The Alaska Vegetation Classification - Alaska Geobotany Center ...

Figure 69-Seral herb stand dominated by Epilobiumlariiolium with scauered Anemlsia rilesii, Crepis nana,Astragalus nufzorinensis, and several other herb specieson the gravel bar of a glacial river in the Alaska Rangein interior Alaska.Successional status-These are early successional communities colonizing recentlyexposed surfaces. If disturbance is not renewed, many will develop into grass orscrub communities depending on locality and climate.Closely related types-Seral herb communities are similar to alpine herb communities,but the former usually are on lowlands (including mountain flood plains)recently or periodically disturbed by a catastrophic agent, commonly moving water(floods on flood plains or storm surges on coastal bluffs). Alpine herb communitiesare typical of talus slopes and rock outcrops, where soil development is minimal anddisturbance comes in the form of frost action or rockfall.Photographs-Figure 69, this publication.Primary references-lohnson and others 1966, Spetzman 1959.Communities-Epilobium latifolium (Scott 1974a, Webber and others 1978).Epilobium lafifolium-Artemisia tilesii (Batten 1977, Bliss and Cantlon 1957, Johnsonand others 1966, Spetzman 1959). Epilobiurn lafifolium-Crepis nana (Young 1974b).Hedysarum alpinurn-Artemisia arctica (Webber and others 1978). Cochleariaofficinalis-Oxyria digyna-Saxifraga rivularis (Potter 1972). Cochlearia officinalis-Phippsia algida-Sfellaria humifusa (Webber 1978). Artemisia arctica ssp. comafa(Meyers 1985). Wilbelmsia physodes-Artemisia arctica-Chrysanthemum arcficum(Thomas 1951). Equisetum variegafum (Helm and others 1984, Young 1974b).Dryas drummondii-€pilobium latifolium (Talbot and others 1984).lll.B.l.b. Alpine Herb-Sedge (Snowbed)Description-This unit includes a wide variety of vegetation types below late-lyingsnowbanks in mountainous areas throughout the State. Dominant species may beherbs (such as Oxyria digyna, Koenigia islandica, Saxifraga rivularis, Cardarninebellidifolia, Poa arctica, Carex lachenalii, and Claytonia sarmenfosa), mosses, andlichens, commonly Cetraria delisei. Woody plants are absent. Cover is sparse, andmuch bare ground generally is present.Distribution and site characteristics-Snowbed communities occur below outcropsand in depressions, streambeds, or other topographic features that break the windand allow substantial snowdrifts to accumulate. Soils are well drained, often stony,and may be dry late in the season. These sites are irrigated, at least seasonally, bywater from late-melting snowdrifts upslope.190