Many traditional models that predict plant–groundwater use based on groundwater level variations, such as the White method, make various simplifying assumptions. For example, these models often neglect the role of plant hydraulic redistribution, a process that can contribute up to 80% of transpiration. Thus, this work aims to avoid such assumptions and subsequently explore the dynamic interactions between groundwater levels and phreatophytic vegetation, including plant nocturnal transpiration, hydraulic redistribution, and response to atmospheric conditions, in shallow-groundwater ecosystems using Loblolly pine (Pinus taeda) as a model species. The model scenarios are formulated using a stomatal-optimization model coupled to the soil–plant–atmosphere continuum. Flow through soil and groundwater are described using the Richards equation and a linear reservoir approximation, respectively, with groundwater in contact with an external water body of fixed elevation. Results show that nocturnal transpiration, mediated by plant residual conductance, and hydraulic redistribution, are able to reduce groundwater levels at night and alter the groundwater recharge rate. Projected atmospheric conditions of increased carbon dioxide and elevated temperature have opposing effects on groundwater levels, which tend to roughly cancel each other under a projected scenario of 500 ppm carbon dioxide and 1.5 oC warming. Such detailed modeling can be used to provide further insights into coupled interactions between vegetation, climate and groundwater levels in phreatophyte-dominated ecosystems.

中文翻译：

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地下水位与水生植物流量之间的动态相互作用


许多基于地下水位变化预测植物-地下水利用的传统模型（例如 White 方法）都做出了各种简化假设。例如，这些模型经常忽视植物水力再分配的作用，这一过程可以贡献高达 80% 的蒸腾作用。因此，这项工作旨在避免此类假设，并随后以火炬松 （Pinus taeda） 为模式物种，在浅层地下水生态系统中探索地下水位与水生植被之间的动态相互作用，包括植物夜间蒸腾、水力再分配和对大气条件的响应。模型情景是使用与土壤-植物-大气连续体耦合的气孔优化模型来制定的。地下水与固定高程的外部水体接触，分别使用 Richards 方程和线性储层近似来描述流经土壤和地下水的流量。结果表明，由植物残余电导和水力再分配介导的夜间蒸腾能够降低夜间地下水位并改变地下水补给速率。二氧化碳增加和温度升高的预估大气条件对地下水位产生相反的影响，在二氧化碳浓度为 500 ppm 和变暖 1.5 oC 的预估情景下，这两种影响往往会大致相互抵消。这种详细的建模可用于进一步了解以植物为主的生态系统中植被、气候和地下水位之间的耦合相互作用。