightness of something—an impressive soccer pass or dance move, a well-spoken phrase, a story with an appropriate ending.

And this story, too, ends well, though not without one final twist. I reached La Selva just in time for dinner that night, and then spent a few good hours with Google Earth finding the way from the hanging bridge at El Roble to Aceituno. I plotted the coordinates of each intersection and drew up a rough map. It turned out that my earlier map and directions had omitted one crucial intersection, sending me out in the wrong direction.

Early the next morning we headed out to finish the final transect, 30 out of 30. I filled up the gas tank on the way through town. Aceituno was another lovely site, open and spacious forest with tall, straight Simarouba trees like cathedral pillars. Again we finished early. On the way out, we came to an intersection I didn’t remember. I stopped the car and got out to take a GPS point. When I got back into the car, the engine refused to turn over. Marisol and I exchanged a wordless glance of consternation. Fortunately, we were on a pretty level stretch of road. And thus end my adventures with the Silver Bullet: me at the wheel, Marisol pushing, until finally the engine caught and we rode off into the sunset.

The entrance to Botarrama.
(c) 2006 S.G. Letcher

Believe it or not, this is one of the best stretches of road between El Roble and Aceituno.
(c) 2006 S.G. Letcher

This is what 1100 plant specimens will do to a girl's office.
(c) 2006 S.G. Letcher

Friday, October 06, 2006

Where there's smoke... and a bucket of dead rats

When I do a vegetation inventory transect, the fieldwork is only the beginning of the process. The rest of the work—pressing the plant specimens and setting them to dry, entering the data, printing herbarium labels, and sorting the specimens when they’re dry—is not quite as fun, though does involve a much lower risk of snake bite, bala stings, etc. The later steps in my inventory work are not without danger, though, as I discovered earlier this week.

The story starts at breakfast. I was sitting outside on Monday morning, eating my rice and beans, papaya juice, and coffee. I waved to Macho and Don Santos, two of the La Selva staff, as they maneuvered heavily loaded cargo bikes up the path by the comedor. On closer inspection, the cargo turned out to be fire extinguishers.

“A dónde van los extintores?” I asked them. Where are the fire extinguishers going?

“Los llevamos al taller para revisión,” they replied. We’re taking them to the workshop for inspection.

Well, you can probably guess what’s coming up next. At 3 pm, a few minutes after I finished pressing the last of my samples, I met with Orlando to go over the remaining unknowns from my transect. Orlando is the station naturalist, with a truly phenomenal memory for plants. Although he has no formal education past high school, he knows the flora of this region better than anyone else. He started working at the station as a day laborer when he was in his teens. Over the years he’s risen through the ranks to become one of the best botanists in Costa Rica.

I picked up a branch from my rapidly shrinking pile of unknowns. “Elaeoluma glabrescens?” It was a species he had taught me to recognize a few weeks ago—white latex, fat brownish petioles, glossy leaves—but I wanted to be sure.

“Correcto.Y ¿qúe mas tiene?” Orlando speaks perfect English, but he humors me by speaking Spanish. He knows I’m always trying to expand my botanical Spanish vocabulary.

Just then, we heard shouts from the building across the walkway. Someone came running into Orlando’s office. “La secadora está quemando! Vengan!” The plant dryer’s burning.

We ran to the room where the dryers are—tall asbestos-sided cabinets with electrical heating elements that blow hot air over the specimens. A giant plume of gray smoke hung over the building. I reached the back patio of the building in time to see Marcos run out with a stack of burning paper and cardboard. He threw it on the ground, where I helped various people stomp out the flames. Fortunately Marcos was unhurt, only slightly singed. And very fortunately, with the extinguishers all in the taller for inspection (on the far side of the river, a good 400 meters away), nothing else had caught on fire yet. When the worst of the flames were gone, I took a look at the material scattered around us: singed leaves, half-burned scraps of newspaper. With my name and collection numbers on the upper right-hand edge. I felt sick, seeing a day’s work scattered and smoking on the ground.

In order to make an herbarium specimen, you carefully press a section of a plant in newspaper, folding the sample to show all the salient features that might be useful for identification: both sides of the leaves, the delicate ends of twigs, etc. (Fruit and flowers, if you’re lucky, but with transect vouchers you take what you can get.) Mark the newspaper with your name and your collection number, a uniqe identifier for each specimen you collect. Between each sheet of newspaper, you place some blotter paper or cardboard so that the twigs of one specimen don’t leave marks or wrinkles on the leaves of the next. Every five or six sheets of cardboard, you add a layer of corrugated aluminum. (These aluminum corrugates, I discovered on a field course some years back, make a great substitute for washboards if you want to play old-time music.) When you have a stack about a meter high, you put wooden frames on either end and pull it tight with straps to keep the specimens flat as they dry.

After we had made sure that the fire was out and nothing else in the dryer had caught, I reassembled as much as I could of the stack of specimens. Most of the plants were burned beyond recognition, but a cursory examination showed that it wasn’t as bad as I had feared. Of the three presses I had filled that day, only one had burned. Marisol carefully gathered the remains of the branches we had discarded, while I sorted through the burned paper and cardboard looking for salvageable pieces.

At La Selva, we have plenty of metal corrugates and wooden press-ends, but we’re rather limited by newspaper and cardboard. Fortunately I have the address of a recycling center in San Pedro where newspaper is 50 colones (about 10 cents) a kilo, and I’d recently picked up a stockpile. But cardboard… I was only able to recover four or five pieces from the burned stack. In order to reconstruct the specimens I’d lost that day, I would need at least eighty.

