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RCA III
Riparian Areas:
Reservoirs of Diversity
Working Paper No. 13
Gerald L. Montgomery
NRCS, USDA
Northern Plains Regional Office
Lincoln, Nebraska
February 1996
Contents
Introduction
Riparian areas are the zones along water bodies that serve as interfaces
between terrestrial and aquatic ecosystems. Riparian ecosystems generally
compose a minor proportion of the landscape. Typically, however, they are
more structurally diverse and more productive in plant and animal biomass
than adjacent upland areas. Riparian areas supply food, cover, and water
for a large diversity of animals, and serve as migration routes and connectors
between habitats for a variety of wildlife (Manci 1989).
Riparian areas are important in mitigating or controlling nonpoint source
pollution. Riparian vegetation can be effective in removing excess nutrients
and sediment from surface runoff and shallow ground water and in shading
streams to optimize light and temperature conditions for aquatic plants
and animals. Riparian vegetation, especially trees, is also effective in
stabilizing streambanks and slowing flood flows, resulting in reduced downstream
flood peaks.
Riparian areas are often important for their recreation and scenic values,
such as hunting, fishing, boating, swimming, hiking, camping, picnicking
and birdwatching. However, because riparian areas often are relatively small
areas and occur in conjunction with watercourses, they are vulnerable to
severe alteration.
Riparian ecosystems throughout the United States have been heavily impacted
by human activities, such as highway, bridge, and pipeline construction;
water development; channel modifications for flood control; recreation;
industrial and residential development; agriculture; irrigation; livestock
grazing; logging; and mining. Offsite disturbances in the watershed that
change watershed hydrology can also have adverse effects on the composition
and productivity of riparian plants and corresponding animal associations (Manci 1989).
Nature and Significance
According to the Oxford English Dictionary, the term "riparian"
is derived from the Latin word ripa, meaning river bank. In recent years,
there have been numerous attempts to refine this definition by including
specific criteria on such features as soil moisture and vegetation. The
term has been expanded by many to include areas along all water bodies,
including lakes, ponds and some wetlands. There are now several definitions
for riparian areas, but all of them have much in common. Riparian areas
are zones that influence and are strongly influenced by an adjacent aquatic
environment.
The Natural Resources Conservation Service (NRCS) defines riparian areas
in its General Manual as "ecosystems that occur along watercourses
and water bodies. They are distinctly different from the surrounding lands
because of unique soil and vegetation characteristics that are strongly
influenced by free or unbound water in the soil. Riparian ecosystems occupy
the transitional area between the terrestrial and aquatic ecosystems. Typical
examples would include floodplains, streambanks, and lakeshores" (190-GM,
Part 411).
NRCS indicators of riparian areas include:
- Vegetation--The kinds and amounts of vegetation will reflect the influence
of free or unbound water from an associated watercourse or water body and
contrast with terrestrial vegetation.
- Soils--Soils in natural riparian areas consist of stratified sediments
of varying textures that are subject to intermittent flooding or fluctuating
water tables that may reach the surface. The duration of the soil-wetness
feature is dependent upon the seasonal meteorological characteristics of
the adjacent water body.
- Water--Riparian areas are directly influenced by water from a watercourse
or water body. Riparian areas occur along natural watercourses, such as
perennial or intermittent streams and rivers, or adjacent to natural lakes.
They may also occur along constructed watercourses or water bodies such
as ditches, canals, ponds, and reservoirs (190-GM, Part 411).
Topography, relief, climate, flooding, and soil deposition most strongly
influence the extent of water regimes and associated riparian zones. Likewise,
the riparian area exerts considerable control on the flows in the landscape,
especially on the movement of water, nutrients, sediments, and animal and
plant species. Thus the appearance and boundary of a riparian area vary
from site to site. Riparian areas occur as complete ecosystems or as ecotones
(transition zones) between aquatic and terrestrial ecosystems. They may
also occur as more gradual transition zones, called ecoclines.
Some riparian areas meet the criteria established for wetlands (Cowardin
et al. 1979). Others do not, because they do not possess the necessary hydrologic
water regime, a predominance of hydric soils, or a prevalence of hydrophytic
vegetation. Even nonwetland riparian areas, however, share many characteristics,
functions, and values with wetlands.
In addition to the vertical transition between aquatic and terrestrial ecosystems,
riparian areas possess a distinct longitudinal structure. Drainage patterns
form an extensive, dendritic network throughout the country. The associated
riparian zones form corridors that extend within and into different regions.
There will also be variation along riparian areas because of changing forces
in the watershed from the headwaters to the mouth of the river. The general
spatial pattern of riparian areas thus forms a longitudinal gradient of
height and width and becomes a network within an overall matrix (Malanson
1993).
Regional Differences
Because of the vast differences in climate, topography, and other features,
riparian areas take on different appearances in different regions of the
country. In humid areas, riparian landscapes are somewhat indistinct, while
in dry areas, the river itself contrasts strongly with the surroundings,
the gradient of moisture away from the river is sharp, and boundaries are
clear.
In arid regions, riparian vegetation is usually more productive than the
adjacent land, so the vegetation stands much taller than the vegetation
in the surrounding landscape. The riparian zone is relatively narrow and
is generally visually distinct. An example is a stream, lined with willows
or cottonwood trees, that flows through native grassland.
While all riparian areas tend to be linear, those along alluvial floodplains
in the southern humid regions are relatively wide. Because the riparian
element is not so distinct, its interactions with surrounding elements are
more difficult to discern. An example is a broad floodplain of mixed bottomland
hardwood trees with intermingled baldcypress swamps adjacent to a forest
of upland hardwood trees. Extensive deforestation and resulting conversion
of much of the riparian area to cropland or other land uses provide examples
where the landscape pattern becomes more apparent.
Farther upstream in the humid temperate forest the riparian zone does not
markedly alter the visual landscape. Nevertheless, these zones are ecologically
distinct.
Riparian areas in western mountain regions are quite variable. They may
be very narrow forests along downcutting streams in mountain valleys. On
the other hand, the ecological distinction may appear only among the understory
species, as the dominant trees may be those generally found also on mesic
sites and not specifically on riparian sites.
In the subarctic, the overall species diversity is less than that at low
latitudes, but it is at its greatest on riparian areas.
Functions and Values
Riparian areas function in different ways and display different values because
of their variation across the country. In spite of their differences, riparian
areas possess some basic ecological characteristics such as energy flow,
nutrient cycling, and community structure. These characteristics often function
in particular ways that give riparian areas unique values. Below are some
of the more recognizable functions and values of riparian areas.
