HomeMy WebLinkAboutIndicators of Freshwater Wetland Function and Value
INDICATORS OF FRESHWATER
WETLAND FUNCTION AND VALUE
FOR PROTECTION AND 1VI~NAGEMENT
Report No. 93-01
May, 1993
North Carolina .Department of Environment,
Heath, and Natura# Resources
Division of Environmental Management
Water Qua#ity Section
INDICATORS OF FRESHWATER WETLAND FUNCTION AND
VALUE FOR PROTECTION AND MANAGEMENT
North Carolina Department of
Environment, Health, and Natural Resources
Division of Environmental Management
Water Quality Section
May, 1993
This document has been approved
Steve W. Tedder
Chief, Water Quality Section
by
~~4 ~ ~ ~~i s y3
Date
TABLE OF CONTENTS
Introduction ........................................................................................................ 1
Water Storage ..................................................................................................... 2
Bank Stabilization ............................................................................................. 6
Retention of Sediment and Associated Pollutants ............................ 1 0
Removal of Nitrogen and Phosphorus .................................................... 1 6
Wildlife Value ................................................................................................... 1 9
Aquatic Life Value .......................................................................................... 2 4
Outdoor Recreation and Education ........................................................... 2 8
Economic Value ................................................................................................ 2 9
List of References ............................................................................................ 3 2
Appendix I: Glossary .................................................................................... 4 1
Appendix II: Rare Plant Species in North Carolina ......................... 4 5
List of Tables
Table 1 Importance of various wetland characteristics to
water storage .............................................................................. ~
Table 2 Plant species of potentially high value for
shoreline anchoring ................................................................. 6
Table 3 Importance of various wetland characteristics
to streambank stabilization ................................................ 9
Table 4 Importance of various wetland characteristics
to sediment retention ............................................................ 1 5
Table 5 Criteria for evaluating nitrogen removal of various
wetland types based on hydroperiod ............................ 1 7
Table 6 Importance of wetland characteristics to nutrient
removal and transformation .............................................. 1 8
Table 7a Common plant species preferred by waterfowl........ 2 0
Table 7b Wetland tree and shrub species important for
wildlife food .............................................................................. 2 1
Table 8 Importance of wetland characteristics to wildlife.... 2 3
Table 9. Importance of wetland characteristics to aquatic
life .................................................................................................. 2 7
Table 10 The potential timber values of forested wetlands... 2 9
Table 11 Estimates of timber value based on basal area (BA)
and diameter at breast height (DBH) .............................. 3 0
i
List of Figures
Figure 1 a Wetland with channel flow .................................................. 4
Figure lb Wetland with no channel flow ............................................ 4
Figure 2 Headwater and bottomland systems relative to
uplands, water movements, and pollutant
sources ......................................................................................... 1 4
Figure 3 Wetland with well balanced proportions and a
high interspersion of vegetation and open water..... 2 6
ii
INTRODUCTION
This report is the product of an extensive scientific literature
search for hydrological, pedological, chemical, and biological criteria
that could prove useful for rapid assessements of wetland functions
or for numeric standards of water quality for wetlands. Qualitative
and some quantitative indicators were chosen from the literature
that could most appropriately be applied to wetlands in North
Carolina.
The results of this work have been incorporated into the third
version of the "North Carolina Division of Environmental Management
Wetland Rating System." This rating system serves as a tool for
making decisions regarding 401 Water Quality Certifications by the
Division of Environmental Management. This system will continue to
be updated as comments are received and more pertinent wetlands
research becomes available.
As a by-product of this work, a database of over 400 references
pertaining to the functions and values of wetlands is available to
those interested in this information. Please write or call (919-733-
1786) Cherri Smith to request a copy of this database.
Much of the terminology in this document was taken from the
Wetlands Evaluation Technique [WETJ (Adamus 1987). A glossary is
provided in Appendix I. Also, refer to Appendix II for a list of rare
plant species in North Carolina. The species are listed by wetland
type.
WATER STORAGE
Water storage is a physical process that occurs in the depression
containing the wetland or within the substrate of the wetland. It
refers to the storage or conveyance of floodwaters or groundwaters
and the storage or retardation of runoff. Geomorphic variables as
well as characteristics of the wetland determine how much water is
stored.
The location and distribution of wetlands within a watershed
influence how flow is retarded and distributed. Wetlands located in
headwaters generally desynchronize peaks in tributaries and main
channels, and lakes and wetlands with restricted outlets hold back
floodwaters and attenuate flood peaks (Carter et al. 1978). A study
by Novitzki (1978a) indicates that 50 percent of the reduction in
flood peaks can result from the first five percent of wetland area in
the watershed. Adamus and Stockwell (1983) state that storage of
flood waters is significant only in palustrine, lacustrine, and upper
riverine wetlands. Tidal riverine and estuarine wetlands rank the
lowest in this method of functional assessment because of their
position in the landscape.
The extent of depressional storage is an important characteristic
determining the ability of a wetland to retain water. Skaggs et al. (in
preparation) note that Carolina Bays provide substantial depressional
storage since they are typically enclosed by a sandy rim that may be
more than three feet higher than the bottom. Adamus et al. (1987)
suggest that the critical size for storage of significant amounts of
flood waters within Carolina Bays and other constricted, depressional,
palustrine wetlands should be at least five acres. Ewel (1990) found
that a small 2.5 to 5 acre depression such as a cypress pond will hold
approximately 20,000 ft3 of water, twice as much as by the same
volume of soil at saturation.
Most pocosins provide much less surface depressional storage per
acre than Carolina Bays. Expanses of pocosins (greater than 200
acres [Adamus et al. 1988]) are, however, effective at attenuating
peak flows since heavy rains will be spread over a large area of
generally flat land (Daniel 1981). Organic soils in pocosin wetlands
also increase the capacity for retention of water. These soils are
generally more porous but less permeable than most mineral soils
and therefore allow infiltration of water but inhibit its movement
(Novitski 1978a). Wetlands within watersheds characterized by
gently sloping topography will have more ability to store water than
those where slopes are steep. Moreover, basins with irregular,
sinuous shorelines have the potential to slow floodwaters through
2
physical resistance in contrast to watersheds where streams have
been heavily channelized (Adamus 1983).
Verry and Boetler (1978) found that floods are affected by the
percentage of either wetland and lake area in a watershed. In their
study of Wisconsin peatlands, flood peaks were reduced by 60 to 80
percent in watersheds with 30 percent wetland or lake area
compared to watersheds with no significant wetland area. Similarly,
Novitski (1978a) found that flood peaks were 80 percent lower in
basins with at least 40 percent lake and wetland area than in basins
without wetlands. Losses of wetlands from basins initially having
little lake or wetland area may have a greater impact on stream flow
than losses of wetlands from basins initially having large percentages
of lakes or wetlands (Conger 1971). Since. the mountains and
piedmont of North Carolina have fewer wetlands than the .coastal
plain (DEHNR 1991 a), wetland losses in these two physiographic
provinces may have more impact on water storage than losses of
similar extent in the coastal plain.
Kittelson's (1988) study at Red Cedar Lake in Minnesota showed
that a wetland which is large relative to the size of the watershed
can result in significant moderation (99 percent) of peak flows even
with an outlet of high capacity (300 feet wide channel) since
inflowing water is spread onto a thin layer over the entire surface of
the wetland. Kittelson's study also showed that depressional
wetlands with highly constricted outlets (roadway embankment and
culvert) which are never overtopped have a dramatic effect on flood
peaks of all sizes (99% average reduction in peak flows).
Adamus et. al (1987) provide some idealized dimensions for
constricted outlets for significant retention of water. For wetlands
with channel flow, a constricted outlet (such as the stream channel)
should be less than one-third the average width of the wetland. For
wetlands with no gradient or channel flow, the width of the outlet
should be less than one-tenth the average width of the wetland
(Figures 1 a and 1 b).
The frictional resistance of a wetland is a critical characteristic
that influences the storage of water. Frictional resistance varies
depending on the width of the wetland, density of vegetation or
other .obstructions (eg. boulders, logs, hummocks) and the rigidity of
these obstructions. Wetlands with relatively low proportions of open
water to vegetation can be more capable of storing flood waters than
open water ponds or lakes. Vegetation slows flood waters by
creating frictional drag in proportion to stem density (Marble 1992).
Channel roughness and the resultant ability to retain flood waters
increases with increasing vegetative density. Adamus et al. (1987)
state that the wetland should be at least 70 percent covered with
3
Cross sectional area:
inlet
~-
outlet
inlet
~... ~:
., :~/
outlet
gradient > 0.00
Figure la. Wetland with channel flow.
inlet
inlet`
y
outlet
gradient = 0.00 .
or tidal situation
wetland with outlet wetland with no outlet
Detention times o/several days or weeks desirable.
Figure 1 b. Wetland with no channel flow.
(From: Marble, Anne D. 1992. A Guide to Wetland
Functional Design. Lewis Publishers, Inc. Missouri)
4
upright woody vegetation to function effectively for the storage of
water.
The type of vegetative cover is also an important characteristic
for the storage of flood waters. From most to least effective, these
vegetative forms are: forested (coniferous), forested (deciduous),
scrub-shrub, emergent persistant, emergent nonpersistant, aquatic
bed (rooted vascular) (Adamus et al. 1983). Because of their rigidity
and persistance, trees and shrubs are the most important vegetative
cover for water storage. Conifers are particularly important for
water storage because of their high rate of evapotranspiration. If the
rate of evapotranspiration is high, then the level of water will
decrease more quickly and provide additional area for storage. The
height of the vegetation in relation to the water depth must also be
considered since vegetative resistance rapidly diminishes as the
water depth becomes greater than the vegetative height.
A wetland adjacent to a major upper-riverine watercourse with a
sinuous shoreline and extensive woody vegetation would have both
the ability and opportunity to store significant amounts of water. A
forested Carolina Bay (less than five acres) would be moderately
valuable for flood storage since it has the ability to store runoff
water but less opportunity to intercept floodwaters. A small pocosin
removed from surface water would have limited capacity for water
storage. Refer to Table 1 for a summary list of wetland
characteristics important to water storage.
