Natural Stream Management Areas Overlay

The natural stream management areas overlay shows river and stream reaches with HNC and aquatic biota values because of the presence of indigenous vegetation on either side of the watercourse. The presence of indigenous vegetation of a minimum qualifying length and width, indicates that the river or stream has good ecological values, particularly as habitat and breeding areas for native fish. The presence of indigenous vegetation means that the stream bed is usually unmodified, allowing the movement of fish up and down the stream, as well as providing natural places for fish to feed and shelter. The presence of vegetation on the bank provides food for fish, keeps water temperatures constant and filters contaminants and sediments reducing the levels entering the stream. Many of these natural stream management areas are found in the upper reaches of a catchment, or in reserve areas and water quality is generally high. The combination of suitable temperature, pH and water quality and the presence of native aquatic plants and aquatic fauna are collectively referred to as "in-stream values".自然溪流管理区叠加图层展示了具备HNC与水生生物群落价值的河流与溪流河段，其成因在于河道两侧生长有本土植被。当存在符合最低长度与宽度要求的本土植被时，即表明该河流或溪流具备优良的生态价值，尤其可作为本土鱼类的栖息地与繁育场所。本土植被的存在通常意味着河床未受人为改造，可保障鱼类在河道内上下洄游，同时为鱼类提供天然的觅食与庇护场所。河岸植被可为鱼类提供食物来源，维持水温恒定，并过滤污染物与沉积物，降低进入溪流的污染物与沉积物含量。此类自然溪流管理区多分布于流域上游或保护区内，水质整体优良。适宜的水温、pH值与水质，搭配本土水生植物与水生动物群落的共同存在，统称为“河道内生态价值”。