A Quick Guide to
Wetland Map Units of the Kenai Lowlands
A Key to the Wetland Ecosystems of the Kenai Lowlands:
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1. Wetland periodically
inundated by salt
water........................................................................... |
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1. Wetland not periodically
inundated by salt
water..................................................................... |
2. |
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2.
A small wetland on a recent moraine, with no wetland connection to navigable
waterway
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2.
Wetland connected by other wetlands to a navigable
waterway.......................................... |
3. |
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3. Channelized flow
present.......................................................................................................... |
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3. If flow is present, not
in a channel exhibiting bed-and-bank morphology..................... .......... |
4. |
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4.
Wetland a large linear feature in a valley bottom, but without a defined
modern channel; or adjacent to an underfit stream; often with a water table
near the surface, even when forested.......................................................................................................................................... |
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4.
If a wet forest is present, then wetland lies along a slope break, or has a
deeper water table, usually over a flat peatland and not in a valley
bottom....................................................... |
5. |
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5. Slope break influences
discharge; usually at a foot- or toe-slope landscape position on a
terraced moraine, often over a mineral
soil................................................................................... |
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5. Wetland not along a
slope break; a peatland, or over a mineral
soil......................................... |
6. |
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6.
A peatland above about 350m elevation in the headwater basin of a first order
stream...... |
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6.
Wetland below about 350m elevation, or otherwise located on the
landscape.................... |
7. |
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7. Wetland above 500m,
often extensive and over mineral soil; if a peatland then smaller......... |
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7. Wetland below 500m, a
peatland.............................................................................................. |
8. |
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8. Wetland
an island floating on a lake, or moored to the shoreline,
rare................................. |
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8.
Wetland not floating on a lake............................................................................................... |
9. |
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9. Wetland an extensive,
flat peatland, below 350 m elevation. Strang and flark features
frequently present or
nearby.......................................................................................................... |
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9. Wetland smaller, usually
near kame(s) which are often modified; can occur up to about 350 meters
elevation, especially near |
MAP UNIT NAMING CONVENTIONS:
·
Ecosystems are
divided into components, mostly based on hydrology (depth to water table).
·
Map units names
are derived from an abbreviation of the name of the ecosystem, followed by a modifier
indicating the ecosystem component. (e.g. 'LB1' is component one
of the relict lakebed ecosystem).
·
A map component
with standing water or a water table near the surface is given a lower numerical
modifier than a component with a deeper water table. Plant physiognomy
typically indicates where the water table might be expected: Sedges often
indicate a shallower water table; shrubs and trees often indicate a deeper
water table.
·
Two ecosystems
use a different component naming scheme: a letter follows the ecosystem
abbreviation. Riparian ecosystem names are based on Rosgen's (1996)
classification. Discharge Slope ecosystem components are based on
dominant plant species (e.g. 'SM' is a Discharge Slope dominated by black
spruce Picea mariana).
·
Map unit names
can be combined using any combination of two components, even across
ecosystems. Combined names indicate either a complex of separate
components smaller than the minimum polygon size, or a more or less uniform
polygon with characteristics of two components (e.g. LB12 indicates a polygon
on a Relict Glacial Lakebed composed of both components 1 and 2 at more than
10% cover. LB1DW2 indicates a polygon with both Relict Glacial Lakebed emergent
(see below) and Relict Glacial Drainageway shallow groundwater components). Minimize naming polygons across ecosystems.
·
To be included in
the map unit name, components must each represent at least 10% of the polygon
area. The most abundant component is
named first- if each covers an equal area then they are listed in
alphanumerically.
·
If more than two
components, each less than the minimum polygon size, comprise more than about
10% of the cover of a polygon and they are in sequential order, then a code
including a dash can be used (e.g. DW1-5; indicates a polygon with all the
components DW1, DW2, DW3, DW4 and DW5 present at more than 10% cover).
·
If more than two
components are present, but not in sequential order, i.e. one or more component
is skipped, then a 'complex' needs to be named separately. Complexes are
named on a case by case basis, and must represent common wetland units.