Table 1. Importance of various wetland characteristics to water
storage (Adapted from Adamus et al. 1987)
Feature Importance
to Function
Geomorphic Characteristics:
Depressional Storage High
Outlet Characteristics High
Vegetation:
Density Moderate
Type Moderate
Gradient of Watershed Moderate
Size Moderate
Other:
Landscape Position High
Wetland to Watershed Ratio High
S
BANK STABILIZATION
Bank stabilization refers to the role of wetlands in protecting the
shorelines of stream, rivers, and lakes from erosive forces. This
value must be rated on the ability of a wetland to anchor a shoreline
as well as the opportunity for highly erosive forces to affect the
shoreline.
The vegetative cover of a wetland is the key to determining its
ability to stabilize a shoreline or streambank. Vegetation both
dissipates erosive forces and anchors the sediments of the
streambank in place. Trees are critical for abating erosion since they
exhibit a rigid growth form and persist all year. Emergents and/or
rooted aquatics are important because of their greater stem density.
Certain species of trees and shrubs are essential for shoreline
anchoring because they have deep roots, layering ability (ability to
root and sprout once buried), high regenerative capacity, and along
lifespan.
Kadlec and Wentz (1974) found that bulrushes ( cir us spp.)
were successful in withstanding the physical action of currents.
Work by Seibert (1968) suggests that reed grass (Phra mg ites sp.) is
most effective at protecting shorelines since the culms of this plant
lignify (become woody) in the autumn so that protection continues
throughout the winter. This plant also has deep intertwined roots.
Species with similar characteristics in North Carolina are important
for streambank stabilization. Table 2 lists plant species with
potentially high value for the anchoring of shorelines.
Table 2. Plant species of potentially high value for shoreline
anchoring, and/or which can be artificially established
with usually good success (Adapted from Kadlec and
Wentz 1974 and Garbisch 1980).
Species
Common Name
Shoreline
Anchoring
Characteristics
Potential to be
Artificially
Established
Acorus calamus
Alnus serrulata
Carex spp.
Cephalanthus
occidentalis
sweetflag
tag alder
sedges.
buttonbush
X
X
X
X
6
(Table 2. Continued)
Species Common Name Shoreline Potential to be
Anchoring Artificially
Characteristics Established
Cornus spp. dogwoods X
Deschampsia hair grass X
caespitosa
Eleocharis spike rush X
palustris
Equisetum scouring rush X
hyemale
Juncus spp. rushes X
Juniperus juniper X
communis
Leersia rice cutgrass X
oryzoides
Nymphaea spp. water lily X
Panicum switchgrass X
virgatum
Phragmites common reed X
communis
Polygonum spp. smartweeds X
Pontederia pickerelweed X
cordata
Populus deltoides cottonwood X
Potamogeton pondweed X
natans
Prunus pumilla sand cherry X
Sagittaria spp. arrowhead X
Salix spp. willows X
Saururus cernuus lizardtail X
Scirpus spp. bulrushes X
Typha spp. cattails X X
Seibert also found that injury to wetland trees and shrubs from
flood waters is offset by layering ability and high regenerative
capacity from suckers (shoots originating from roots or stems).
Species of low-growing willow ( lix ~urpurea) and alder (Alnu
spp.) yield under pressure but are resilient enough to recover when
flood waters subside. Work by Kite (1980) showed that alder is
effective for long-term protection of banks because the roots of this
plant are water-tolerant and support the bank material by
penetrating to a considerable depth within the aeration zone. In
summary, those tree and shrub species with low growth forms,
branching morphology, deeply penetrating root systems, high
regenerative capacity (suckers), and resiliency under pressure are
most effective for bank stabilization.
The width of erect shoreline vegetation should be at least 20 feet
(Adamus et al. 1987) for effective shoreline stabilization. This width
includes the zone of emergent herbs below or at the edge of the
water, the seasonally flooded obligate species, and the variably
saturated facultative species.
The opportunity for a wetland to stabilize a shoreline refers to the
magnitude of erosion in the watershed as well as the erodability of
the adjacent lands. Urbanization contributes to greater peak flows
because of an increase in impervious surface area. According to
Adamus et al. (1987), if greater than 10 percent of a watershed is
urbanized (impervious surface), wetlands within the watershed have
good potential for streambank stabilization. Adamus (1983) lists
some important characteristics to also consider when determining
the potential erodability of an area adjacent to a wetland. These
characteristics include: steep basin gradient, erodable bank soils,
evidence of scour, and evidence of flow.
By these criteria, most riverine and contiguous palustrine
wetlands would be rated moderate to high. A wetland which is
hydrologically contiguous to surface water with good vegetative
cover in an urban watershed would have high value for streambank
stabilization. A forested wetland contiguous to surface water in an
agricultural watershed would have moderate value for bank
stabilization. In contrast, a wetland removed from surface water
with little woody vegetational cover in an undeveloped watershed
would not be valuable for bank stabilization. Refer to Table 3 for a
summary of wetland characteristics and their relationship to
streambank stabilization.
s
Table 3. Importance of various wetland characteristics to
streambank stabilization (Adapted from Adamus et al.
1987).
Feature Importance
to function
Connection to surface water High
Vegetation:
Type Moderate
Width High
Land use in watershed Moderate
9
RETENTION OF SEDIMENT AND ASSOCIATED POLLUTANTS
Ph, sy ical Removal
Sediments often contain chemically and physically attached
nutrients and toxicants such as phosphorus, heavy metals, PCB's, and
pesticides. When transported into a wetland, these sediments and
associated pollutants can be removed by burial, chemical breakdown,
and/or assimilation into plant tissue. In addition, they may also be
temporarily retained by a wetland before moving downstream.
The evaluation of this function is related to the ability of a
wetland to trap sediments as well as its opportunity to receive these
sediments. The opportunity for a wetland to trap sediments is
influenced by land use in the watershed, source of water to the
wetland, and position of the wetland in the watershed. The principle
factor affecting the ability of a wetland to trap sediments is the
change in velocity or energy level of incoming water. This ability is
affected by the outlet of the wetland; gradient of the watershed;
fetch of open water; extent and duration of flooding; and density,
type, and extent of vegetation.
Wetlands with constricted or no outlets function most effectively
at retaining sediments and adsorbed substances (Adamus et al.
1987). As retention time increases, more sediments will settle out.
Large inorganic particles are heaviest and, therefore, settle out the
fastest, whereas lighter particles such as colloidal clays have the
longest sedimentation rate. Refer to the section on water storage for
specific characteristics of effective outlets.
Since water velocity decreases with decreasing slope, those
wetlands in areas of gradual topography will more effectively retain
sediment (Marble 1992). Wetlands in areas that have been
artificially channelized are also less able to trap sediments because of
increased water velocity and reduced flooding frequency (Kuenzler
et al. 1977).
Sheltered wetlands with minimal fetch are more effective at
retention of sediment since these areas are less prone to wind mixing
(Adamus et al. 1987). Adjacent vegetation and topographic relief are
important characteristics to minimize wind mixing and resuspension
and transport of sediment out of the wetland.
The settling of suspended sediments and associated pollutants is
related to the seasonal extent of flooding in a wetland. Yarbro et al.
(1984) compared several floodplain systems on the coastal plain of
North Carolina with varying flooding regimes and calculated removal
efficiencies of phosphorus. Since phophorus is often attached to fine
10
sediments, the capacity to attenuate phosphorus is related to the
ability of wetlands to trap and retain sediments. The results showed
that when less than 50 percent of the floodplain was inundated,
between 10 and 17 percent of the incoming total phosphorus was
retained. Above 50 percent inundation, between 46 and 69 percent
of the phosphorus was retained. Phosphorus is, therefore, efficiently
retained in riverine wetlands during flooding conditions. Jordan et
al. (1986) compared four wetlands, two that flood frequently and
two that rarely flood. The forested and herbaceous wetlands that
flooded on a frequent basis accumulated significantly greater
quantities of sediment than the two wetland areas that rarely
flooded.
The presence of vegetation is one of the most important
characteristics determining the ability of a wetland to retain
sediment. In addition to providing frictional resistance to flowing
water, vegetation lengthens the path of water through the wetlands.
Dieter (1990) found that the resuspension of sediments was
significantly greater in areas of open water than in areas protected
from wind by emergent vegetation.
Sediment trapping by wetlands occurs to a large extent during
periods of high flow. Trees and shrubs offer the most physical
resistance to storm flows and thus most effectively facilitate
deposition. Persistent emergent vegetation such as cattails (Tvnha
spp.) and phragmites (Phra mg ites spp.) may bend and fold over
during heavy storm flows and therefore are less able to trap
sediment (Ammann et al. 1990).
Reppert et al. (1979) suggest that the cover of woody vegetation
should be greater than 80 percent for a wetland area to effectively
trap sediments and associated pollutants. A wetland with vegetative
coverage between 50 and 80 percent can retain moderate amounts of
sediment, and an open canopy of 20 to 50 percent retains only a
small proportion of incoming sediment. Although basal coverage is
the primary factor indicating the ability of a wetland to retain
sediment, canopy coverage is often used because it is easier to
estimate in the field.
The width of the vegetated riparian zone also greatly affects the
ability of a wetland to retain sediment and associated pollutants.
This width will be dependent on the slope and erodability of soils
within the watershed. Extensive work has been done on vegetated
buffers and streamside management zones as a means of protecting
the quality of rivers, streams, and lakes from nonpoint source
sediments (Trimble 1957; Budd et al. 1987; Cooper at al. 1987;
Howard and Allen 1988; Nutter and Gaskin 1989; Nieswand et al.
11
1990; DEHNR 1991 b). Width serves as an important criteria for
determining the effectiveness of wetlands as buffers to protect
surface waters from eroded sediments.