The importance of riparian areas is mostly attributed to their spatial relationship
in the landscape. Few other ecosystem types possess such a large amount
of transition zone relative to the area that they occupy. These transition
zones are the points at which terrestrial and aquatic ecosystems interface
and the sites of important exchanges of material and energy in the landscape
(Brinson et al. 1981).
Fluvial Processes
Natural fluvial processes are responsible for many of the diverse, often
subtle, topographic features on floodplains and consequently responsible
for forming riparian ecosystems. These processes (Leopold et al. 1964) are
driven by flooding events. Basically, they result from a combination of
the deposition of alluvial materials (aggradation) and downcutting of material
(degradation) over many years. Floodplain features do not necessarily remain
static; in fact, morphological features of floodplains continually change.
As river channels meander laterally and in a downstream direction, material
is removed from the outside curve of a meander, resulting in erosion of
the riparian area. The eroded sediment, however, is deposited on the inside
curve farther downstream, forming point bars. Eventually, the point bar
begins to support vegetation and develops into a stable riparian area.
Once flood waters overtop the streambanks, they lose much of their velocity
and their ability to carry sediment. Flood-borne sediments are then deposited
in the floodplain. The coarser, heavier material drops out first, forming
natural levees adjacent to the channel. Finer material is deposited in the
floodplain further away from the channel. Severe flooding may scour areas
in the floodplain and redeposit the sediment elsewhere, resulting in increased
undulation of the floodplain.
These fluvial processes are important to riparian ecosystems because they
create a diverse set of conditions in a seemingly level floodplain. The
small topographic variations can mean the difference between a waterlogged,
anaerobic environment and a well-drained, aerated substrate. Many plant
species are intolerant of even brief periods of inundation, while few species
are adapted to survive in constantly waterlogged soil. In addition to the
variation in soil moisture, major differences may occur in soil texture
and fertility. Coarser, less fertile soils will be found in certain areas
and finer, more fertile soils in other areas. As a result, abrupt changes
in species composition may occur in floodplains with elevational variations
of only a few centimeters (Brinson et al. 1981).
Hydrology
The flooding that shaped the floodplain is also important to riparian ecosystems
because it can affect the metabolism and growth of vegetation in three basic
ways. First is water supply, whereby water storage is recharged through
seepage and channel overflow to floodplains. Secondly, nutrient supply in
riparian ecosystems depends partly on sedimentation of particulate matter
transported by overbank flow and partly on the availability of dissolved
nutrients in the water in contact with floodplain soils. Finally, flowing
water in floodplains ventilates soils and roots so that gases are exchanged
more rapidly. Oxygen is supplied to roots and soil microbes, while the release
of gaseous products of metabolism such as carbon dioxide and methane is
enhanced. Water flow then provides the medium for the export of these dissolved
organic compounds (Brinson et al. 1981).
The hydroperiod of the riparian ecosystem, which includes its flooding duration,
intensity, and timing, is the ultimate determinant of the ecosystem structure
and function. The timing of flooding is particularly important because flooding
in the growing season has a greater effect on ecosystem productivity than
does an equal amount of flooding in the nongrowing season (Mitsch and Grosselink
1986).
Ground water in the alluvial aquifer has an intimate relationship with surface
water in streams and floodplain depressions (e.g., oxbow lakes). The normal
gradient and direction of ground water movement is toward these surface
water features through ground water discharge. During periods of high river
stages, the gradient is reversed and water moves from the stream to the
aquifer.
Base Flows
Alluvial soils in riparian areas are usually deep and store large quantities
of water, from rainfall and from water moving downslope. Many alluvial aquifers
in the western United States are maintained by infiltration of upland runoff
in the stream channel or riparian alluvial deposits. Water storage in such
aquifers is partly responsible for maintaining base flow in many rivers (Lowrance et al. 1985). Base flows are further maintained by riparian vegetation
that shades the water, keeping it cooler and thus reducing rapid evaporation.
Nutrient Cycling
Dissolved nutrients and those attached to sediment are transported from
terrestrial ecosystems into streams during runoff events and carried downstream
where they come in contact with the soils of riparian areas. Other nutrients
moving toward a stream, either in ground water or surface runoff, may be
intercepted by riparian areas before they reach the stream. Once these nutrients
enter a riparian area, they are exposed to mechanisms that may utilize or
alter them in different ways.
Nutrients, especially nitrogen, phosphorus, calcium, magnesium, and potassium
dissolved in overflow water and those attached to deposited sediments, are
taken up by shallow-rooted riparian vegetation. Dissolved nutrients moving
with the ground water and those that are leached in the soil may be intercepted
by deeper-rooted riparian vegetation. Local cycling of nutrients occurs
with the uptake of transported nutrients by root systems, to be temporarily
stored in the leaves and then returned to the soil surface when the leaves
(or needles) are shed. Long-term accumulation of some nutrients occurs in
the boles and branches of trees and shrubs.
Not all nutrients remain in the riparian area, and the release processes
are seasonal. Some nutrients pass through with no significant detention.
Some that were taken up by riparian vegetation may be reintroduced into
the water column when the vegetation dies. This form of release produces
nutrients that are highly soluble.
Vegetation supplies litter that, when covered with sediment during overflow,
rapidly decomposes to release nutrients and adds humus to the soil. This
adds to the complex mosaic of sands, silts, and clays deposited by flowing
water. These seasonally waterlogged soils and subsoils that are rich in
organic matter provide ideal conditions for production of microbial organisms
that are important in the transformation of nitrogen.
A thin oxidized layer at the soil-water interface results from the diffusion
of oxygen from water or the atmosphere into the soil. This aerobic layer
is a small refuge of aerobic bacteria that are responsible for conversion
of ammonium N to nitrate (nitrification). This form of nitrogen is soluble
and subject to leaching to the anaerobic layer, where anaerobic bacteria
convert the nitrate-nitrogen to gaseous forms (denitrification) that eventually
escape to the atmosphere.
Energy Transfer
Riparian areas are unique ecosystems in the manner in which some of the
energy as organic matter or organic carbon is transferred from producer
to consumer organisms. This uniqueness derives from the fact that litter-fall
produced within the riparian ecosystem may be transported laterally and
made available to instream animal communities as well as those downstream
from the source of organic matter production. As compared with purely aquatic
or terrestrial ecosystems, organic matter produced in riparian ecosystems
has the potential of supporting a diversity of food webs within both habitat
types.
