Major rivers across the Amazon region are experiencing an alarming decline in water levels because of the effects of El Niño, File Photo by Paolo Aguilar/EPA

Aug. 27 (UPI) -- Major rivers across the Amazon region are experiencing an alarming decline in water levels because of the effects of El Niño, threatening to isolate hundreds of riverside communities and disrupt river transportation weeks earlier than expected.

Across the region, the water crisis is exposing the vulnerability of the Amazon basin, prompting Peru and Brazil to implement contingency measures.

Peru's National Service of Meteorology and Hydrology, known as Senamhi, reported Thursday that water levels in the main Amazon rivers in the Loreto region are declining progressively and rapidly.

The climate anomaly, intensified by El Niño, has prompted authorities to closely monitor major river basins, including the Amazon, Marañón, Ucayali and Huallaga, where water levels are well below historical averages for this time of year.