Trimble and Sartz (1957) studied the impacts of logging roads on
sedimentation in streams and recommend a minimum forested
buffer size of approximately 25 feet on level land in non-sensitive
watersheds. The width of this area should increase two feet for each
one percent increase in slope. In watersheds where the maintenance
of higher levels of water quality is important (water supplies, trout,
outstanding resource waters, etc.), a doubling of these criteria is
strongly suggested. The criteria recommended by these authors does
not distinguish between intermittent and perennial streams.
Howard and Allen (1989) recommend a minimum of 50 feet of
forested riparian buffer for small intermittent streams to protect
water quality in general as well as wildlife habitat. For perennial
streams this width increases to 100 feet for protection of water
quality. Neiswald et al. (1990) conclude, on the other hand, that on
perennial streams and lakes where the slope is less than 15 percent,
a forested buffer of 50 feet is sufficient to protect water quality.
They suggest that this criterion be doubled to 100 feet around water
supply reservoirs where water quality is of utmost importance.
Budd et al. (1987) studied eight streams within a watershed with
various soil types, levels of development, and vegetative cover.
These researchers found that a buffer width of 50 feet was adequate
to protect most of the streams within the watershed. In two
instances, a buffer of 25 feet was adequate to protect the stream.
One stream was intermittent without steep slopes and the other site
was characterized by level topography, permeable soils, and good
vegetative cover.
Based on these data, in non-sensitive watersheds a forested
buffer of 25 feet on each side of the stream channel can provide
some reasonable level of protection for small intermittent streams
from sediment. For perennial streams and lakes, these data indicate
that a distance of 50 feet of adjacent forested buffer (on each side of
the channel for streams) would be needed to provide safeguards
from incoming sediments. It has been suggested that sensitive
waters such as trout, Outstanding Resource Waters (ORW), and water
supplies require more protection and that something in the range of
twice these minimum values should provide some additional defense
from sediments and associated pollutants. As slope increases,
however, these numbers should incremently increase as Trimble and
Sartz (1957) recommend.
12
Wetlands in predominantly urban, agricultural, or otherwise
disturbed watersheds have more opportunity to receive sediments
and associated pollutants than wetlands in pristine watersheds.
Wetlands in these disturbed areas will, therefore, be more critical to
protect downstream water quality.
Surface waters such as channel and overland flow have the
potential to transport sediments into a wetland from the watershed.
In contrast, if the main source of water for a wetland is groundwater,
subsurface flow, or precipitation, there will be less opportunity for a
wetland to receive sediments (Marble 1992).
The position of a wetland in the landscape is a particularly
important characteristic determining the opportunity of a wetland to
receive and retain sediments. Headwater riparian wetlands are the
most critical in terms of water quality. Since small streams comprise
most of the total stream length within a watershed (Leopold 1974),
these areas intercept the greatest proportion of eroded sediments
from uplands before these pollutants reach waters downstream.
Whigham et al. (1988) state that in general the percentage of total
river flow that contacts wetland environments decreases as stream
order increases. Moreover, Novitzki (1978b) found that
approximately 80 percent of the sediments entering a stream were
retained in the headwater wetlands.
Depressional wetlands (e.g. ombrotrophic bogs) located in
headwater areas receive inputs of water almost exclusively from
precipitation. Since little water flows through these wetlands, there
is limited opportunity for retention of sediments in these areas
(Brinson 1988).
Higher order streams with broad floodplains deposit sediments
not retained by headwaters through overbank transport (Brinson
1988). There may also be considerable downstream transportation
of sediments within the floodplain itself (Figure 2). These areas are
vital for retention of sediments during flooding events when
discharge exceeds channel capacity.
By these criteria, a wetland with high value for removing
sediments might be located in a headwaters situation where
agricultural sediment is settled out through a buffer of forested
wetland. A bottomland hardwood wetland located in a primarily
forested watershed without significant sediment loading may only
have moderate importance for sediment retention even if it has the
ability to perform this function. A wetland removed from surface
water with little vegetative cover in an undisturbed watershed
would lack both the ability and opportunity to trap and retain
13
A. FEAOWATER SYSTEMS
\~ ~ ~ ~ -
, `~
, ~~
,a
` ~ Forest -
~~_._ _, Farmland
Riparian Farmland
Wetland
WETLAND SWIPE
WATER FLOW
long, narrow
letr-al to str~
a~rfec~, ~b-s~rfecv
FiOOOINC RESPONSE local stony
POL1UTANT SOURCES ~+oatly nonpoint
8. BOTTpiAND SYSTEii ;, , ~ ~ a^
a~Crh•. ~ cw y; .
`? "a~~7 ~ ~ WTP Town
~••A
,
y~~'~t7i: ~~J L19
,,~~, c,;o_~"
:~~ ~'w ~ `S ~' :°c, ,., • Farmland
`' a C
::
n ~ ~, `O. ~ ?,,~ ,
' ate` • L h '1
~ry ~ - : h
1 .\
1
~~ .~`!. ~ 4 :1 ~
.,'7`~' I',r7.
WETLAND SHAPE long, broad
WATER FLOW mostly longftudinel
floodplein end cherxwl
FLOODING RESPONSE seasonal, extended
POLLUTANT SOURCES point, nonpoint
Figure 2. Headwater and bottomland systems relative to uplands,
water movements (arrows), and pollutant sources.
(From: Kuenzler, Edward J. 1990. Wetlands as Sediment
and Nutrient Traps for Lakes. Enhancing State's
Lake/Wetland Programs: 105-112)
14
sediments. Refer to Table 4 for a summary of wetland characteristics
and their importance for sediment retention.
Table 4. Importance of various wetland characteristics to sediment
retention (Adapted from Adamus et al. 1987)
Feature
Importance to
function
Water Source High
Land Use of the Watershed Moderate
Landscape Position High
Flooding Extent and Duration Moderate
Vegetation:
Density Moderate
Type High
Width High
Geomorphic Characteristics:
Outlet Characterics High
Gradient of the Watershed High
Other:
Fetch/Exposure Moderate
15
REr/IOVAL OF NITROGEN AND PHOSPHORUS
chemical and Microbial Transformations
Wetland vegetation stores nutrients, but this removal is only
shout term. Once the plants die or defoliate, nutrients are returned
to the system through decomposition. Microbial and chemical
processes within a wetland, however, may function to completely
remove nutrients. Moreover, interactions within wetland sediments
may immobilize phosphorus by adsorption and precipitation.
The process of denitrification results in the permanent loss of
nitrogen from the wetland. This biological process involves the
com~ersion of nitrate to gaseous nitrogen by microbes in anaerobic
con~jitions. Since ammonium is nitrified into nitrate by bacteria
under aerobic conditions, the processes of nitrification and
sub;>equent denitrification proceed most rapidly where aerobic and
anaerobic conditions occur in close proximity. The volatilization of
amnnonia proceeds abiotically and also results in removal of nitrogen
frorn the system.
Numerous authors have studied the effectiveness of riparian
wetland forests for nutrient retention and transformation (Jones et
al. 1976; Yates and Sheridan 1983; Brinson et al. 1984; Lowrance et
al. 1984; Peterjohn and Correll 1984; Jacobs and Gilliam 1985; Budd
et a.l. 1987; Groffman et al. 1991). The physical retention of
sediments and associated pollutants directly relates to the ability of a
wetland to remove these nutrients. Many of the characteristics
important for physical removal of sediments will, therefore, also be
critical for nutrient transformations. These characteristics include
the outlet of the wetland; gradient of the watershed; and density,
type;, and width of vegetation. In addition, the opportunity for a
wetland to remove nutrients is also influenced by land use in the
watershed, source of water to the wetland, and position of wetland in
the watershed. For details of these variables, refer to the section on
retention of sediment and associated pollutants. Other criteria
important and unique to nutrient transformations include: soil type,
hydroperiod, and pH.
Several studies show that peat-based soils are most effective at
nitrogen removal (Whigham and Bayley 1978; Whigham 1982;
Groffman et al. 1991). The high organic content (carbon) of this
substrate fuels microbial activity and consequently favors
denitrification. Alternatively, Richardson (1985) found that the
ability of a wetland ecosystem to adsorb phosphorus is directly
related to the mineral and extractable aluminum content of the soil.
16
Wetlands such as swamps are, therefore, more effective at
phosphorus retention than patlands. In general, those wetlands
with alluvial, ferric, clay, or other fine soils will be most effective at
phosphorus retention (Marble 1992).
Sustained nitrogen removal in wetlands requires flooding with at
least annual periods of drydown since nitrification and denitrification
occur under aerobic and anaerobic conditions, respectively (Whigham
1982; Brinson et al. 1984; Jacobs and Gilliam 1985). Reppert et al.
(1979) suggest criteria to evaluate the hydroperiod of various
wetland types. Refer to Table 5.
Table 5. Criteria for evaluating nitrogen removal of various wetland
types based on hydroperiod
Hydroperiod Value
Semi-diurnal intertidal High
Seasonally flooded riverine High
Irregularly flooded intertidal Moderate
Permanently flooded lacustrine Moderate
Intermittently flooded riverine Low
Intermittently flooded lacustrine Low
or palustrine
Groffman et al. (1979) found that wetland sites with high pH (5.9
compared to < 4.5) also had the highest denitrification capacity. From
a landscape perspective, factors that control the pH of soils such as
geologic setting, parent material, and land use will be useful for
assessing the value of wetland sites for nitrogen removal.
These soil and hydrologic criteria serve to supplement the criteria
influencing the physical retention of sediment and associated
toxicants. According to these criteria, an alluvial swamp forest that
is semi-permanently flooded in an agricultural watershed would
probably be highly valuable for nutrient and especially nitrogen
removal. A temporarily flooded, second terrace, bottomland
hardwood forest may only be moderately important for nutrient
removal. A strongly acidic mountain bog removed from surface
water would generally lack both the opportunity to receive as well as
the ability to transform significant quantities of nutrients. Table 6
summarizes the importance of wetland characteristics for nutrient
removal and transformation.
1~
Table 6. Importance of wetland characteristics to nutrient removal
and transformation (Adapted from Adamus et al. 1987).
