May 6

The boto, also known as the pink river dolphin, has started to recover from record droughts in the Amazon.  

The 2010 drought saw the Amazon River at its lowest levels for half a century, with severe impacts on the wildlife. But now a team of conservationists has found that many species show signs of recovery more quickly than expected.

Photo of botos playing with floating Macucu seed

Botos playing with floating Macucu seed

Research is currently being carried out in the Pacaya Samiria National Reserve in the upper reaches of the Amazon, Peru. It falls within one of the three regions worst affected by the 2010 drought. 

In this remote area of the Peruvian Amazon, the number of botos dropped by nearly half in October 2010 compared with 2009, as the level of the Samiria River, a major tributary of the Amazon, fell. Along a 12 mile stretch of the river, the boto population of 250 declined to about 140.

Photo of boto emerging from water

Boto emerging from water

Strong recovery 

However, according to surveys conducted in March, boto numbers are now 10% higher than they were before the 2010 drought. 

This is a very good sign and suggests that the Samiria River is recovering from the drought of 2010,” says Dr Richard Bodmer from the University of Kent, who has published extensively on the area for the last 25 years. 

Other species appear to have recovered well too, including the tucuxi dolphin, which also inhabits freshwater rivers in the Amazon and has increased by 30% from March 2010. Chestnut-fronted macaws, which had apparently left Pacaya Samiria or died in significant numbers during the 2010 drought, have also recovered strongly now that the rivers are back to high levels. 

However, the spectacled caiman, a smaller relation of the crocodile, continues to be a cause for concern. Its numbers in the first 3 months of 2011 were still 60% lower than in 2010.

Photo of young spectacled caiman at the water's edge

Young spectacled caiman at the water's edge

Vulnerability to rising temperatures 

Last year’s drought in the Amazon raises concerns about the Amazon’s vulnerability to rising global temperatures. Researchers recently confirmed that the 2010 Amazon drought was more widespread than the one in 2005, which was regarded at the time as “a once in a century event“. 

The two droughts have been associated with warmer waters in the North Atlantic off the Brazilian coast, caused by warmer global temperatures. Some computer models suggest that the Amazon could suffer more droughts as the planet warms. 

We cannot ignore these larger global events, which are impacting the local ecosystems and people here, and testing the resilience of the wildlife,” added Dr Bodmer.

At the moment, these impacts worry me, but they are not as dramatic as they could be. But if these weather extremes continue in the future, this will change.” 

Read the fully story at the BBC – ‘Pink dolphins bounce back from 2010 Amazon drought’ 

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Alex Royan, ARKive Species Text Author