Long-term effects of climatic and hydrological variation on natural vegetation production and characteristics in a semiarid watershed: The northern Negev, Israel Eli Argaman a, ⁎, Rafael Barth b , Yitzhak Moshe c , Meni Ben-Hur d a Soil Erosion Research Station, Department of Soil Conservation and Drainage, Ministry of Agriculture, Israel b University of Applied Forest Sciences, Rottenburg am Neckar, Germany c Soil Conservation & Forest Unit, KKL southern region, Israel d Institute for Soil, Water and Environmental Sciences, Volcani Center, ARO, Israel HIGHLIGHTS • Perennial vegetation benefits from run- off water, rainfall, and residual water. • Reduced runoff amount affects annual vegetation cover and density in drought years. • Perennial vegetation is less sensitive to drought years than annuals. GRAPHICAL ABSTRACT abstract article info Article history: Received 20 May 2020 Received in revised form 19 July 2020 Accepted 19 July 2020 Available online 24 July 2020 Editor: Manuel Esteban Lucas-Borja Keywords: Annual and perennial vegetation Climate variation Evapotranspiration NDVI Runoff/rainfall Sayeret Shaked Park Soil Surface runoff Climate models for semiarid and arid regions predict increasing average temperatures and reduced amounts of total annual rainfall. This warming and drying trend could have critical, adverse effects on natural vegetation ac- tivity and survival in arid and semiarid zones. We investigated the long-term effects of climate change and surface-runoff variations on the production of natural vegetation in a dry, undisturbed, first-order watershed in the northern Negev, Israel. Vegetation dynamics were estimated by normalized difference vegetation index. Yearly annual vegetation cover varied greatly during the monitoring period (2000-2013), but a significant pos- itive regression was found with annual rainfall and runoff amounts, suggesting a strong relationship between an- nual vegetation dynamics and rainfall amount in a given year. A significant positive linear regression was found between annual ET 0 values and year of measurement (1994–2013), with no corresponding decrease in vegeta- tion condition. Surface runoff in the watershed affected the vegetation's water source. Large variation in annual runoff amounts was observed for 1994–2011, averaging 22.3 and 9 mm for the first (2000–2006) and second (2007–2013) vegetation-monitoring subperiods, respectively. Perennial vegetation was less sensitive to drought years than annual vegetation, likely due to differences in water-source availability. Perennials also benefited from the arrival of nutrients, organic matter, and fertile soil flowing with the surface runoff and eroded soil into their growing area. © 2020 Elsevier B.V. All rights reserved. Science of the Total Environment 747 (2020) 141146 ⁎ Corresponding author. E-mail address: eliar@moag.gov.il (E. Argaman). https://doi.org/10.1016/j.scitotenv.2020.141146 0048-9697/© 2020 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv