Asymmetric responses of resource use efficiency to previous-year precipitation in a semi-arid grassland

1. Intensified inter-annual fluctuations in precipitation could profoundly impact terrestrial ecosystems. However, how changes previous-year precipitation influence current ecosystem functioning (e.g., resource use efficiency) in semi-arid regions remains unclear.

2. In this study, water use efficiency (WUE) and light use efficiency (LUE) were investigated in a multi-year precipitation gradient experiment with seven treatment levels: 20%, 40% and 60% decreases and 20%, 40% and 60% increases in the amount of natural rainfall plus ambient precipitation. Plots receiving 60% less precipitation were representative of extreme dry years whereas the other treatment levels fell within the normal year-to-year range in precipitation change. Measurements made in both the post-treatment period (2013-2015) and the treatment period (2010-2012) provided an opportunity to quantify the legacy effects of precipitation on resource use efficiency (RUE).

3. Sensitivities of LUE to previous-year precipi...