The effects of afforestation and cultivation on water yield in the Andean páramo

Abstract

Over the last decades, the Andean highlands of Ecuador have been characterised by intense afforestation efforts, in order to increase the economic return of less viable agricultural areas, reduce erosion and, more recently, to sequestrate atmospheric carbon. Afforestation with Pinus species is widespread in the high altitudinal grasslands known as páramos. The impact of Pinus patula afforestation on the water yield is studied and compared to the more common practice of intensive grazing and potato cultivation in four microcatchments in the Paute river basin in south Ecuador. Two catchments are covered with natural grassland vegetation, one is converted to pine forest, and one is drained, partly intensively grazed, and partly cultivated with potatoes. The results indicate that afforestation with P. patula reduces the water yield by about 50%, or an average of 242 mm year À1 . The water yield of the cultivated catchment is very similar to that of the natural catchments, but analysis of the flow duration curves suggests a faster response and a loss of base flow. These effects may have important implications for a sustainable management of the páramo ecosystem, given that the páramo is the major water supplier for the Andean highlands. #

Interactions between payments for hydrologic services, landowner decisions, and ecohydrological consequences: synergies and disconnection in the cloud forest zone of central Veracruz, Mexico

“…In addition to the relatively sparse canopy of mature P. patula trees, the relatively low ET in the mature P. patula stand was in part attributable to previous selective logging activities that had reduced stand basal area. Thus, from a purely hydrologic services standpoint, planting of native pine trees on degraded pasture areas at this site did not produce a dramatic increase in ET or reductions in water yield, in contrast to findings reported elsewhere (Farley et al 2005, Buytaert et al 2007, Huber et al 2008, Wang et al 2008, Little et al 2009). Notwithstanding, the higher infiltration rates recorded for pine stands versus grazed pasture suggests a positive impact of pine reforestation on soil hydraulic properties, which should enhance subsurface recharge and therefore baseflow as long as ET losses remain comparable (Muñoz-Villers et al 2015).…”

Land‐Use and Land‐Cover Change in the Páramo of South‐Central Ecuador, 1979–2014

“…The wetlands, which mainly comprise small lakes or seasonally and permanently saturated terrain, vary considerably in area (Table 2). Although they are important in generating runoff [60], the wetlands were not mapped as their area is relatively small compared to páramo and native forest, and the climatological and hydrological data required to explain their fluctuations were not available to the researchers at the time the research was carried out. Table 3.…”

Rapid decline of snow and ice in the tropical Andes – Impacts, uncertainties and challenges ahead

“…Wagnon et al (1999) Characterizing evapotranspiration from non-glacierized surfaces has equally been a challenge and studies are limited due to lack of meteorological data. Buytaert et al (2007) and Córdova et al (2015), suggested values between 1.8 and 2.0 mm d A reduction of glacier cover will therefore reduce streamflow, because of increased evapotranspiration from newly ice-free areas (Frans et al, 2015). However, this effect tends to reduce quickly with catchment size and distance from the glacier terminus.…”