Besides water level (WL) variability, several lakes worldwide have shown water level decline trends and total desiccation. In maar lakes, there is paleoenvironmental evidence of water level responses to climate and groundwater inflow changes; however, historical studies are scarce. Understanding the relative contributions of natural variability and anthropogenic impacts to the decline of lakes' water level is fundamental to preserving these ecosystems. In this study, we developed a conceptual baseline of the response of tropical maar lakes to climate and groundwater variability at different time scales in near natural conditions. The four analyzed maar lakes are in a semiarid, endorheic basin in central Mexico and the study time frame (1959 to 1992) includes a historical period before direct human impact. We analyzed the effects of meteorological records, large-scale climate phenomena indices (ENSO, PDO, and AMO), and regional groundwater levels on WL datasets using multiple linear regression models, trend analysis and cross correlations. WL responded to meteorological seasonality and climate variability indices. All lakes lost more water to evaporation than they gained from precipitation, which partially explains long-term WL declines. Regional groundwater levels decreased, suggesting a reduction of groundwater inflow to the lakes, which contributed to WL declines. The latter may reflect a lagged effect of long-term recharge decrease, probably due to long-term climate change in the region since the formation of the lakes evidenced in previous studies. The results add to evidence of water level declines caused by groundwater-mediated natural variability, warning about how this process is being exacerbated by anthropic activities under the context of global change.

中文翻译：

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墨西哥中部玛珥湖水位对气候和地下水变化的长期响应

除了水位 (WL) 变化外，世界各地的一些湖泊还表现出水位下降趋势和完全干燥。在玛珥湖中，有古环境证据表明水位对气候和地下水流入变化的响应；然而，历史研究却很少。了解自然变化和人为影响对湖泊水位下降的相对影响对于保护这些生态系统至关重要。在这项研究中，我们制定了热带玛珥湖在接近自然条件下不同时间尺度对气候和地下水变化的响应的概念基线。所分析的四个玛珥湖位于墨西哥中部的一个半干旱内流盆地，研究时间范围（1959 年至 1992 年）包括人类直接影响之前的历史时期。我们使用多元线性回归模型、趋势分析和互相关分析了气象记录、大尺度气候现象指数（ENSO、PDO 和 AMO）以及区域地下水位对 WL 数据集的影响。 WL 对气象季节性和气候变化指数做出反应。所有湖泊因蒸发而损失的水量都多于因降水而获得的水量，这在一定程度上解释了水位长期下降的原因。区域地下水位下降，表明流入湖泊的地下水减少，从而导致水位下降。后者可能反映了长期补给减少的滞后效应，这可能是由于先前研究证明湖泊形成以来该地区的长期气候变化所致。这些结果进一步证明了地下水介导的自然变化导致水位下降，并警告人们在全球变化的背景下人类活动如何加剧这一过程。