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AN INTEGRATED APPROACH FOR RIPARIAN INVENTORY
Mark Jensen and Pat Green
Riparian and aquatic ecosystems comprise a relatively
small fraction of National Forest lands; however, their
value for a variety of resources uses is considerable. Increased interest in management of these ecosystems dictates that an integrated systematic approach to riparian
description be employed if the following questions are to
be addressed:
1. What types of riparian areas do we manage?
2. What is the location and extent of such areas?
3. How do different types of riparian areas respond
to management?
4. What is the existing condition of our riparian areas?
5. What is a reasonable "desired future condition" for
such areas?
6. What types of treatment are appropriate if desired
future conditions for riparian areas are to be achieved?
Current information for these ecosystems has been generated from various inventories of existing condition (for
example, timber survey, fishery survey, best management
practice monitoring, water quality monitoring). A description of riparian and aquatic ecosystem site potential is required if existing information is to be utilized in answering
the questions posed earlier. To meet management needs,
this site potential description must be hierarchical in design and integrate both riparian and aquatic ecosystem
components with upland systems. The methods of riparian
map unit design and sampling (Jensen 1990) utilized by
the Northern Region, Forest Service, accomplish these
needs. This paper presents an overview of those methods.
graphic maps, aerial photos, land systems inventory). Basic climate, geology, landform, and soil parameters that
affect stream sediment delivery and transport, upland
slope hydrology, and upland potential vegetation are synthesized at this level of mapping. Map unit descriptions
are stored in various databases for characterization of
watersheds and stream reaches. Level 1 map units are
commonly delineated on 1:100,000 to 1:24,000 topographic
base maps for future geographic information system
application.
Level 2 map unit descriptions and databases are developed from field reconnaissance-level surveys of stream
reaches. Stream channel morphology, bank stability,
sedimentation, and potential riparian vegetation-soil
relationships are examples of information contained
within such riparian descriptions. Level 2 map units
are commonly delineated as line segments or polygons
on 1:24,000 or larger base maps and are used to characterize stream reach segments.
Level 3 map unit descriptions are developed based upon
project level objectives. The following surveys are examples of data sources from which level 3 map unit descriptions may be developed: order 1 soil survey, fishery habitat survey, riparian site type survey. Level 3 map units
are delineated on 1:24,000 (or larger) base maps and are
commonly used to describe, in detail, specific components
oflevel2 map units (for example, soil taxa and stream
habitat).
HIERARCHICAL MAP UNIT COMPONENTS
Nine hierarchical components (table 2) are utilized
in describing riparian and aquatic map units following
Jensen and others (1989). These hierarchical components
describe the landscape by progressively more refined criteria, from which increasingly specific interpretations of
the landscape may be derived. The various scales of description facilitated by these components allow regional
to site-specific assessments of site potential. Site-specific
information used to describe lower component levels can
also be aggregated to develop interpretations for higher
component levels.
SITE POTENTIAL MAP UNIT DESIGN
A description of site potential is required if assessments
of riparian condition are to be made; consequently, site
potential map units are commonly the first item developed
in riparian inventory. Riparian site potential map units
may be developed at different scales of resolution dependent upon management needs.
Three levels of map unit design are presented, which
are approximately equivalent to those utilized by other
Forest Service Regions in riparian inventory (USDA FS
1990, 1989). These levels range from rapid, office-based
procedures Oevel 1) to detailed, field-verified procedures
Oevel 3). Mapping scale, classification, and map use are
all influenced by the level of map unit design utilized in
riparian inventory (table 1). Following is a brief description of the three levels of riparian site potential map unit
design utilized in the Northern Region.
Level 1 map unit descriptions are developed in the office
utilizing existing sources of information (for example, topo-
CONCLUSIONS
Site potential map unit descriptions provide a conceptual categorization of the landscape useful in assessing
riparian condition (the value of a riparian area for a particular set of resource uses relative to its potential). Given
the fact that many of the components of levels 1 and 2
map units do not change in response to management activities (for example, landform, geology, and valley bottom
gradient), these map units may be used to consistently
describe similar environments regardless of disturbance
history.
