Wadi Shita is a medium-sized drainage basin located between the northern and southern Arava, in an extremely hyper-arid region. Since 2015, it has served as a KKL Long-Term Ecological Research (LTER) site, focusing on understanding the links between flash flood dynamics and the resilience of Acacia tree populations using ecological, geomorphological, and hydrological tools.
Annual rainfall averages 41 mm and varies greatly (8–86 mm), with floods occurring an average of 1.5 times per year. Flash floods typically develop when rainfall exceeds 11 mm, though local runoff and partial flows can occur with as little as 3–10 mm.
Flash floods are the sole water source for the Acacia tree population in Wadi Shita, and the high interannual variability in rainfall strongly influences tree condition. Long-term monitoring reveals a significant correlation between rainfall in the previous season and Acacia growth and canopy condition. Trees in the secondary channels show greater sensitivity to fluctuations in precipitation compared to those in the main channel. Their response is driven by increases in soil moisture following flood events (reaching ~45%), and different lithologies retain moisture at varying rates over time, affecting water availability to the trees.
A comprehensive field survey mapping all trees within Wadi Shita found that size and density indicators of both live and dead trees suggest a mostly natural, undisturbed population. Except for localized effects near Road 90, the Acacia community appears healthy and largely unaffected by anthropogenic disturbances.
Given its ecological integrity and largely pristine condition, Wadi Shita can serve as a valuable reference site for future dryland ecosystem studies, afforestation initiatives, and biodiversity conservation efforts.
