Abstract ID: 3.10519 | Accepted as Talk | Talk/Oral | TBA | TBA

Roots represent an important structural component of alpine soils and vary in terms of morphology and symbioses. From surveys of plant species distributions in ongoing studies at sites in the Northern Rocky Mountains of Montana, we found variations in root structure and symbioses with habitat. At Goat Flat (2792 m, 46° 3′ 1.74″ N, 113° 16′ 46.61″ W), periglacial patterned ground alternates between edges and polygonal centers. Vascular plant and moss cover is approximately 90% on the edges, which form channels and delineate the sparsely (5-10%) vegetated polygons. The edges are inhabited by a range of species with woody root systems, including the ectomycorrhizal Picea engelmannii, and the dwarf shrubs Salix arctica, and Dryas octopetala, which are clonal via adventitious roots. However, plants of the polygon edges likely extend their roots into the adjacent polygon centers. The polygon centers are predominantly inhabited by herbaceous perennial species with arbuscular mycorrhizae and a variety of root systems, including taproots and fibrous roots. Approximately 10% of the polygon center plants are in the Fabaceae, symbiotic with N-fixing bacteria. In contrast, and at a snowfield uphill from the Goat Flat patterned ground (2837 m, 46° 3′ 17″ N, 113° 15′ 43″ W), is dominated by fibrous-rooted, often arbuscular mycorrhizal herbaceous species, including the monocots Calamagrostis purpurea, Poa alpina, and Carex sp.,and the dicots Antennaria alpina, Polygonum bistortoides, and Epilobium anagallidifolium. A range of woody-rooted dwarf shrubs lives beyond the summer edges of the snowfield and includes the ectomycorrhizal D. octopetala, S. arctica, and the ericaceous Cassiope mertensiana and Phyllodoce empetriformis. Differences in root structure and symbionts with habitat contribute to mountain soil biodiversity.