Groundwater-dependent ecosystems and species (GDEs) are found throughout watersheds at locations of groundwater discharge, yet not all GDEs are the same, nor are the groundwater systems supporting them. Groundwater moves along a variety of flow paths of different lengths and with different contributing areas, ranging from shorter local flow paths with low discharge and large seasonal variability to streams, springs and wetlands to longer regional flow paths with potentially larger discharge and low seasonal variability, commonly at low basin elevations. How does this variation in physical hydrology affect the type and distribution of GDEs? Using data on hypsographic position, groundwater-dependent species distributions, groundwater pumping and streamflow from Oregon, USA, we provide a conceptual model and initial supporting evidence demonstrating that spatial variation in groundwater flow path scales, illustrated using basin hypsography, is a driver of non-random distribution of GDEs across watersheds. Further, we posit that the spatial variation in primary stressors to groundwater (e.g. pumping and climate change) will differentially affect GDEs depending on their hypsographic position. Furthermore, because of their use for irrigation and municipal water supply, regional groundwater systems and associated species are more likely to be studied and receive regulatory protection. Our initial data point to a disproportionate focus on larger discharge, lower elevation GDEs, which leads to a bias in our understanding of the full suite of biodiversity associated with groundwater discharge as well as their stressors and potential mechanisms for protection.

中文翻译：

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地下水、生物多样性和水流系统规模的作用

地下水依赖型生态系统和物种 (GDE) 遍布整个流域的地下水排放位置，但并非所有 GDE 都相同，支持它们的地下水系统也不同。地下水沿着各种不同长度和不同贡献区域的流动路径移动，从较短的局部流动路径，低流量和较大的季节性变化到溪流，泉水和湿地，到较长的区域流动路径，可能有更大的流量和低季节性变化，通常在低盆地海拔。物理水文的这种变化如何影响 GDE 的类型和分布？使用来自美国俄勒冈州的海平面位置、依赖地下水的物种分布、地下水抽取和河流流量的数据，我们提供了一个概念模型和初步支持证据，证明地下水流动路径尺度的空间变化（使用盆地高度图说明）是跨流域 GDE 非随机分布的驱动因素。此外，我们假设地下水的主要压力源（例如抽水和气候变化）的空间变化将根据 GDE 的高度位置不同影响 GDE。此外，由于它们用于灌溉和市政供水，区域地下水系统和相关物种更有可能被研究并获得监管保护。我们的初始数据表明，人们不成比例地关注较大流量、较低海拔的 GDE，