Rivers - River Plants

The crack willow is one of the most common trees growing along the bank. It often used to be pollarded i.e. the branches were cut back regularly to produce a supply of poles for rural industries. The willow’s roots help to stabilize the banks. Many emergent plants may be found i.e. those rooted underwater but much of their growth is above the water surface. The arrowhead is a small emergent with some leaves underwater, and the reedmace, a large example, can form a dense reedbed. Other bankside plants grow well in marshy ground, such as the yellow marsh marigold and the pink great willowherb. Plants such as curled pondweed are rooted in the bottom and remain either submerged in deep water or their leaves reach the surface.

In what ways are these plants, and other river-dwelling species, useful to the animals of a river?