The effects of gully erosion on the ecology of arid loessial agro-ecosystems, the northern Negev, Israel

Abstract Drylands are exposed to gully erosion expressed by an incised channel surrounded by affected landforms. Although each relevant landform has unique patterns, their connectivity with the gully creates geomorphological interrelations that affect the ecological functioning of the entire area. The Wadi Attir area in the northern semiarid Negev of Israel was chosen to analyze these processes. This area is characterized by an arid climate and intensive agricultural utilization on loess soil, enhancing gully erosion and the formation of gullied landforms. To address biomaterial flows we designed a comprehensive scheme based on the analysis of five separate geomorphological profiles from nearby landforms into their influent gullies. We determined in a historical perspective the floral changes occurring from the area's flat state before intensive utilization, through the formation of gullies to the current state of enhanced gully incision. From the temporal perspective, we established the bi-directional biomaterial flows caused by ecosystem engineers and species invasion into the gully and outward to its surrounding areas.