Enhancing connectivity index to assess the effects of land use changes in a mediterranean catchment

In the Mediterranean region, the long history of cultivation is associated with significant changes in the original landscape. Agricultural intensification and subsequent land abandonment and reforestation have significantly affected the hydrological behaviour and connectivity patterns of hydrological systems. Thus, information on the spatial distribution of land use/cover is essential for monitoring the runoff response to interpret catchment hydrology. A medium‐sized catchment of the central part of the Ebro Basin (NE Spain), representative of Mediterranean mountain agroecosystems, was selected to assess the effect of land use/cover changes during the last few decades on the hydrological network of the catchment. To this end, a topography‐based index, the ‘index of connectivity’, was applied to assess the effects of land use changes from 1957 to 2010. The sediment connectivity was estimated by using a geomorphometric approach to simulate how connectivity changes due to the different land covers. To improve this index, we used a combination of C‐factor, rugosity index and the novel application of a total aerial biomass equation over pine‐reforested areas as a weighting factor. A high‐resolution (1 × 1 m) digital elevation model was created by filtering and applying a multiscale curvature classification algorithm. The connectivity values show a decrease directly related to ~71% decrease of agricultural land. Understanding landscape patterns, changes and interactions of human activities is essential for land management in Mediterranean agroecosystems.