Wetland versus Riparian Reference is often made to wetland vegetation versus riparian vegetation and, in fact, these terms often are used interchangeably. Although there are areas of overlap, both spatially and within the context of the definitions, these two terms have distinctly different meanings.
Wetland plants are those that have developed special adaptations to live in saturated soils. Wetlands and "Waters of the U.S." are those areas specifically administered by the U.S. Army Corps of Engineers and the Environmental Protection Agency (EPA) under the Clean Water Act. Jurisdictional wetlands are defined as:
"...those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas."
To qualify as a wetland, using this definition, the site must meet a three part test. First, it must contain soils saturated by surface or ground water during a specific period of the growing season. Hydric soils are those that form under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic (lacking oxygen) conditions. Second, the site must exhibit evidence of wetland hydrology. An area has wetland hydrology if it is inundated or saturated to the surface for at least 5% of the growing season in most years. Third, the site must be dominated by hydrophytic vegetation which are those species tolerant of and specially adapted to live in saturated soil conditions. All three of these factors must be present to classify a site as a wetland.
Often, these conditions are difficult to meet in the arid West. In many cases, the hydrophytic vegetation might be present but either the wetland hydrology is lacking or the soils are too gravely or sandy to qualify as hydric. Although many of our drainages do not possess all three wetland characteristics, they support plants that are definitely more diverse and more robust than surrounding upland sites. These "riparian" sites also support a more diverse group of wildlife species. Approximately 75% of the wildlife species known or likely to occur in Colorado are dependent on riparian areas during all or a portion of their life cycle. This is especially significant when we realize that riparian areas make up less than 1% of the land mass in Colorado. Due to their importance to wildlife, and because of the restrictive nature of mapping jurisdictional wetlands, the Colorado Division of Wildlife has decided instead to map riparian habitats.
As such, we feel it important to provide a definition of riparian vegetation that we use when mapping this unique habitat type.
"Riparian areas are those plant communities adjacent to and affected by surface or ground water of perennial or ephemeral water bodies such as rivers, streams, lakes, ponds, playas, or drainage ways. These areas have distinctly different vegetation than adjacent areas or have species similar to surrounding areas that exhibit a more vigorous or robust growth form."
Riparian areas, as mapped by the Colorado Division of Wildlife, are inclusive of jurisdictional wetland areas. For purposes of simplicity, no mapping distinction is made between riparian vegetation and wetland vegetation. The goal of the Colorado Division of Wildlife's riparian mapping project is to delineate these important habitats to enhance our management of the wildlife resource and not to perform a regulatory function.
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