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Drought Leaves Paraguayan Caimans in Peril

A wildlife crisis on the Pilcomayo River spurs “futile” rescue effort by citizens

They call it Agrophil Cemetery. A desiccated wasteland is all that’s left of a vast marsh that stretched along the Pilcomayo River in Paraguay. Now, dozens of dead and dying caimans lie mired in mud, bare earth extends to the horizon, and patient vultures perch in the branches of leafless trees.

Agrophil is at the epicenter of the worst drought the region has weathered in nearly two decades. As wildlife suffer and Argentina and Paraguay jockey for control of the river’s remaining waters, some activists have travelled to the river to take matters into their own hands: relocating the aquatic reptiles to wetter areas and demanding that the government drill wells for the surviving wildlife.

caimanPhoto by Dick KnightAs the drought in the region worsens, some wildlife activists have begun relocating caimans to wetter areas,

But the Pilcomayo is a dynamic river undergoing unprecedented change, and the activists’ actions have prompted debate and derision. Many fear their attempts to rescue wildlife are misguided, if not futile, and direct attention away from the root causes of the river’s plight.

Alberto Meza, president of the group Ya Estamos Cansados de Sus Leyes (which translates to “We’re Tired of Their Laws”), says his team of volunteers has helped rescue more than 130 animals over three trips to the river. And with every trip, he’s seen the situation on the Pilcomayo worsen. “Ninety percent of the animals still there are already dead,” he says. A nearby ranch owner told Meza that vultures were feasting on the dead and dying alike.

Ordinarily, the Pilcomayo supports an abundance of wildlife. Tens of thousands of caimans sun themselves along the river’s banks and hunt for frogs, fish and small mammals in its waters. (Caimans are closely related to alligators and crocodiles, though they are often smaller and have much narrower bodies). Capybara, one of the world’s largest and most adorable rodents, live along the shores, and sábalo and other fish migrate up the river to spawn.

Meza says “hundreds and hundreds” of caiman have already perished in the drought, along with fish, capybaras, and livestock. But the crocodilians bear the brunt of the drought because most other animals are more mobile and can seek water elsewhere when the river runs dry.

Officials from Paraguay’s Secretary of the Environment (SEAM) and the

Ministry of Public Works and Communications dispute Meza’s account. They say that only three large marshes, or bañados, have been severely impacted by the drought along a stretch of about 80 miles of river, resulting in the deaths of no more than 100 caimans and some livestock. That’s out of an estimated total population of at least 60,000 caimans in the region. And they allege that activists and journalists have sensationalized the drought for political ends.

Regardless, the director of the Pilcomayo Commission, which oversees the river’s management, was fired earlier this year over irregularities in the Commission’s $10 million budget. Government officials recently met with representatives of Meza’s group and promptly began digging wells and installing pumps to provide water for the wildlife. They even hired a bus for the activists’ latest trip to the affected areas.

Meza’s oddly-monikered group, Ya Estamos Cansados de Sus Leyes, was formed in response to proposals for a new transit law in Paraguay. But once it succeeded in modifying the law, the group took advantage of its 58,000-member Facebook page and expanded into other projects, such as giving talks on motorcycle safety and, now, rescuing caimans stranded by drought. About 40 people took part in the third expedition, and their rescue techniques have become more sophisticated, using snare poles and winches to hoist larger caimans out of the dry marshes.

SEAM, the environmental agency, has tried moving caimans during past droughts with little success — half of the animals died during transit, and more perished after being transferred.

Still, Meza stands by his group’s approach: “We’re going to rescue as many animals as we can.”

A river vanishes

Pilcomayo RiverPhoto by Walter Segovia/Wikimedia CommonsThe Pilcomay River channel is collapsing. Over the course of the twentieth century, the channel has retreated hundreds of miles upriver, its lower reaches blocked by sediment and log jams.

Attempts to save the wildlife of the middle Pilcomayo might soon be for naught as the remnants of the Pilcomayo slowly, inexorably erases itself.

The waters of the Pilcomayo River are born high in the Bolivian Andes. They flow swiftly southeast into the broad plains of the Gran Chaco, an arid and sparsely populated region spanning parts of Argentina, Bolivia, and Paraguay. Here, the meandering river roughly tracks the boundary between Paraguay and Argentina, before emptying into the Paraguay River, some 1,550 miles below the Pilcomayo’s headwaters.

