Feral horses preferentially utilise aquatic landscape elements. Damage to stream banks by feral horses potentially degrades water quality and affects aquatic ecosystems. Despite the global predominance of horse activity in or near water, there is poor understanding of in-stream impacts. Motion-sensing cameras were used near subalpine streams to quantify frequency and behaviour of horses interacting with streams. Deployed turbidity loggers were used to indicate the presence of suspended sediment from interactions and to assess long-term (3 year) seasonal suspended sediment regime at sites with very small and large amounts of horse activity. In summer, 99.9% of large grazer interactions with streams were horses and we estimate 130 horse interactions per kilometre of stream per day, resulting in stream turbidity increases up to 100 NTU. Long-term turbidity at sites with greater riparian damage from horses was significantly greater than at control sites. Turbidity in horse-affected streams peaked at 50 times the national turbidity guideline and, in summer, averaged eight times the guideline. Suspended sediment leads to a high risk of loss of aquatic diversity and impairment of ecosystem function. Linear relationships between turbidity and riparian damage suggest that any level of horse presence affects subalpine waterways.

野马优先利用水生景观元素。野马对河岸的破坏可能会降低水质，并影响水生生态系统。尽管在水中或附近水域的马活动在全球范围内占主导地位，但人们对河内影响的了解甚少。在亚高山溪流附近使用运动感应相机来量化马匹与溪流互动的频率和行为。部署的浊度记录仪用于指示相互作用产生的悬浮沉积物的存在，并评估马匹活动量非常少的地点的长期（3年）季节性悬浮沉积物状况。夏季，大型食草动物与溪流的互动中，有99.9％是马，我们估计每天每公里溪流有130匹马交互作用，导致溪流浊度增加到100 NTU。马对河岸造成较大破坏的地点的长期浊度显着大于对照地点。受马匹影响的河流中的浊度达到国家浊度指南50倍的峰值，而在夏季，平均值为指南的8倍。悬浮的沉积物导致丧失水生生物多样性和损害生态系统功能的高风险。浊度和河岸损害之间的线性关系表明，任何水平的马匹存在都会影响亚高山水道。