Sithole Hendrik, Motitsoe Samuel N, Mutshekwa Thendo, Mlambo Musa C
Conservation Services Division, Scientific Services, South African National Parks (SANParks), Kimberley, South Africa.
School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, 2050, South Africa.
Environ Monit Assess. 2025 Jul 14;197(8):914. doi: 10.1007/s10661-025-14343-5.
The burgeoning population growth and landscape developments over the last decades have had a profound effect on natural resources including riverine water quality and quantity. This resulted in increased pollution events, loss of aquatic biodiversity and the introduction of alien invasive species, which cumulatively have transformed freshwater ecosystem structure, processes and functions. Macroinvertebrate-based biomonitoring, like the South African Scoring System version 5 (SASS5), is a fast and effective way to assess water and habitat quality. However, studies reporting long-term biomonitoring are rare in many Global South systems. Also, river health within protected areas is generally regarded better than those outside, with the park potentially offering refugium and ideal conditions for rivers to recover. However, Kruger National Park (KNP) rivers get impacted by mining and domestic sewage upstream, before entering the park, and it is not clear how much remediation happens as the rivers flows downstream within the park. The current study was initiated to investigate the long-term river health status of four major river systems flowing across the iconic KNP, using SASS5 biomonitoring and selected physico-chemical parameters. Our results showed that SASS5 indices showed difference in their sensitive to anthropogenic impacts, both in space and time. Long-term dataset revealed that the ability of the rivers to recover from poor to good quality (and vice versa) was quite rapid, and also some rivers were progressively declining (e.g. Olifants and Crocodile rivers) while others were improving (e.g. Luvuvhu and Sabie rivers). Consequently, SASS5 appeared to be a useful tool in assessing the long-term health of KNP rivers, providing valuable insights into the overall ecological conditions and water quality of these important aquatic ecosystems that will assist in the park water resource management strategies. Further, our results demonstrated high sensitivity and quick response of macroinvertebrates to disturbance, and an improvement potential as the rivers transversed the park.
在过去几十年中，迅速增长的人口和景观开发对自然资源产生了深远影响，包括河流水质和水量。这导致污染事件增加、水生生物多样性丧失以及外来入侵物种的引入，这些因素共同改变了淡水生态系统的结构、过程和功能。基于大型无脊椎动物的生物监测，如南非评分系统第5版（SASS5），是评估水质和栖息地质量的快速有效方法。然而，在许多全球南方的系统中，报道长期生物监测的研究很少。此外，保护区内的河流健康状况通常被认为比保护区外更好，公园可能为河流提供避难所和恢复的理想条件。然而，克鲁格国家公园（KNP）的河流在进入公园之前，会受到上游采矿和生活污水的影响，目前尚不清楚河流在公园内向下游流动时会发生多少修复。本研究旨在利用SASS5生物监测和选定的理化参数，调查流经标志性KNP的四个主要河流系统的长期河流健康状况。我们的结果表明，SASS5指数在对人为影响的敏感性方面，在空间和时间上都存在差异。长期数据集显示，河流从水质差恢复到水质好（反之亦然）的能力相当迅速，而且一些河流在逐渐下降（如奥利凡茨河和鳄鱼河），而另一些河流则在改善（如卢武胡河和萨比河）。因此，SASS5似乎是评估KNP河流长期健康状况的有用工具，为这些重要水生生态系统的整体生态状况和水质提供了有价值的见解，这将有助于公园的水资源管理策略。此外，我们的结果表明大型无脊椎动物对干扰具有高度敏感性和快速反应能力，并且随着河流穿过公园具有改善的潜力。