Streams in the upper reaches of a watershed that have negligible or narrow
floodplains receive organic matter from the riparian zone principally as
litter falling directly from streamside vegetation to the surface of the
stream. Flood events may transport litter from the streambanks into the
channel and on downstream. In comparison, not only do streams farther down
in the watershed (and thus having a higher proportion of floodplain to upland
surface area) receive the litter falling directly into their channels, but
the inundation of broad floodplains provides the opportunity for transport
of additional organic matter from the floodplain (Brinson et al. 1981).
Downstream Flooding
Riparian areas serve an important function in reducing downstream flood
peaks by reducing floodwater velocities. As floodwater flows through a vegetated
area, the plants act as resisters to the flow and dissipate the energy.
Riparian areas are important in this regard, because these areas support
much vegetation during periods of expected flood flows.
Not all plants are equal in their effectiveness in slowing floodwater. Low-growing
plants are usually quite dense and provide excellent resistance. However,
once the floodwater rises to a height that submerges these plants, very
little reduction in velocity is then achieved. Trees, on the other hand,
may not grow quite as dense, but they continue to provide resistance during
severe floods.
Water Quality
As previously mentioned, as floodwaters spread over a floodplain, water
velocities are reduced, allowing much of the sediment to settle out with
little likelihood of its reentering the stream. Additional sediment carried
by overland flow from adjacent uplands is intercepted by the riparian area,
where it settles out. Riparian vegetation further increases sedimentation
in the floodplain by filtering additional sediment from runoff and floodwaters.
The result is that riparian areas serve as effective sediment traps and
reduce the amount of sediment that might otherwise get to a stream or downstream
water body.
Riparian vegetation also plays an important role in reducing sediments in
water by decreasing the rate of bank erosion. This is especially true of
deep-rooted woody vegetation. Vegetation protects a streambank from erosion
by reducing the tractive force of water, by protecting the bank from direct
impacts, and by inducing deposition (Parsons 1963).
Nutrients, pesticides, and heavy metals that are transported with sediment
are also trapped in the riparian area. Many of these are broken down by
physical or biochemical processes and reduced to harmless forms. Some are
taken up by riparian vegetation and incorporated into their living tissues
during the growing season. Others are bound to the sediments and permanently
stored in the soils of the riparian area.
Most sediment and nutrient studies associated with riparian areas have been
conducted in southeastern floodplain forests, where the presence of relatively
long hydroperiods and broad floodplains has considerable influence on water
quality of streams and rivers. Results vary somewhat, but most indicate
a considerable reduction in sediment and nutrients, especially nitrogen
and phosphorus transported downstream in comparison with the amount that
entered the riparian area.
Riparian vegetation also can have a great impact on water temperatures.
Reduced stream temperature can increase a stream's oxygen-carrying capacity
and reduce nutrient availability. This is particularly important during
the hot summer months.
Solar radiation is selectively absorbed and reflected as it passes through
the riparian canopy. The degree of shading of streams is a function of the
structure and composition of riparian vegetation. Dense, low, overhanging
canopies greatly reduce light intensity at the water's surface, but high,
relatively open canopies allow greater amounts of light to reach the stream.
Deciduous riparian vegetation shades streams during summer, but modifies
light conditions only slightly after leaf fall, whereas evergreen riparian
zones shade stream channels continuously. As channel width increases, the
canopy opening over the stream increases and the influence of streamside
vegetation on solar inputs to the stream channel decreases (Gregory et al.
1991).
Aquatic Life
Riparian vegetation is important to aquatic ecosystems because it regulates
the energy base by shading and supplying plant detritus to the stream. Shading
affects both stream temperature and light available to drive primary production.
In shaded streams, detritus becomes the basis of a food chain that results
in a unique and diverse community (Cummins 1974).
Narrow headwater streams are influenced most by riparian vegetation, both
through shading and as the source of organic matter inputs. These low-light,
high-gradient, constant-temperature streams receive an abundant supply of
coarse particulate matter in the form of plant detritus. A group of macroinvertebrates
known as shredders reduce detrital material to smaller particulate organic
matter which becomes the food for another group of invertebrates, collectors.
The abundance of life further supports both macroinvertebrate and fish predators
(Vannote et al. 1980).
As the stream widens and more light penetrates the water, algae replace
detritus as the primary food source. Here collectors become more abundant
in the community, along with grazers, invertebrates that feed directly on
the algae. Invertebrate and fish species that are more tolerant of warmer
conditions replace species that depend on the cooler, shaded stream. The
abundance of individuals within a species may increase, but species diversity
usually decreases as the stream becomes less influenced by the riparian
vegetation (Vannote et al. 1980).
Rooting herbaceous and woody vegetation also helps shape aquatic habitat
by stabilizing streambanks, retarding erosion, and, in places, creating
overhanging banks which serve as cover for fish. Above ground, woody riparian
vegetation is an obstruction to highwater streamflow and to sediment and
detritus movement and is a source of large organic debris. Large organic
debris in streams controls the routing of sediment and water through the
system; defines habitat opportunities by shaping pools, riffles, and depositional
sites and by offering cover; and serves as a substrate for biological activity
by microbial and invertebrate organisms (Meehan et al. 1977).
Terrestrial Life
Undisturbed riparian ecosystems normally provide abundant food, cover, and
water. Often they contain some special ecological features or combinations
of features that are not found in upland areas. Consequently, riparian ecosystems
are extremely productive and have diverse habitat values for wildlife (Brinson
et al. 1981).
The most visible evidence of the importance of riparian areas for wildlife
has been demonstrated in the western United States. Even though riparian
habitat comprises less than one percent of the total land area in the western
United States, these areas support a tremendous number and diversity of
terrestrial wildlife. In parts of southeastern Oregon and southeastern Wyoming,
more than 75 percent of terrestrial wildlife species are dependent upon
riparian area for at least a portion of their life cycle. In Arizona and
New Mexico, at least 80 percent of all animals use riparian areas at some
stage of their lives, and more than half of these species are considered
to be riparian obligates (Chaney et al. 1990).
Studies in the southwestern United States show that riparian areas support
a higher breeding diversity of birds than all other western habitats combined
(Anderson and Ohmart 1977, Johnson et al. 1977, Johnson and Haight 1985).
Western riparian habitats also harbor the highest noncolonial avian breeding
densities in North America (Johnson et al. 1977). Stevens et al. (1977)
reported riparian plots to contain over ten times as many migrant passerine
species as adjacent nonriparian plots. They also found at least twice as
many breeding individuals and species in riparian zones as in nonriparian
zones. Additionally, over 60 percent of the species which are identified
as neotropical migratory birds use riparian areas in the West as stopover
areas during migration or for breeding habitat (Krueper 1993).
