Ecofish Research Limited , Suite 1220-1175 Douglas Street , Victoria , British Columbia Canada.
Environmental Research Institute , University of Waikato , Private Bag 3105 , Hamilton 3240 , New Zealand.
Environ Sci Technol. 2019 Aug 20;53(16):9439-9452. doi: 10.1021/acs.est.9b03120. Epub 2019 Aug 1.
Quantifying environmental changes relative to ecosystem reference conditions (baseline or natural states) can inform assessment of anthropogenic impacts and the development of restoration objectives and targets. We developed statistical models to predict current and reference concentrations of total nitrogen (TN) and total phosphorus (TP) in surface waters for a nationally representative sample of ≥1033 New Zealand lakes. The lake-specific nutrient concentrations reflected variation in factors including anthropogenic nutrient loads, hydrology, geology, elevation, climate, and lake and catchment morphology. Changes between reference and current concentrations were expressed to quantify the magnitude of anthropogenic eutrophication. Overall, there was a clear increase in lake trophic status, with the most common trophic status being oligotrophic under a reference state and mesotrophic under current conditions. The magnitude of departure from reference state varied considerably within the sample; however, on average, the mean TN concentration approximately doubled between reference and current states, whereas the mean TP concentration increased approximately 4-fold. This study quantified the extent of water quality degradation across lake types at a national scale, thereby informing ecological restoration objectives and the potential to reduce anthropogenic nutrient loads, while also providing a modeling framework that can be applied to lakes elsewhere.
量化相对于生态系统参考条件（基线或自然状态）的环境变化，可以为评估人为影响以及制定恢复目标和指标提供信息。我们开发了统计模型，以预测新西兰≥1033 个具有代表性的湖泊的表层水中总氮（TN）和总磷（TP）的当前和参考浓度。湖泊特有的养分浓度反映了包括人为养分负荷、水文学、地质学、海拔、气候以及湖泊和集水区形态在内的多种因素的变化。通过参考浓度与当前浓度之间的变化来表示，以量化人为富营养化的程度。总体而言，湖泊营养状况明显改善，在参考状态下最常见的营养状态是贫营养型，而在当前条件下则是中营养型。样本内参考状态与当前状态之间的偏离程度差异很大；但是，平均而言，TN 浓度在参考状态和当前状态之间大约增加了一倍，而 TP 浓度则增加了约 4 倍。这项研究在全国范围内量化了不同类型湖泊水质退化的程度，从而为生态恢复目标和减少人为养分负荷的潜力提供了信息，同时还提供了一种可应用于其他湖泊的建模框架。
