Differences in water and carbon fluxes along a climate/elevation gradient within a sagebrush ecosystem are quantified, and inferences are made about climate warming using a network of eddy covariance systems. Sites are located within the Reynolds Creek Critical Zone Observatory in southwestern Idaho, USA, with elevations ranging from 1425 to 2111 m, annual precipitation ranging from 290 to 795 mm and annual temperature ranging from 9.1 to 5.4 °C. Annual gross ecosystem production (GEP) for the sites averaged (± uncertainty) 385 ± 6, 549 ± 19, 684 ± 25, and 818 ± 26 gC m⁻² from lowest to highest elevation. Annual net ecosystem production indicated that the sites are carbon sinks with annual uptake typically ranging from 100 ± 10 to 200 ± 30 gC m⁻². Exceptions to this are: the lowest elevation site which was carbon neutral (1 ± 16 gC m⁻²) during a year with a summer rainfall respiration pulse, and the highest elevation site, where carbon uptake dropped to 42 ± 20 gC m⁻² during a heavy snow year. Carbon flux and evapotranspiration (ET) peaked about a month earlier at the lower elevation sites, but with limited precipitation, these sites encountered water stress for much of the growing season. Model simulations suggest that climate warming will likely have a negligible impact on annual ET and GEP at lower elevations, but rather shift ET and GEP earlier in the season and prolong the period of water stress. ET and GEP may increase with climate warming at higher elevations where precipitation is above a threshold of about 450 mm.

在鼠尾草生态系统中，沿着气候/海拔梯度的水和碳通量的差异被量化，并使用涡度协方差系统网络推断气候变暖。这些站点位于美国爱达荷州西南部的雷诺兹克里克临界区天文台内，海拔范围从1425至2111 m，年降水量从290至795 mm，年温度范围从9.1至5.4°C。从最低海拔到最高海拔，这些地点的年平均生态系统总产量（GEP）为385±6、549±19、684±25和818±26 gC m ^-2（±不确定度）。年度生态系统净产量表明，这些地点是碳汇，年度吸收量通常为100±10至200±30 gC m ^-2。例外情况是：最低海拔站点是一年中具有夏季降雨呼吸脉冲的碳中性（1±16 gC m ^-2），最高海拔站点是碳吸收降至42±20 gC m ^-2。在大雪的一年。在较低海拔的地点，碳通量和蒸散量（ET）在一个月前达到峰值，但由于降水有限，这些地点在整个生长季节的大部分时间内都遇到了水分胁迫。模型模拟表明，气候变暖对较低海拔地区的年ET和GEP的影响可能微不足道，但在季节较早时转移ET和GEP并延长了缺水时间。ET和GEP可能会随着气候变暖而升高，在海拔更高的地区，降水量超过约450 mm的阈值。