Or so it was. Now, the river channel is collapsing. Over the course of the twentieth century, the channel has retreated hundreds of miles upriver, its lower reaches blocked by sediment and log jams.

Historical records indicate that boats sailed up the Pilcomayo from its confluence with the Paraguay River as early as 1546 and perhaps as late as 1906. But over the past hundred years, the Pilcomayo’s channel has moved upriver as the lower portion fills with successive deposits of driftwood and sediment. In 1984 alone, the end of the riverbed shifted 28 miles upriver. Thwarted by the ever-lengthening log jam, the remaining waters of the Pilcomayo spill out into a complex network of temporary lakes, channels, and swamps until they eventually merge with the Paraguay River via other small tributaries.

This situation is due in part to the extreme flatness of the region — all of western Paraguay and parts of Argentina comprise a massive alluvial fan of more than 77,000 square miles — and in part to the nature of the Pilcomayo’s waters. The river carries a tremendous sediment load. Weighing in at about 140 million tons of solids each year, the Pilcomayo is among the most particulate-heavy rivers in the world.

Adding to the river’s dynamism, its levels fluctuates between annual periods of high and low flow linked to rains in the Bolivian headwaters. At one monitoring station, the maximum discharge measured over three decades was 5,500 cubic meters per second, and the minimum a mere 3.2 cubic meters per second, about .06 percent of the peak.

Elias Diaz Peña, director of the Paraguayan environmental organization Sobrevivencia, thinks humans are primarily to blame for the river’s increasingly speedy retreat. “I would attribute it to a drastic change in the use of land in the upper watershed — mostly deforestation,” he says. In fact, the Pilcomayo has been contaminated by human activities since mining began at Bolivia’s Cerro Rico de Potosí in 1545, but the rate of land-use change increased greatly over the course of the last century.

Fish and caiman deaths along the Pilcomayo are a somewhat regular occurrence, exacerbated by global warming and the “El Niño” and “La Niña” weather cycles, according to Lucy Aquino, director of the Paraguayan branch of the World Wildlife Fund. Other human interventions such as the construction of small dams and canals also have deleterious impacts downstream, she writes.

WWF-Paraguay feels that despite the volunteers’ best intentions, moving caimans is irresponsible. They say it stresses the animals, interferes with natural mechanisms of population control, and directs attention away from larger threats to Paraguay’s wildlife. “The most important issue for the conservation of the caiman and other wildlife species is the protection of its habitats: water courses, wetlands, and forests,” Aquino writes. “Currently, our country is suffering the severe consequences of land use changes, owing to a great increase in lands devoted to agriculture and livestock production.”

But the blame for the deaths of wildlife along that key 80-mile stretch of river has another, more immediate source.

Water wars

The middle reaches of the Pilcomayo River are important to Argentina and Paraguay for their fisheries and as source of water for communities and ranches along its banks.

Unsurprisingly, the two nations have long jockeyed for control of the river. In 1991, Argentina and Paraguay agreed to dig a twin pair of canals to distribute the waters equally between both countries. In subsequent years, however, the river hasn’t played along, leaving the less-diligent nation’s canal clogged with silt.

Critics allege that the Paraguayan government has not taken adequate care of its canal over the past few years. The entrance is now completely clogged with sediment, making it unlikely that much water would reach Paraguay’s parched caimans even in a year with normal water flow. But the two countries recently announced an agreement that will allow Paraguay to dig a new entrance to the canal, intruding more than a half-mile into Argentinian territory.

As the underlying causes of the drought continue go unaddressed and the Pilcomayo slowly chokes itself with silt, Peña believes the best short-term action is to dig a new canal so water can flow to the Paraguayan side of the Pilcomayo. Moving animals and pumping water are trivial actions compared to the scale of the problem. “You can’t move 100,000 caimans,” he says.

But if water is to reach Paraguay’s desperate wildlife, “the work has to be urgent,” Peña says, “because the rains will start in November.”

Caleb O'Brien
Caleb O’Brien is a journalist based in Paraguay, where he reports on issues surrounding science, social justice, and the environment. His Twitter handle is @caleb_obrien.

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