Natural springs, recognized as biodiversity hotspots and keystone ecosystems, exert positive ecological influences beyond their immediate extent, particularly in dryland environments. The water ...feeding these springs, largely governed by natural climatic conditions, is susceptible to anthropogenic impacts. The objective of this study was to determine the factors that cause fluctuations in water availability to springs of the hyper-arid Arava Valley (Israel/Jordan). Using the Standard Precipitation Index, we statistically classified the historical record of yearly rainfall for the past four decades into clusters of dry and wet sub-periods. We assessed changes in vegetation cover around the springs using the Landsat-derived Normalized Difference Vegetation Index (NDVI) for each sub-period. To assess the anthropogenic effects, we examined the correlations between vegetation cover, water extraction from the aquifer, and the status of adjacent agricultural plots that share a hydrological connection with the springs. Our findings revealed fluctuations between wet and dry sub-periods over the last four decades. We observed high responsiveness of vegetation cover around the springs to these fluctuating sub-periods. Of the 25 studied springs, 12 were directly influenced by anthropogenic factors—7 experienced a decline in vegetation, which we attributed to water extraction from the aquifers, while vegetation increase in 5 springs was attributed to water seepage from agricultural areas upstream. In conclusion, addressing vital habitats such as natural springs in arid drylands requires a holistic approach that integrates long-term climatic, ecological, and anthropogenic observations.
Attributing the extent of changes in vegetation cover which are the result of human actions or of climate variability is challenging. The Negev Desert, bordered by two countries and the Palestinian ...Authority and crossing three climate zones, provides a natural laboratory for unveiling the impact of land practices on natural vegetation. Desert vegetation on both sides of the border was traditionally subject to herds grazing and bush gathering, but in recent decades; grazing policy, military training areas, and nature protection have excluded traditional uses. We used remotely sensed derived proxies of vegetation (the Normalized Difference Vegetation Index) and surface albedo from satellite images inside and outside of the large exclosures to estimate the anthropogenic impact on vegetation cover in the past four decades, and ultimately isolate the effect of traditional land uses on vegetation cover. Our results showed that the cross-border differences in land use led to a significant impact on vegetation cover outside the exclosed areas. These cross-border differences were more pronounced in the semi-arid - arid climate regions and decreased in the hyper-arid climate region. Exclosures provide a natural experiment which enables us the testing of the factors driving changes in natural vegetation.
•We analyzed the impact of exclosures (borders and army bases) on desert vegetation.•We quantified proxies of vegetation cover using time series of MODIS and Landsat.•Cross-fence differences in traditional land use significantly impacted vegetation.•Cross-fence differences decreased in the hyper-arid climate region.
