"In 15 years, paramo area will fall by 75 percent. This will reduce the country's water supply and have a very serious effect on the human population in the Andes - which is where about 75 percent of the country's population lives," he said.

"Colombia's water supply could fall by more than 40 percent in the next 50 years," Castano wrote in a brief report.

Over the past three decades, some 27 percent of high Andean woodland and cloud forests - which grow higher than 10,000 feet (3,000 metres) above sea-level - have been cut down. Paramo area has fallen by 58 percent, he said.

Colombia is one of the five nations with the greatest diversity of plant and animal species in the world, and is home to a greater variety of birds and amphibians than any other country.

But the country's 38-year-old guerrilla war and its huge cocaine industry also pose massive environmental problems. Marxist guerrillas regularly cause oil spills by bombing pipelines, and highly toxic byproducts of cocaine production are dumped in rivers or leach into waterways via the soil.