Respuesta hidro-sedimentaria en dos cuencas mediterráneas representativas afectadas por el cambio global

Abstract

The abandonment of marginal cropland during the second half of the twentieth century led to a process of afforestation in Mediterranean Europe. Meanwhile, the increased availability of biomass has increased the surface area affected by forest fires. With the aim of determining the effect of these processes related with the global change on to the hydro‐sedimentary response, an analysis was conducted in two representative catchments of the Mediterranean environments in the Mallorca Island. In both catchments, hillslopes were terraced and intensely used for agricultural activities until the 1960s decade when was abandoned and then afforested. In addition, one of the catchments has been recurrently perturbed by wildfires. The analysis was carried out by monitoring the flow and suspended‐sediment transport during the 2013-14 hydrological year. The contrasting characteristics of precipitation between both catchments (1,316 mm in front of 517 mm in the burned one), due to its location in different affinity areas of precipitation on the island of Mallorca mainly determined the hydro-sedimentary response. The impact of wildfire was demonstrated because both catchments yielded ≈20 t km 2 of sediment despite the burned catchment accumulated 61% fewer of rainfall. However, these sediment yields are considered very low if compared with Mediterranean environments due to the massive presence of soil conservation structures and carbonate lithology limited runoff generation and sediment transport.