Feature Importance to
function
Watf;r Source High
Lancl Use of the Watershed Moderate
Landscape Position High
Flooding Duration (Hydroperiod) Moderate
Vegetation:
Density Moderate
Type Moderate
Width High
Geomorphic Characteristics:
Outlet Characterics High
Gradient of the Watershed High
Othf;r:
Soil Texture High
Soil pH Moderate
is
WILDLIFE VALUE
Assessing wildlife value is particularly difficult because of the
diversity of wildlife species and the varied food and habitat needs of
those species which may use wetlands. Most research has focused on
game species of mammals and waterfowl, but generally
requirements for habitat are similar for game and nongame animals.
For the purposes of this work, wildlife includes those species of birds
and mammals which normally use wetlands but are not necessarily
restricted to these habitats.
Several of the features discussed in the section on aquatic life also
apply to wildlife values. These features include presence of
permanent water, vegetative diversity, land use in the watershed,
and width of streamside habitat. Additional criteria relating
specifically to wildlife include vegetative structure, sources of food,
sites for nesting, and size of the wetland.
More wildlife species are supported in wetlands that are
hydrologically connected to permanent water within one mile (Golet
1978). Vegetative diversity within a wetland is also important for
wildlife (Golet 1976; Adamus et al. 1987; Ammann 1991; Bradshaw
1991; Marble 1992). Diversity of vegetation is associated with the
diversity of habitat and sources of food in the wetland. Moreover, as
discussed in the section on aquatic life, human disturbance in the
surrounding landscape can adversely affect the habitat of a wetland.
The importance of protected wildlife habitat along aquatic
systems is well known. These areas are often wetlands but can also
contain upland habitat. Determining the adequate size or width of
riparian habitat for wildlife is particularly difficult since some
species live primarily in wetland habitats, others require wetlands
during their reproductive stages, and others spend most of their time
in uplands but still require wetlands for survival. Understandably
the adequate width of protected zones along streams and rivers for
wildlife habitat varies greatly between studies. Moreover, there are
few studies that are specific to the Southeast.
For the most part, the primary goal of protected riparian zones
appears to be the maintenance of minimum viable populations of
both game and nongame wildlife species. Brinson et al. (1981)
determined that the zone within 600 feet of a stream or other open
water appears to be the most heavily used by terrestrial wildlife in
North Carolina. Using maps, literature, and other general sources of
information, Brown et al. (1990) determined that in Florida wildlife
buffers should generally range from approximately 300 to 900 feet.
19
Requirements for buffer widths tend to be substantially higher
for wildlife habitat than for protection of water quality. In addition,
unlike protection of water quality, increasing the width of a buffer
continues to increase its value for wildlife. Similar to water quality,
width requirements should depend on the type of human activity in
the watershed as well as the resources involved.
Since plant species provide food and cover for wildlife, the
horizontal and vertical diversity of vegetation has been positively
correlated with the diversity of wildlife species (Beecher 1942;
Patterson 1974; Golet 1976; Anderson et al. 1979; Odum et al. 1979;
Harris et al. 1983; Adamus et al. 1987; Ammann 1991; Bradshaw
1991). In forested wetlands the presence of well developed
herbaceous, shrub, sapling, and tree layers is important for wildlife
diversity. The presence of standing dead trees or "snags" is
particularly important for cavity nesters like wood ducks,
woodpeckers, owls, as well as mammals such as squirrels, bats, and
deer mice (Porter 1981). Hardwood mast and cone-bearing trees and
trees and shrubs with fleshy fruits greatly increase the value of a
wetland for wildlife habitat. Forested wetlands should also ideally
have patches of mature (diameter at breast height [DBHJ greater than
10 inches) and over-mature trees essential for the maintenance of
viable populations of interior species (eg. wild turkey, black bear)
(Anderson et al. 1979). Greater than 80 percent canopy closure is
also important for interior species (Marble 1992). Refer to Tables 7a
and 7b for a list of common plant species preferred by waterfowl
and species of wetland trees important for wildlife.
Table 7a. Common plant species preferred by waterfowl (From
Marble 1992)
Species Common Name
A a is Bed Species
Brasenia schreberi
Ceratophyllum demersum
Lemna spp.
Najas spp.
Nuphar spp.
Nymphaea spp.
Potamogeton spp.
Rorippa spp.
watershield
coontail
little duckweeds
naiads
spatterdocks
water lillies
pondweeds
water cress
20
(Table 7a. Continued)
Species
Common Name
Ruppia maritima wigeongrass
Spirodela spp. big duckweeds
Vallisneria spp. wild celery
Wolffia spp. watermeals
Zostera marina eelgrass
Emergent Species
Acnida cannabinus water hemp
Carex spp. sedges
Echinochloa spp. wild millet
Eleocharis spp. spikerushes
Equisetum spp. horsetails
Juncus spp. rushes
Leersia oryzoides rice cutgrass
Panicum spp. panic grass
Paspalum boscianum bull paspalum
Peltandra virginica arrow arum
Polygonum spp. smartweeds
Salicornia virginica woody glasswort
Scirpus spp. bulrushes
Setaria spp. bristle grasses
Sparganium spp. burreeds
Zizania aquatica annual wildrice
Table 7b. Wetland tree and shrub species important for wildlife
food (From Pozzanghera 1992)
Species
Alnus serrulata
Amelanchier arborea
Carya spp.
Common Name
tag alder
downy service-berry
hickory
21
(Table 7b. Continued)
Species Common Name
Celtis occidentalis hackberry
Celtis laevigata sugar-berry
Cephalanthus occidentalis buttonbush
Chamaecyparis thyoides Atlantic white cedar
Crataegus spp. hawthorn
Diospyros virginiana persimmon
Fraxinus caroliniana Carolina ash
Fraxinus pennsylvanica green ash
Ilex decidua deciduous holly
Ilex myrtifolia myrtle holly
Ilex opaca American holly
Nyssa aquatica swamp tupelo
Nyssa sylvatica black gum
Pinus palustris long-leaf pine
Pinus serotina pond pine
Quercus spp. oak
Salix babylonica weeping willow
Salix nigra black willow
Viburnum dentatum arrow-wood
Viburnum lentago nannyberry
A densely forested wetland edge has value to wildlife for
concealment, bedding, and roosting areas. Willson (1974) and Weller
(1978a) found an increase in bird diversity in wetlands having
wooded borders. Peterson (1979) noted heavy usage of wooded
wetland borders by red tailed hawks, presumably as vantage points
to spot danger before landing. A thick border along urban wetlands
is especially important for wildlife. Wary species such as herons will
often use even small urban wetlands if a shielded border is intact.
Thick vegetative borders are also important along travel corridors
used by wildlife.
Several authors have offered insight concerning the minimum
wetland acreage required for viable populations of wildlife. Brown
and Dinsmore (1986) in their work with breeding birds found that
10 of the 25 species surveyed did not occur in marshes less than 12
acres in size. Their data also indicate that smaller marshes 50 to 75
22
acres in size that form a complex were more efficient in preserving
bird species than larger isolated marshes (450 acres).
In Golet's (1978) system of rating wetlands for wildlife, the
lowest ranked category is less than 10 acres, and the highest is
greater than 500 acres with various mid-range categories. Adamus
et al. (1987) in the Wetland Evaluation Technique (WET) use a
minimum threshold of 30 acres for wildlife, but this number is
apparently based on limited research.
Since the value of a particular wetland for wildlife will also
depend on the uniqueness of the system, its vegetative structure and
diversity, and the scarcity of wetlands in the system, selecting a
minimum size is virtually impossible. Research by Brown and
Dinsmore (1986) suggests that areas less 12 acres tend to lose
diversity of bird species. Areas smaller than 12 acres will also tend
to contain more edge and fewer interior species. In addition, based
on classic island biogeography theory, areas that are regularly
shaped will support more species than a patch of equal area with an
irregular outline (MacArthur and Wilson 1967).
In summary, a forested wetland with a complex vegetative
structure and mast and cone-bearing trees would tend to be highly
valuable for wildlife. A Carolina Bay with primarily scrub-shrub
vegetation and a sparse pine overstory would probably be
moderately important for animals. On the other hand, a small (less
than 12 acres) pine flat with low species diversity and a thin
understory would often have little value for wildlife. Refer to Table
8.
Table 8. Importance of wetland characteristics to wildlife
(Adapted from Adamus et al. 1987).
Feature Importance to
function
Food and Cover:
Vegetative Diversity High
Vegetative Species Composition High
Presence of Permanent Water High
Land Use in the Watershed Moderate
Dimensions:
Width Moderate
Size Moderate
23
AQUATIC LIFE VALUE
Aquatic life value refers to the ability of a wetland to support
fish, amphibians, reptiles, and invertebrates. The aquatic life
discussed here is dependent on or spends some phase of its life in
the water. Features that are important to the support and variability
of aquatic life in wetlands include: presence of permanent water,
flooding, pH, vegetation, and surrounding land use.
More fish and invertebrates are supported in wetlands with at
least some areas of permanent water or which are contiguous to
permanent water. Permanent water provides a refuge for aquatic
life when other areas are dry. The highest value wetlands for fish
and invertebrates are permanently flooded over at least 10 percent
of their area (Marble 1992).
Many species of amphibians, however, are dependent on
ephemeral wetlands (e.g., vernal pools) for reproduction (Bradshaw
1991). Because ephemeral wetlands are often completely dry in the
fall, fish cannot survive in these areas. This condition allows
amphibians to successfully reproduce without fish predation.
Ephemeral wetlands are often small, found within floodplain
wetlands or in upland areas. Although timing and duration of
flooding will vary from year to year, in North Carolina, ephemeral
wetlands should begin filling with water from November to January.
Ideally, these systems should retain water from mid-May to the
beginning of July for optimal amphibian habitat. Successful
empheral pools usually have one to three feet of water at full depth
during the late winter to early spring. Amphibians in pools fed by
seepage springs can tolerate shallower water since the water level
will be more stable (Braswell 1992). When identified, these areas
should be given high priority in terms of protection of aquatic life.