Mark Jensen is Regional Soil Scientist, Northern Region, Forest Service,
U.S. Department of Agriculture, P.O. Box 7669, Missoula, MT 59807. Pat
Green is Forest Soil Scientist, Nez Perce National Forest, Forest Service,
U.S. Department of Agriculture, Route 2, Box 475, Grangeville, ID 83530.
237
Table 1-Comparison of riparian/aquatic site potential map unit design levels
Map unit level
Item
2
1
3
Level of application
Regional assessments,
forest planning
Forest and project
planning
Project
planning
Minimum mapping scale
1 :100,000-1 :24,000
1:24,000
1:24,000
or more
detail as
needed
Components
Ecoregion/area
Valley bottom
subtype
Appropriate
to need
Geologic group
Rosgen stream
type
landtype association
Fishery habitat
Valley bottom Landtype
Riparian
vegetation and
soil composition
Upland vegetation and
soil composition
Stream channel
and bank
characteristics
General watershed
description;
synthesis of existing
information;
describe sedimentation
General stream
reach
description
Specific stream
reach
description
Describe
stream system
equilibrium
Baseline
monitoring
Describe high-water
yield areas
Describe
stream
sedimentation
Quantify stream
condition
Describe unstable
watersheds
Describe highvalue fisheries
Quantify
riparian
condition
Describe high-energy
watersheds
Describe
potential
riparian
vegetation
Validate forest
planning
standards and
guidelines
Common application
Hansen, P.; Pfister, R.; Joy, J. 1988. Classification and
management of riparian sites in southwestern Montana.
Missoula, MT: Montana Riparian Association, University
of Montana.
Jensen, M. E. 1990. Riparian and aquatic ecosystem
sampling and analysis procedures. Missoula, MT: U.S.
Department of Agriculture, Forest Service, Northern
Region.
Jensen, S.; Ryel, R.; Platts, W. S. 1989. Classification of
riverine/riparian habitat. Unpublished paper on file at:
U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Boise, ID.
Rosgen, D. L. 1985. A stream classification system. In:
Riparian ecosystems and their management. Fourth
North American riparian conference; 1985 April 16-18;
Once the site potential map unit has been determined
for a given reach, its current features are contrasted to
other managed expressions of similar site potential to determine its condition. Assessments of riparian condition
are meaningless without an understanding of site potential; consequently, site potential map unit development
should be the first process undertaken in riparian inventory. An example of a level 2 site potential map unit description (developed by Green) is provided in appendix A.
REFERENCES
Bailey, R. G. 1978. Description of the ecoregions of the
United States. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Region.
238
U.S. Department of Agriculture, Forest Service. 1990.
Integrated riparian evaluation guide. Ogden, UT: U.S.
Department of Agriculture, Forest Service, Intermountain Region.
Wertz, W. A.; Arnold, J. F. 1972. Land systems inventory.
Ogden, UT: U.S. Department of Agriculture, Forest
Service, Intermountain Region.
Tucson, AZ. Gen. Tech. Rep. RM-120. Fort Collins, CO:
U.S. Department of Agriculture, Forest Service, Rocky
Mountain Forest and Range Experiment Station: 91-95.
U.S. Department of Agriculture, Forest Service. 1989.
Riparian area survey and evaluation system.
Albuquerque, NM: U.S. Department of Agriculture,
Forest Service, Southwestern Region.
Table 2-Hierarchical components of riparian map unit design. Ecoregions through valley bottom landtype
are used in designing Levell map unit descriptions and are not significantly altered by management practices. Valley bottom subtypes through landform are used in designing Level 2 map unit
descriptions and are not commonly significantly altered by management practices. Vegetation
type through stream state are used in designing Level 3 map unit descriptions and may be significantly altered by management practices
Component
Description
Ecoregion
An area determined by similar physiographic province and dominant lifeform
(Bailey 1978).
Ecoregion area
A portion of an ecoregion with similar climate and natural vegetation. Factors
such as seasonal storm pattern, annual temperature, and biogeography are utilized in describing ecoregion areas.
Geologic group
A portion of an ecoregion area with relatively homogeneous parent materials,
distinguished from surrounding groups by structure, degree of weathering, dominant size-fractions of weathering products and water-handling characteristics (for
example, porosity, permeability, runoff potential). Geologic groups include both
uplands and bottom lands, and are commonly derived from Forest Service land
system inventory subsection maps (Wertz and Arnold 1972).
