From desert to Mediterranean rangelands: will increasing drought and inter-annual rainfall variability affect herbaceous annual primary productivity?

Climate change is predicted to alter the rainfall regime in the Eastern Mediterranean Basin: total annual rainfall will decrease, while seasonal and inter-annual variation in rainfall will increase. Such changes in the rainfall regime could potentially lead to large-scale changes in aboveground net primary productivity (ANPP) in the region.We conducted a data-driven evaluation of herbaceous ANPP along an entire regional rainfall gradient, from desert (90 mm MAR [Mean Annual Rainfall]) to Mesic-Mediterranean (780 mmMAR) ecosystems, using the largest database ever collated for herbaceous ANPP in Israel, with the aim of predicting consequences of climate change for rangeland productivity. This research revealed that herbaceous ANPP increases with increasing rainfall along the gradient, but strong dependence on rainfall was only apparent within dry sites. Rain Use Efficiency peaks at mid-gradient in Mediterranean sites without woody Climatic Change DOI 10.1007/s10584-013-0758-8 Electronic supplementary material The online version of this article (doi:10.1007/s10584-013-0758-8) contains supplementary material, which is available to authorized users. C. Golodets (*) :M. Sternberg Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel e-mail: [email protected] J. Kigel Institute for Plant Sciences and Genetics, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot Campus, Rehovot 76100, Israel B. Boeken Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Sede Boqer 84990, Israel Z. Henkin Agricultural Research Organization, Newe Ya’ar Research Center, Ramat Yishai 30095, Israel N. G. Seligman Northern Research and Development, Galilee Technology Center, Kiryat Shemona 11016, Israel E. D. Ungar Department of Agronomy and Natural Resources, Institute for Plant Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel vegetation (560 and 610mmMAR). Inter-annual coefficients of variation in rainfall and herbaceous ANPP decrease along the rainfall gradient up to ca. 500mmMAR. Climate change is more likely to affect herbaceousANPP of rangelands in the arid end of the rainfall gradient, requiring adaptation of rangeland management, while ANPP of rangelands in more mesic ecosystems is less responsive to variation in rainfall. We conclude that herbaceous ANPP in most Mediterranean rangelands is less vulnerable to climate change than generally predicted.