* 1 Productivity of dryland communities is often co-limited by water and nutrients. Since atmospheric CO2 enrichment induces water savings by plants, elevated CO2 and nutrients could interact to reduce growth limitation, irrespective of the direct influence of CO2 on photosynthesis. We studied CO2 effects in model communities from the semi-arid Negev of Israel with 17 mostly annual C3 species at three CO2 concentrations and three nutrient treatments. * 2 Community biomass increased at elevated (440 and 600 �L L?1) compared to pre-industrial CO2 (280 �L L?1) by 34% on average in the low-nutrient control, by 45% in the high P and by 50% in the high NPK treatment. Less evapotranspiration at elevated CO2 increased soil water content by [...]
