Vegetation-rock mosaics maximize water services in high-mountain areas in central Argentina
In systems with seasonal rainfall, the dry season water yield (streamflow relative to the catchment area) depends on the antecedent rainfall as well as on infiltration and evapotranspiration, processes which, in turn, are affected by the landscape characteristics. Our objective was to evaluate the effect of different landscape variables on water yield and the recession rate (rate of decrease in streamflow) during the dry season in high-mountain catchments in central Argentina. We selected 33 catchments 9-61 ha and, during the last part of the 2017 dry season, we measured streamflow in the catchment output points once a week, for seven consecutive weeks. For each catchment, we calculated the average water yield (mm/month) and a recession index (dimensionless) as the normalized difference between the water yield of the latest and the first dates. The landscapes extensively occupied by a tussock grassland-rock mosaic, with intermediate steepness and roughness, had the highest water yields (>5 mm/month). Conversely, water yield was lower either in smooth and vegetated landscapes as in extremely rugged, steep and rocky landscapes. On the other hand, recession rate was slower in the most rugged landscapes and abrupt in the smooth landscapes. Possibly, in smooth and vegetated landscapes, high amounts of water are lost through evapotranspiration, while in the most rugged landscapes, large amounts of water are lost by runoff after rainfall. Intermediate landscapes covered by a mosaic of rock and vegetation would be those that optimize water storage, minimizing losses through evapotranspiration. Therefore, to sustain current water yields, these types of landscape must be conserved, preventing soil erosion, leading to an increase in rocky areas.
| Main Authors: | , , , , , , , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Asociación Argentina de Ecología
2023
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| Online Access: | https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/2127 |
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