Analysis of spatiotemporal variations in forest ecohydrological characteristics is critical for understanding the impacts of climate change on forest ecological functions. In this study, using gross primary productivity (GPP), ecosystem water balance residual (eWBR) and ecosystem water use efficiency (eWUE) as forest ecohydrological function indices, and annual mean precipitation (MAP) and temperature (MAT) as climate indicators, we assessed the impacts of climate change on forest ecosystem in the Lancang-Mekong Region (LMR) during 1992-2016 (baseline) and 2020-2099 under different Representative Concentration Pathway (RCP) climate scenarios. The coupled Carnegie-Ames-Stanford Approaches-Gramineous Crop Growth (CASA-GRAMI) model, the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, and the Hargreaves-Sumani method were employed to estimate GPP, eWBR, evapotranspiration (ET) and eWUE. The main findings are as follows: (i) GPP, eWBR and eWUE showed an increasing trend in the western parts of LMR during 1992-2099, with high values in the central and south-west of Myanmar, west and south of Thailand; (ii) eWBR decreased in most scenarios; while eWUE increases under RCP 2.6 scenario during 2030’s (0.15 gC.kg⁻¹.H₂O.yr⁻¹) and 2050’s (0.13 gC.kg⁻¹.H₂O.yr⁻¹) and slightly increases with a trend of 0.02 gC.kg⁻¹.H₂O.yr⁻¹) under RCP 8.5 scenario during 2050’s; (iii) evergreen and deciduous broadleaved forests exhibit high GPP values, while deciduous broadleaved forest was characterized by lowest eWBR and declining trends in eWUE in future scenarios; (iv) MAT significantly correlated with GPP, eWBR and eWUE (R² >0.70) while MAP indicated a week correlation with GPP and eWUE (R² <0.50) in all the RCPs scenarios, which indicating that water-carbon cycles coupled with hydrothermal conditions may be a key control factor for carbon sequestration in LMR in the context of climate change.

分析森林生态水文特征的时空变化对于理解气候变化对森林生态功能的影响至关重要。本研究以总初级生产力（GPP）、生态系统水分平衡残差（eWBR）和生态系统水分利用效率（eWUE）作为森林生态水文功能指标，年平均降水量（MAP）和气温（MAT）作为气候指标，我们评估了1992-2016年（基线）和2020-2099年在不同代表性浓度路径（RCP）气候情景下气候变化对澜沧江-湄公河地区（LMR）森林生态系统的影响。Carnegie-Ames-Stanford Approaches-Gramineous Crop Growth (CASA-GRAMI) 耦合模型，生态系统服务和权衡综合评估 (InVEST) 模型，和 Hargreaves-Sumani 方法用于估计 GPP、eWBR、蒸散量 (ET) 和 eWUE。主要研究结果如下： (i) 1992-2099 年间，LMR 西部地区的 GPP、eWBR 和 eWUE 呈上升趋势，其中缅甸中部和西南部、泰国西部和南部的值较高；(ii) eWBR 在大多数情况下降低；而 eWUE 在 2030 年的 RCP 2.6 情景下增加（0.15 gC.kg^-1 .H ₂ O.yr ^-1 ) 和 2050 年代 (0.13 gC.kg ^-1 .H ₂ O.yr ^-1 ) 并以 0.02 gC.kg ^-1 .H ₂ O.yr ^-1的趋势略微增加) 在 2050 年代的 RCP 8.5 情景下；(iii) 常绿和落叶阔叶林的 GPP 值很高，而落叶阔叶林的特征是 eWBR 最低，并且在未来情景中 eWUE 呈下降趋势；(iv) MAT 与 GPP、eWBR 和 eWUE 显着相关（R ² > 0.70），而 MAP 表明与 GPP 和 eWUE 存在一周相关性（R ² <0.50) 在所有 RCP 情景中，这表明水-碳循环与热液条件相结合可能是气候变化背景下 LMR 碳固存的关键控制因素。