So far three have been named: LBSF, the lakebed strang-flark complex; DWR a
relict Glacial Drainageway complex common along underfit streams; and Tr a
Tidal ecosystem complex common at the estuaries of smaller streams.
Tidal Flat
Ecosystem Components:
T0- Bare mud
T1-
saltpannes. Sparse, low glasswort (Salicornia maritima) and
pearlwort (Sagina maxima).
T2- Mud with
creeping alkaligrass (Puccinellia phryganodes).
T3- Bare
ground with goosetongue (Plantago maritima) and seaside arrowgrass (Triglochin
maritima). T4-
Alkaligrass (Puccinellia nootkaensis and P. Hultenii) often with
beachrye (Leymus mollis).
T5-
Ramensk's sedge (Carex ramenskii) dominates with pools. Mare's
tail (Hippuris), spikerush (Eleocharis spp.), saltmarsh starwort
(Stellaria humifusa) found in and around the pools.
T6-
Lyngbye's sedge (Carex lyngbyei) cover nearly continuous.
T7-
Beachrye (Leymus mollis ssp. mollis) diverse plant community on
storm berms.
T8- Pacific
silverweed and largeflower speargrass (Poa eminens) and sometimes
circumpolar reedgrass (Calamagrostis
deschampsioides) dominate.
T9- Upper
reaches of low gradient river mouths; dominated by manyflower sedge (Carex
pluriflora).
TR- More
than two non-consecutive units at a scale too small to map.
Tcs- Barren
sand, gravel, cobbles and some boulders, at the high storm line below bluffs.
Tidal map component
combinations used so far: T04, T1-4, T35, T40, T43, T45, T46, T4-6, T51, T54, T56, T58, T64, T65, T6-8, T6DW3, T76, T78, T86, T87, T96
Depression
Ecosystem Map Components:
D1- Standing water.
Floating or emergent vegetation.
D2 - Water table at or near
the surface. Sedge and/or sweetgale dominated.
D3 - Water table not at
surface. Shrubs or bluejoint grass (Calamagrostis canadensis)
dominant.
D4 - Redoximorphic features
or deep peat the wetland indicator.
Depression map component
combinations used so far: D12, D13,
D1-3, D1-4, D21, D23, D24, D2-4, D32, D34, D43
Riparian Ecosystem
Map Components:
REl- Linear, low gradient,
pool dominated, on glacial deposits.
REs- Sinuous, low gradient,
pool dominated, on glacial deposits.
REb- Bank-full due to
beaver dam, roads, logging debris or natural obstruction. Low gradient,
on glacial deposits.
REa- Stream
surface not discernable on 1:25,000 B&W aerial photography. Low
gradient, pool dominated. On glacial deposits.
RB- Higher gradient
(>2%); riffle dominated.
RC- Floodplain developed.
Point bars. Riffle/pool morphology.
RDA- Multiple low gradient,
pool dominated channels on glacial deposits.
Relict Glacial
Drainageway Ecosystem Map Components:
DW1- Standing water.
Floating (rare) or emergent vegetation.
DW2- Water at or near the
surface. Sedges, buckbean (Menyanthes trifoliata) and/or sweetgale
(Myrica gale) dominant.
DW3- Deeper water table:
hummocky or tussocky microtopography. Variety of plants; usually with a
shrubby component.
DW4- Water table
variable. Bluejoint (Calamagrostis canadensis) dominated (uncommon
map unit).
DW5A- Deeper water
table. Peat or redoximorphic features the wetland indicators.
Forested.
DW5- Deeper water
table. Usually with a deep peat layer and well-developed sphagnum
mat. Not forested.
DWR- A complex, usually of
DW2 and DW3 with either DW5A or DW5. This is most often a wet forest
(DW5A) with a sedge (DW2) and shrubby, hummocky (DW3) understory.
Drainageway Map Component
combinations used so far: DW12, DW1-3, DW1-4, DW1-5, DW1-5A, DW21, DW23, DW24, DW2-4, DW25, DW2-5, DW25A, DW2-5A, DW31, DW32, DW34, DW35, DW3-5, DW35A, DW3-5A, DW43, DW45, DW45A, DW4-5A, DW52, DW53, DW54, DW55A,
DW5A2, DW5A3, DW5A4, DW5A5
Discharge Slope
Ecosystem Map Components:
SM - Black spruce (Picea
mariana) dominated.
