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Wetland Classification and Mapping of the Kenai Lowland, Alaska
Map Unit Descriptions Ecosystem: Relict Glacial Lakebed
Map Unit Complex: LBSF
Extent: 91 wetland polygons; 3241.4 ha; 2.29% of wetland area; 0.55% of wetland polygons. |
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From emergent vegetation in a permanent pool to a tree island in the 1000 ha strang-flark complex near the Kenai Airport (polygon 8075).
A low strang between two pools in a smaller LBSF complex near Kasilof (polygon 9289). |
Wetland Indicators Type: Peat Average depth to water table: LB1: n/a LB2: 11.3 cm; n=32 LB3: 9.9 cm; n=13 LB4: 19.5 cm; n=50 LB5: 57.0 cm; n=2 LB6: 31.4 cm; n=46 Organic layer thickness: LB1: n/a LB2: 146.6 cm; n=36 LB3: 119.2 cm; n=13 LB4: 116.0 cm; n=52 LB5: 78.5 cm; n=2 LB6: 70.2 cm; n=62 Average depth to redoximorphic features: LB1: n/a LB2: n/a LB3: n/a LB4: 79.0 cm; n=3 LB5: n/a LB6: 51.0; n=14 Common Soils: LB1: pond LB2: STARICHKOF, DOROSHIN LB3: STARICHKOF, DOROSHIN LB4: STARICHKOF, DOROSHIN, SALAMATOF, NIKOLAI LB6: STARICHKOF, KALIFONSKY, DOROSHIN, NIKOLAI Common Plant communities: LB1 component:
LB2 component: Tufted bulrush - Tall cottongrass Sweetgale – Dwarf birch / Water horsetail Tufted bulrush – Fewflower sedge
LB3 component: Sphagnum moss - Ericaceous shrub Sphagnum moss / Tall cottongrass Sphagnum moss - Manyflower sedge Tufted bulrush – Fewflower sedge Fewflower sedge – Tall cottongrass LB4 component: Sweetgale - Shrubby cinquefoil Sphagnum moss - Ericaceous shrub Bog blueberry – Dwarf birch – Tufted hairgrass
LB5 component:
LB6 component: Black spruce / Woodland horsetail - Labrador tea Black Spruce / Crowberry - Lingonberry Lutz spruce / Barclay's willow / Field horsetail / Crowberry
NWI: PEM1/SS1,3&4Eg HGM: Terrene Slope/Flat groundwater-dominated Throughflow |
| Accuracy assessment: 33 polygons interpreted as LBSF on aerial photographs were field checked. 23 remained LBSF; 2 each were revised to LB26 and LB2; 1 each was revised to: DW2, K23, LB21, LB23, LB24 and LB3. | |
LBSF is a complex of the Relict Glacial Lakebed Ecosystem components LB1-LB6, although all of the components are not present in any LBSF wetland. LBSF indicates well-developed strang-flark topography. Strangs (low peat ridges about 0.5-2 meters high) alternate with flarks (more or less linear sedge-dominated low spots, or pools with standing water). Strangs, flarks and pools are oriented perpendicular to groundwater flow, which is usually imperceptible. A commonly occurring form of this complex is when LB1, the open water/emergent component (pool), and LB2, the sedge and sweetgale component (flark), occur with LB4, a shrubby component dominated by sweetgale and shrubby cinquefoil (strang). Occasionally the sphagnum moss component LB3 and/or a forested component, LB6 are also present.
Although not particulary numerous, LBSF wetlands can be very large. The largest polygon in the study area is the nearly 1000 ha strang - flark complex northwest of the Kenai Airport. This probably represents the dominant peatland process in maritime environments at our latitude.
