Hydrological influences on the resilience of Quercus spp. dominated geoecosystems in central Spain

Differences in vegetation cover within a landscape having a similar land use history, can be used to identify differences in recovery following disturbance according to landscape position. The objective of this study was to determine the resilience of oak-dominated communities at different landscape positions in a research area in central Spain as indicated by the relative recovery of Quercus ilex and Q. coccifera, and to relate this to the most important hydrological processes and properties at the slope sections scale. The results indicate that the geoecosystems on slope sections on north-facing slopes are more resilient than those on south-facing slopes. On the more degraded shrubland sites, the higher values of vegetation cover on the lower slope sections indicate the systems on these slope sections to be more resilient than those on the slope sections located higher up the slope. The hydrological factors that could possibly explain differences in vegetation type and cover were found to be distance to water resources at greater depths and incoming radiation controlling evapotranspiration. A conceptual model is presented that links the resilience of these systems to the hydrological conditions. On the basis of the presented model, it is postulated that recovery of the system is determined partly by access to deep water resources. It is suggested that differences in or degree of access to such water resources may cause these comparably looking systems to react differently to degradation and recovery.