黄河流域作为我国典型的生态脆弱区，由于早期区域经济的发展，使得当地生态环境变得异常脆弱，植被大面积退化。黄河流域内蒙古段位于黄河流域的最北端，属于典型的干旱半干旱地区，大规模的植被恢复工程必然会加剧区域水资源的短缺的状况。在水资源有限的地区进行植被恢复工程虽然有利于退化的生态系统进行恢复，同时也造成了生态系统和人类对水资源潜在的需求冲突。因此黄河流域内蒙古段植被恢复工程是否可持续，以及在变化环境下黄河流域内蒙古段生态水文状况是否可以协同发展，是本文主要解决的问题。鉴于此，本论文以干旱半干旱区黄河流域内蒙古段为研究区，首先基于压力—状态—响应模型对近20年黄河流域内蒙古段生态环境压力进行分析；其次基于改进后的PT-JPL模型与机理—数据协同驱动模型，模拟长时序、区域尺度蒸散发数据及其各组分数据与生态系统总初级生产力数据，以准确掌握黄河流域内蒙古段生态系统质量和可持续发展能力；最后针对黄河流域内蒙古段典型的生态系统类型，分析不同生态系统类型生态水文协同机制。本文主要的研究结论如下：

（1）1999年起黄河流域内蒙古段实施了生态恢复工程，但近几年区域生态环境压力依旧处于逐渐升高的状态。研究区生态环境压力极显著的区域主要位于巴彦淖尔市，占研究区总面积的24.16%；生态环境压力显著的区域主要位于鄂尔多斯市与呼和浩特市，占研究区总面积的57.19%。人口密度、煤炭开采量、人均GDP、火灾事故、农药施用量、化肥施用量等造成黄河流域内蒙古段生态环境压力增大和具有空间异质性的主要因素。

（2）1982~2020年黄河流域内蒙古段实际蒸散发呈逐年上升的趋势，变化速率为0.519 mm/yr。其中植被蒸腾速率呈明显增加的趋势，变化率为0.858 mm/yr。生态恢复工程明显增大了研究区植被的蒸腾能力，近20年来植被蒸腾增加了18.551 mm，增速提高了42%。土壤蒸发有明显的下降趋势，变化速率为-0.327 mm/yr，多年平均土壤蒸发降低了约10 mm。从空间分布来看，位于黄河流域内蒙古段东部与南部地区的年均蒸散发量较高，基本可以维持在300~400 mm。鄂尔多斯是西南部地区的蒸散发量最低，基本在100 mm及以下。

（3）机理—数据协同驱动模型模拟得到的GPP数据与GOSIF-GPP数据验证的R²达到0.864，证明该模型可以有效的模拟长时间、高精度、大区域的GPP数据。模拟结果表明，近40年来植被总初级生产力呈整体缓慢上升的趋势，上升速率为0.827 gC/m²·yr，实施生态恢复工程之后GPP上升的速率达到2.146 gC/m²·yr，是1999年之前的8倍，年变幅在180~278 gC/m²·yr之间，多年平均GPP为233.768 gC/m²·yr，较之前增加了12.177 gC/m²·yr。

（4）在当前气候条件下，黄河流域内蒙古段允许的植被总初级生产力阈值为240.01~263.95 gC/m²·yr，但是2018年与2019年区域植被总初级生产力已达到了237.54 gC/m²·yr 与238.63 gC/m²·yr，接近了区域植被生产力的阈值，持续的植被恢复将不可避免地使可供人类使用的水量减少到需水量以下，使得植被恢复具有不可持续性。

（5）典型农业生产区—河套灌区作物水分胁迫程度较大，主要通过引水工程进行灌溉，多年年均调水接近45亿m³，且地下水位埋深在2013年之后达到了3.0 m以上，未来区域可供水量将成为干扰区域生态水文协同发展的主要因素。典型荒漠草原区—十大孔兑区植被多为覆盖度较低的草地、植被质量不高，且区域水土流域面积逐年增大，风蚀与水蚀导致的水土流失是造成该区域生态水文不能协同发展的主要原因。典型林草恢复区—大黑河流域、浑河流域区域径流呈明显下降的趋势，且多年平均总初级生产力已达到区域的最大值，区域水分胁迫压力较大。同时，浑河流域由于种植树木单一，林分结构不稳定，已有部分区域形成干梢、枯死等大面积的退化林分是造成该区域未来生态水文不能协同发展的主要原因。

