Frequently Asked Questions



What is a riparian area? What is a wetland area?

Riparian and wetland areas are the green zones bordering lakes, reservoirs, estuaries, potholes, springs and seeps, peatlands, wet meadows, vernal pools, and ephemeral, intermittent, or perennial streams. The riparian zone is the interface or linkage between the upland (terrestrial) zone and the deep water (aquatic) zone. Riparian and wetland ecosystems are important islands of diversity within extensive upland ecosystems and provide an important functional linkage between aquatic and terrestrial ecosystems. They are of prime importance to water quality, water quantity, stream stability, and fisheries habitat. Abundant water, forage, and habitat attract a proportionately greater amount of use and conflict than their small area would indicate. They are vital to the livestock grazing industry, mining, and many are also well suited for development as high quality agricultural farmland. In addition, many riparian and wetland areas are excellent timber producing sites. Most wetland sites provide critical habitat needs for many species and they support a greater concentration of wildlife species, recreation, and other activities than any other type of location on the landscape."Riparian" and "wetland" are not synonyms and usage varies greatly. We often use the terms in combination when speaking of general situations that include both.

Riparian and wetland areas in western North America tend to have the following characteristics (Thomas and others 1979):

1) They create well-defined habitat zones within the much drier surrounding areas.

2) They make up a minor proportion of the overall area (between 1-5 percent).

3) They are generally more productive in terms of total biomass than the remainder of the area.

4) They are a critical source of biological diversity. Both density and diversity of species tend to be higher at the land/water ecotones than in adjacent uplands, especially in the arid West.

What criteria do scientists use to delineate riparian and wetland areas?

Defining wetlands has become more difficult as greater economic stakes have increased the involvement of politics and decreased the involvement of science. A universally accepted wetland definition satisfactory to all users has not yet been developed because the definition depends on the objectives and the field of interest. However, scientists generally agree that wetlands are characterized by one or more of the following features:

1) wetland hydrology, the driving force creating all wetlands,

2) hydric soils, an indicator of the absence of oxygen, and

3) hydrophytic vegetation, an indicator reflecting wetland site conditions.

The problem is how to define and obtain consensus on thresholds for these three criteria and various combinations of the three criteria.

Jurisdictional and Functional Wetland Criteria--Much of the disagreement on thresholds has been focused on differences between jurisdictional wetlands, and functional wetlands.

For more detailed information, see pages 6-7 (Jursidictional and Functional Wetland Criteria) of the Introduction to our Classification and Management of Montana's Riparian and Wetland Sites Document (9.8MB).

What is the difference between a lotic and a lentic wetland?

Running Water (Lotic) Wetlands vs. Still Water (Lentic) Wetlands

To distinguish between the aquatic ecosystems of wetlands in the semiarid and arid interior West, the terms lotic and lentic were defined.

Lotic wetlands are associated with running water systems such as rivers, streams, and drainageways. Such wetlands contain a defined channel and floodplain. The channel is an open conduit which periodically, or continuously, carries flowing water, dissolved and suspended material. Beaver ponds, seeps, springs, and wet meadows on the floodplain of, or associated with, a river or stream are part of the lotic wetland.

Lentic wetlands are associated with still water systems. These wetlands occur in basins and lack a defined channel and floodplain. Included are permanent (e.g., perennial) or intermittent bodies of water such as lakes, reservoirs, potholes, marshes, ponds, and stockponds. Other examples include fens, bogs, wet meadows, and seeps not associated with a defined channel.

Several authors have used lotic and lentic to separate wetlands associated with running water from those associated with still water. The following definitions represent a synthesis and refinement of terminology from Shaw and Fredine (1956), Stewart and Kantrud (1972), Boldt and others (1978), Cowardin and others (1979), American Fisheries Society (1980), Johnson and Carothers (1980), Cooperrider and others (1986), Windell and others (1986), Environmental Laboratory (1987), Kovalchik (1987), Federal Interagency Committee for Wetland Delineation (1989), Mitsch and Gosselink (1993), and Kent (1994).

How do you determine the "health" of a riparian or wetland area?

In a broad sense, the "health" of a riparian or wetland area may be defined as its ability to perform its normal functions. These functions include sediment filtering, streambank building, storing water, aquifer recharge, providing fish and wildlife habitat, and dissipating stream energy. Evaluating a stream's health requires consideration of upstream and adjacent management. For example, although noxious weeds such as Centaurea maculosa (spotted knapweed) or Euphorbia esula (leafy spurge) along a streambank may help to trap sediment and provide deep soil-binding properties necessary for maintaining the streambanks, its presence would be a management concern and indicates poor health.

For more detailed information, see our Health Assessment User Guides.

What is a habitat type? What is a community type?

A habitat type is defined as the land area that supports, or has the potential of supporting, the same climax vegetation type (association). A phase is a finer subdivision of a habitat type representing a minor variation in climax vegetation. Each habitat type represents a relatively narrow segment of environmental variation having a certain potential for vegetation development. Although any given habitat type may support a wide variety of disturbance-caused or seral vegetation, the ultimate product of vegetational succession anywhere within that habitat type will be a similar plant community. Therefore, the habitat type is a vegetation-based ecological site classification that uses the plant community as an indicator of integrated environmental factors as they affect species reproduction and plant community development. Changes in site conditions such as drying and filling of potholes or sufficient deposition of alluvium on floodplains to create a drier site over time can change the habitat type. Cyclical changes that do not change long-term site conditions will remain the same habitat type. Habitat types have been used extensively to classify grasslands, shrublands, woodlands, and forests throughout the western United States and to some areas in the central and eastern United States.

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