Carolina Bays that are inundated during the winter and spring
and dry up during the fall (similar to ephemeral wetlands) are also
important for amphibian reproduction (Semlitsch 1987 and
Pechmann et al. 1989). Studies at the University of Georgia's
Savannah River Ecology Laboratory indicate that the reproductive
success and survival to metamorphosis of resident amphibians were
correlated with the number of days in a year that a pond had
standing water. Semlitsch (1987) found that a threshold of
approximately 145 days of standing water was needed at a breeding
pond for the eggs of the mole salamander, Ambystoma talpoideum.
to develop and for larvae to reach metamorphosis. During this study,
drought conditions caused catastrophic mortality of larval
24
amphibians in all ponds regardless of the characteristics of these
ponds. During years of adequate rainfall, early drying in shallow and
disturbed Carolina Bays also resulted in catastrophic mortality of
larvae. The greatest reproductive success of amphibians was found
in Carolina Bays with a depth at maximum level of approximately
three feet since these bays would tend to dry later than others of
shallower depths.
Wetlands which are adjacent to surface water that seasonally
floods and which remain inundated during the late winter through
early summer are critical for aquatic life by providing essential
spawning, feeding, and nursery areas for invetebrates and fish.
Flooding also helps replenish dissolved oxygen for these organisms.
Larson et al. (1981) found that southeastern bottomland hardwood
forests are used by nearly all fishes of the adjoining river as feeding,
spawning, and/or nursery grounds. The value of a particular section
of bottomland hardwood forest to fish depends on the timing and
duration of flooding. Early, prolonged flooding provides advantages
in terms of expanded habitat and abundant sources of food
transported with the floodwaters. These conditions allow the rapid
growth of larval fishes to a size where predation is reduced.
Acidic waters (pH < 5.6) can limit aquatic life by mobilizing toxic
metals and decreasing plant productivity (Marble 1992). Barry and
Schlinger (1977) found depauperate fish and aquatic invertebrate
populations in wetlands with acidic waters.
Many authors have referenced the importance of vegetative
diversity within a wetland for habitat (Golet 1976; Adamus et al.
1987; Ammann 1991; Bradshaw 1991). Diversity of vegetation is
associated with diversity of habitat and sources of food available in
the wetland. Broad-leaved, deciduous, wooded wetlands are high
detritus producers and can therefore support high densities of
invertebrates and fish if flooding occurs. Plant diversity and
vegetative layers are important for aquatic life. The most important
wetlands in terms of habitat contain a mixture of trees and shrubs,
emergent plants, aquatic macrophytes, and open water.
Generally, wetlands with well interspersed patches of vegetation
(Figure 3) or diffuse open stands of vegetation provide the best
aquatic habitat (Marble 1992). Interspersed patches of vegetation
and water provide cover and also allow aquatic organisms mobility.
Studies on the optimal proportions of vegetation and water suggest
that the most valuable wetlands in terms of habitat have from 25 to
75% coverage by emergent plants (Weller 1978b; Bradshaw 1991;
Marble 1992).
25
vegetation ~,
open water
Figure 3. Wetland with well balanced proportions and a high
interspersion of vegetation and open water.
(From: Marble, Anne D. 1990. A Guide to Wetland
Functional Design. Lewis Publishers, Inc. Missouri)
26
Human disturbance in the surrounding landscape can adversely
affect the habitat value of a wetland. Golet (1976) suggests that if
over 90% of the land within 300 feet of a wetland is either forested
or otherwise in natural vegetation, then the wetland is relatively
undisturbed by human beings. The area is significantly impacted by
human beings if less than 50% of the surrounding landscape is
naturally vegetated.
A bottomland hardwood forest adjacent to a river that seasonally
floods in a primarily forested watershed would generally provide
highly significant habitat for aquatic life. An undisturbed second
terrace bottomland hardwood forest with good vegetational diversity
that rarely floods, however, may only be moderately important for
aquatic life. A pocosin removed from surface water in an urbanized
watershed would in most cases have minimal value as aquatic
habitat. Refer to Table 9.
Table 9. Importance of wetland characteristics to aquatic life
(Adapted from Adamus et al. 1987).
Feature Importance to
function
Water:
Presence of Permanent Water High
Flooding Extent and Duration High
Presence of Vernal Pools High
Vegetation:
Vegetative Diversity High
Vegetative Interspersion with Water High
Land Use in the Watershed Moderate
Other:
pH Moderate
27
OUTDOOR RECREATION AND EDUCATION
This value refers to the use of a wetland for both consumptive
(hunting, fishing) and nonconsumptive (birding, botanizing, canoeing,
aesthetics) forms of recreation and education that occur in either an
incidental or obligatory manner in wetlands. The value is based on
the quality of the wetland itself as well as public access to the
wetland.
Public access is a key feature determining the potential value of a
wetland for recreation and education. If a wetland is not near public
roads or publicly accessible waterways, it has low potential for this
value. Alternatively, a publicly owned and accessible wetland with
parking facilities, water access facilities, and boardwalks has high
potential for recreational activities (Adamus et al. 1987; Ammann
and Stone 1991; Bradshaw 1991).
Other features relating to the quality of wildlife and aquatic life
habitat also affect the value of a wetland for recreation and
education. A viable animal population directly relates to the use of a
wetland for hunting, fishing, and birding. A diversity of vegetation
not only affects wildlife and aquatic life, but is also important for
botanical studies and aesthetic enjoyment. In addition, direct access
to open water enhances the recreational value of the wetland
(Ammann and Stone 1991).
Disturbance within the wetland and the surrounding landscape
affects the aesthetic quality of the area. Undisturbed, natural
wetlands provide more aesthetic enjoyment than those with
detractions such as trash and abandoned cars. Wetlands in which
birds, wildlife, and other naturally occurring sounds predominate are
generally more desirable than those where continuous traffic and
construction sounds are audible. Moreover, a wetland surrounded by
urbanization may have less visual appeal than one adjacent to
woodland, agricultural land, or well landscaped residential and
commercial areas (Reppert et al. 1979; Ammann and Stone 1991).
An undisturbed, publicly owned and accessible bottomland
hardwood forest with a diverse flora and fauna would provide
valuable recreational and educational benefits. A publicly accessible
mountain bog with diverse flora would be moderately important for
recreation. Any type of wetland isolated from public access would at
present have little value for recreation or education.
2s
ECONOMIC VALUE
Economic value primarily concerns timber, hunting leases, and in
rare cases production of commercial fish. This value refers to the
existing or potential economic value of a wetland for timber
production under both extensive (natural) and intensive (with
appropriate best management practices) management. In the
majority of cases in North Carolina, a wetland is evaluated for
economic value based on its timber value.
Timber value is based on the actual value of the trees at the site
or the potential for that site to produce marketable trees. Potential
timber value is especially important when a site must be evaluated
but the vegetation has been disturbed or removed. Refer to the
following table (Table 10) for a list of potential timber values for
forested wetlands.
Table 10. The potential timber values of forested wetlands (White
1992).1
Potential Timber Value
Natural Artificial
Type ~ W tlan Regeneration Regeneration
Muck/Peat Swamp 3 3
First Terrace Bottomland 5 5
Second Terrace Bottomland 5 5
Blackwater River Bottomland 5 5
Non-Alluvial Swamp 2 3
Wet Flat 2 5
Pocosin, high 2 5
Pocosin, low 2 3
Pine Savanna 3 5
Carolina Bay 2 3
Perched 2 2
1 Values range from 2 (low timber value) to 5 (excellent timber
value).
Estimates of timber value can be based on the basal area per acre
of stems. Table 11 provides an estimate of timber value based on
basal area (BA) and diameter at breast height (DBH).
29
Table 11. Estimates of actual timber value .based on basal area
(BA) and diameter at breast height (DBH) (White 1992).2
Timber Value
Average DBH (inches) BA > 100 ft2/acre BA < 100 ft2/acre
DBH > 10 5 3
6 < DBH <10 3 1
DBH<6 0 0
2 Values range from 0 (no timber value) to 5 (excellent timber
value).
Basal area per acre can be estimated using a forester's prism or
sighting by hand. To sight by hand, the evaluator's arm must be
fully extended parallel to the ground. With the thumb pointing up,
the evaluator then counts how many trees are equal to or wider than
the thumb while rotating 360 degrees. The number of trees that are
counted is multiplied by ten to yield basal area in ft2 per acre
The location as well as the resources that are present affect the
value of a parcel of land for the sale of hunting leases. Those areas
within the city limits where hunting is not allowed or public lands
where private landowners could not charge for hunting leases have
no value for hunting. Kozicky (1987) found through a poll of
successful operators of hunting preserves that the highest value
lands in terms of location are within cone-hour drive from a center
of high human population (500,000 or more).
Numbers presented by Shelton (1987) suggest that hunters are
willing to pay more for hunting leases for choice waterfowl habitat
than for other types of hunting. Returns for all types of hunting
leases from bottomland hardwood forests along the Mississippi River
ranged from $12-$30/acre. Hunters were willing to pay $25/acre up
to $300/acre for waterfowl leases. Landowners with property
containing good waterfowl habitat such as freshwater marshes may
be able to charge the highest fees for hunting leases.
For optimal bird hunting (not waterfowl) an area must have
sufficient vegetation to provide good cover but not so dense as to
impede movement of both hunters and dogs. Evans (1989) notes
that for quail habitat, a mixture of pines, oaks, and understory trees
is more desirable than a solid forest of any single species of tree.
Deer do not require special habitat and thrive in all forest types,
fields, and marshes. Deer eat many types and parts of plants
30
including fortis, grasses, vines, woody browse, mushrooms, fruits,
acorns, and agricultural crops. In general, deer prefer the growth of
new vegetation. For sustained food production within reach of deer,
an open canopy is necessary so that sunlight will reach the forest
floor. Deer have no special cover requirements. Thickets or old fields
would be suitable for cover and fawning areas. Moreover, since deer
can obtain much of their required water from the vegetation they
eat, close proximity to bodies of water is not essential (Hurst 1989).
A freshwater marsh with species important for waterfowl food in
close proximity to a large urban center would generally have high
economic value for the sale of hunting leases. A pine savannah with
widely spaced mid-sized trees may be moderately important as a
timber resource. Mountain bogs, however, would generally have
little if any economic value.