Landtype association
A portion (or all) of a geologic group that is distinguished by a dominant geomorphic process (for example, glacial, fluvial, alluvial, lacustrine). Landtype associations include both uplands and bottomlands and are commonly described in
Forest Service land system inventories.
Valley bottom
landtype
A portion of a landtype association distinguished by landform and position.
Landtypes correlate with associations of soils and plant communities, and constitute the most refined level of land systems inventory conducted in the Northem
Region of the Forest Service.
Valley bottom
subtype
A portion of the valley bottom landtype distinguished by fluvial geomorphic
properties that influence the manner in which water and sediment move through
the system. Valley bottom subtypes are commonly distinguished by significant
changes in Rosgen (1985) stream type.
Landform
A portion of the valley bottom subtype with distinctive morphology (for example,
channel, flood plain, levee, and alluvial fan). Landforms are usually highly correlated with soils and vegetation community distribution.
Vegetation type
A distinctive plant community that is usually identified by lifeform class (for example, forested, shrub, herbaceous) and dominant plant species in the overstory
and understory canopies.
Stream state
The existing state of the stream relative to its equilibrium condition within the valley bottom subtype. Factors such as stream downcutting or widening are considered in assessing stream state.
239
APPENDIX A: EXAMPLE OF A LEVEL 2 RIPARIAN MAP UNIT DESCRIPTION
DEVELOPED BY PAT GREEN, NEZ PERCE NATIONAL FOREST
C6 CHANNELS, GRANITIC SOURCE AREA
CARROS·CARAQU/DANINT·ABLA/CACA VEGETATION COMPLEX
Beaked sedge-Aquatic sedge/timber danthonia-Subalpine fir/bluejoint reedgrass
ENVIRONMENTAL DESCRIPTION
Elevation (It):
Landforms:
,
.-..
~"
CHANNEL DESCRIPTION
Range = 5000 - 6000
Mean = 5170
In undisturbed systems this C6 channel (Rosgen 1985) is narrow,
%), high sinuosity
deep and meandering, with a low gradient
(>2.5) and width/depth ratio of 3 or less. Channel materials are
gravels and sands, and the stream is deeply entrenched and poorly
confined, with seasonal flooding.
«.9
Narrow to moderately broad (1 ()().6QO
feet wide) nearly flat low relief alluvial
basins, including weamsides and depressions, low floodplains, old flooplains
and rolling uplands with lower slopes
within the stream influence zone.
Stream gradient:
Range = .5 - .9
Mean = .7
Microclimate:
Frost pocket
Corresponding National Wetlands Inventory Map Unit:
PEMIC
Corresponding
General Forest Riparian Type:
F4
SOIL DESCRIPTION
Sandy Typic Cryofluvents and Cryopsamments occur in low floodplains in this riparian type. Organic surface layers up to 20 inches
thick may be present in the wettest low lying positions. Soils with
these layers are Cryohemists.
Medial over sandy Andeptic Cryofluvents and Typic Cryopsamments are on higher floodplains. Sandy Andic Cryochrepts are on
upper terraces and lower slopes of adjacent uplands.
Range In Soil Characteristics
Sandy Typic Cryofluvents and Cryopsamments have dark brown
sandy loam surface layers 5 to 7 inches thick that overly dark gray to
light brownish gray loamy sands and sands.
LOCATION AND RIPARIAN LANDFORMS
This riparian type commonly occurs on nearly flat, low lying alluvial
floodplains at middle to upper elevations in the Florence basin and
other geologic zones dominated by quartz monzonite of the Idaho
batholith. Surrounding uplands are low rolling hills and moderately
steep rolling uplands.
Depth to gleying is 5 to 24 inches. The seasonaly low water table is
o to 40 inches, and the water table is near or slightly above the soil
surface much of the growing season.
The map below shows the typical position of this riparian reach in the
landscape.
Andeptic Cryofluvents have loam or silt loam surface layers and
grayish brown subsoils and substrata. The seasonaly low water table
is 30 inches or more.
