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.

Saturday, April 25, 2009

Hard to believe the course will finish in two weeks. A few notes on the last places we have visited, then. Photos will have to wait, since they are on my home computer and I am once again in the field.

At the beginning of April we visited San Gerardo Biological Station at the edge of the Children’s Eternal Rainforest in Monteverde. The reserve, a complex of cloud-laden mountaintops along the contintental divide, came about through one of those heartwarming 1980s “children save the world” efforts, in which kids from all over the globe contributed to purchase protected land. Twenty-some years later, it is gratifying to see the land still protected and the forest growing back. The managers of the field station were a family who had lived there when the area was still farmed, and they pointed out where their pastures had been. You can still see the difference clearly between the new forest—spindly Heliocarpus trees with an understory of shrubs and a few grasses—and the gnarled, moss-covered, hulking trees of the old forest. Almost all the pastures have grown in, though, and the birds are beginning to come back into the young forests. We saw a blue and gold tanager (which, if you know birds, is apparently a big deal) hopping around in the edge of the old pasture area. I went looking for umbrella birds and bellbirds, a pair of unusual and attractive species endemic to this mountain range, but I didn’t spot any. One of my students saw four umbrella birds while he was out looking for plants. Figures!

One of the best things about San Gerardo was the unobstructed view of Arenal, an active volcano that is a major tourist attraction for this part of the country. The lava flows on Arenal aren’t smooth rivers, but rather tumbling aggregations of half-molten bolders. I think the technical term is a pyroclastic flow. Visually, it looks like the mountain is full of trapped light that occasionally struggles to the surface. The view from San Gerardo was better than anything I saw in La Fortuna (the tourist trap village at the base of the volcano); at night when it was clear we could see the glint of orange lava where the mountainside broke open. Even in the day we could occasionally see puffs of smoke in lines where flaming boulders went bouncing away down the slope.

I was surprised how many clear nights we had at San Gerardo. From my limited experience of cloud forests, I had expected unrelenting gloom. This is the tail end of the dry season, though, and we only got rained on twice. The second time was on the hike out—4 km uphill with all our gear in backpacks. I was actually glad it was raining; it kept the temperature down and made the steep uphills more bearable. I was reminded of a day on the Appalachian Trail years ago, when I was hiking through the rain with the inimitable Waterfall. I’ve never liked rain very much, especially cold rain, but Waterfall had a way of seeing the best in every situation.

“Don’t the plants look happier being wet?” she said. I had to agree.

The plants at Monteverde certainly seemed happier in the rain, and the landscape, too, seemed to take on its true dimensions with wisps of fog and rain obscuring the distant mountains. It was impossible to see how far the mountains extended, impossible to see the pastures and cleared areas in the lowlands. Aside from the road—a one-lane mud track suitable only for quad bikes and intrepid horseback riders—it seemed that we were in the wilderness primeval.

Leaving Monteverde, we headed for Cabo Blanco on the tip of the Nicoya Peninsula. Cabo is closer to wilderness primeval, actually, although the scrubby, dry, vine-festooned secondary forest there is not nearly as interesting. Cabo Blanco is an absolute reserve: only researchers and a select few students ever get to see the place. When no academic groups are visiting—much of the year—the station is boarded up and left for the land crabs, racoons, and monkeys. Cabo was Costa Rica’s first national park, in 1963. At the time it was converted to park, the area was all cornfields and pastures, so the forest is not much to look at. But the park was really established to protect the shoreline and the marine areas. At low tide, rock formations make a natural lagoon that is home to shells, corals, anemones, fanworms, and shoals of colorful fish. Very few people ever get to see an undisturbed reef like this one. We even spotted a sea turtle, a small leatherback, making its ponderous way along the sea floor in the lagoon. My favorite animal was a tiny blenny, about as big around as a pencil, with a green body and rings of bright red like makeup around its eyes and mouth. Their googly eyes and oversize bright red lips give them something of a Betty Boop look.

The one drawback of being at the beach, for me, is that my skin just doesn’t tan. Aside from a few freckles, I go from white to burned faster than toasted Wonder Bread. I’ve always been more of a forest person than a beach person, partly for this reason. I was very careful to keep myself slathered with sunscreen and covered up as much as possible, even to the point of wearing long sleeves and long pants while I was snorkeling. (I’m sure it wasn’t the most attractive beach outfit—sopping wet button-down shirt and field pants—but besides the anti-burn protection it also kept me insulated in the relatively cool Pacific waters.) Despite my precautions, I ended up with a perma-freckled face.

