The subzone description below lists Alaska plant communities along a toposequence on acidic and non-acidic substrates; in subzones C, D and E; in the three floristic provinces of Northern Alaska (
), Beringian Alaska (
) and Northern Beringian Island (
). Blocks of rows are positions along a mesotopographic gradient (see Mesotopographic gradient). Dominant plant functional types and species are listed where data were available. Literature citations (in small font) include unit names, habitat, citation and location.
| Habitat along the meso-topographic gradient | Acidic substrates
(community # 1-7) | Non-acidic substrates
(community # 8-12) |
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| Dry exposed sites | 1. Prostrate dwarf-shrub: Salix rotundifolia;
Lichen: Alectoria nigricans, Bryocaulon divergens, Dactylina arctica;
Grass: Arctagrostis latifolia;
Forb: Potentilla hyparctica, Pedicularis lanata;
Bryophyte: Polytrichum strictum, Dicranum elongatum, Gymnomitrion corallioides. Nodum
II (Webber 1978); Sphaerophorus globosus-Luzula confusa comm., subtype Salix rotundifolia (Elias et al. 1995) (Barrow,
dry beach and river terrace).
| 8. Type B12, coastal dry nonacidic gravelly sites (Walker 1985) (North Slope, Alaska).
Prostrate dwarf-shrub:
Dryas integrifolia;
Sedges: Carex rupestris,
Lecanora epibyron,
Thamnolia subuliformis;
|
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| Moist sites | 2. Nodum IV (Webber 1978); Type 6 and 7 (Walker 1977); Saxifraga cernua-Carex aquatilis comm. (Elias et al. 1995) (Barrow, moist, fine-grained soils).
Sedge: Carex aquatilis, Eriophorum angustifolium;
Grass: Poa arctica, Dupontia fisheri;
Rush: Luzula arctica;
Prostrate dwarf shrub: Salix rotundifolia;
Forb: Saxifraga cernua, S. hieracifolia, S. hirculus, Cardamine pratensis, Petasites frigidus, Ranunculus nivalis;
Moss: Oncophorus wahlenbergii, Sarmenthypnum sarmentosum, Aulacomnium turgidum. | 9. Type U12, moist calcareous coastal meadows (Walker 1985) (North Slope, Alaska) Sedge: Carex aquatilis;
Prostrate dwarf-shrub: Salix pulchra, S. reticulata, Dryas integrifolia;
Moss:
Tomentypnum nitens, Oncophorus wahlenbergii, Campylium stellatum, Distichium capillaceum
|
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| 3. Nodum 1 (Webber 1978); Type 5 (Walker 1977); Sphaerophorus globosus-Luzula confusa comm., subtype Saxifraga foliolosa (Elias et al. 1995) (mesic high-centered polygons, zonal vegetation in Barrow area).
Rushes: Luzula confusa, L. arctica;
Grasses: Poa arctica;
Forbs: Potentilla hyparctica, Pedicularis lanata;
Lichens: Alectoria nigricans, Sphaerophorus globosus, Dactylina arctica, Cladonia spp., Ochrolechia frigida;
Mosses: Polytrichastrum alpinum, Polytrichum strictum, Sarmenthypnum sarmentosum.
| |
| Wet sites | 4. Noda V and VI (Webber 1978); Types 9, 10, 12 and 13 (Walker 1977); Eriophorum angustifolium-Carex aquatilis comm. (Elias et al. 1995) (Barrow, wet sites without standing water).
Sedges: Eriophorum angustifolium, Carex aquatilis;
Grasses: Dupontia fisheri, Arctophila fulva;
Mosses: Sarmenthypnum sarmentosum, Limprichtia revolvens. | 10. Type M10 , wet calcareous coastal meadows (Walker 1985) (North Slope, Alaska).
Sedge: Carex aquatilils, Eriophorum angustifolium;
Grass: Dupontia fisheri, Arctophila fulva;
Moss: Drepanocladus brevifolius, Limprichtia revolvens, Sarmenthypnum sarmentosum. |
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| Snow beds | 5. Salix rotundifolia-Cetraria delisei comm. (Elias et al. 1995) (Barrow, early-melting snow beds).
Prostrate dwarf shrub: Salix rotundifolia;
Lichens: Cetrariella delisei. | 11. No data. Probably similar to snowbeds in Subzone D. |
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| 6. Nodum VIII (Webber 1978); Type 15 (Walker 1977) (Barrow, late-melting snow beds).
Grasses: Phippsia algida, Alopecurus alpinus;
Forbs: Cochlearia groenlandica , Ranunculus pygmaeus, Stellaria humifusa, Saxifraga rivularis | |
| Riparian areas | 7. Nodum VIII (Webber 1978); Type 15 (Walker 1977) (Barrow, unstable stream margins).
Grasses: Phippsia algida, Alopecurus alpinus;
Forbs: Cochlearia groenlandica , Ranunculus pygmaeus, Stellaria humifusa, Saxifraga rivularis | 12. Epilobio latifolii-Salicetum alaxensis ass. prov. (Schickhoff et al. 2002) (North Slope, coastal active floodplains).
Forb:
Epilobium latifolium, Artemisia arctica, Artemisia campestris ssp. borealis, Papaver lapponicum, Polemonium boreale, Astragalus alpinus, Wilhelmsia physodes, Parrya nudicaulis
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