Abstract Relationships between groundwater levels, surface water levels, and the distribution and habitat use of two cyprinid fishes, Least Chub (Iotichthys phlegethontis) and Utah Chub (Gila atraria), were examined at a spring complex in the Snake Valley of the Great Basin, USA to test the hypothesis that the distribution and structure of fish populations in the spring complex is regulated by the influence of shallow groundwater levels on the depth and distribution of surface water and the availability of suitable spawning and juvenile habitat. Groundwater levels explained 97% of the temporal variation in surface water levels measured at 47 monitoring points and exhibited annual cycles linked to evapotranspiration rates. Least Chub and Utah Chub migrated from springs to ponds, which were used as spawning and juvenile habitat, when groundwater and surface water levels were high during the early spring, but became concentrated in deep springs as ponds receded during the late summer and early fall. Populations of both species became increasingly fragmented as groundwater and surface water levels declined. Specific differences in the relative abundances and body sizes of juvenile Least Chub inhabiting different seasonally isolated regions of the spring complex persisted over multiple years, suggesting that juvenile growth rates and survival were influenced by connectivity of core spring habitats to seasonally deep ponds. The nature of the relationship between groundwater and surface water levels indicated that long-term declines in shallow groundwater levels of ≥ 40 cm would eliminate most of the spawning and juvenile habitat in the spring complex.

中文翻译：

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地下水波动对沙漠泉复合体中两种鲤科鱼类分布及种群结构的影响

摘要 在大盆地蛇谷的一个泉水群中检查了地下水位、地表水位以及两种鲤科鱼类 Least Chub (Iotichthys phlegethontis) 和 Utah Chub (Gila atraria) 的分布和栖息地利用之间的关系，美国测试的假设是，春季复合体中鱼类种群的分布和结构受浅层地下水位对地表水深度和分布的影响以及合适产卵和幼鱼栖息地的可用性的影响。地下水位解释了在 47 个监测点测量的地表水位时间变化的 97%，并表现出与蒸散率相关的年度循环。Least Chub 和 Utah Chub 从泉水迁移到池塘，用作产卵和幼鱼栖息地，当早春地下水和地表水位高时，但随着夏末和初秋池塘的消退，地下水和地表水位集中在深泉中。随着地下水和地表水位下降，这两个物种的种群变得越来越分散。居住在春季复合体的不同季节性隔离区域的幼鱼的相对丰度和体型的具体差异持续多年，这表明幼鱼的生长速度和存活率受到核心春季栖息地与季节性深池塘的连通性的影响。地下水与地表水位之间关系的性质表明，≥ 40 cm 浅层地下水位的长期下降将消除春季复合体中的大部分产卵和幼鱼栖息地。