Notes from the Edge

Natural History, March, 2007 by Robert R. Dunn

The first reports home from early European explorers in the tropics told of impenetrable jungles ("we hacked through a dense, green hell ..."). But truth be told, the average tropical forest is fairly open. Large trees darken the forest floor, discouraging understory growth. What is impenetrable is the edge of the forest, where weedy species clamber for light, jostling into every empty space. The edge was the thorny tangle the explorers first confronted. Those who pushed on found a more inviting forest--albeit one that harbored malaria, the odd poisonous snake, and assorted other perils.

Those early encounters came to mind when I began teaching a summer field class in the Dominican Republic for college students from New York City. The course was held in a small patch of forest next to a seaside resort hotel (a location that posed multiple challenges, including how to keep students attention when a topless bather walks by). One of my first goals was to get my charges used to the forest. They could appreciate nature, I reasoned, only if they learned to be comfortable in it.

So with practiced nonchalance, I began walking backward down a trail through the forest, twelve students in tow, waving my arms, pointing to snails, crabs, lizards, leaf forms, epiphytes. I was bout to mention the amazing abilities of fungus-farming ants, when one of my waving arms hit something. I felt two sharp stabs in my neck then a third, then a fourth. A most unscholarly series of expletives poured out of my mouth, and I ran a few steps farther down the trail, away from the angry wasps.

Unfortunately, with me out of the picture, the wasps changed targets. When I looked back, all I could see were flailing arms and legs as my students took off in the other direction. A few of them were screaming. Then I heard a louder scream as someone at the front of the pack discovered one more of nature's secrets: another wasp nest. Soon, all the students were running toward me again. It went on like this for a while, the fleeing mob bouncing back and forth between nests, until three students were stung, several were crying, and one was protesting loudly, "I want to go home."

The class did get better (though there was that brief incident with a manta ray ...), but I feared that for most of the students the forest would remain forbidding. The wasps, a species most at home in disturbed parts of the forest, were a part of the forest's edge, the tangle beside the well-worn trail where weedy species thrive. The students would go home to tell their parents of a "dense, green hell." Worse, by virtue of its small size, our forest was more edge than middle, more barrier than invitation. Had we come to the Dominican Republic several hundred years earlier, the forest would have been both taller, with old growth, as well as deeper, less carved up into small plots, and with an open under-story crisscrossed by animal paths.

Later in the summer I invited the students on another trip into the forest, this one optional, by night. I didn't expect many volunteers; even my wife opted out. I arrived early at the meeting place. No one was there. I turned off my light and waited in the dark, listening to the wild calls of forest insects, and the wilder calls of tourists jumping into the hotel pool.

As I was about to give up, one student arrived, then another. Soon, almost everyone was present, headlamp on, ready to go in. We walked slowly along the path, fanning our lights across the leaves, looking for the shine of eyes (I also kept an eye out for wasps).

That night we saw hundreds of animals that had been hiding during the day: crabs, sleeping lizards, sleeping birds, snakes, and even, as everyone crowded around me, a small mammal. It stumbled away through the leaves and branches before we could identify it. We followed it, down off the trail, past the wasps and weeds, beyond the tangled edge. No one said a word.

ROBERT R. DUNN is an assistant professor of zoology North Carolina State University in Raleigh, and a frequent contributor to Natural History. His most recent article ("Dig It!") appeared in the December 2006/ January 2007 issue.