I must have looked pretty glum and resigned as I headed over to the cardboard recycling pile behind the Taller. Erin and Isabel, two recently arrived long-term researchers, met me on the bridge.

“What’s up?” Erin asked. “You don’t look so hot.”

When I explained the situation, they came to the rescue. They helped me lug all the useable cardboard scraps back to the lab, and slice them into proper-sized pieces with box cutters. A job that would have taken me well into the night was finished before dinner, and I was able to reconstruct all my lost specimens—all but one—by 9:30 at night. The one I lost was a common and easily identified species, Smilax domingensis. Orlando examined the dryer, and found that one of the shelves has been mis-positioned after a routine cleaning, placing it too close to the heating elements. There are new signs on the dryers now, showing clearly where the shelves are supposed to go. I guess the adage is true, all’s well that ends well. But I shudder to think what might have happened if nobody had spotted the smoke.

The bucket of dead rats really had nothing to do with the immolation of my specimens. It was just the other noteworthy thing to happen to me this week. Dennis, a herpetologist and the current record-holder for longest consecutive stay at La Selva (among current researchers), is radio-tracking fer-de-lances. These giant pit vipers—a meter and a half, or sometimes even bigger—are one of the things in the forest that I go out of my way to avoid, but Dennis has been capturing them, surgically implanting radios, and tracking them, for more than two years straight. He has about ten snakes now in the field with little transmitters sutured to their ribcages. Every day, alternating day and night, he goes out with a giant antenna and a little beeping receiver, and he records their whereabouts. Even by day it’s not for the faint of heart—he works in swamps, treefall gaps, and hideously tangled spots. The mosquitoes are horrendous. And as Dennis’s assistant Vinny discovered the other day when one crawled over his foot, not all the fer-de-lances have radios.

In the past few months, Dennis has been conducting a feeding experiment with half his tagged snakes, in order to see how food supply affects their home ranges. As it turns out, the fed snakes have much smaller home ranges. I guess it makes sense; if there was a Krispy Kreme shop right outside my door I wouldn’t move much either. But it’s not Krsipy Kremes that the snakes prefer. It’s rats.

A few nights ago, Dennis and Vinny invited a few other researchers along for Feeding Night. We gathered on the back porch of the old lab, beside the hammock and the much-mildewed leather rocking chairs in the “rincon de vagos” (lazy people’s corner). As the last straggler came out of the lab building (Erin, pulling on her wet boots with a curse), the rain began.

“Typical,” Dennis said. “We’ve done, what, like eight feedings now? And I swear, seven of those nights it’s been raining.” He shouldered his transmitter and a long, extendable plastic pole, and he slung a bucket in my direction. “Here, you can carry this.”

I looked in the bucket and rather wished I hadn’t. There was a thermos full of hot water—pit vipers, after all, won’t eat cold food—and a bag of slowly defrosting white rats. Mmm, whiskers.

We headed out into the Research Swamp for the nearest snakes. With the moon behind rainclouds, the night had a velvety darkness so thick that the walls of forest outside the narrow beam of my headlamp seemed to be closing in. Rain dripped incessantly off the leaves, the sound blending with the little murmurings of night creatures.

After maybe twenty minutes of crashing around in the underbrush beside the swamp, listening for the transmitter’s faint beep above the sound of the rain, Dennis located the first snake. Her raised head was sticking out, alert, from under a rotting log. It was hard to tell how big she was, except for the glimpses of hefty wrist-sized coils stacked up under the log.

“Good, she’s hunting,” Dennis whispered. “Drop a rat in the water.” (Fortunately this task fell to Vinny and not to me.) “You guys stay over there. Turn off your lights and be quiet. She’ll spook if she hears us, and then she won’t eat.” We complied. Dennis made a few adjustments to the plastic pole, and fished the now-steaming rat out of the water. He tied a slip knot around its tail with the string at the end of the pole. “OK, here we go.”

He turned his headlamp to the place under the log where the snake had been. There was nothing there. In that moment the fitful rain stopped and the moon came out, lurid and brilliant, lighting up the layers of black leaves and the long streaks of water dripping from the canopy. Low branches hung with moss looked skeletal and furtive. In the eery light I strained my eyes for a glimpse of anything that might indicate the whereabouts of the snake: the white patch beneath her chin, or the zigzag pattern of her back. Nothing.

“You got a signal, Vinny?” Dennis asked. I heard the boop-boop-boop of the transmitter, rising in volume. “Ah. Under that palm. Step back, Vinny. Step back.”

Dennis directed us to the far side of the log, where we would have a clear view of the snake and its dinner. Then, carefully balancing the plastic pole on the waist-high rotten log, he extended the pole until the rat dangled right in front of the snake. She came forward slightly, and WHAM! She lunged upward, allowing us a momentary glimpse of the lethal fangs as she sank them, rather superfluously, into the neck of the reheated rat. Some profane exclamation escaped my lips. Even after witnessing Franklin’s anaconda bite, I had forgotten just how quickly snakes can move.

In other herpetological radio-transmitter news, Steven (another resident herpetologist) has come up with a great way to deal with the crocodile issue. On hot days like today, it would be delicious to go floating down the river on inner tubes the way we used to—but with a crocodile frequenting our old swimming beaches, floating activity has come to a halt. Steven’s idea is that we should contact Google and have them send down a team of specialists to capture the crocodile and tag it with a GPS transmitter. It could become a new feature on Google Earth—any time you wanted to know where the crocodile was, you’d just have to go on line and check. They could also paint the Google logo on its side, opening a brand new dimension of corporate sponsorship. I’m sure Google Crocodile, as we would call him, has the potential to become a great tourist attraction as well.