SL - Lutz spruce (Picea X
lutzii) dominated.
SS -
SG - White spruce (Picea
glauca) dominated.
SC -
Bluejoint grass (Calamagrostis canadensis) dominated.
SA - Alder (usually thinleaf
alder, Alnus incana ssp tenuifolia) dominated.
Discharge
Slope Ecosystem Map Component combinations used so far: SAC, SAG, SAL, SAS, SCA, SCL, SGS, SLA, SLM, SLS, SMA, SMG, SML, SMS, SSA, SSC, SSL, SSM
Headwater
Fen Map Components:
H1: Headwater Fen 1. A small lake in a headwater
basin.
H2:
Headwater Fen 2. Sedge
dominated peatland in a headwater basin; water table at or very near the
surface.
H3: Headwater Fen 3. Shrub or bluejoint dominated
peatland in a headwater basin; deeper water table.
H4: Headwater Fen 4. Woodland/forested peatland in
headwater basin.
Headwater
Fen Ecosystem Map Component combinations used so far: H1-3, H21, H23, H24, H2-4, H32, H34,
H43
Late
Snow Ecosystem Components:
LSP: Late Snow Plateaus. Above 500 meters
elevation. Mineral soil; shallow water
table or redox features indicating the water table is seasonally near the
surface.
LSF1: Late Snow Fen 1. A small, high elevation lake
at the head of a swale.
LSF2:
Late Snow Fen 2. A small, high
elevation peatland dominated by sedges.
Water table at or near surface.
LSF3: Late Snow Fen 3. A small, high elevation
peatland dominated by shrubs.
Late Snow Ecosystem Map
Component combinations used so far:
LSF1-3, LSF21, LSF23,
LSF31, LSF32
Relict Glacial Lakebed
Ecosystem Map Components:
LB1- Standing water.
Floating or emergent vegetation.
LB2- Water table at or near
the surface. Sedge and/or sweetgale (Myrica gale) dominated.
LB3- Sphagnum peat
well-developed, though not necessarily fibric (undecomposed). A variety
of sphagnum - sedge and sphagnum - ericaceous shrub communities, with sphagnum
cover continuous and vascular plant cover sparse.
LB4- Peat well-developed.
Shrubby strangs.
LB5- Water table
variable. Dominated by bluejoint (Calamagrostis canadensis)
(uncommon map unit).
LB6- Deep peat.
LB7- Deep peat or mineral
soil with redoximorphic features near the surface. Black spruce forest or
woodland with woodland horsetail.
LBTI- Tree island in a
large lakebed. A discontinuous island on a terrace shoulder or as a weak
kame-like feature, rather than the endpoint of a gradient from peat to
forest. Many forested communities.
Lakebed Complexes:
LBSF- More than two of the
above units present in a pattern too fine grained to map separately.
Often shallow pools alternating with peaty ridges about 20-50 meters apart.
Map Component combinations
used do far: LB12, LB13, LB1-3, LB1-4, LB1-5, LB21, LB23, LB24, LB2-4, LB2-5, LB26, LB2-7, LB31, LB32, LB34, LB36, LB3-6, LB3-7, LB41, LB42, LB43, LB45, LB46, LB4-7, LB52, LB54, LB57, LB62, LB63, LB64, LB67, LB72, LB74, LB76
Kettle Ecosystem Map
Components:
K1- Standing water; often a
lake. Submerged, floating and emergent vegetation.
K2- Water table at or near
the surface. Sedge and/or sweetgale (Myrica gale) dominated.
K3- Water table not at the
surface. Usually shrub dominated. Can contain ombrotrophic bogs.
K4-
Kettle
Ecosystem Map Component combinations used so far: K12,
K13, K1-3, K1-4, K21, K23, K24, K2-4, K32, K34, K31, K42, K43
Components outside of Ecosystems:
WU- Wetland /
DISTURB- Wetlands with human generated disturbance sufficient to mask pre-disturbance character of entire polygon.