":" ..,--'
Andic Cryochrepts have dark brown or strong brown silt loam or
sandy loam loess influenced surface layers and brown sand or
loamy sand substrata. The seasonal low water table is 40 inches or
more. In lower slope positions, subsoil and substrata horizons may
have few to common strong brown mottles.
240
VEGETATION DESCRIPTION
The natural vegetation of this riparian type is a complex dominated
by sedge and grass plant communities. These plant communities
are illustrated in the diagram below.
1) Carex rostrata is the dominant plant species along low stream
margins and in depressions. This plant community occupies 45 percent of the riparian reach.
2) The Carex aquatilis/Danthonia intermedia plant community Is on
drier sites. This plant community occupies 35 percent of the reach.
3) The Abies lasiocarpalcalamagrostis canadensis habitat type 0ccurs on low terraces and lower slopes of adjacent uplands. Pinus
contorta and Vaccinium scoparium usually dominate these stands.
This habitat type occupies about 20 percent of the reach (i.e., riparian area and riparian influence zone).
3
----_.-
P.alpinum, C. aquatilis, C. canadensis, and Agrostis exerata are
heavily grazed. Trifolium repens and Fragaria vesca tend to increase
their cover on compacted sites.
Along the channel, C. rostrata and C. aquatilis form a dense root mat
that is highly resistant to erosion. Stream banks readily undercut
below this root mass, especially in this geologic material where thin,
finer textured surface soil layers overlay sands. This process forms
pools with good shade and hiding cover for resident fish. However,
the banks will slough with trampling. Once banks are damaged and
stream dynamics are changed, renewed stream downcutting may
lower the water table and make maintainance of the sedge plant
community difficult.
Within elevations of 4000 to 6500 feet, and where water tables are
close to the surface, C. rostrata is a good bank restoration species
(Hansen and others 1988).
Pool quantity and quality can easily be damaged in this riparian type
due to the high proportion of sands in channel sediments and noncohesive bank materials which are susceptible to trampling and
sloughing. Trees and shrubs are not readily available for in stream
cover or debris reruitment. Timber management on adjacent forest
sites can influence this type through raising the water table temporarily as a consequence of timber harvest, and introducing additional
sand size sediment through road construction and harvest operations.
Grazing and wildlife management influence the condition of this
riparian type. Management should maintain natural channel and
vegetation characteristics and low stream width/depth ratios which
help sustain flushing flows to move excess sands out of the system.
MANAGEMENT
Herbage production in the C. rostrata plant community is high (1700
to more than 3500 pounds per acre) but utilization of C. rostrata is
low. C.aquatilis is only lightly utilized. Calamagrostis canadensis,
Agrostis tenuis, Phleum alpinum and Triseum wolfii are heavily utilized when the site is dry enough to be accessible to cattle. As much
as 80 percent of the available forage from these species is used on
the drier sites that are accessible for much of the growing season.
Herbage production in the C. aquatilis/D. intermedia community is
moderate (1200 to 1800 pounds per acre). C. canadensis and P.
alpinum are heavily utilized. This community is on drier sites than the
C. rostrata community, Is available for cattle grazing for longer periods, and can suffer greater trampling damage. It is less often adjacent to streambanks, and grazing impacts are less likely to affect
stream channels.
The Ables lasiocarpalCalamagrostls canadensis habitat types are on
drier sistes that offer shade and resting sites as well as areas of
forage. Production is moderate (1000 to 1600 pounds). These areas
are heavily used by cattle, deer, and elk. Even X. tenax and V.
scoparium are browsed and hedged. Palatable grasses, Including
241
This channel type is very sensitive to vegetation change. Impacted
areas commonly change to C3 or C4 channels, which display unstable banks, stream downcutting and a drop in the local water table.
Under uncontrolled season long grazing systems, soils are compacted and native plants are damaged. This process results in bank
damage and soil erosion.
Since C. rostrata is not highly palatable, more palatable associated
species such as Calamagrostis canadensis should be used to assess utilization levels. Proper levels of grazing range from light to
moderate (40% utilization).
Salix boothii at lower elevations and Salix wolfii at higher elevations
may be planted to assist in bank stabilization by providing deeper
rooting material. Physical bank protection measures, such as fences
or log barriers, may be necessary to prevent livestock trampling of
bank•.
