AS soundless as a shadow, the canoeglides through one of the innumerableinland waterways. Sparkling in the morningsun, moss-green beads of water dripfrom the hardwood paddle our freelanceguide, Barbara Hartung, wields with skill.Peacefulness predominates this Septemberday in Tortuguero National Park, on thenorthern Caribbean coast, interrupted solelyby the shriek of a toucan and the muffledroar of a distanthowler monkey.MAJESTIC figtrees, mimosas andleguminous plants,such as the bloodtree, trim the banksof the lagoon. Hugefronds of raphiaswamp palms dipinto the canal. Thesky and dense rivervegetation are reflectedin the pristine,dark-coloredwater, revealingtwin views of bluesand multi-shades ofgreens, both beautifuland eerie.To r t u g u e r oNational Park,founded in 1975, ison Costa Rica’snortheast Caribbeancoast, and consistsof 26,125 terrestrialand 50,000 marinehectares. The parkand the adjoiningBarra del Coloradowildlife refuge tothe north comprisethe largest remaining tract of tropical lowlandrain forest on the country’s Atlanticcoast. Its 22 miles of quiet, undisturbedsandy beaches are the green turtle’s mostimportant nesting sites in the WesternHemisphere (see sidebar).WHILE we admire the white blossomsof a water chestnut, Hartung spots twopairs of mating bare-throated tiger heronsstrutting on high branches. And, totallyundisturbed, a kingfisher flits abeam thecanoe, searching for prey.“Nearly half of the 878 Costa Rican birdspecies are found in this area,” Hartungexplains in a low voice. “With some luck,even the great green macaw can be seen.”German-born Hartung, 41, holds amaster’s degree in biology, and specializedas a zoologist at the University ofTübingen, in the southwest of her nativecountry. After 10 years living and workingin Tortuguero, she is still fascinated by thebiodiversity of the rain forest. “Each day isdifferent here,” she says. “It’s never thesame.”DOMINATED by water, this CostaRican Amazon is a world of its own, accessibleonly by boat or plane. An infinitenumber of channels and navigable lagoonscrisscross the park from southeast to northwest.Fed by rivers that flow from theCentral Mountain Range, they swell withthe torrential rains common to the area. At5,000-6,000 mm (197-236 inches), theannual precipitation is among the highestin the country.Tortuguero is one of the most biologicallydiverse wilderness areas in all ofCosta Rica. Atotal of 11 habitats, includinggallery forest, raphia woods and swamps,have been identified in the park.Endangered mammal species include theanteater, jaguar, tapir and manatee.Paddling deeper into this waterlabyrinth, the tour is fortunate enough toobserve a group of rare spider monkeysplucking fruit from a tree. These highlyendangered animals are threatened bydeforestation and fragmentation of range.According to Hartung, spider monkeysrequire large preserves of unbroken rainforest for survival, and Tortuguero isamong its few remaining refuges in CentralAmerica.Along the aquatic trail of Caño Harold,we listen to the busy hammering of awoodpecker, hear the strange cry of an oriole(Montezuma oropendola), and watch aschool of tiny jumping fish dance a silver-shimmeringballet.PROTECTED by the shadow of thecanopy, a caiman waits, motionless. Itsentire body is clearly visible in the shallowwater of the riverbank, but only its vertically SOME 65,000 tourists visit Tortugueroannually, and the numbers are increasing.To save the fragile ecosystems of the tropicalrain forest, Hartung, a committedguide, dreams of boats equipped with quietelectric motors, and of canoes.“It is believed the farther you get intothe forest, the more wildlife you see,” shesays. “But this is an illusion. Noise fromairplanes and motorboats are stressful tothe animals. Moving slow in small numbersis the best way to observe and to protectnature at the same time.”Another of the park’s main attractionsare nesting turtles. Spending their entirelife in the ocean, marine turtles are shycreatures. To lay their eggs, they emergefrom the sea at night and make their wayup to the edge of the beach above the highwaterline. Watching them is a rewardingbut strictly regulated activity, requiring theutmost respect for the nesters. Access tothe beach is possible only with an experiencedguide.Dressed in dark garments, the tour followsHartung in single file. She isequipped with a red-filter flashlight, as anyother kind of illumination, even lit matchesor cigarettes, could frighten a turtle backinto the water.“NAMED after their green body fat,these turtles feed on sea grass,” Hartungexplains. “Adult females can reach 1.1meters in length and 150 kilos in weight,and they lay around 110 eggs.”Under the pale light of the rising moon,we spot impressions of turtle flippers in thesand. Though elegant swimmers in theirocean element, sea turtles move ratherawkwardly ashore.First, our group watches a female makingher way back into the water. A littlelater, our multilingual guide finds a nestingturtle. Eventually, we are allowed toapproach the large animal from behind.The size of golf balls, one whitish egg afteranother softly glides into the depths of thebrood chamber, from where the hatchlingswill emerge in approximately 60 days.Inexplicably, 25 to 35 years from now thefew turtles that survive their predators willreturn from the sea to nest for the first timeat the same beach.Additional trek options with Hartung –who is also a specialist on medicinal plants– include two- or three-hour hikes in therain forest, with emphasis on the life cyclesof plants and their interactions with smallerfauna, such as bats and snakes, as wellas insects.Outside the turtle season, Hartungoffers walking tours through Tortuguerovillage, encompassing history, culture andthe impact of both tourism and conservationon daily life.As a solution to various communityproblems, such as waste management,fresh water supply, medical care and education,and to preserve this coast so rich inbiodiversity, Hartung has an eco-tax inmind. Moreover, she suggests linking partsof the money from park-entrance fees ($ 7for tourists, $1.35 for residents), directly totown management.Tours with Hartung can be bookedeither individually or as a package includingtransportation, room and board. Aminimumstay of two nights is recommended.Lodging in Tortuguero comes in allprice ranges.For more information on rates and howto get there, visit Hartung’s Web site at:www.tinamontours.de, e-mail firstname.lastname@example.org or call 842-6561.A Place Where the Turtles AboundTORTUGUERO, as its Spanish name translates, was once“a place where the turtles abound.” Four of the world’s sevenmarine turtle species come here to complete the nesting ritualthey have been performing for eons. Leatherback, loggerhead,hawksbill and greenturtles are all endangeredand under strictprotection.Famed U.S. conservationistDr. ArchieCarr discovered thatTortuguero is thelargest nesting site ofthe green turtle(Chelonia mydas) inthe Western Hemisphere.The Florida-basedCaribbean ConservationCorporationwas founded in 1956to support the work ofDr. Carr, called the“father of sea turtleresearch.”“THE nestingpopulation at Tortuguero,50 miles up theCaribbean coast fromPuerto Limón, hasbeen under continuousobservation since 1955,” wrote Dr. Carr. “Atagging program begunthen has been resumed every season, and recoveries of tags onthe nesting beach, and at a distance from it, have revealed a numberof features of the life cycle.”TODAY, more than 35,000 adult female green turtles havebeen registered. Once avidly hunted for their meat, fat and eggs,they are now returning in increasing numbers. Records show thata female may comeashore to lay eggsfrom one to seventimes during her seasonat the breedingground.Human impact isthe main reason whythese reptiles arehighly endangered.Among the causes oftheir decline arewater pollution, fishingnets, beach developmentand risingocean temperaturesdue to global warming.POACHING andillegal commerce ofturtle-shell productsand eggs are also anunresolved issue.Since scientificresearch in the oceanis extremely difficult,several green turtleshave been satellite-tracked. Miss Junie 2 is the only one whosetransmitter is still sending signals. For information on sea turtlesand to observe their migration, visit: www.cccturtle.org.