After a short few days at home, I’ve re-joined the course at La Selva for the final stretch. I don’t feel quite as rested as I would like to be, but it’s just two weeks…

Saturday, April 04, 2009

Palo Verde

A post written some weeks ago, and not uploaded till now thanks to RACSA’s breakdown…

I am back in Heredia again, after a three-week stint in Palo Verde. It wasn’t nearly as bad as I’d been led to believe—the hordes of mosquitoes I recall from the wet season were almost entirely absent, the ungodly heat was tempered by a breeze, and the scorpions (large and abundant though they were) mostly kept to themselves. I think I could develop a taste for Guanacaste in the dry season. It was strange, though, to see a tropical forest with hardly any leaves. I've become so accustomed to the evergreen forests of the Atlantic lowlands. I think many people,when they think tropical forests, think rain forests. But 42% of tropical forests are dry forests, and many dry forest trees are deciduous. Hence the strange combination of blinding sun, scorching heat, and leafless trees.

Some researchers have argued that dry forests are even more endangered than rain forests. One reason is that dry forest makes great cattle pasture, and it's easy to keep it clear by burning. The trouble is that burning favors invasive, exotic species, here particularly the pernicious pasture grass jaragua (Hyparrhenia rufa), which can form stands so dense that tree seedlings don't stand a chance. Parque Nacional Palo Verde protects one of the last remaining fragments of tropical dry forest in Central America, clinging to the steep sides of limestone ridges along the edge of the Tempsique floodplain.

In Costa Rica, most of the formerly dry forest areas have been converted to giant ranches, making Guanacaste the Wild West of Costa Rica. Cowboys (sabaneros; literally "men of the savannah") on horseback are a common sight along the dirt roads, and vast expanses of ranch land with emaciated Zebu cattle stretch off as far as the eye can see. Even within the park, cattle concessions still operate, though the cattle are now pastured in the marshy river floodplains rather than the few fragments of remaining forest. I never did get a clear answer as to why there are cattle in the park; my cynical side expects that there is a payoff somewhere. According to certain factions, the cattle help keep down the cattails (Typha domingensis), another invasive species, in the marsh... but none of the scientists I met agreed with this view, and there certainly seemed to be plenty of cattails in the areas with cattle.

Aside from cattle, the floodplain marsh supports an amazing variety and quantity of water birds: ducks, herons, egrets, storks, spoonbills, rails, etc. The marsh was dried rapidly; we watched areas go from deep water to dried, cracked dirt in the three weeks that we were there. Flocks of birds congregated in ever-smaller spaces as the water receded, making their numbers stand out even more. One afternoon I was fortunate enough to spot a jabiru stork. These massive birds can stand up to 1.5 m (5 ft) tall. I stalked out into the marsh to try to get a picture of it. No luck-- they are very wary birds-- but I did get a picture of my footprint next to the bird's. (For reference, I wear a size 10-11 shoe.) Outside the marsh I also spotted a pair of scarlet macaws, my first, but once again I was not quick enough with the camera.

The marsh at Palo Verde had a somewhat otherworldly aspect, with the weirdly-shaped limestone mountains rising up all around and giant, ungainly waterfowl flapping in slow motion against the constant wind. I sometimes felt (especially before my coffee in the morning) that I'd landed on an inhospitable marsh planet from the Star Wars universe, where the only human habitations cluster around the base of mountain ranges. It would not have surprised me unduly to see Imperial Walkers approaching from the Tempisque.

In the middle of our stay at Palo Verde we took a side trip to a mangrove swamp, which really looked like something out of Star Wars. At the outskirts, the white mangrove (Avicennia germinans) formed a monospecific stand. The regularly-spaced, sandy-brown trunks looked almost too orderly, as though they'd been planted. Here's the weird part: Avicennia has aerophores, little nobbly roots that allow gas exchange in the fine, silty soil. They stick up like a congregation of miniature snorkels, ankle-high all over the forest floor. We walked towards the ocean a ways (smelling the salt and hearing distant surf above the rush of wind in the trees), and we came to the red mangroves (Rhizophora mangle). I don't imagine many people have seen old-growth mangrove trees. Hopefully my pictures (scroll down) will do them justice, but I will add a few words as well. From ten feet up they look like a forest of aspens (same gray trunks, same cheery yellow-green in their leaves as aspens in about mid-June); from among the roots they look like a crazy jungle gym. They look like they walked there. They look like they could take off any time they wanted, like the jumping trees in the E.T. book (which was so much better than the movie, by the way!)

On the way back from the mangroves we visited Megafauna Park, a collection of statues of the extinct fauna of Central America. For anyone who wants to buddy up to a gomphothere, here's your chance! It was neat to see how large some of these animals really were.

Well, this entry is long enough by far. I will upload some photos and post it before it gets any longer!