A stream or river and the associated vegetation on the banks and flood plain are collectively called the 'riparian zone'. Riparian habitat often supports a lot of animals because of the constant water supply and the associated diversity of plants. A source of water is vital for most small native animals. Vegetation cover around the water prevents erosion and supplies nutrients for aquatic life. Seeds and insects which fall into the water from the bank are a valuable food source for many fish and other animals.
Shade cast by trees on the bank makes a dark corridor of water which is safer for migrating fishes.
Trees which fall into streams provide shelter, with some fish spawning in hollow logs. Encouraging wildlife starts with providing areas of native vegetation. The 'building blocks' of habitat will help make any remnant or planting suitable for a wide range of animals. Provide nest boxes if there are no hollows. Leave plants in and around dams to improve them for wildlife .