Opening Pandora's Locks

Opening Pandora's Locks Will Panama's planned widening of the famed interocean canal spell ecologic trouble? By Andrea Gawrylewski ARTICLE EXTRAS 1 "Many EIAs are laughably superficial," writes Laurence. He cites a case involving a proposed apartment complex that would require clearing of forests. Surveyors hired by developers identified 12 bird species in the area, but when experienced bird-watchers conducted a two-hour census of the same area, they identified 121 bird species, many endangered or rare. The project was approved anyway. STRI researchers are trying to come up with the best plan for replanting some already cleared areas edging the canal to compensate for the increased runoff and erosion caused by deforestation. The canal infrastructure itself is vulnerable to heavy rainfall events. Jefferson Hall runs a replanting experiment on the hills bordering Soberania National Park, 15 miles northwest of Panama City. He is examining which species - both native and non-native - grow the fastest; the exotic teak is by far the best performing. However, all the planting lots are quickly overgrown by canal grass, an invasive species that chokes out the native species and encroaches on any open spots. By spearheading this project and another watershed-wide evaluation of water availability, Hall hopes to determine how to best manage water flow using plants and trees, especially during certain times of the year. "One ounce of dry-season water is worth its weight in gold for the operation of the Panama Canal," Hall says. STRI's longest-lived research station at Barro Colorado Island in the middle of the canal has been purely devoted to science research since 1923. Docks and power generation buildings will have to be moved uphill from the water, says Oris Acevedo, the science coordinator there. A Panama native, Acevedo says she thinks some of the ecologic costs of the expansion project are well worth the financial and employment opportunities that the Panamanian government has said will accompany the project. "I think [the decision process] was very democratic," she says. "The government risked that we would say no." The increased canal income will provide vital services, including jobs and enhanced living conditions, she says. "If we don't do it, [another country] will." It's late morning in Panama, and the steamy air coats everything and everyone with a slick residue. Dominique ("Dom") Roche, a graduate researcher at the STRI, drives a white Toyota pickup past the rigid security guards at the entrance to the Panama Canal Zone, on the west bank of the canal only a few kilometers from Panama City. Down a bumpy dirt road, small coatis scatter at the sound of the truck, monkey-like tails bobbing after them. Roche slows suddenly, spotting the turn he's been looking for: a dirt path veering down the embankment to the left, almost completely overgrown by canal grass. The truck turns and descends slowly, as a still, green lake comes into view. "We might see some crocs laying around down here," he says, sounding hopeful. Once at the shore of the 400-meter wide lake known as Miraflores Third Lock Lake, Carmen Schloeder and Yulang Kam hop out of the truck, pull on water shoes, and help Roche get a small motorboat off the truck's trailer and into the water. Kam's eyes scan the water intermittently for approaching crocodiles. The team piles into the boat and then speeds across the water. "In Panama, it's astonishing how little study there has been on the movement of organisms around the world as a result of the canal; 30 years with essentially no publication on the subject." -Andrew Cohen Third Lock Lake is one of the abandoned excavation sites of the Panama Canal; dug out in the 1930s for a third set of locks but left uncompleted at the start of the Second World War. The water is brackish; freshwater and saltwater separate into distinct layers beneath the surface to create the perfect environment for Rhithropanopeus harrisii, the thumbnail-size Harris mud crab. An invasive species from the east coast of North America, R. harrisii is one of several exotic species that are under observation both in the canal and its extremities. In the near corner of the lake Roche slows the motor and the team scours the surface for a red or white buoy indicating one of the traps they've set for the mud crab. "Did we put it more to the left, maybe?" Schloeder offers. "I know we put one here in the corner," says Roche, but the buoy has sunk below the surface. "We'll have to bring back a long hook or something to fish it out next week." 14,000 ships travel the Panama Canal each year. Before the current expansion project, the Culebra Cut (right) was widened in 2001 by 222 meters in some places. Roche, Schloeder, and Kam are researchers in Mark Torchin's lab at the Naos laboratories, STRI's molecular labs, on the Amador Causeway, which stretches onto a peninsula curving below the southern coast of Panama City. As the boat motors the length of the lake, the engine's hum reverberates off the black basaltic walls that were carved into during the original excavation. Eyes fixed on the water, they