The Effects of Land-Use Change on the Hydrological Properties of Andisols in the Ecuadorian Paramo

The Ecuadorian páramo is characterized by unique soil properties that allow the ground to hold large amounts of water. These páramo grasslands support Andean cities and communities as a source of water for municipal, industrial, and agricultural use. Although recent research has suggested that changes in land use can decrease the amount of water and affect the water-holding capabilities of the soil, the hydrologic effects of different land uses, including burning for livestock grazing and pine planting for carbon credits, are currently under debate. This research tested hypotheses about moisture-related properties of páramo soils under different land uses at two study areas in Ecuador. Bulk density, volumetric water content, water retention, and general physical properties were identified and compared between sites at those study areas. Soil structure differed between pine sites and other sites at both study areas, and moisture consistency differed between pine and other sites at the Mazar Wildlife Reserve. Volumetric water content values were high (mean of 86% at one Mazar site) but the pine sites contained less water by volume than the other sites. Water retention data showed that the surface horizons of all sites at both study areas require more pressure to release moisture than the subsurface horizons. Compared to other sites studied, the pine sites from both study areas have lower gravimetric water contents at saturation through -6.0 kPa. Different burning regimes do not appear to affect soil properties, in-situ moisture content, or water-retention capacity. The introduction of pine plantations in the páramo at both study areas appears to have lowered soil moisture contents and reduced bulk density in the soil profile. This research adds to a growing group of studies that show that changes in land management can affect the hydrological properties of soils