Riparian areas have also been shown to be important to wildlife throughout
the rest of the country as well. Along the Rio Grande in west Texas, several
avian species are present that are absent or rare elsewhere, and numerous
species utilize the river corridor as routes through inhospitable habitat (Hauer, 1977). Tubbs (1980) reported that 73 percent of birds which have
bred in the Great Plains are associated with riparian areas. In the southeastern
United States, studies have shown that floodplain forests support more birds
than upland pine stands (Dickson 1978).
Brinson et al. (1981) summarized some of the key factors making riparian
areas valuable for wildlife habitat. They include woody plant communities,
surface water and soil moisture, spatial heterogeneity of habitats (edges/ecotones),
and corridors (migration and dispersal routes).
Woody riparian communities offer a variety of wildlife habitat values and
may be critical to animal populations where extensive forests are lacking.
In grasslands, rangelands, and intensively farmed regions of the United
States, woody vegetation along waterways is essential for survival of many
wildlife populations.
Dead woody vegetation is an important component of wildlife habitat in riparian
woodlands. Standing dead trees or snags provide nest sites for cavity-dwelling
birds, den trees for small and medium-sized mammals, and feeding, loafing,
and hunting sites for many species. Fallen logs function as cover for wildlife
and as feeding and reproduction sites. Dead woody material that is partly
submerged in water provides excellent habitat for aquatic, amphibious, and
certain terrestrial species.
Surface water is a requirement of many wildlife species ( as an environment
for feeding (e.g., waterfowl, fish-eating birds), reproduction (e.g., amphibians),
travel (e.g., beaver, muskrats), and escape (e.g., amphibians, muskrat,
and beaver). Consequently, many species are rarely found far from water.
Thus water bodies add a dimension of habitat to riparian ecosystems.
Even in the absence of surface water, soil moisture may be ultimately responsible
for major differences in species composition and productivity between riparian
and upland ecosystems. Generally, moister sites are more productive of wildlife
because foods (vegetation, seeds, and insects) are more abundant there,
and vegetation structure is more favorable to a greater number of species.
Several small mammal species (e.g., water shrew) are physiologically restricted
in distribution to areas with high soil moisture. Moist soils are required
by some bird species for feeding (e.g., American woodcock) and as preferred
nesting habitat for others (e.g., prothonotary warbler).
Associated with most riparian ecosystems is substantial development of edge
at the interface between stream channel and riparian vegetation and in the
transition from floodplain to upland plant communities. The interface between
stream and woody plant communities may be one of the greatest values to
wildlife of riparian ecosystems because both density and diversity of species
tend to be higher at this ecotone than in adjacent uplands. Many species
occur almost entirely in this zone. Riparian-upland edges are also very
important for many upland and edge species of wildlife, especially where
woody riparian communities adjoin relatively open rangeland, grassland,
or farmland.
The linear nature of riparian ecosystems provides distinct corridors that
are important as migration and dispersal routes and as forested connectors
between habitats for wildlife. Woody vegetation must be present for many
terrestrial species to find needed cover while traveling across otherwise
open areas. Animals involved in population dispersal may use food and water
from riparian areas during their movements. The value of waterway corridors
for migratory movements may be more accentuated in arid regions than in
humid, more heavily vegetated areas.
Disturbances to Riparian Areas
Flooding and the resulting erosion and deposition are common forces that
shape the riparian area. During extreme flooding, these forces can sometimes
appear devastating, but in most cases the riparian area recovers rapidly.
Other natural disturbance elements include fire, wind, and wildlife (i.e.,
beaver) alterations. Again, these elements usually help build the character
of the riparian area and are not considered to have long-lasting adverse
impacts.
Man-made changes, on the other hand, often do have long-term adverse effects.
Hydromodification --the building of dams across channels, the construction
of levees, and the channelization of the streams--may have the most adverse
impacts upon riparian areas. These modifications significantly alter the
hydrology that is so important to the riparian system. Hydromodifications
also disrupt the continuity of the longitudinal gradient of the riparian
system. Water withdrawals from streams also may reduce base flow, depriving
riparian areas of needed moisture.
The most common disturbance to riparian areas involves clearing vegetation
and converting the area to other uses such as cropland and urban land. Excessive
logging can denude the banks of vegetation. Overgrazing can be quite devastating
to riparian areas because livestock tend to congregate in riparian areas
for extended periods, eat much of the vegetation, and trample streambanks.
Even recreational development can destroy natural plant diversity and structure,
lead to soil compaction and erosion, and disturb wildlife. It should be
noted that some of these disturbance factors can be managed and the damaged
riparian system will recover.
Invasion by exotic plant species (Tamarix, Elaeagnus, and Eucalyptus)
can also adversely impact riparian areas by outcompeting the native vegetation.
As these species become dominant in a riparian area, the overall vegetative
diversity decreases. This results in less favorable habitat for most wildlife
species.
Not all impacts to riparian areas are caused by direct manipulation of the
riparian zone. Offsite disturbances may also have significant effects. The
character of a riparian area is dependent upon the condition of its watershed.
Likewise, the condition of the riparian area is a reflection of the watershed.
Most important is the relationship of watershed hydrology to the riparian
area. In general, the amount and type of vegetative ground cover, the areal
extent of the watershed, and the slope of the terrain are directly related
to the percentage of water that will enter the drainage system as surface
flow or as percolated water. Riparian plant composition, habitat structure,
and productivity are determined by the timing, duration, and extent of flooding.
Modification of the natural dynamic regime, such as land use changes, paving
areas, or vegetation removal, can lead to extended extremes of drought or
flooding, with a resultant drastic decline in productivity (Manci 1989).
Riparian Evaluation Procedures
In recent years a large number of riparian classification, inventory, and
evaluation procedures have been developed. Most of these were developed
to fit local needs or specific programs. Some are comprehensive, requiring
detailed onsite surveys; others are very general. The NRCS West National
Technical Center developed a "Stream and Stream Corridor Physical Inventory"
procedure and the Midwest National Technical Center developed a "Soil
Bioengineering Inventory" procedure. Both of these procedures address
physical features of the stream channel as well as components of the riparian
area. Gebhardt et al. (1990) reviewed eleven procedures selected from a
lengthy list. They are all regional or national in scope, they provide management
information, and they integrate stream attributes and riparian vegetation.
A brief comparison of these eleven procedures is provided in the appendix.