locate nearly every one of 25 traps (actually artificial habitats) they set in July to collect, count, and sex the crabs living in the lake. The harrisii species has been spotted all over the world, and five specimens were collected in the canal in 1969, but none since then. Indeed, Torchin's group placed a handful of traps in the canal itself, but to date they have yet to see a Harris crab there. In Third Lock Lake, however, the species is abundant. In March, Torchin and Roche collected 88 specimens within one hour of inspecting the shoreline.2 Among those collected, 16 were egg-carrying females, and eight were juveniles. The age distribution and abundance of the crabs suggested to Torchin that the lake is supporting a fully functional population of Harris crabs. But until Torchin completes more systematic surveys and expands his sampling distribution, it will be difficult to predict the effects that exotic species might have on the native ecosystem. His proposed project to monitor the crab and other invasive species in the canal area received funding in July. "In Panama there is limited knowledge about [species] invasions," Torchin says, "and there hasn't been a standardized, quantitative survey of invasive species. People have done rapid surveys, but we're trying to set up a standard methodology and have it be quantitative." Currently thriving in Third Lock Lake, the Rithropanopeus harrisii or Harris mud crab, is barely the size of a thumbnail. Courtesy of Dominique Roche Other invasive species that have been transported into the waters of the canal, thanks to the many ships on the waterway, include the Asian clam - which heavily populates the bottom of the canal's lakes and channels - and many fish species, including the peacock bass, Oscar fish, and tilapia. Other surveys have identified a dozen or so Atlantic marine species that live exclusively at the Pacific mouth of the canal, and vice versa. A study published in 2002 showed that eight fish species had been established in the Chagres and Rio Grande rivers. The fish were introduced during the construction of the canal and established their populations by the 1930s.3 The researchers also found that all native species populations (originally identified in a 1910-1912 STRI census) remained intact. Nevertheless, "it's not reasonable to assume the impacts aren't there," says Andrew Cohen, director of the bioinvasions program at the San Francisco Estuary Institute. Cohen adds that the canal expansion will directly impact the global scheme of shipping around the globe, with correlated shifts in the movements of organisms around the world as well. "In Panama, it's astonishing how little study there has been; 30 years with essentially no publication on the subject." With the expansion, "the whole intermeshed shipping network will shift, and no one has a handle on what that means when it comes to moving organisms around." Torchin says that within the next year his group hopes to collaborate with molecular biologists to map the genetic origin of the mud crabs and possibly piece together how they came to be in Third Lock Lake. A week after checking on the location of the traps, Roche and his assistants returned to Third Lock Lake to recover the habitats in their first of several collections over the next six months. Each trap is a square crate filled with seashells cinched into a mesh bag to capture any inhabitants. The specimens are taken to the labs at Naos to be counted and sexed. Just to the north of Third Lock Lake, the group collects specimens from another freshwater lake where they've also left traps. In the pacific entrance to the canal, they find that the tide has carried away some of the traps, which they replace and anchor with concrete blocks. The team also set up 20 traps in Miraflores Lake so it can begin monitoring crab populations there as well. The researchers are in an unspoken race with the ACP, which plans to drain Third Lock Lake and begin construction of a third set of locks, beginning by the end of 2008. When the new set of locks is built, water will be redirected from the main channel of the canal to power them. The invasive crab population could be spread into the canal and adjoining waterways, become abundant, and clog drains and pipes. Or, the draining and construction in the lake could destroy the crab population. Either way, Torchin's team hopes to anticipate the outcome - if it can get enough done in time. References 1. W. Laurence, "Road to ruin," The New Scientist, 194:25, June 9, 2007. 2. D. Roche, "Established population of the North American Harris mud crab, Rhithropanopeus harrisii (Gould 1841) (Crustacea: Brachyura Xanthidae) in the Panama Canal," Aquatic Invasions, 2:155-61, September 2007. 3. S. Smith et al., "Cross-Cordillera exchange mediated by the Panama Canal increased the species richness of local freshwater fish assemblages," Proc Royal Soc London, 271:1881-96, 2004.

Opening Pandora's Locks

Oct 1, 2007

Opening Pandora's Locks

Will Panama's planned widening of the famed interocean canal spell ecologic trouble?

ARTICLE EXTRAS

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