Under badly degraded conditions, appropriate fish habitat improvement structures include bank placed boulders, floating log covers or
submerged log shelters located on straight reaches, and reestablishment of deep rooted vegetation along stream banks.
GENERAL PLANT COMMUNITY CHARACTERISTICS
The following is a series of tables which summarize
basic ecosystem data collected at 6 sites used to describe this riparian reach.
Species
Forbs
ANEPIP
ANTMIC
ASTOCC
COPOCC
EPIWAT
FRAVES
SANSIT
TRIREP
VIOLA
XERTEN
Average Percent Canopy Cover by Life Form for Each Plant
Community
CARROS
CARAQU/
DANINT
ABILAS/
CALCAN
Life Form
Tree
Shrub
Graminoid
Forb
Fern
1
0
87
20
0
0
0
80
20
0
80
30
30
30
.5
Ferns!
Mosses
MOSS
The following table displays constancy and average canopy cover
values for important plant species by plant community.
Species
CARROS
CARAQU/
DANINT
Graminoids
AGREXA
AGRSCA
AGRTEN
CALCAN
CARAQU
CARl NT
CARROS
DANINT
JUNENS
MUHFIL
PHLALP
life Form
ABILAS/
CALCAN
100(2.2)
100(38.6)
Graminoid
Forb
Shrubs
VACCES
VACSCO
100( 2.2)
CARAQU/
DANINT
100(5.0)
ABILAS/
CALCAN
100(1.2)
100(1.4)
100(1.6)
100(1.2)
100( 1.3)
100(6.3)
100( 4.5)
80(5.6)
100( 2.2)
100(2.1)
100(30.0)
Production (Ibs/ac/yr-dry wt.) by Plant Community
Shrub
Trees
ABILAS
PINCON
CARROS
80(3.2)
100(18.4)
CARROS
CARAQU/
DANINT
ABILAS/
CALCAN
0-50
0
50-200
1700-3600
1200-1800
800-1200
60-200
100-300
50-200
Ground Cover Composition (%) by Plant Community
CARROS
CARAQU/
DANINT
ABILAS/
CALCAN
0-10
0-3
0-10
0
0
0
Basal Vegetation
.5-10
1-10
1-10
Woody Debris
.5-10
0-1
10-30
Litter
20-70
60-80
50-80
Component
70 (3.5)
100(3.4)
100( 4.5)
100( 7.7)
100(17.7)
100(1.3)
100(31.0)
Bare SoiVGravel
100(3.0)
100(7.2)
100(3.2)
100(2.4)
Rock
100(13.2)
100( 3.7)
100(6.4)
100( 1.3)
100(1.4)
242
Average Summer Forage Values (Lbs/ac/yr - dry wt.) by Plant
Community
RESOURCE VALUE RATINGS
Animal
Species
The following is a listing of resource value ratings associated with the
community types described in this riparian reach. Analysis employed follows methods outlined in Chapter 5 (ECODATA Data
CARROS
CARAQU/
DANINT
ABILAS/
CALCAN
1171
749
686
792
580
461
Elk
1082
815
689
Moose
885
616
557
Cattle
Bases and ECOPAC Analysis Software) of the Ecosystem ClassificaWhite
Deer
tion Handbook, U.S. Forest Service, Northern Region.
Wildlife Cover Table by Plant Community
Index
CARROS
CARAQU/
DANINT
ABILAS/
CALCAN
Hiding
Cover (%)
at 4.0 ft.
View Height
0
0
27
Plant Cover, 40 ft. Index
0
Summer
Thermal
Cover
Index
33
Winter
Thermal
InCover
dex
0
Wind
Blockage
Index
0
Tail
Percent Elk-Cattle Forage Similarity by Season of Use and Plant
Community Type
CARROS
CARAOU/
DANINT
ABILAS/
CALCAN
Summer
96
99
94
Winter
92
80
92
Season
0
33
63
73
Indices of Plant Community Diversity
Diversity
Index
0
0
CARROS
CARAOU/
DANINT
ABILAS/
CALCAN
.19
.15
.82
1.09
1.20
1.08
37
3043
42
Structural
Diversity
ShannonWeaver Index
4
Species
Richness
Note: Index values range from 0 (low) to 100 (high).
243