Current Status, Conditions, and Trends
No known comprehensive national inventory has been completed on the status,
conditions, or trends of riparian areas. Local inventories have been conducted
to provide information for specific needs. The U.S. Forest Service and the
Bureau of Land Management routinely gather riparian information for activities
on land they oversee. The U.S. Fish and Wildlife Service has been mapping
riparian areas in selected areas and has published maps for New Mexico and
Arizona. However, very little mapping information that is national in scope
exists for private land.
Swift (1984) estimated that originally the conterminous United States had
30.3 to 40.5 million hectares (75-100 million acres) of riparian habitats
and that between 10 and 14 million hectares (25-35 million acres) currently
remain in the 48 conterminous states.
The 1982 National Resources Inventory (NRI) contained a section on riparian
areas. Data were gathered from points that fell on riparian areas. These
data included the kind of area, kind of vegetation, and width of strip.
Unfortunately, this information was rarely utilized locally and never summarized
nationally. The riparian category was then dropped from later NRI updates.
In 1993 the Environmental Protection Agency (EPA) began a regional assessment
of riparian areas as part of the Environmental Monitoring and Assessment
Program (EMAP). The study involves pilot projects on approximately 1,000
streams across the country. Assessments include the condition of instream
habitat and of riparian vegetation. A summary of results from these regional
pilot projects is expected to be available in May 1996, but these results
are not intended to be extrapolated to represent all riparian areas. At
this time no decisions have been made on expanding the EMAP effort to obtain
data that will be representative of all riparian areas throughout the country.
In September 1993 NRCS conducted a survey of all NRCS State Offices to determine,
among other things, estimates of the extent and quality of riparian areas.
Results from that survey indicated that only three states (Oklahoma, Connecticut,
and Rhode Island) had a statewide inventory of riparian areas. A fourth
state (Arizona) is in the final phase of completing a riparian inventory.
In the absence of a comprehensive inventory of riparian areas, inventories
of water bodies provide a rough indication of the extent and distribution
of these ecosystems. One of the most widely used sets of numbers for the
extent of streams and other water bodies in the United States comes from
the biennial nationwide water quality report to the Congress as required
under Section 305(b) of the Clean Water Act. This inventory, however, is
not yet comprehensive; it is based on data reported by the states to the
Environmental Protection Agency and is primarily a survey of water quality.
The 1990 report indicated that 1.8 million miles of perennial streams and
39.4 million acres of lakes in the United States had been assessed for water
quality (table 1). Some states added nonperennial streams, canals, and ditches
to the 1992 report. This brought the total estimate of assessed rivers and
streams to 3.5 million miles (table 1). It can be assumed that riparian
zones of varying conditions are associated with these water bodies. It is
anticipated that the 1992 NRI data will contain information on the acreage
of perennial streams in different width categories.
In response to a Government Accounting Office (GAO) request for information
on areas that might be involved if the Conservation Reserve Program (CRP)
were to be redesigned to give priority to stream buffer areas, a team at
the Agricultural Experiment Station in Temple, Texas, developed estimates
of miles of streams on agricultural land by three different width classes (Clive Walker, personal communication, June 13, 1995). The team developed
data from the following basic assumptions:
- Where the 1:100,000 scale digitized line graph (DLG) maps showed lines
for both banks of rivers, the rivers were assumed to be perennial.
- Where stream lines were displayed on the 1:100,000 scale DLG maps
but not on the 1:2,000,000 scale DLG maps, those streams were assumed to
be perennial also but narrower than the streams identified in the first
assumption.
- Where stream lines could be found only on the 1:100,000 scale DLG
maps and not on any of the smaller-scale maps, it was assumed that those
small streams were all intermittent.
The total length of rivers and streams on agricultural land was estimated
to be 1.07 million miles. Of this total, 13,000 miles are considered to
be wide rivers, over 89,000 miles are narrow perennial streams, and over
976,000 miles are classified as intermittent streams (table 2). No attempt
was made by the team to estimate the condition of riparian areas along these
streams.
Brinson et al. (1981) estimated the amount of land subjected to flooding
(100-year floodplain) with the potential of supporting riparian ecosystems
at 121 million acres, or 6 percent of the land in the United States, excluding
Alaska. In reality, much less exists in a natural or seminatural forested
condition, and the authors provide a conservative estimate of 23 million
acres for existing riparian vegetation. They also cite another source to
estimate that about 70 percent of the original floodplain forest has been
converted to urban and cultivated agricultural land uses.
Case histories of the status and condition of riparian ecosystems show large
differences in loss from place to place, but as much as a 95-percent loss
of natural vegetation has been reported in some areas. Examples for the
lower Mississippi, Colorado, Sacramento, and Missouri Rivers have been particularly
well documented and, in comparison with estimates of loss of natural vegetation
in uplands, put riparian lands in the category of the most severely altered
ecosystems in the country (Brinson et al. 1981).
Treatment and Management Opportunities
A number of agencies and organizations provide information and assistance
to private land users on methods to protect, enhance, and restore riparian
areas. This assistance includes informational and educational material on
functions and values of riparian areas, planning assistance, design of practices,
financial assistance through cost sharing, and direct assistance in installing
practices. Practices and measures include (but are not limited to) grazing
management systems, fencing, livestock watering facilities, buffer strips,
tree and shrub planting, timber harvesting, installation of culverts and
stream crossings, wildlife habitat management, recreational development,
bank stabilization, and use of instream structures to enhance aquatic habitats.
Some of the most notable USDA programs that offer specific assistance for
riparian areas on private lands are the Conservation Reserve Program (CRP),
the Wetland Reserve Program (WRP), and the Stewardship Incentive Program
(SIP). Many State agencies have programs targeted to riparian areas. The
Pennsylvania Game Commission, for example, cooperates in the Chesapeake
Bay Program with various other state agencies, conservation districts, the
Cooperative Extension Service, NRCS, and the Farm Service Agency (FSA) by
offering financial and technical assistance to farmers who participate in
one of the commission's cooperative public-access programs. The commission
purchases materials for fencing and installs the fence. Private organizations
like the Izaak Walton League of America and Trout Unlimited also have programs
aimed at educating the public on the importance of riparian areas and their
management.
Recommendations
-
Develop a national classification system and evaluation procedure
for riparian areas.
Existing riparian classification systems and evaluation procedures were
developed to address specific local conditions and objectives. As these
systems and procedures use different data, comparisons of results are difficult
or impossible to make. A classification system and evaluation procedure
designed to address national objectives will allow for a nationwide inventory
of riparian conditions. Information on the extent and condition of riparian
areas could then be used in developing agency policies and programs and
in natural resource planning activities.
