Long-term effects of anthropogenic activities on semi-arid sand dunes

Semi-arid and and sand dunes are considered sensitive ecosystems which may be affected by external disturbances. As many other semi-arid and and ecosystems, their recovery ability is in the focus of many studies, whose consequences are important not only for the field of ecology but also for conservation and human welfare. I used aerial photograph analysis to study the effect of anthropogenic disturbance on dunesystem along the border between Israel and Egypt. The political changes in the border status over the last 40 years created a 'natural' experiment in the area, which enabled me to compare similar dune ecosystems under various anthropogenic regimes. The findings revealed a significant difference in recovery rate between the two border sides, and along the dune topography, which correspond with differences in human management (i.e. grazing and wood gathering). Nevertheless, a recovery process was detected in all parts of the dune ecosystem, even following long years of heavy anthropogenic use. The results of this study contribute to the ongoing debate about desertification processes, and indicate that some arid ecosystems may exhibit high resilience in the face of long-term exploitation. (C) 2008 Elsevier Ltd. All rights reserved.