31
LIST OF REFERENCES
Adamus, Paul R. and L.T. Stockwell. 1983a. A Method for Wetland
Functional Assessment: Volume I. Critical Review and Evaluation
Concepts. Federal Highway Administration Rep. No. FHWA-IP-82-
23.
Adamus, Paul R. 1983b. A Method for Wetland Functional
Assessment: Volume II. FHWA Assessment Method. Federal
Highway Administration Rep. No. FHWA-IP-82-24.
Adamus, Paul R., Ellis J. Clairain, R. Daniel Smith, and Richard E.
Young. 1987. Wetland Evaluation Technique (WET). Volume II:
Methodology. Federal Highway Administration Report No. FHWA-
IP-88-029.
Ammann, Alan P., Robert W. Franzen, and Judith L. Johnson. 1990.
Method for the Evaluation of Inland Wetlands in Connecticut: A
Watershed Approach (Draft). Department of Environmental
Protection. Natural Resources Center.
Ammann, Alan P. and Amanda Lindley Stone. 1991. Method for the
Comparative Evaluation of Nontidal Wetlands in New Hampshire.
New Hampshire Department of Environmental Services. Concord,
New Hampshire. NHDES-WRD-1991-3.
Anderson, Bertin W., Robert D. Ohmart, and John Disano. 1979.
Revegetating the Riparian Floodplain for Wildlife. In: Johnson, R.
Roy, J. Frank McCormick (eds.). Strategies for Protection and
Management of Floodplain Wetlands and Other Riparian
Ecosystems. U.S. Department of Agriculture. Forest Service.
Washington, D.C.
Barry, W. J. and E. I. Schlinger (eds.). 1977. Inglenook Fen: A Study
and Plan. California Department of Parks and Recreation.
Sacramento, California.
Beecher, W. J. 1942. Nesting birds and the vegetation substrates.
Chicago Ornithol. Soc. Chicago, Illinois.
32
Bradshaw, Julie G. 1991. A Technique for the Functional Assessment
of Nontidal Wetlands in the Coastal Plain of Virginia. Virginia
Institute of Marine Science. Special Report No. 315.
Braswell, Alvin. 1992. Curator of Amphibians. Museum of Natural
Sciences. Raleigh, North Carolina. personnal communication.
Brinson, Mark M., B. L. Swift, R. C. Plantico [and others]. 1981.
Riparian ecosystems: their ecology and status. U. S. Department of
the Interior, Fish and Wildlife Service, FWS/OBS-81/17.
Brinson, Mark M., H. David Bradshaw, and Emilie S. Kane. 1984.
Nutrient assimilative capacity of an alluvial floodplain swamp.
Journal of Applied Ecology 21, 1041-1057.
Brinson, Mark M. 1988. Strategies for Assessing the Cumulative
Effects of Wetland Alteration on Water Quality. Environmental
Management Vol. 12, No. 5, pp. 655-662.
Brown, Mike and James J. Dinsmore. 1986. Implications of Marsh Size
and Isolation for Marsh Bird Management. J. Wildl. Manage. 50(3):
392-397.
Brown, Mark T., Joseph Schaefer, and Karla Brandt. 1990. Buffer
Zones for Water, Wetlands, and Wildlife in East Central Florida.
The Center for Wetlands. University of Florida. Gainesville, Florida.
Budd, William W., Paul L. Cohen, and Paul R. Saunders. 1987. Stream
Corridor Management in the Pacific Northwest: I. Determination of
Stream-Corridor Widths. Environmental Management Vol. 11, No.
5, pp. 587-597.
Carter, Virginia, M. S. Bedinger, Richard P. Novitzki and W. O. Wilen.
1978. Water Resources and Wetlands. In: Greeson, Phillip E., John
R. Clark, Judith E. Clark (eds.). Wetland Functions and Values: The
State of Our Understanding. American Water Resources
Association. Lake Buena Vista, Florida.
Conger, D. H. 1971. Estimating Magnitude and Frequency of Floods in
Wisconsin. U. S. Geological Survey, Madison, Wisconsin, Open-File
Report. Cited from: Novitzki, Richard P. 1978. Hydrologic
Characteristics of Wisconsin's Wetlands and Their Influence on
Floods, Stream Flow, and Sediment.
33
Cooper, J. R., J. W. Gilliam, R. B. Daniels and W. P. Robarge. 1987.
Riparian areas as filters for agricultural sediment. Soil Sci. Soc. Am.
J. 51: 416-420.
Daniel, Charles C. III. 1981. Hydrology, Geology, and Soils of Pocosins:
A Comparison of Natural and Altered Systems. In: Richardson,
Curtis J. (ed.). Pocosin Wetlands. Hutchinson Ross Publishing
Company. Stroudsburg, Pennsylvania.
Department of Environment, Health, and Natural Resources (DEHNR).
Division of Environmental Management. 1991 a. Original Extent,
Status and Trends of Wetlands in North Carolina: A Report to the
N. C. Legislative Study Commission on Wetlands Protection.
Raleigh, North Carolina.
Department of Environment, Health, and Natural Resources (DEHNR).
Division of Environmental Management.1991 b. An Evaluation of
Vegetative Buffer Areas for Water Quality Protection. Raleigh,
North Carolina.
Dieter, Charles D. 1990. The Importance of Emergent Vegetation in
Reducing Sediment Resuspension in Wetlands. Journal of
Freshwater Ecology, Volume 5, Number 4, pp. 467-473.
Evans, Rocky. 1989. Managing for Quail in Southern Woodlands. Vol.
48(8), pp. 12-14.
Ewel, Katherine C. 1990. Multiple Demands on Wetlands. BioScience
Vol. 40, No. 9.
Garbisch, E. W. Jr. 1980. Highways and wetlands: compensating
wetland losses. Unpublished report. Federal Highway
Administration, Washington, D. C.
Golet, Frank C. 1976. Wildlife wetland evaluation model. In: Larson,
J.S. (ed.). Models for assessment of freshwater wetlands.
Publication No. 32. Water Resources Research Center. Univ. of
Massachusetts, Amherst.
Golet, Frank C. 1978. Rating the Wildlife Value of Northeastern Fresh
Water Wetlands. In: Greeson, Phillip E., John R. Clark, Judith E.
Clark (eds.). Wetland Functions and Values: The State of Our
34
Understanding. American Water Resources Association.
Minneapolis, Minnesota.
Groffman, Peter M., Eric A. Axelrod, Jerrell L. Lemunyon, and W.
Michael Sullivan. 1991. Denitrification in grass and forest
vegetated filter strips. Journal of Environmental Quality. Vol. 20,
no. 3. pp. 671-674.
Harris, H. J., Mark S. Milligan, and Gary A. Fewless. 1983. Diversity:
Quantification and Ecological Evaluation in Freshwater Marshes.
Biological Conservation 27. pp. 99-110.
Howard, Rebecca J. and James A. Allen. 1989. Streamside Habitats in
Southern Forested Wetlands: Their Role and Implications for
Management. In: Hook, Donal D., Russ Lea (eds.). The Forested
Wetlands of the Southern United States. Southeastern Forest
Experiment Station. Gen. Tech. Rep. SE-50.
Hurst, George A. 1989. Deer Management in the Southern Pine Forest.
Vol. 48(8), pp. 10-11.
Jacobs, T. C. and J. W. Gilliam. 1985. Riparian losses of nitrate from
agricultural drainage waters. Journal of Environmental Quality.
Vol. 14, no. 4. pp. 472-478.
Jones, J. R., B. P. Borofka, and R. W. Bachmann. 1976. Factors affecting
nutrient loads in some Iowa streams. Water Research Vol. 10. pp.
117-122.
Jordan, T. E., D. L. Correll, W. T. Peterjohn, and D. E. Weller. 1986.
Nutrient flux in a landscape: The Rhode River watershed and
receiving waters. In: Correll, D. L. (ed.). Watershed research
perspectives. Smithsonian Institution Press, Washington, D. C.
Kadlec, J.A. and W.A. Wentz. 1974. State-of-the-Art Survey and
Evaluation of Marsh Plant Establishment Techniques: Induced and
Natural. Vol. I: Report of Research, Contract Report D-74-9. U.S.
Army Engineer Waterways Experiment Station, CE, Vicksburg,
Mississippi.
Kite, D.J. 1980. Water Courses -open drains or sylvan streams? In:
Trees at Risk. Tree Council Annu. Conf. (in association with World
Wildlife Fund) March 1980, London.
35
Kittelson, John M. 1988. Analysis of Flood Peak Moderation by
Depressional Wetland Sites. In: Hook, D. D. et al. The Ecology and
Management of Wetlands. Volume 1: Ecology of Wetlands. Timber
Press. Portland, Oregon.
Kozicky, Edward L. 1987. Hunting Preserves for Sport or Profit.
Caesar Kleberg Wildlife Research Institute. Texas A&I University.
Kingsville, TX.
Kuenzler, Edward J. 1990. Wetlands as Sediment and Nutrient Traps
for Lakes. Enhancing State's Lake/Wetland Programs: 105-112.
Larson, J. S., M. S. Bedinger, C. F. Bryan (and others). 1981. Transition
from wetlands to uplands in southeastern bottomland hardwood
forests. pp. 225-273. In: Clark, J. R. and J. Benforado (eds.).
Wetlands of bottomland hardwood forests. Elsevier Scientific
Publishing Co. New York.
Leopold, L. B. 1974. Water: A Primer. W. H. Freeman and Co., San
Francisco, CA.
Lowrance, Richard, Robert Todd, Joseph Fail, Jr., Ole Hendrickson, Jr.,
Ralph Leonard, and Loris Asmussen. 1984. Riparian forests as
nutrient filters in agricultural watersheds. BioScience. Vol. 34, No.
6. pp. 374-377.
MacArthur, R. H. and E. O. Wilson. 1967. The Theory of Island
Biogeography. Princeton Univ. Press. Princeton, New Jersey.