-
Conduct a periodic national inventory of the status of riparian areas.
At present, riparian area inventories are local or regional in nature and
do not cover the entire country, and attempts to use surrogate measures
(i.e., miles of streams) can provide only "ballpark" estimates
of the extent of riparian areas. These indicators are of no use in determining
the condition of the areas. A direct national inventory utilizing a standard
classification system and evaluation procedure is the only way to obtain
accurate information on the extent and condition of riparian areas. Periodic
inventories, using the same protocols, will provide data that can be used
to evaluate trends in the extent and condition of riparian areas.
-
Increase the amount of research on the functions of riparian areas.
A considerable amount of information has been gained in recent years on
the functions of riparian areas, but much more is needed to support management
decisions at the regional or local level. For example, much of the knowledge
of riparian effects on water quality is based on research in the Southeast
under very specific geologic, hydrologic, topographic, and climatic conditions.
Yet little or no information of this type is known in many other regions.
The water quality improvement processes in the southeastern studies may
apply universally, but the effectiveness of their results may vary considerably.
The need for further research generally applies to all functions of riparian
areas.
-
Improve hydrological, geomorphological, and ecological models.
Computer models are available that make predictions on the various processes
that affect riparian areas. Few of these models, however, contain functions
that specifically integrate hydrological, geomorphological, or ecological
relationships specific to riparian areas. Models need to be improved or
developed for site-specific as well as watershed-level application.
-
Acquire multispectral and high spatial resolution imagery to inventory
and monitor riparian areas.
Remote sensing from LANDSAT Thematic Mapper (TM) and SPOT imageries have
the potential of providing excellent information on riparian communities,
structure, and possibly quality that is relatively easy and time/cost-effective
to obtain in comparison with traditional onsite field mapping. LANDSAT TM
scenes can be used along with USGS hydrography DLG's to help map riparian
ecosystems and their changes through time. Mapping of riparian areas can
be improved by coupling contemporary digital orthophotography with multispectral
SPOT imagery, although very narrow riparian areas would still require traditional
field mapping techniques.
-
Base riparian area management decisions on landscape needs as well
as site-specific requirements.
Direct or indirect disturbances of riparian vegetation may result in habitat
conditions more conducive to a different group of wildlife species than
the communities originally inhabiting the area. These species tend to be
"ecological generalists" that may add to the biological diversity
at the local level. The invading species, however, may also outcompete or
hybridize with unique, native species and actually cause a reduction in
regional biodiversity. Management, therefore, should consider the historical
extensiveness and composition of the riparian area at issue and the risks
involving the invading wildlife and plant species. It is of at least equal
importance that management decisions should not be made exclusively at such
a large scale that they tend to be off-the-shelf remedies. Once the desired
riparian area condition is reached, local resource data should be used to
make site-specific applications.
-
Emphasize riparian areas in many of the natural resource conservation
policies and programs.
Riparian areas have received increased emphasis in recent years in many
agency policies and programs; yet there remain many opportunities through
which these efforts can be strengthened. Existing policies and programs
that affect riparian areas should be evaluated to ensure that clearly stated
objectives for riparian areas are included. An evaluation should also be
conducted to identify weaknesses or missing elements in riparian policy
and programs. Based on these results, new or revised policies, including
executive orders, and programs should be proposed.
Table 1. River Miles Reported from the National Water
Quality Report to Congress
| River miles assessed |
State | 1990 Report | 1992 Report |
Alabama | 40,600 | 76,825 |
Alaska | -- | 405,400 |
Arizona | 6,671 | 148,896 |
Arkansas | 11,506 | 93,275 |
California | 26,970 | 189,300 |
Colorado | 14,655 | 27,195 |
Connecticut | 8,400 | 8,118 |
Delaware | 500 | 3,208 |
Delaware River Basin | 206 | 206 |
District of Columbia | 36 | 186 |
Florida | 12,659 | 52,887 |
Georgia | 20,000 | 67,567 |
