Despite the large body of riparian literature for rivers and lakes, there are few studies on the catchments of mine pit lakes. Therefore, the broad objective of this research was to determine if catchment characteristics were related to pit lake nutrient concentrations. We hypothesised that: (1) catchment characteristics would vary among pit lakes, (2) pit lake catchments would differ from co-occurring naturally-forested catchments, and (3) connecting a pit lake (Kepwari) to a naturally-forested catchment via a river flow-through would increase C accumulation in the lake. The research was conducted in pit lakes of the Collie lake district in Western Australia and examined catchment characteristics (soil nutrients, litter biomass, vegetation, and biomass), carbon and sedimentation rates in pelagic and benthic materials, and establishment of a simple nutrient budget for Lake Kepwari. Broadly, results indicated that catchment vegetation differed significantly among pit lakes (although parts were similar to co-occurring natural forest), with differences largely driven by catchment age. None of the pit lake catchments had true riparian species surrounding the pit lakes. The hypothesis that connecting a pit lake to a watercourse would increase carbon concentrations and sedimentation was not supported. Most (87%) of the water that entered the lake was from the river, and river outflow was slightly greater than river inflow. However, the lake acted like a nutrient sink, with more N, P, and TOC calculated in the inflows than the outflow. We found that it took 10–15 years of growth for actively rehabilitated pit lake catchments to approximate natural forest and 60 years for unrehabilitated pit lake catchments. Active rehabilitation that includes riparian-specific planting would likely lead to better outcomes for pit lake catchment vegetation. Connecting a pit lake to a river substantially increased catchment size and large amounts of river-derived carbon were deposited in the lake. However, carbon concentrations were relatively low compared to the size of the lake. Our results suggest that active intervention is required if stakeholders are unwilling to wait decades for the biological development of pit lakes.

中文翻译：

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集水区对矿坑湖的重要性：对关闭的影响

尽管有大量关于河流和湖泊的河岸文献，但对矿坑湖流域的研究却很少。因此，本研究的广泛目标是确定流域特征是否与坑湖养分浓度有关。我们假设：(1) 坑湖之间的流域特征会有所不同，(2) 坑湖流域不同于共存的天然林集水区，以及 (3) 将坑湖 (Kepwari) 连接到天然林流域河流流经会增加湖中的 C 积累。该研究在西澳大利亚柯利湖区的坑湖中进行，并检查了流域特征（土壤养分、枯枝落叶生物量、植被和生物量）、中上层和底栖物质中的碳和沉积率，并为 Kepwari 湖建立一个简单的养分预算。从广义上讲，结果表明，坑湖之间的流域植被存在显着差异（尽管部分类似于共生的天然森林），差异主要受流域年龄驱动。坑湖集水区没有一个坑湖周围有真正的河岸物种。不支持将坑湖连接到水道会增加碳浓度和沉积的假设。入湖水大部分（87%）来自河流，河流流出量略大于河流流入量。然而，湖泊就像一个养分汇，流入的 N、P 和 TOC 比流出的要多。我们发现，积极修复的坑湖集水区需要 10-15 年的时间才能接近天然林，而未修复的坑湖集水区则需要 60 年的时间。包括特定河岸种植在内的积极修复可能会为坑湖集水植被带来更好的结果。将坑湖与河流连接起来，大大增加了集水区的规模，大量河流衍生的碳沉积在湖中。然而，与湖泊的大小相比，碳浓度相对较低。我们的结果表明，如果利益相关者不愿意为坑湖的生物发展等待数十年，则需要积极干预。将坑湖与河流连接起来，大大增加了集水区的规模，大量河流衍生的碳沉积在湖中。然而，与湖泊的大小相比，碳浓度相对较低。我们的结果表明，如果利益相关者不愿意为坑湖的生物发展等待数十年，则需要积极干预。将坑湖与河流连接起来，大大增加了集水区的规模，大量河流衍生的碳沉积在湖中。然而，与湖泊的大小相比，碳浓度相对较低。我们的结果表明，如果利益相关者不愿意为坑湖的生物发展等待数十年，则需要积极干预。