Marble, Anne D. 1992. A Guide to Wetland Functional Design. Lewis
Publishers, Inc. Missouri.
Nieswand, George H., Robert M. Hordon, Theodore B. Shelton, Budd B.
Chavooshian and Steven Blau. 1990. Buffer Strips to Protect Water
Supply Reservoirs: A Model and Recommendations. Water
Resources Bulletin. Vol. 26, No. 6.
Novitzki, Richard P. 1978a. Hydrologic Characteristics of Wisconsin's
Wetlands and their Influence on Floods, Stream Flow, and
Sediment. In: Greeson, Phillip E., John R. Clark, Judith E. Clark
(eds.). Wetland Functions and Values: The State of Our
36
Understanding. American Water Resources Association. Lake
Buena Vista, Florida.
Novitzki, R. P. 1978b. Hydrology of the Nevin Wetland Near Madison,
Wisconsin. U. S. Geological Survey, Water Resources Investigations
78-48.
Nutter, Wade L. and Julia W. Gaskin. 1989. Role of Streamside
Management Zones in Controlling Discharges to Wetlands. In: Hook,
Donal D., Russ Lea. The Forested Wetlands of the Southern United
States. Southeastern Forest Experiment Station. Gen Tech. Rep. SE-
50.
Odum, William E., Michael L. Dunn, and- Thomas J. Smith III. 1979.
Habitat Value of Tidal Fresh Water Wetlands. In: Greeson, Phillip
E., John R. Clark, Judith E. Clark (eds.). Wetland Functions and
Values: The State of Our Understanding. American Water
Resources Association. Minneapolis, Minnesota.
Patterson, J. H. 1974. The role of wetland heterogeneity in the
reproduction of duck populations in eastern Ontario. Can. Wildl.
Serv. Rep. Ser. No. 29, 31-32.
Pechmann, Joseph H. K., David E. Scott, J. Whitfield Gibbons, and
Raymond D. Semlitsch. 1989. Influence of wetland hydroperiod on
diversity and abundance of metamorphosing juvenile amphibians.
Wetland Ecology and Management. Vol. 1, No. 1. pp. 3-11.
Peterjohn, William T. and David L. Correll. 1984. Nutrient dynamics
in an agricultural watershed: observations on the role of a
riparian forest. Ecology 65(5). pp. 1466-1475.
Petersen, L. 1979. Ecology of Great Horned Owls and Red-Tailed
Hawks in Southeastern Wisconsin. Tech. Bulletin #111.
Department of Natural Resources. Madison, Wisconsin.
Porter, Bruce W. 181. The Wetland Edge as a Community and Its
Value to Wildlife. In: Richardson, Brandt (ed.). Selected
Proceedings of the Midwest Conference on Wetland Values and
Management. Freshwater Society.
Pozzanghera, Steve. 1992. Habitat Conservation Program. Wildlife
Resources Commission. Raleigh, NC. personnal communication.
37
Reppert, Richard T., Wayne Sigleo, Eugene Stakhiv, Larry Messman,
Caldwell Meyers. 1979. Wetland Values: Concepts and Methods for
Wetlands Evaluation. LJ. S. Army Corps of Engineers. Institute for
Water Resources. IWR Research Report 79-R1.
Richardson, Curtis J. 1985. Mechanisms controlling phosphorus
retention capacity in freshwater wetlands. Science Vol. 228. pp.
1424-1427.
Schafale, Michael P. and Alan S. Weakley. 1990. Classification of the
Natural Communities of North Carolina: Third Approximation.
North Carolina Natural Heritage Program. Division of Parks and
Recreation. N. C. Department of Environment, Health, and Natural
Resources. Raleigh, NC.
Seibert, P. 1968. Importance of natural vegetation for the protection
of the banks of streams, rivers, and canals: In: Nature and
Environment Series (Vol. Freshwater). Council of Europe, pp. 35-
67.
Semlitsch, Raymond D. 1987. Relationship of Pond Drying to the
Reproductive Success of the Salamander Ambystoma Talpoideum.
Copeia Vol. 1. pp. 61-69.
Shelton, Ross. 1987. Fee Hunting Systems and Important .Factors in
Wildlife Commercialization on Private Lands. In: Decker, Daniel J.
and Gary R. Goff (eds.). Valuing Wildlife: Economic and Social
Perspectives. Westview Press. Boulder and London.
Skaggs, R. W., J. W. Gilliam, and R. O. Evans. in preparation. Computer
Simulation Study of Pocosin Hydrology. North Carolina State
University. Raleigh, North Carolina.
Sutter, Robert D. 1990. List of North Carolina's Endangered,
Threatened and Candidate Plant Species, February 1990. Plant
Conservation Program. N. C. Department of Agriculture. Raleigh,
NC.
Trimble, George R. Jr. and Richard S. Sartz. 1957. How far from a
stream should a logging road be located? J. of Forestry. pp. 339-
341.
38
Verry, Elon S., Don H. Boetler. 1978. Peatland Hydrology. In: Greeson,
Phillip E., John R. Clark, Judith E. Clark (eds.). Wetlands Functions
and Values: the State of Our Understanding. American Water
Resources Association. Lake Buena Vista, Florida.
Weller, Milton W. 1978a. Wetland habitats. In: Greeson, Phillip E.,
John R. Clark, Judith E. Clark (eds.). Wetland Functions and Values:
The State of Our Understanding. American Water Resources
Association. Minneapolis, Minnesota.
Weller, Milton W. 1978b. Management, of Freshwater Marshes for
Wildlife. In: Good, Ralph E., Dennis F. Whigham, Robert L. Simpson
(eds.). Freshwater Wetlands: Ecological Processes and Management
Potential. Academic Press. New York.
Whigham, Dennis F. and Suzanne E. Bayley. 1978. Nutrient dynamics
in fresh water wetlands. In: Greeson, Phillip E., John R. Clark,
Judith E. Clark (eds.). Wetland Functions and Values: The State of
Our Understanding. American Water Resources Association.
Minneapolis, Minnesota.
Whigham, Dennis F. 1982. Using freshwater wetlands for wastewater
management in North America. Gopal, Brij, R. Eugene Turner,
Robert G. Wetzel, Dennis F. Whigham (eds.). Wetlands: Ecology and
Management. National Institute of Ecology.
Whigham, Dennis F., Carin Chitterling and Brian Palmer. 1988.
Impacts of Freshwater Wetlands on Water Quality: A Landscape
Perspective. Environmental Management Vol. 12, No. 5 pp. 663-
671.
White, Fred. 1992. Assistant State Forester. Department of
Environment, Health, and Natural Resources. Division of Forest
Resources. Raleigh, North Carolina. personnal communication.
Willson, M. F. 1974. Avian community organization and habitat
structure. Ecology 55(5) 1017-1029.
Yarbro, L. A., E. J. Kuenzler, P. J. Mulholland and R. P. Sniffen. 1984.
Effects of stream channelization on exports of nitrogen and
phosphorus from North Carolina coastal plain watersheds.
Environmental Management Vol. 8, pp. 151-160.
39
Yates, P. and J. M. Sheridan. 1983. Estimating the effectiveness of
vegetated floodplains/wetlands as nitrate-nitrite and
orthophosphorus filters. Agriculture, Ecosystems and
Environment. Vol. 9. pp. 303-314.
40
APPENDIX I
GLOSSARY
Alfisols - Soils generally well supplied with calcium and .magnesium.
11 vi 1 Soils -Soils that develop from streams or deltas.
Aquatic B~1 -Wetland habitats dominated by plants that grow
principally on or below the surface of the water during most of the
growing season in most years.
Constriction - An inlet or outlet of a wetland is defined as constricted
if it is less than one-third the maximum width of the wetland. The
outlet of a broad bottomland hardwood forest in the Coastal Plain
would generally be considered constricted since the adjacent wetland
would be proportionately wider than the channel (river). A narrow
bottomland hardwood forest in the Piedmont, however, may have a
relatively unconstricted outlet depending on the dimensions of the
channel and the floodplain.
Conti ug_ous -Abutting, adjacent, or in close proximity and being
connected by surface water.
Denressional Storage - A wetland has depressional storage if it is
located in a depression of the landscape or is characterized by
hummocky topography enabling relatively large amounts of water to
be stored. A wetland without these characteristics is said to have
little depressional storage.
Detention Time -The length of time a molecule of a substance is
physically detained within a specified area.
Emergent Vegetation -Erect, rooted, herbaceous vegetation excluding
mosses and lichens.
Ephemeral We 1 n -Small wetlands (usually) found within
floodplains or in upland areas that are inundated during the winter
to late spring or early spring and are often completely dry during the
fall. These areas are critical for amphibian reproduction.
Ferric oils -Soils with high iron content.
41
APPENDIX I (continued)
Fetch/Ex osure -The maximum open water distance unimpeded by
intersecting islands, erect vegetation, or other obstructions.
F r - A wetland class characterized by woody vegetation that is
20 feet or taller.
Geomorphic -The surface configuration of the earth.
r ien -The inclination or slope of the topography.
radual Topographx - A landscape characterized by flat or gently
sloping topography.
Hydroperiod - A term used to indicate the seasonal occurrence of
flooding and/or saturated soil conditions.
Impervious Surface -Surfaces where water infiltration is impeded
by impermeable materials on top of the soil (e.g., concrete, asphalt).
Inlet -The point at which surface water enters a wetland via a
channel.
IntermittentlX Flooded -Flooded from an adjoining body of water or
channel for at least ten consecutive days at least once every ten
years, and dry for at least ten consecutive days every growing
season.
Interspersion -The degree of intermingling of different cover types,
regardless of the number of types or their relative proportions.
Vegetation interspersion with water refers to the degree of
intermingling of different vegetation types with water.
Irregularly, Flooded
than daily.
- Tidal water floods the land surface less often
42
APPENDIX I (continued)
Landsc~e Position - The location of a wetland in the watershed.
Headwater systems, for example, are in the upper reaches of a
watershed and are usually adjacent to first and second order
streams. Bottomland systems are lower in the watershed and are
usually adjacent to fairly major (third and fourth order) rivers.
