Española Part 2: Counting Albatross and Measuring Cactus

June 1, 2015

By guest author Dr. James Gibbs of the State University of New York’s College of Environmental Science and Forestry (SUNY-ESF). All photos © James Gibbs.

Espanola Island

The seas finally calmed sufficiently to allow us to head to Española. After two hours on a speed boat, we — Wacho Tapia, park rangers Carlos Vera and Carlos Gaona, Novarino Castillo, and myself — step ashore at Playa Manzanillo on the north central coast. Carrying our gear up the beach, we are delighted to see sea turtle hatchlings emerging from their nests. They “flipper” their way down the beach, get scooped up by a wave that throws them back, then “flipper” on down again. As these little guys head off so earnestly for their new life in the big blue ocean, I wonder: will the hatchling I am watching be the 1 in 1,000 that makes it to maturity?

Trekking through Espanola.After eating a quick lunch of rice with canned tuna and a dash of hot sauce, we pack up and head inland into the scrub, loaded with gear and food for four hungry men for six days. Novarino will stay camped on the beach and make a daily trek to our camp to resupply us with water. As we climb, we encounter dense, lush vegetation, a rare sight on this normally arid island, a result of recent heavy rains. We come across a long winding track with the vegetation plowed flat — sign of a giant tortoise. Seeing this so close to the beach and far from prime tortoise country is rare; proof these animals, released on Española as part of the decades-long tortoise repatriation program of the Galapagos National Park Directorate, are expanding their range, especially when conditions are lush.

After two hours, we arrive at our first tortoise exclosure — 24 meters of chain-linked fence surrounding a huge spreading tree cactus. These exclosures constructed two An Espanola tortoise with characteristic yellow chin.years ago by men from the highlands of Santa Cruz were built to last. Inside the exclosure, we find numerous cactus pads and fruit on the ground that would normally be vacuumed up by tortoises; this was expected. But there was also an unexpected pronounced shift toward herbaceous plants (that is, not grasses). Over the next two days we measure plants in all exclosures but the changes are obvious. Clearly tortoises can shift plant communities over short periods as can the absence of tortoises — evidence that tortoises are important for ecological reasons alone. We are eager to digitize our 30 pages of grubby field sheets of numbers to extract patterns of change.

We camp at El Caco, on the saddle that defines the top of the island. El Caco is a magnificent and massive lone Erythrina velutina tree. Although native to Galapagos, this is the only one known on the island; it was likely a favorite forage species of the once present introduced goats. We settle in under its spreading branches as darkness falls.

Base camp at the El Caco tree.

Wacho asks about the pirates that collected tortoises here; what trails did they use? Who else might have sat under this very Caco tree (it must be at least 200 years old)? What did they talk about? This island experienced pirates, whalers with odd accents, then Spanish-speaking fishermen. The first park rangers arrived in the 1970s to kill the goats that had infested the island, remove the few remaining tortoises, and eventually return the young tortoises produced in the breeding center on Santa Cruz. Now we sit under the same tree, likely having many of the same conversations.

We spend several days measuring the plants in the tortoise exclosures and controls (unfenced plots). One day, with machetes in hand, we make our way through the dense Espanola waved albatross.vegetation over the top of the island to the “central colony” of waved albatross, a colony that was considered extinct by some – but not so! Large numbers of albatross remain scattered throughout. We trek down to the sloping nesting zone to count albatross around the “albatross airstrips” — long open avenues through dense woody vegetation that allow the massive birds to land and take off. One bird tries five times, but each time the wind weakens and it crashes down again. We count albatross in the five clearings we created two years ago. However, the heavy rains have flooded many nests and numbers are down. “Crunching the numbers” will tell us if albatross prefer the human-made clearings.

Espanola cactus being measured.One morning, loud thunder stops us before we head out, followed by a two-hour downpour. When the rain lets up, we slog back into the field. We can hear a rushing stream and waterfalls pouring over the cliffs. At times we walk hip-deep in water. We complete our final task for the trip-marking cactus for long-term monitoring. We measure cactus height, note GPS location, and apply a metal tag. The base of a few cactus stand deep in water. Data collected over the next several years will show how the cactus population changes over time.

It is an extraordinary time on Española. Finch songs fill the air, the repetitive groans of mating tortoises resound from all directions, mockingbirds gather nest material, and caterpillars seem to be everywhere. It’s been a productive if wet trip and we look forward to analyzing our data to shake out what has happened inside the tortoise exclosures and on the albatross airstrips. I enjoyed experiencing Española in a rare time of heavy rain — a short interregnum of biological exuberance and reproduction before the austere aridity that normally defines the island sets in yet again and creatures revert to survival mode.

 

Read Part 1 of the Española blog series by James Gibbs.

 

Dr. James Gibbs is Professor of Vertebrate Conservation Biology and Associate Chair of the Department of Environmental and Forest Biology at the State University of New York (SUNY-ESF). He has partnered with Galapagos Conservancy for many years in efforts to restore giant tortoise populations in Galapagos through the Giant Tortoise Restoration Initiative, and is a frequent guest contributor to the GC blog.

 

 

Share this article:

Comments (1)

Latest News