Sensitivity of productivity to precipitation amount and pattern varies by topographic position in a semiarid grassland

Aboveground net primary productivity (ANPP) in grasslands is an important integrator of terrestrial ecosystem function, a key driver global biogeochemical cycles, and critical source food for wild domesticated herbivores. ANPP exhibits high spatial temporal variability, driven by suite factors including precipitation amount pattern, biotic abiotic legacies, topographic heterogeneity. Global climate models forecast altered hydrological cycle due to change, higher variability more extreme events, which may further increase spatiotemporal ANPP. Therefore, it essential understand the sensitivity this central function various metrics, positions better inform sustainable grassland management. In study, we analyzed long-term (36-yr) data collected across sequence semiarid shortgrass steppe North America examine patterns drivers We observed that (1) varied substantially position, with greater divergence during years production, (2) was temporally (16-fold maximum difference years) than spatially (4-fold positions), (3) warm-season perennial grasses were dominant plant functional type all strongly influenced total dynamics, (4) had strong sensitivities current year pattern type, as well weaker legacies. Overall, lowest position highest precipitation, likely resource availability via downhill movement water nutrients large rainfall events. These results suggest primarily combined effects year, governing these responses.