Human impact on the hydrology of the Andean pلramos

This paper analyses the problems involved in the conservation and management of the hydrological system of the South American pلramo. The pلramo consists of a collection of neotropical alpine grassland ecosystems covering the upper region of the northern Andes. They play a key role in the hydrology of the continent. Many of the largest tributaries of the Amazon basin have their headwaters in the pلramo. It is also the major water source for the Andean highlands and a vast area of arid and semi-arid lowlands, where pلramo water is used for domestic, agricultural and industrial consumption, and the generation of hydropower. Recently, the pلramo is increasingly used for intensive cattle grazing, cultivation, and pine planting, among others. These activities, as well as global phenomena such as climate change, severely alter the hydrological regime. A review on the state of knowledge of its hydrology is given in a first part. In a second part, the impact of human activities and climate change on the hydrology of the pلramo is discussed.