**3. Study area**

The scope of study territorially includes the Huarán basin with the towns of Canchacancha (13° 14<sup>0</sup> 34.9" S and 72° 01<sup>0</sup> 13.4" W) located at 4548 m.a.s.l. and Contorkayku (13° 16<sup>0</sup> 03.7" S and 72° 01<sup>0</sup> 02" W) at 4310 m.a.s.l. between the limits of the provinces of Calca and Urubamba; the Wayoqhari-Yanacocha basin, locality K0 elloq'ocha (13° 16<sup>0</sup> 34.3" S and 72° 03<sup>0</sup> 09.7" W) at 4343 m.a.s.l. belonging to the district of Huayllabamba, and the Manthanay basin, locality Manthanay (13° 12<sup>0</sup> 08.4" S and 72° 08<sup>0</sup> 42.8" W) at 4778 m.a.s.l. located in the heights of the Yanahuara Valley in the province of Urubamba, Peru.

### **3.1 Natural life zones**

## *3.1.1 Subtropical sub-Andean very humid páramo (pmh-SaS)*

This life zone also known as wet puna in the South of Peru; it presents a total annual precipitation that varies between 640 mm and 800 mm and an average annual biotemperature between 6°C and 3°C. It is a cold climate zone. According to the Holdridge Diagram, this life zone has potential evapotranspiration that varies between a quarter (0.25) and a half (0.5) of the average total precipitation per year. Life includes the dense forests of *Polylepis*, located from 3900 to 4500 m. of altitude, with a thick forest of shrubs and herbs as well as an abundant presence of mossy mattresses between the rocks of the forest floor and the trunks of the trees, which is due to the high humidity prevailing inside [14].

### *3.1.2 Subtropical sub-Andean pluvial tundra (tp-SaS)*

Life zone includes the ecological system of the cold Andean desert of the humid puna. It is located on the very humid-subalpine and subtropical paramo and below the Nival floor. It has a cold climate, the soils are mostly rocky due to erosion of the old glacial mountains, in whose cracks there is scattered and discontinuous vegetation conditioned and adapted to the daily alternation of ice-thaw and where *Polylepis subsericans* ascends through the tongues of cryoturbated soils in a clear process of colonization toward the rocky crests caused by glacial erosion. Altitudinally, they are above 4500 m [14].
