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Functions
& Conditions - Characteristics
of Riparian Areas
Key
Points
1. The
key components of riparian areas are water, soil, vegetation,
and landform.
2. Healthy
riparian areas perform functions that provide direct benefits
to humans as well as other elements of the natural world.
These include: providing quality water, water storage, sediment
trapping, bank building and maintenance, flow energy dissipation,
and primary biotic production.
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Riparian areas
are the "green zones" which lie between stream channels
and uplands. They are the link between aquatic (water) environments
and terrestrial (upland) ecosystems. Riparian areas are closely
related to their adjacent waterways since the presence of water
for all or part of the growing season is their distinguishing characteristic.
Moreover, the nature and condition of the riparian area beside a
stream channel f undamentally affects the aquatic environment. For
this reason, the terms "riparian ecosystems" and "riparian
areas" often refer to both the land area and the stream channel
with which it interacts.
Riparian areas
are usually much more dynamic than uplands. Plant communities may
be especially susceptible to rapid change, but soil and water conditions
may change dramatically as well, often in relatively short periods.
These changes might include:
- Flooding
(either temporary or more long term, as caused by beavers or man-made
structures);
- Deposition
of sediment on streambanks and across floodplains;
- Accumulation
of organic materials in areas such as wet meadows and bogs;
- Dewatering
of a site by a variety of means; and
- Changes in
actual channel location.
Each of these
physical modifications can change the associated vegetation. Conversely,
vegetation, or the lack of it, may contribute to many of the above
phenomena.
The natural
variation of riparian areas is an important consideration in seeking
to understand and to manage these areas because it is often difficult
to distinguish between natural and human-caused impacts. In addition,
the inherently dynamic nature of riparian systems is such that natural
events may override human-caused impacts, including efforts at instream
and streambank rehabilitation.
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