The riparian zone is the green ribbon of life alongside a stream. This ribbon is a mixture of vegetation types, which varies greatly from place to place. Riparian vegetation along a desert stream may be small and sparse while the vegetation along a mountain stream may be tall and lush.
The riparian zone is critical to the health of every stream and its surroundings environment. It connects the upland zone (the area of the watershed that does not receive regular flooding by a stream) to the aquatic zone (the area of the stream channel covered by water, controlling the flow of water, sediment, nutrients, and organisms between the two. Without a proper functioning riparian zone, the other zones suffer.
How does the variety of species differ in the riparian zone?
The riparian zone generally has a greater variety of species than the other zones. It is also denser and more structurally complex (plants have a greater variety of shapes and heights). Plants such as sedges and rushes can be found int he riparian zone and are not found in most of the upland areas because they require a lot of water.
How do riparian plants affect streams?
- Riparian vegetation contributes shade, food and shelter for aquatic organisms. The riparian zone is also home to many animals that move between land and water, such as insects, amphibians and waterfowl.
- Riparian vegetation and litter reduces erosion and regulates the overland flow of water to the stream (uplands vegetation serves this function, too).
- The riparian zone acts as a natural sponge, soaking up water as it runs off the land, and slowly releasing that water back into the stream.