# Impact of Shifts in Vegetation Phenology on the Carbon Balance of a Semiarid Sagebrush Ecosystem
## 3 Results
### Influence of Environmental Drivers on Respiration in the Semiarid Ecosystem
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline  & \multicolumn{2}{c}{**H**} & \multicolumn{2}{c}{**ET**} & \multicolumn{2}{c}{**NEE**} & \multicolumn{2}{c}{**GPP**} & \multicolumn{2}{c}{**R\({}_{\text{eco}}\)} & \multicolumn{2}{c}{**R\({}_{\text{soil}}\)**} \\  & **2019** & **2020** & **2019** & **2020** & **2019** & **2020** & **2019** & **2020** & **2019** & **2020** & **2019** & **2020** \\ \hline January & \(-1.0\) & \(-4.0\) & \(6.1\) & \(10.4\) & \(1.1\) & \(2.4\) & \(-11.5\) & \(-11.8\) & \(12.6\) & \(14.2\) & \(10.6\) & \(12.6\) \\ February & \(3.4\) & \(17.0\) & \(5.0\) & \(12.3\) & \(-3.1\) & \(-9.2\) & \(-7.2\) & \(-21.5\) & \(4.1\) & \(12.3\) & \(7.2\) & \(10.5\) \\ March & \(23.1\) & \(39.1\) & \(16.5\) & \(23.7\) & \(-6.7\) & \(-23.8\) & \(-17.4\) & \(-33.7\) & \(10.7\) & \(9.9\) & \(11.7\) & \(12.0\) \\ April & \(44.0\) & \(75.6\) & \(47.3\) & \(17.3\) & \(-28.3\) & \(-7.6\) & \(-57.2\) & \(-18.5\) & \(28.9\) & \(10.9\) & \(20.6\) & \(11.2\) \\ May & \(88.6\) & \(84.5\) & \(31.6\) & \(22.1\) & \(-17.6\) & \(16.1\) & \(-32.3\) & \(-3.5\) & \(14.7\) & \(19.6\) & \(17.7\) & \(14.9\) \\ June & \(92.1\) & \(97.1\) & \(20.7\) & \(23.2\) & \(-9.3\) & \(13.8\) & \(-23.8\) & \(-4.1\) & \(14.5\) & \(17.9\) & \(11.7\) & \(14.8\) \\ July & \(93.7\) & \(113.6\) & \(16.8\) & \(10.9\) & \(-5.1\) & \(13.3\) & \(-19.8\) & \(-0.9\) & \(14.7\) & \(14.1\) & \(11.9\) & \(9.0\) \\ August & \(78.4\) & \(89.8\) & \(17.3\) & \(7.9\) & \(12.7\) & \(7.4\) & \(-12.8\) & \(-2.6\) & \(25.4\) & \(10.0\) & \(20.3\) & \(7.1\) \\ September & \(50.1\) & \(51.3\) & \(13.2\) & \(7.9\) & \(4.0\) & \(3.2\) & \(-9.6\) & \(-4.8\) & \(13.6\) & \(8.0\) & \(12.4\) & \(6.0\) \\ October & \(28.1\) & \(29.3\) & \(8.4\) & \(8.2\) & \(4.5\) & \(7.6\) & \(-4.8\) & \(-1.1\) & \(9.3\) & \(8.7\) & \(11.9\) & \(6.9\) \\ November & \(9.7\) & \(5.2\) & \(5.3\) & \(8.3\) & \(-3.0\) & \(7.6\) & \(-7.5\) & \(-2.2\) & \(4.5\) & \(9.8\) & \(8.4\) & \(14.4\) \\ December & \(0.5\) & \(-0.4\) & \(3.9\) & \(4.5\) & \(3.9\) & \(1.2\) & \(-Figure 9: Daily sums of (**a,b**) ecosystem respiration (Reco) and (**c,d**) soil respiration (Rsoil) against (**a,c**) air temperature (Tair) and (**b,d**) soil temperature (Tsoil) during the two-year study period. Data are divided into four groups according to the daily average soil water content (SWC). The solid lines indicate fitted exponential relations for the divided groups. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & \multicolumn{2}{c}{**Tair**} & \multicolumn{2}{c}{**T\({}_{\text{soil}}\)**} \\  & & **A** & **B** & **A** & **B** \\ \hline \multirow{6}{*}{Reco} & 0–3\% & 0.19 (0.11, 0.27) & 0.03 (0.02, 0.05) & 0.11 (0.06, 0.17) & 0.04 (0.02, 0.05) \\  & 3–6\% & 0.22 (0.18, 0.26) & 0.04 (0.03, 0.05) & 0.22 (0.18, 0.26) & 0.03 (0.02, 0.04) \\ \cline{1-1}  & 6–10\% & 0.21 (0.17, 0.25) & 0.07 (0.06, 0.08) & 0.20 (0.16, 0.24) & 0.05 (0.05, 0.06) \\ \cline{1-1}  & 10–15\% & 0.24 (0.21, 0.26) & 0.09 (0.08, 0.10) & 0.28 (0.24, 0.31) & 0.06 (0.06, 0.07) \\ \cline{1-1}  & 0–3\% & 0.15 (0.09, 0.20) & 0.03 (0.01, 0.04) & 0.08 (0.05, 0.12) & 0.04 (0.02, 0.05) \\ \cline{1-1}  & 3–6\% & 0.28 (0.21, 0.34) & 0.02 (0.01, 0.03) & 0.30 (0.23, 0.38) & 0.01 (0.00, 0.02) \\ \cline{1-1}  & 6–10\% & 0.34 (0.27, 0.42) & 0.04 (0.02, 0.05) & 0.34 (0.26, 0.42) & 0.03 (0.02, 0.04) \\ \cline{1-1}  & 10–15\% & 0.27 (0.22, 0.33) & 0.08 (0.07, 0.10) & 0.30 (0.25, 0.35) & 0.06 (0.05, 0.07) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Coefficients (with 95% confidence bounds) of the fitted exponential relationships between respiration (Reco and Rsoil) and temperature (Tair and Tsoil) in the form of y = Ae\({}^{Bx}\).