Lignify - To convert into or become wood by the deposition of lignin
(similar to cellulose) in the cell walls of a plant.
Marsh - A wetland charaterized by herbaceous (non-woody)
vegetation.
Mast -The nuts (such as acorns) of forest trees.
Nonpersistent Emergent Vegetation -Emergent vegetation that falls
to the surface of the substrate, or below the surface of the water at
the end of the growing season, so that at certain seasons of the year
there is no sign of emergent vegetation.
Opportunitx -The chance a wetland has to perform a function. For
example, a wetland may have the physical attributes required to
remove sediments, but unless the wetland is positioned in the
watershed where it will receive sediment, it will not have the
opportunity to perform this function.
Order (Stream) - A syste
tributaries. For example,
stream has no tributaries.
stream begins where two
on. Usually major rivers
streams.
m of ranking streams based on their
a first order (higher in the watershed)
A second order (lower in the watershed)
first order tributaries come together and so
are fourth and sometimes fifth order
Outlet -The point at which surface water exits the wetland.
Outstanding Resource Waters RW - An official designation given to
waters that have excellent water quality and that are of exceptional
state or national recreational or ecological significance.
Pedolo ig cal -Pertaining to soils, their origins, characteristics, and
uses.
43
APPENDIX I (continued)
Permanently Flooded -Surface water covers the land surface
throughout the year in all years.
Persistent Emergent Vegetation -Vegetation species that normally
remain standing until the beginning of the next growing season.
Regularly flooded -Tidal water alternately floods and exposes the
land surface at least once daily.
Ri ap rian Wetlands -Wetlands associated with streams and rivers.
Scrub-shrub - A wetland class dominated by woody vegetation less
than 20 feet.
Seasonally Flooded -Surface water persists throughout the growing
season in most years.
na - A standing, dead tree with a DBH of at least 10 inches.
urface Wa er -Water above the surface of the ground that is in
channels, diffuse flow, or standing. Not necessarily permanent.
wam - A wetland charaterized by woody (trees and shrubs)
vegetation.
Temporarily Fl a -Surface water is present during brief periods
during the growing season, but the water table usually lies well
below the soil surface for most of the season.
Toxicants -Any substance present in water, wastewater, or runoff
that may kill aquatic life, or could be harmful to the public health.
Tr v 1 rri r - An area that is used by wildlife to move from one
place of suitable habitat to another.
44
APPENDIX II
Rare Plant Species in North Carolina (Schafale and Weakley 1990;
Sutter 1990)
Muck/Peat Swamp
Lilaeopsis carolinensis Carolina lilaeopsis T C2
First Terrace Bottomland Hardwood
cies Common Name N to Federal Status
Carex projects necklace sedge C
Cirsium carolinianum Carolina thistle C
Phacelia ranunculacea buttercup phacelia C
Second Terrace Bot tomland Hardwood
e i Common Name NC Status Federal Status
Amorpha schwerini Schwerin's -leadplant C
Carya laciniosa big shellbark hickory C
Ilex amelanchier sarvis holly C
Phacelia. ranunculacea buttercup phacelia C
Wet Flat
species Common Name ~1C Status Federal Status
Hypericum adpressum bog St. John's-wort C
Lysimachia rough-leaf loosestrife E E
asperulaefolia
Tofieldia glabra glabrous false asphodel C
High Pocosin
i
Common Name
NC Status
Federal Status
spec
es
Amphicarpum purshii Pursh's goober grass C
Calamovilfa brevipilis pine barrens sandreed E C2
Kalmia cuneata white wicky E Cl
Lysimachia rough-leaf loosestrife E E
asperulaefolia
45
APPENDIX II (continued)
Low Pocosin
Kalmia cuneata white wicky E Cl
Lysimachia rough-leaf loosestrife E E
asperulaefolia
Rhynchospora alba white beakrush C
Pine Savanna
Agalinis aphylla scale-leaf gerardia C
Agalinis virgata virgate gerardia C
Amorpha georgiana Carolina leadplant C
Amphicarpum purshii Pursh's goober grass C
Andropogon mohrii bog bluestem C
Aristida palustris longleaf three-awn C
Asclepias pedicellata stalked milkweed C
Balduina atropurpurea honeycomb head C
Calamovilfa brevipilis pine barrens sandreed E C2
Helenium brevifolium littleleaf sneezeweed C
Hypericum adpressum bog St. John's-wort C
Hypoxis sessilis sessile-flowered yellow C
stargrass
Lophiola aurea golden-crest C
Lysimachia rough-leaf loosestrife E E
asperulaefolia
Macbridea caroliniana Carolina bogmint C
Oxypolis ternata savanna cowbane C
Parnassia caroliniana Carolina grass-of-parnassus E CZ
Pinguicula pumila small butterwort C
Plantago sparsiflora pineland plantain E
Platanthera Integra yellow fringeless orchid T
Polygala hookeri Hooker's milkwort C
Rhexia aristosa awned meadow-beauty T CZ
Rhynchospora few-flowered beakrush C
oligantha
Rhynchospora pale beakrush C
pallida
Rhynchospora littleleaf beakrush C
stenophylla
Schwalbea americana chaffseed E C2
Scleria georgiana Georgia nutrush C
Scleria verticillata savanna nutrush C
Solidago pulchra savanna goldenrod E C1
Solidago verna spring-flowering goldenrod E C2
Spiranthes longilabris long-lip ladies'-tresses C
Sporobolus teretifolius wireleaf dropseed T C2
46
APPENDIX II (continued)
Thalictrum cooleyi Cooley's meadowrue E E
Tofieldia glabra glabrous false asphodel C
Trillium pusillum Carolina least trillium E C2
Xyris flabelliformis savanna yellow-eyed grass C
Perched Forest
Trillium pusillum Carolina least trillium E
Freshwater Marsh
mmon Nam
Aeschynomene sensitive jointvetch E
virginica
Cyperus dentatus toothed-leaf flatsedge C
Lilaeopsis carolinensis Carolina lilaeopsis T
Limosella australis awl-leaf mudwort C
Ranunculus ivy buttercup C
hederaceus
Lake/Pond/Sound Shoreline
~,pecie,~, Common Name NC Status
Myriophyllum laxum loose watermilfoil T
Myriophyllum leafless watermilfoil C
tenellum
Utricularia olivacea dwarf bladderwort T
Brackish Marsh
C2
Federal Status
CZ
C2
Federal Status
C2
cies Common Name NC Status Federal Status
Cyperus dentatus toothed-leaf flatsedge C
Eleocharis halophila salt spikerush T
Mountain Bog
i
me
N
C
NC Status Federal Status
es
c
Arethusa bulbosa ommon
a
bog rose E
Botrychium oneidense blunt-lobed grapefern C
Carex barrattii Barratt's sedge E Cl
Carex buxbaumii Buxbaum's sedge C
Carex collinsii Collins's sedge C
Carex oligosperma few-seeded sedge C
Carer projects necklace sedge C
47
APPENDIX II (continued)
Carer schweinitzii
Chelone cuthbertii
Cladium mariscoides
Epilobium
leptophyllum
Filipendula rubra
Geum aleppicum
Helenium brevifolium
Helonias bullata
Hierochloe odorata
Ilex collina
Juncus gymnocarpus
Lilium grayi
Marshallia grandiflora
Schweinitz's
Cuthbert's
twig-rush
narrowleaf
sedge
turtlehead
E
C
C
C
Menyanthes trifoliate
Myrica gale
Narthecium
willowherb
queen-of-the-prairie
yellow evens
littleleaf sneezeweed
swamp pink
holy grass
long-stalked holly
naked-fruited rush
Gray's lily
large-flowered Barbara's
buttons
buckbean
sweet gale
bog asphodel
C
C
C
T
C
T
C
T
C
T
C
E
americanum
Platanthera white fringeless orchid
integrilabia
Platanthera peramoena purple fringeless orchid
Poa paludigena bog bluegrass
Rhynchospora albs white beakrush
Sagittaria fasciculata bunched arrowhead
Sarracenia jonesii mountain sweet pitcher
plant
Sarracenia oreophila green pitcher plant
Saxifrage pensylvanica swamp saxifage
Schlotheimia lancifolia highlands moss
Thelypteris simulate bog fern
Tofieldia glutinosa sticky bog asphodel
Utricularia minor lesser bladderwort
Mountain Fen
E
C
C
C
E
E
E
C
T
T
C
C
T
CZ
Cl
C2
C2
C2
E
E
E
Federal Status
Carex buxbaumii
Carex conoidea
Carer oligosperma
Cladium mariscoides
Lilium grayi
Muhlenbergia
glomerate
Parnassia grandifolia
Rhynchoshpora albs
Tofieldia glutinosa
Buxbaum's sedge C
cone-shaped sedge T
few-seeded sedge C
twig-rush C
Gray's lily T
bristly muhly C
large-leaved grass-of- C
parnassus
white beakrush C
sticky bog asphodel C
48
C2
APPENDIX II (continued)
LYQ Lth S~~ ~.i.aSx~ ~S~
ENDANGERED (E): The most critically imperiled species, those that may become
extinct or disappear from a significant .part of their range if they are not
immediately protected.
THREATENED (T): The next most critical level of imperiled species, those that
may become endangered in or disappear from the state if they are not
protected.
CANDIDATE (C): Species that are under review for listing as endangered or
threatened because of few populations, small populations, or occurrence in a
rare and threatened habitat.
~]. Status Codes
ENDANGERED (E): The most critically threatened species, those that may
become extinct or disappear from a significant part of its range if they are not
immediately protected.
THREATENED (T): The next most critical level of threatened species, those that
may become endangered if they are not protected.
Cl: Candidate species presently under review for federal listing for which
adequate information exists on biological vulnerability and threat(s) to list the
taxa an Endangered or Threatened.
C2: Candidate species presently under review for federal listing for which
imformation indicates that listing as Endangered or Threatened is possibly
appropriate, but for which adequate data on biological vulnerability and
threat(s) are not currently known or on file to support proposed rules.
49