Sail due west from Manzanillo for 440 miles and you’ll hit what’s known as the Archipiélago Revillagigedo, named for a late 18th-century reformist viceroy.
We don’t know if last week’s designation of this cluster of four small islands and their surrounding waters as a national park and marine reserve will really protect them. But the act itself brought welcome attention to one of the more remarkable natural wonders in Mexican territory, as well as to an intriguing suspense story.
The islands poke out of the water because of ancient volcanic activity that hasn’t quite stopped. They knew no human footprint until Spanish explorers stumbled upon them in the 16th century. Even then, they were left pretty much alone until the 19th century.
It’s worth pondering what that tells us about life. While a series of great civilizations ran their course and died in Mesoamerica, while cities were built and leveled across what is now Mexico, wars fought, constitutions drafted, massacres carried out, elections contested, families struggled to make it, an entirely different cast of species was playing its role in life, about as far away from the human-dominated stage as it is possible to be.
The protagonists of Mexican history are mostly people, with maybe a few plants like corn and the maguey making appearances. Animals get cameos at best.
On the Revillagigedo islands, in contrast, everything alive matters — boobies, shearwaters (including the endangered Townsend’s shearwater), frigatebirds, egrets, hawks and ospreys, opuntia cacti, bromeliads, orchids, green turtles.
More than 60 of the plant and animal species are endemic, meaning they’re found nowhere else in the world, which in turn means they’ve been on their island long enough to have evolved into something different than what they were.
Four of the endemic species are reptiles, including the famed Clarión nightsnake (Clarión is the name of one of the islands). Its fame has nothing to do with the snake itself, but rather with the failure of any expedition, amateur or scientific, to find one after the American naturalist William Beebe brought a specimen back in a bottle in 1936.
That inevitably led to a new moniker — the “Lost Clarión nightsnake” — until a group that included Juan Martínez Gómez, Mexico’s leading Revillegigedo expert, spotted one a few years ago (as published in PLOS-One here and reported by the Associated Press’s Mark Stevenson in 2014 here.)
The new marine reserve designation prohibits fishing, but recreational divers and marine life enthusiasts (who can only get there by diving boats and cannot dock anywhere) have to be encouraged by the promised protection. The Revillagigedo straddles two marine bioregions, making it an important stopover for migratory marine species, thus bringing a potpourri of life forms together, like the bar in Star Wars.
UNESCO, which named the archipelago a protected region a year before Mexico did, says the waters around the islands “host some of the largest aggregations of pelagic fauna in the world.”
The United Nations body even notes an aesthetic appeal that divers the world over already know about: “The seascape has sheer drops in crystal clear water and encompasses abyssal plains with depths down to 3,700 meters, all contributing to underwater scenes of great beauty.”
Swimming in that beauty are more than 20 species of sharks, as well as humpback whales, which have been breeding near the islands for millennia, and, most notably, giant manta rays that interact with humans in a way that divers swear is personal.
Here’s where we come to the point in the article when, obligatorily, we warn of the threats to this paradise (to us it is a paradise; to the non-human inhabitants it just . . . is.)
First know that the major recent problems have been natural — hurricanes, plagues and the aforementioned volcanic activity. For example, a volcanic eruption in 1952 (pictured here in a famous photograph taken by Robert Petrie from a boat offshore) left one of the islands (San Benedicto) denuded — all life on it was wiped out, though it has been coming back.
Isla Socorro, the biggest and biologically richest of the islands, is basically the top of a shield volcano, the gently sloping kind like Mauna Loa. It was most recently active in 1993.
Roca Partida, the smallest of the four at about 300 by 25 feet, is a stratovolcano, lifeless save for resting birds, essentially a guano-covered rock alone in the sea.
An early 19th century visitor to the islands was one Andrew Jackson Grayson, who discovered four endemic birds, including the Socorro dove, or Zenaida graysoni (you find it, you get your name on it).
Two naturalists, Bayard Brattstrom and Thomas Howell, visited Socorro in the 1950s and in a 1956 report mentioned the Socorro dove (pictured here) as common around the lava rocks and under fig trees.
They were optimistic about the island’s future, noting that few ships came near, no humans lived there, and the introduced sheep population was stable and apparently harmless.
“While this fortunate condition still exists,” they wrote. “it may be hoped that the Mexican government will guard against the introduction of mammals such as rabbits, cats, goats and others that have invariably brought disaster to the flora and fauna of insular regions.”
The next year, the Mexican government established a naval base on the island. It was (and is) small, but big enough for mammals, both human and feline. By the 1970s, no more Socorro doves were ever seen on the island.
Feral cats have been suspected, though not convicted. Perhaps the sheep were causing more mischief than thought. Or maybe it was something — or someone — else. At any rate, the Socorro dove is extinct.
But not completely. The accurate term for the dove’s condition is Extinct in the Wild. On at least two occasions in the 20th century, specimens were collected and bred abroad. There are colonies of Socorro doves in Europe, the United States and Mexico.
The Mexican population is being prepared for release onto Socorro Island. This is no simple task; the preparation has been going on for more than a decade. Breeding aviaries have been built on the island, but there are issues.
Disease is one. So is interbreeding over the years – just how Socorro-ite are the descendent captive doves? The most important, though, may be the need to make sure that the doves have the environment they require once released.
“It's not restoration by restoring or reintroducing one species," says Dr. Martínez, who is leading the project (that's him exploring the island in the photo above). "At the end what you want is to restore the ecological interactions that interplay on the island. And once you do that, the island will go back to its original course."
Dr. Martínez, of the Mexican Institute of Ecology, was speaking to the science writer Loretta Williams earlier this year on NPR. You can read the article here, where you can also click to the radio program.
The Socorro dove's rescue team is competent and dedicated. But once released, the birds will do what they want, which is not necessarily what the releasers want. That's how life's been on those islands for hundreds and thousands of years.
No comments:
Post a Comment