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Bolivia’s second largest lake disappears, due to desertification and contamination

  • Among the causes are excessive sedimentation, mining activities, the diversion of rivers, climate change, and other natural phenomena.
  • One of the signs came on November 2014, when communities on the western shore of the lake noticed millions of dead fish.
  • Despite its seemingly hostile setting, this ecoregion is an important source of biodiversity where 200 animal and plant species lived.
A year after millions of fish were found dead ashore, Lake Poopó is almost completely dried up. December 2015. Photo courtesy of CEPA.

“We’re no longer the men of the lake. If the lake goes, we will too.”

With these words, Simiano Valero expresses his sadness over the disappearance of Poopó Lake, the second largest in Bolivia –after Lake Titicaca— located in Oruro department.

Valero is a leader from the indigenous community of Uru Murato, which has made the eastern side of the lake home for hundreds of years. “For generations, we’ve called ourselves hunters, fishermen, and gatherers. That’s why we call ourselves Men of the Lake, but we’re losing this identity now,” he says.

Other fishing communities, like the Aymara of Untavi, Ayllu Pumasara and various others who live nearby, are currently being affected by the disappearance of the lake and have been forced to search for new ways to make a living.

Under normal conditions, Poopó Lake was larger than 1,000 square miles in size. Now there are only a few marshes left in the salty desert of the high plateau, where some dead animals and abandoned boats can be found.

A lethal combination of natural and human-induced factors destroyed it, including excessive sedimentation, mining activities, the diversion of rivers, climate change, and other natural phenomena. 

For Limbert Sánchez, coordinator of the Center for Ecology and Andean Peoples (Centro de Ecología y Pueblos Andinos, or CEPA), “the lake’s disappearance was only a matter of time.” He recognizes that, despite the multiple warnings, nothing was done to avoid it. One of the signs appeared on November 2014, when communities on the western shore of the lake noticed millions of dead fish. Finally, a year later, on December 2015, Poopó Lake simply disappeared.   

With the loss of this body of water, one of the most important ecosystems of the region is also gone; a national patrimony and a Ramsar site with wetlands of global importance.

Flamingos resisting the low level of Poopó Lake. November 2014. Photo courtesy of CEPA.

A hostile ecosystem 

Poopó Lake is connected to Lake Titicaca through the Desaguadero River, and together they form the Titicaca – Desaguadero – Poopó and Salt Flats water system (TDPS).

With a high altitude climate characterized by limited precipitation and high solar radiation, this region makes up the semi-arid and arid highlands of the Bolivian altiplano.

Despite its apparent hostility, ornithologist Carlos Capriles confirms that this region was an important source of biodiversity, where approximately 200 animal and plant species lived. “You would think there is no life in the altiplano, but it is home to a great quantity of wild fauna and flora,” he says. 

Some studies confirm that Poopó Lake was the habitat for around 131 plant species; 111 of them terrestrial and 20 of them aquatic. Among them, you could find a great diversity of queñua, large reeds, and shrubs. The aquatic plants were typically algae and macrophites.

Among the bird species were a great variety of flamingos. It was also the habitat for ducks, and a stopping point for a number of migratory birds.

With the lake’s disappearance, this delicate balance was broken, and a majority of of these species have lost their natural habitat, so they’ve had to migrate. Others, like fish and amphibians, have simply died.

Millions of fish died on the shores of Lake Poopó. November 2014. Photo courtesy of CEPA.

Causes of the disaster

Sánchez explains that one of the main causes of the lake’s disappearance was excessive sedimentation. “Since it is an endorheic basin, the water can’t exit and the sediments stay there. The lake doesn’t have a slope; it’s practically a flat lake. The depth is of only 50 centimeters, so even when there is a lot of water, it is only about a meter deep.” 

According to Sánchez, thousands of tons of sediments enter the lake every day; they are a byproduct of the desertification and soil erosion around the basin, but they are also toxic waste from the neaby mining operations. 

Mining has been the main economic activity in Oruro since the Colonial era. It is estimated that in the region there are more than 300 mining encampments, most of which dump their untreated waste into the 15 to 23 waterways that end up on the lake, contaminating it with heavy metals like cadmium, zinc, arsenic, and lead. The Poopó Lake Basin Program (Programa de la Cuenca del Lago Poopó), created in 2010 to address its pending disappearance, calculates that 2,000 tons of solid minerals enter the lake on a daily basis.

Another problem which has worsened the lake’s situation is the high deficit and lack of stability of Poopó Lake’s subbasin. 

“The evaporation and evapotranspiration levels considerably exceed rain precipitation, besides the erosion caused by infiltration,” explains Coronado. This has been magnified by global warming factors. Government authorities confirm that in the past 56 years, the lowest temperature in the Poopó Lake basin increased by 2.06 ºC, speeding up water evaporation. According to Sánchez, between four and five millimeters of water a day had been evaporating from the lake. 

Another fundamental cause that contributed to the lake’s disappearance is the diversion of its feeder waterways for mining and agricultural activities. This is what’s happening with the Desaguadero River, estimated to contribute up to 90% of Poopó’s water.

Impacts on climate, indigenous peoples, and their food sources

Experts say that the loss of an important lakeside ecosystem could coincide with a greater variation in the region’s climate, since the lake played an important role in the local bioclimatic regulation. In other words, the cycles of the lake’s life were closely tied to the regional weather patterns, so it is possible that aridity will increase around the lake’s side, as well.

The lack of rainfall in the region and the disappearance of the lake have had grave social consequences for the nearby communities, in particular the vulnerable Uru Murato. They’ve witnessed how the near collapse of their agricultural system, and the absence of fish and migratory birds threaten their food security to the point that it may drive people to migrate, too.

That’s the fear of Doña Alejandrina Álvarez de Vilañeque, from one of the nearby Uru Murato communities. “The lake has dried up completely. How are we going to support our children? There is nothing here. We used to live off of the lake, off the fish. But now there isn’t even rain so we can’t grow food. That’s why one of my brothers has left to look for work, because there is none to be found here,” tells Álvarez de Vilañeque, worryingly.

Boats come into Poopó Lake when it still had some water. Photo courtesy of CEPA.

A gradual recovery?

According to Felipe Coronado, Poopó Lake is a dynamic ecosystem with remarkable environmental resilience; he’s convinced that naturally, it may even gradually recover. However, it could be that this recovery won’t reach its previous conditions.

“It’s good to remember that the volume of water in the lake has been drastically reduced in recent years. The difference now is that due to all the factors, life and biodiversity in the lake are so vulnerable,” he says.

One of the factors that is hardest to control is the local climate –in order for the lake to recover, it would need great quantities of river flow and rainfall. Yet climate change and other phenomena like El Niño are having a great impact on water cycles everywhere, bringing with them drought and high temperatures.

It’s hard to predict what could happen, but Sánchez hopes that if rivers are allowed to flow into Poopó Lake again, and if mining is banned around its basin, the body of water could come back to life within 10 to 20 years. 

But by the same token, if nothing is done, it’s possible that the problem could worsen all along the basin and lead to the degradation of various ecosystems in the area. What’s more, it could give way to conflicts over water use, as is already happening in other parts of Bolivia’s altiplano.

Communities and fishing cooperatives that depend on Poopó Lake. Map courtesy of Miranda-Moricio.