Low water levels threaten river dolphins, fish species, and macaws

NEW YORK (November 12, 2010) – A wide range of wildlife – from pink river dolphins to macaws – are being adversely affected by the worst drought on record gripping the Peruvian Amazon, according to the Wildlife Conservation Society (WCS), which is monitoring Peru’s Samiria River.  

WCS researchers are working with local communities in the 7,700-square-mile Pacaya Samiria National Reserve to observe how changes in water levels are affecting fishing and hunting. So far, the WCS team has noted significant declines in numbers of pink and grey river dolphin, several species of fish, spectacled caiman, and chestnut-fronted macaw.

Following flooding in 2009, the Peruvian Amazon region is now reeling from the lowest water levels since records were started in 1902. The drought is linked to climate change, which scientists say is causing more extreme weather events in the region.

In collaboration with Earthwatch Institute, Operation Wallacea, and the Gordon and Betty Moore Foundation, WCS has studied the impact of climate change on wildlife and people in the Amazon since 2005.

“This ongoing research adds to a growing scientific consensus that no ecosystem is immune from the effects of climate change, whether in the high Arctic or Amazon basin,” said Steve Sanderson, President and CEO of the Wildlife Conservation Society. “Understanding how climate change affects the Amazon will allow conservationists to implement interventions to protect both people and wildlife.”   

The decline in dolphins can be attributed to populations leaving the low waters of the Samiria River for larger channels in the Amazon River where they are forced to compete with other dolphin populations. Like the dolphins, many fish species have left the Samiria River, or have succumbed to the very low oxygen-depleted waters.

Scientists believe low fish populations have in turn caused a decline in spectacled caiman, which are being preyed upon by larger, more aggressive black caiman. Meanwhile, the decrease of the chestnut-fronted macaw appears to be related to the fact that the fruit they depend on is not available during the low water and dry conditions. Researchers use the macaws to indicate the health of the forest in terms of fruit production.  

Many Amazon wildlife species are adapted to large fluctuations in water levels. During the high water months, December to June, the fish expand into the forests and feed on a wide variety of flora and fauna. Mammals retreat to small areas of land, making fishing difficult for local peoples but bushmeat hunting more successful. In the low water months, July to November, the mammals are more spread out, avoiding predators and hunters, while the fish are more concentrated and provide food for the communities.  However, as a result of climate change, the extreme flooding and drought interrupt this delicate cycle.

“This research will continue to help us better understand the impacts of the climate change occurring in the Amazon in hope of finding solutions for the local people that will not deplete the fisheries and bushmeat species,” said Richard Bodmer, Durrell Institute of Conservation and Ecology (DICE) at the University of Kent.

The rainy season begins in November and communities who have been affected will again use travel and supply routes. The valuable knowledge gained by WCS researchers and partners brings them one step closer to comprehending how climate change is altering this area and what can be done to prevent a repeated cycle of drought.

WCS has worked in the Amazon since the early 1970s when it began supporting research and spearheading conservation efforts. Today, WCS researchers are working to reconcile the needs of humans and wildlife. They hope to improve protected area management by setting conservation priorities. The exploration team there recently discovered several new species, including two new primates.

WCS’s New York Aquarium will open the new Conservation Hall exhibit in April, 2011 that will feature many species native to the Amazon’s flooded forests, including dolphin catfish, red-bellied pacu, festivum, and other species. 

Sophie Bass: 212-439-6527; sbass@wcs.org
Stephen Sautner : 718-220-3682; ssautner@wcs.org
Steve Fairchild: 718-220-5189; sfairchild@wcs.org

The Wildlife Conservation Society saves wildlife and wild places worldwide. We do so through science, global conservation, education and the management of the world's largest system of urban wildlife parks, led by the flagship Bronx Zoo. Together these activities change attitudes toward nature and help people imagine wildlife and humans living in harmony. WCS is committed to this mission because it is essential to the integrity of life on Earth.

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