Hawaii | 349 | 250 |
Idaho | -- | 118,064 |
Illinois | 14,080 | 34,950 |
Indiana | 90,000 | 36,047 |
Iowa | 18,300 | 83,192 |
Kansas | 19,791 | 131,562 |
Kentucky | 18,465 | 88,518 |
Louisiana | 14,180 | 64,921 |
Maine | 31,672 | 31,672 |
Maryland | 9,300 | 17,000 |
Massachusetts | 10,704 | 8,728 |
Michigan | 36,350 | 56,475 |
Minnesota | 91,944 | 92,680 |
Mississippi | 15,623 | 83,381 |
Missouri | 19,630 | 116,750 |
Montana | 20,532 | 178,896 |
Nebraska | 10,212 | 80,610 |
Nevada | -- | 142,700 |
New Hampshire | 14,544 | 10,841 |
New Jersey | -- | 6,587 |
New Mexico | 3,500 | 119,633 |
New York | 70,000 | 51,729 |
North Carolina | 37,378 | 37,699 |
North Dakota | 11,284 | 11,912 |
Ohio | 43,917 | 29,270 |
Ohio River Valley | 981 | 981 |
Oklahoma | 19,791 | 88,063 |
Oregon | 90,000 | 90,966 |
Pennsylvania | 50,000 | 55,000 |
Puerto Rico | 5,373 | 5,370 |
Rhode Island | 724 | 772 |
South Carolina | 9,900 | 9,900 |
South Dakota | 9,937 | 10,011 |
Tennessee | 19,124 | 18,988 |
Texas | 80,000 | 201,529 |
Utah | -- | 11,808 |
Vermont | 5,162 | 5,264 |
Virgin Islands | -- | -- |
Virginia | 27,240 | 54,418 |
Washington | 40,492 | 40,280 |
West Virginia | 28,361 | 33,044 |
Wisconsin | -- | 56,680 |
Wyoming | 19,437 | 120,260 |
Totals | 1,150,482 | 3,510,464 |
Source: U.S. Environmental Protection Agency, National Water Quality
Report to Congress |
Table 2. River Length Totals on Agricultural Land
State | All rivers and streams, total* | Perennial rivers and streams | Intermittent rivers and streams |
All | Wide | Narrow |
| ------------------------ miles ------------------------- |
Alabama | 17,166.9 | 1,490.4 | 194.2 | 1,296.2 | 15,676.5 |
Arizona | 3,861.4 | 142.9 | 24.0 | 118.9 | 3,718.5 |
Arkansas | 29,749.4 | 2,271.9 | 722.5 | 1,549.4 | 27,477.5 |
California | 32,592.1 | 1,684.8 | 677.1 | 1,007.7 | 30,907.3 |
Colorado | 19,155.2 | 1,469.6 | 167.0 | 1,302.6 | 17,685.6 |
Connecticut | 736.8 | 98.2 | 35.9 | 62.3 | 638.5 |
Delaware | 1,074.0 | 63.0 | 19.0 | 44.0 | 1,011.1 |
Florida | 18,418.2 | 715.5 | 48.2 | 667.2 | 17,702.7 |
Georgia | 13,416.3 | 1,519.2 | 178.1 | 1,341.1 | 11,897.1 |
Idaho | 18,549.6 | 1,496.7 | 269.9 | 1,226.8 | 17,052.8 |
Illinois | 55,778.2 | 6,194.0 | 472.9 | 5,721.1 | 49,584.2 |
Indiana | 22,672.7 | 3,118.6 | 480.7 | 2,637.9 | 19,554.1 |
Iowa | 61,228.1 | 7,303.6 | 521.4 | 6,782.2 | 53,924.5 |
Kansas | 84,402.3 | 4,944.1 | 486.6 | 4,457.5 | 79,458.2 |
Kentucky | 20,794.1 | 2,149.9 | 489.6 | 1,660.4 | 18,644.2 |
Louisiana | 17,746.4 | 2,423.2 | 368.5 | 2,054.7 | 15,323.2 |
Maine** | 1,494.7 | 184.2 | 200.8 | 0.0 | 1,310.5 |
Maryland | 4,333.2 | 433.2 | 391.6 | 41.6 | 3,900.0 |
Massachusetts | 909.0 | 75.9 | 39.4 | 36.5 | 833.1 |
Michigan | 24,679.3 | 2,710.3 | 268.0 | 2,442.3 | 21,968.9 |
Minnesota | 44,543.2 | 5,368.0 | 359.5 | 5,008.6 | 39,175.2 |
Mississippi | 30,810.2 | 2,151.4 | 191.5 | 1,959.8 | 28,658.8 |
Missouri | 61,801.2 | 6,948.9 | 444.1 | 6,504.7 | 54,852.3 |
Montana | 33,271.1 | 2,756.6 | 457.6 | 2,299.0 | 30,514.6 |
Nebraska | 53,291.2 | 4,408.2 | 443.2 | 3,965.0 | 48,883.1 |
Nevada | 3,415.6 | 164.9 | 2.5 | 162.4 | 3,250.7 |
New Hampshire | 678.9 | 49.0 | 74.1 | 0.0 | 629.9 |
New Jersey | 1,960.0 | 222.7 | 32.7 | 190.0 | 1,737.3 |
New Mexico | 3,561.9 | 276.6 | 86.7 | 189.9 | 3,285.3 |
New York | 17,368.0 | 1,628.2 | 416.1 | 1,212.1 | 15,739.8 |
North Carolina | 16,175.6 | 1,706.4 | 186.4 | 1,519.9 | 14,469.2 |
North Dakota | 37,011.6 | 2,753.4 | 146.9 | 2,606.5 | 34,258.2 |
Ohio | 40,001.9 | 3,901.2 | 391.0 | 3,510.1 | 36,100.7 |
Oklahoma | 41,879.5 | 3,674.5 | 532.6 | 3,141.9 | 38,205.1 |
Oregon | 14,915.4 | 1,276.3 | 259.5 | 1,016.8 | 13,639.1 |
Pennsylvania | 18,452.0 | 1,900.2 | 261.1 | 1,639.1 | 16,551.8 |
Rhode Island** | 69.1 | 2.0 | 6.2 | 0.0 | 67.1 |
South Carolina | 6,872.6 | 1,031.6 | 106.4 | 925.3 | 5,841.0 |
South Dakota | 42,828.6 | 2,554.6 | 132.7 | 2,421.9 | 40,273.9 |
Tennessee | 24,898.0 | 1,795.8 | 265.4 | 1,530.4 | 23,102.2 |
Texas | 49,554.5 | 5,894.4 | 694.8 | 5,199.6 | 43,660.1 |
Utah | 6,636.2 | 440.8 | 30.9 | 409.9 | 6,195.4 |
Vermont | 1,953.0 | 247.0 | 133.4 | 113.5 | 1,706.1 |
Virginia | 13,752.1 | 1,239.6 | 435.0 | 804.6 | 12,512.5 |
Washington | 17,396.4 | 1,281.8 | 249.1 | 1,032.7 | 16,114.6 |
West Virginia | 4,948.6 | 401.3 | 167.9 | 233.4 | 4,547.3 |
Wisconsin | 28,050.8 | 2,922.6 | 269.1 | 2,653.5 | 25,128.1 |
Wyoming | 9,845.7 | 1,006.8 | 177.6 | 829.3 | 8,838.9 |
48 States | 1,074,700.9 | 98,494.1 | 13,009.7 | 85,530.4 | 976,206.6 |
Source: USDA Agricultural Research Service, Texas Agricultural Experiment
Station, Blackland Research Center, Temple, Texas.
* Includes all streams shown on USGS digitized line graph maps at the 1:100,000
scale.
**Discrepancies in the numbers given for these states are due to inconsistencies
between the two maps used (1:100,000 and 1:2,000,000).