The Yellow River Basin, as a typical ecologically fragile area in China, has experienced significant degradation of local ecosystems and widespread vegetation deterioration due to early regional economic development. The Inner Mongolia segment of the Yellow River Basin, located at the northernmost part of the basin, falls within a typical arid to semi-arid region. Large-scale vegetation restoration projects are bound to exacerbate the scarcity of water resources in the region. Although vegetation restoration projects in water-limited areas are conducive to the recovery of degraded ecosystems, they also give rise to potential conflicts between ecosystem and human demands for water resources. Therefore, the sustainability of vegetation restoration projects in the Inner Mongolia segment of the Yellow River Basin, as well as the synergistic development of eco-hydrological conditions in this region under changing environments, constitute the main focus of this study. In view of this, this paper takes the Inner Mongolia segment of the Yellow River Basin in the arid to semi-arid region as the research area. Firstly, the ecological environmental pressures in the Inner Mongolia segment of the Yellow River Basin over the past 20 years are analyzed based on the Pressure-State-Response model. Secondly, utilizing an improved PT-JPL model and a mechanism-data synergy-driven model, long-term, regional-scale evapotranspiration data and its components data are simulated along with the data on total primary productivity of ecosystems, aiming to accurately grasp the ecosystem quality and sustainable development capability of the Inner Mongolia segment of the Yellow River Basin. Finally, focusing on typical ecosystem types in the Inner Mongolia segment of the Yellow River Basin, the ecological-hydrological synergy mechanisms of different ecosystem types are analyzed. The main research conclusions of this paper are as follows:

Despite the implementation of ecological restoration projects in the Inner Mongolia reach of the Yellow River Basin since 1999, regional ecological environmental pressure remains in a state of gradual increase. The areas with extremely significant ecological environmental pressure in the study area are mainly located in Bayannur City, accounting for 24.16% of the total area of the study area; areas with significantly notable ecological environmental pressure are primarily located in Ordos City and Hohhot City, covering 57.19% of the total area of the study area. Factors such as population density, coal mining volume, per capita GDP, incidence of fire accidents, pesticide application, and fertilizer usage are the main contributors to the increased ecological environmental pressure and spatial heterogeneity in the Inner Mongolia reach of the Yellow River Basin.

From 1982 to 2020, the actual evapotranspiration in the Inner Mongolia section of the Yellow River Basin showed a year-on-year increasing trend, with a change rate of 0.519 mm/yr. Specifically, the vegetation transpiration rate exhibited a significant increasing trend, with a change rate of 0.858 mm/yr. The ecological restoration projects notably enhanced the transpiration capacity of vegetation in the study area, with vegetation transpiration increasing by 18.551 mm in the past 20 years, representing a 42% increase in growth rate. Soil evaporation showed a distinct decrease, with a change trend of -0.327 mm/yr, resulting in an average reduction of soil evaporation by approximately 10 mm over multiple years. Spatially, the eastern and southern regions of the Inner Mongolia section of the Yellow River Basin exhibited higher annual evapotranspiration, typically maintaining levels between 300 to 400 mm. Ordos experienced the lowest evapotranspiration in the southwestern region, generally remaining at 100 mm or below.

The Mechanism-Data Collaborative Driving Model simulated Gross Primary Productivity (GPP) data, which achieved an R-squared value of 0.864 when validated against GOSIF-GPP data. This demonstrates the model's effectiveness in simulating long-term, high-precision, and large-scale GPP data. Simulation results indicate that over the past 40 years, there has been a gradual increase in total vegetation primary productivity, with a growth rate of 0.827 gC/m²·yr. Following the implementation of ecological restoration projects, the rate of GPP increase reached 2.146 gC/m²·yr, which is 8 times higher than before 1999. The annual variability in GPP ranged between 180-278 gC/m²·yr, with a multi-year average GPP of 233.768 gC/m²·yr, representing an increase of 12.177 gC/m²·yr compared to previous levels.

Under current climatic conditions, the allowable threshold for total vegetation primary productivity in the Inner Mongolia section of the Yellow River Basin ranges from 240.01 to 263.95 gC/m²·yr. However, in 2018 and 2019, the regional total vegetation primary productivity reached 237.54 gC/m²·yr and 238.63 gC/m²·yr, respectively, approaching the threshold of regional vegetation productivity. Continuous vegetation restoration will inevitably reduce the available water resources to below the required amount, making vegetation restoration unsustainable.

In the typical agricultural production area, the Hetao Irrigation District, crops face significant water stress mainly mitigated through irrigation projects, with an annual average water diversion close to 4.5 billion cubic meters. Since 2013, groundwater levels have dropped below 3.0 meters. Future water availability in the region will become a major factor affecting the coordinated development of ecological hydrology in the area. In the typical desert steppe area, ten tributaries region, vegetation mainly consists of low-cover grasslands with poor vegetation quality. Additionally, the area of soil erosion has been increasing annually, with wind and water erosion leading to significant soil loss. These factors contribute to the inability of ecological hydrology to develop cohesively in the region. In the typical forest and grassland restoration area, including the Dahei River Basin and the Hun River Basin, there is a noticeable downward trend in regional runoff, and the multi-year average total primary productivity has reached its maximum value. Consequently, the region faces significant water stress pressure. Additionally, due to the monoculture of trees in the Hun River Basin and unstable forest structure, some areas have experienced extensive degradation, including large-scale deforestation and dieback.