Riparian Ecosystems

A typical riparian ecosystem consists of life that has evolved in flowing freshwater rather than in static waters. Any ecosystem that has adapted to living in running water is called a loticecosystem. Part of the riparian ecosystem also consists of animals that use areas as migration corridors and feed on riparian plants and animals. Riparian ecosystems represent edges, a place where two different habitats meet. Lush and shady conditions next to a stream, for example, differ from the sunny dry meadow a short distance from the stream. Some predators seek edges because they contain a greater number and variety of prey animals, and when predators hunt in riparian habitats, they also become part of the ecosystem.

Rivers and streams are general terms for bodies of flowing water: rivers
are larger and usually empty into an ocean, bay, or large lake; streams
are smaller and empty into larger streams, rivers, and seashores. The following
four types of rivers or streams make up riparian habitat:

» perennial (or permanent) rivers/streams—flow year-round

» intermittent rivers/streams—flow only in certain seasons, after storms, or when snow melts

» ephemeral rivers/streams—flow for short periods of time in rainy seasons, but hold shape year-round

» interrupted rivers/streams—flow aboveground in some places and belowground in others

Riparian habitat contains only a one-way flow of freshwater— downhill— and with the capacity to transport sediment and reshape the land. Therefore, ecosystems at the low-volume head of a river—even the Mississippi River starts as a stream—differ greatly from the ecosystems in a large tributary a few miles from the sea.

The ecosystems in large slow-moving rivers resemble lake ecosystems. Phytoplankton, tiny invertebrate plant life, dominates the open waters and captures the Sun’s energy by photosynthesis. River food chains build upon the single-celled phytoplankton, with larger invertebrates, fish, and predator fish toward the top of the food chain. As water flows faster, phytoplankton density falls, and the water becomes clearer. Phytoplankton may build up, however, in swirling pools carved from the riverbank by fast-flowing rivers or produced by rocks. These areas of choppy water called riffles provide young fish with a safe place to hide from predators and to eat. When the fish grow large enough, they leave the riffles and spend the rest of their time in the main body of water.

Some large rivers contain extensive wetlands that provide safety for fish spawning and for waterfowl to hatch eggs and raise their young. These areas, called backwaters, also provide the normal benefits of wetlands: cleaning water of pollution; removing silt; providing specialized habitat; and controlling floodwaters.

Streambeds contain a mixture of organic (phytoplankton, zooplankton, insects, worms) and inorganic (sediment, rocks, insoluble minerals) nutrients. Faster-flowing streambeds contain less of these nutrients than slow-flowing streambeds, but because streams are shallow, terrestrial creatures make use of them as well as aquatic life. Rocks in streams also contain slippery sheets of bio film that hold a mixture of organic and inorganic matter captured from the flowing water.

Streams also house an assortment of insects, insect larvae, and nymph forms, and invertebrates that transfer energy from plant life to a form usable by predators. Leeches, worms, mollusks, and crustaceans make up the next level in the riparian food chain. These lower levels of the food chain nourish fish, large insects, reptiles, amphibians, and birds. Waterfowl, rabbits, and rodents eat aquatic grasses and plants along the stream’s banks. The riparian ecosystem contains the varied components that characterize healthy ecosystems, while it harbors changing conditions affected by heavy rainfalls, flooding, and droughts.

Source of Information : Green Technology Conservation Protecting Our Plant Resources