Data from: Multi-scale landscape and wetland drivers of lake total phosphorus and water color

We quantified relationships between local wetland cover in the riparian lake buffer and lake total phosphorus (TP) and water color (color) using multilevel mixed-effects models that also incorporate landscape features such as hydrogeomorphology and land use at broad regional scales to determine 1) Within regions, are local wetland relationships with TP and color affected by interactions with local land use or hydrogeomorphic variables? 2) Across regions, are local wetland relationships with TP and color different? And if so, 3) Are differences in local wetland relationships with TP and color a result of cross-scale interactions? We answered these questions by analyzing TP, color, and multi-scaled landscape data for 1790 North temperate lakes. We found that local wetland-TP and wetland-color relationships were not affected by local-scale interactions; we found that local wetland-TP and wetland-color relationships were different across regions; and these differences were related to cross-scale interactions with regional landscape characteristics. For example, regional human land-use affected local wetland-TP relationships such that in regions with high amounts of agriculture, local wetlands were associated with decreased lake TP. However, in regions with low amounts of agriculture, local wetlands were associated with increased lake TP. In contrast, regional hydrogeomorphic characteristics influenced local wetland-color relationships such that in regions with high groundwater contribution, the strength of local wetland relationships were weak. Regional landscape setting influences local wetland relationships with TP and color through cross-scale interactions and lake TP and color are controlled by both local-scale wetland extent and regional-scale landscape variables.

本研究借助纳入了区域尺度景观特征（含水文地貌学（hydrogeomorphology）与土地利用）的多级混合效应模型（multilevel mixed-effects models），定量解析了河岸湖缓冲区本地湿地覆盖率与湖泊总磷（total phosphorus, TP）、水色（water color, color）之间的关联，旨在解答以下三个问题：1） 区域内部，本地湿地与总磷、水色的关联是否会受到本地土地利用或水文地貌变量的交互作用影响？2） 跨区域而言，本地湿地与总磷、水色的关联是否存在差异？若存在差异，3） 本地湿地与总磷、水色的关联差异是否由跨尺度交互作用导致？
研究团队通过分析1790个北温带湖泊的总磷、水色及多尺度景观数据解答了上述问题。结果显示，本地湿地-总磷、湿地-水色的关联不受本地尺度交互作用的影响，但跨区域存在显著差异，且该差异与区域景观特征的跨尺度交互作用相关。例如，区域人类土地利用会调控本地湿地与总磷的关联：在农业占比高的区域，本地湿地与湖泊总磷浓度降低相关；而在农业占比低的区域，本地湿地则与湖泊总磷浓度升高相关。与之相对，区域水文地貌特征会影响本地湿地与水色的关联：在地下水补给占比高的区域，本地湿地的关联强度较弱。综上，区域景观背景通过跨尺度交互作用调控本地湿地与总磷、水色的关联，而湖泊总磷与水色同时受本地尺度湿地覆盖范围及区域尺度景观变量的共同调控。