|
References
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Appendix
Riparian Classification Comparison (Physiographic, Geologic, and Climatic
Features)
Name of Classification or Description | Physiographic Features | Geologic Features | Climatic Features |
1. Standard Ecological Site Description | General orientation, geomorphic landform, slope ranges, elevation ranges | Specific formations, parent rock or material included | Range of average and seasonal distribution of precipitation and temperature for soil and ambient air |
2. Southwest Wetlands | Inherent to some degree in biogeographic realm | Not provided | Inherent in climate zone |
4. Riparian Zone Associations | Provided in description | Provided in description | Provided in description |
5. Riparian-- Wetland Sites in Montana | Geomorphic landform & orientation, elevation ranges, provided in narrative | Provided | Provided |
6. Nevada Task Force Approach | Provided at ecological site description level as in (1) above |
7. Riverine Riparian Habitats | Provided as geologic district, land type association, and land type | Provided as geologic district, land type association | Provided as domain and division (Trewartha and Horn 1980) |
9. Ecosystem Classification Handbook | Includes geomorphic landform, valley bottom type and subtype, Horton stream order | Parent material description | Not provided |
10.Wetlands and Deepwater Habitats | General, from Bailey 1976 | Not provided | General, from Bailey 1976 |
11.Riparian Community Types | Provided | Provided | Provided |
Source: Gebhardt et al., 1990. Classifications 3 and 8 are not included
here. |
Riparian Classification Comparison (Soils, Water, and General Physical
Features)
Name of Classification or Description | Soils Features | Water Features | General Physical Features |
1. Standard Ecological Site Description | Description of major properties,associationof soils, NRCS conventions, & soil taxonomy standards | Stream type as defined by Rosgen. Flow regime, surface-ground-water features | Given in site description; similar to a site type |
2. Southwest Wetlands | Not provided | Not provided | Not provided |
4. Riparian Zone Associations | Provided | Riverine systems are not specifically discussed, but water regime and fluvial process are generally covered | Basic unit is riparian landform. Includes soils, fluvial process and water regime |
5. Riparian--Wetland Sites in Montana | Provided as standard NRCS soil taxonomy | Flow regime and sub-surface features aregenerally covered | Given in site description. Includes soils, fluvial processes and water regimes |
6. Nevada Task Force Approach | Provided in naming convention | Stream type as defined by Rosgen. Moisture condition as defined by Johnson & Carothers, 1981 | Provided in naming convention |
------ Also provided at the ecological level of classification ------ |
7. Riverine Riparian Habitats | Provided in land type, valley bottom units valley bottom units | Described in riverine-riparian complexes and in riverine types | Described at the riverine site level |
9. Ecosystem Classification Handbook | Uses NRCS conventions | Stream type as defined by Rosgen | Basic physical description is called site type |
10.Wetlands and Deepwater Habitats | Provided as modifiers. Uses NRCS hydric soils descriptions | Identified at the sub-system level, substrate at the class and sub-class level, water persistence at the subsystem level | Provided as modifiers |
11.Riparian Community Types | Provided, NRCS standard | Not provided | Provided |
Source: Gebhardt et al., 1990. Classifications 3 and 8 are not included
here. |
Riparian Classification Comparison (Ecosystem Description, Existing Vegetation)
Name of Classification or Description | Ecosystem Description | Existing Vegetation |
Class | Subclass | Dominance | Composition |
1. Standard Ecological Site Description | Major land resource area (MLRA) given | Can be derived from dominance and composition | Provided | Provided |
2. Southwest Wetlands | Inherent in bio-geographic realm, formation type, vegetation, regional formation (biome) | Obtained from formation type and regional formation | Series and association | Provided |
4. Riparian Zone Associations | Provided | Can be obtained from dominance information | Provided | Provided |
5. Riparian--Wetland Sites in Montana | Provided Can be used with USFWS (10) | Provided | Provided | Provided | Provided |
(called formation class and subclass) |
6. Nevada Task Force Approach | Generally provided by land classes | Provided | Provided | Provided | Provided |
--- Also provided at the ecological site level of classification --- |
7. Riverine Riparian Habitats | Provided | Can be obtained from dominance information | Provided | Provided |
9. Ecosystem Classification Handbook | Provided | Provided in range, ecosystem, and vegetation type | Provided | Provided |
10.Wetlands and Deepwater Habitats | Generally provided at system level as marine, estuarine, riverine, etc. | Provided | Provided | Provided | Not required |
11.Riparian Community Types | Provided | | | Provided | Provided |
Source: Gebhardt et al., 1990. Classifications 3 and 8 are not included here. |
Riparian Classification Comparison (Functional Ecological Description,
PNC, Ecological Units/Site, Community Type)
Name of Classification or Description | Functional Ecological Description | PNC | Ecological Units Ecological Site | Community Type |
1. Standard Ecological Site Description | Provided in site narrative | Provided | Provided | Provided in site interpretation narrative |
2. Southwest Wetlands | Inherent to some degree at all levels | Not specifically provided | Association |
4. Riparian Zone Associations | Provided | Provided | Riparian association | Provided |
5. Riparian-- Wetland Sites in Montana | Provided | Provided; called habitat type, or riparian association in describing what could occur on a riparian site type | Provided |
6. Nevada Task Force Approach | We assume a site description would accompany the site name | Provided | Provided | Provided; called riparian community |
7. Riverine Riparian Habitats | Provided | Provided | Provided | Provided |
Also includes riverine-riparian complexes, which appear very useful in relating riparian and riverine sites |
9. Ecosystem Classification Handbook | Provided | Provided; called habitat type, and a more detailed habitat type phase | Provided; includes broader unit, called vegetation type, which groups similar community types |
10.Wetlands and Deepwater Habitats | Not included | -------------------- Not required -------------------- Could be placed as modifiers |
11.Riparian Community Types | Provided | Not given. Stable community given | Not provided | Provided |
Source: Gebhardt et al., 1990. Classifications 3 and 8 are not included
here. |
Riparian Classification Comparison (Description of Procedures' Relevance
to Site Mangement)
Name of Classification or Description | Description of Procedures' Relevance to Site Management |
1. Standard Ecological Site Description | Provided in site interpretation narrative. Relates various seral stages or community types with management actions, such as grazing, wildfire, and recreation. Also provides description of water-soil interaction and related limiting factors. |
2. Southwest Wetlands | Not provided, but could be easily accommodated in a site description, if information on cause and effect and site correlation is collected. |
4. Riparian Zone Associations | Provided in site interpretation narrative. Relates various plant zone associations and community types with management actions, such as grazing, wildfire, and recreation. Also provides description (Kovalchik) of water-soil interaction and related limiting factors. |
5. Riparian-- Wetland Sites in Montana | Provided in site interpretation narrative. Relates various community types with management actions, such as livestock,timber, wildlife, fisheries, fire, soil management and rehabilitation opportunities, and recreational uses and considerations. |
6. Nevada Task Force Approach | The reference provides an example of how site management relates to the classification system. It is assumed that site management features would be included in a classification conducted by the procedure. |
7. Riverine Riparian Habitats | Provided in site interpretation narrative. Relates various community types with management actions, such as grazing, wildfire, recreation, etc. Also provides description of water-soil interaction and related limiting factors. |
9. Ecosystem Classification Handbook | The ECODATA procedure includes a number of analysis techniques specifically for management. It is assumed that site management features would be included in classification documentation produced as a part of the interpretation and analysis of the ECODATA data base. |
10.Wetlands and Deepwater Habitats | Not provided. |
11.Riparian Community Types | Some information is given on application to site management. Management information is given under succession/management sections. |
Source: Gebhardt et al., 1990. Classifications 3 and 8 are not included
here. |
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