Figure 2. Topographic features of Fort Greely roads, cantonement (outlined), and impact areas

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Braided river drainages are an important feature of

Jorgenson et al. (2000) classified and mapped 37

the base (Fig. 4a). The more stable margins were domi-

local ecosystems on the basis of a combination of physi-

nated by tall alder and willow scrub communities, and

ography (i.e., alpine, lowland, riverine, etc.), moisture

large areas of open gravel bar were dominated by Dryas

status, soils or substrate, and dominant vegetation

drummondii, legumes such as Hedysarum sp. and

growth form: 12% of the area is occupied by Alpine

Oxytropus sp., and low scrub such as Salix glauca and

ecosystems (i.e., Alpine Rocky Moist Low Scrub), 20%

Elaeagnus commutata. The endemic willow Salix

by Upland ecosystems (i.e., Upland Moist Low and Tall

setchelliana was found at most open gravel bar sites.

Scrub), 55% by Lowland ecosystems (with Lowland

Wet to moist, fairly stable sedge-forb meadows (such

Tussock Scrub Bog being the most common type cov-

as site 38) were not common, though the vast majority

ering 21% of the base), and 8% by Riverine ecosys-

of the Delta River Bar was closed because of

tems (i.e., Riverine Gravelly Barrens).

unexploded ordinance and could possibly contain more

Habitats

of this species-rich habitat. Wind blown sand, encroach-

Plant species are associated with particular habitats

ing on neighboring forest and scrub, was encountered

on portions of Jarvis Creek.

and communities that are determined by the soil mois-