The retreating snowfields and glaciers of Glacier National Park, Montana, USA, present alpine plants with changes in habitat and hydrology. The adjacent and relic periglacial patterned ground consists of solifluction terraces of green, vegetation-rich stripes alternating with sparsely vegetated brown stripes. We established georeferenced transects on striped periglacial patterned ground for long-term monitoring and data collection on species distribution and plant functional traits at Siyeh Pass and at Piegan Pass at Glacier National Park. We documented species distribution and calculated the relative percent cover (RPC) of qualitative functional traits and used 16S rRNA from soil samples to characterize microbial distribution on green and brown stripes. Plant species distribution varied significantly and there were key differences in microbial distribution between the green and brown stripes. The rare arctic-alpine plants Draba macounii, Papaver pygmaeum, and Sagina nivalis were restricted to brown stripes, where the RPC of xeromorphic taprooted species was significantly higher at the leading edge of the Siyeh Pass snowfield. Brown stripes had a higher percentage of the thermophilic bacteria Thermacetogenium and Thermoflavimicrobium. Green stripes were co-dominated by the adventitiously-rooted dwarf shrubs Salix arctica and the possibly N-fixing Dryas octopetala. Green stripes were inhabited by Krummholz and seedlings of Abies lasiocarpa and Pinus albicaulus. Prosthecobacter, a hydrophilic bacterial genus, was more abundant on the green stripes, which had 6,524 bacterial sequences in comparison to the 1,183 sequences from the brown stripes. While further research can determine which functional traits are critical for these plants, knowledge of the current distribution of plant species and their functional traits can be used in predictive models of the responses of alpine plants to disappearing snowfields and glaciers. This research is important in conservation of rare arctic-alpine species on periglacial patterned ground.

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The glaciers and snowfields at Glacier National Park, Montana are disappearing due to climate change [1]. Snowfield plants rely on melting snow from the edges of snowfields and glaciers during the brief summer growing season in this otherwise harsh environment. Since the edges of snowfields and glaciers move as these icy bodies recede, snowfield plants live on changing edges and may lose this habitat altogether with the disappearance of snowfields and glaciers. Glacier National Park is home to rare arctic-alpine plants that inhabit the snowfield's edges and that live downstream and obtain their water, at least in part, from summer snowmelt. Thus, the habitats of these rare plants are endangered.Plants are intrinsically linked to their environments, and plant functional traits are those characteristics of plants that influence their interactions with the environment [2]. Plant functional traits exist on the macroscopic, microscopic, physiological, biochemical, and temporal levels. For example, the presence of rhizomes is a plant functional trait. Rhizomes are macroscopic, underground horizontal stems that occur frequently in snowfield plants. Rhizomes provide a ready reservoir of carbohydrates that if mobilized and metabolized, can be used by snowfield plants for rapid growth; for withstanding adverse conditions before snowmelt; for production of adventitious roots; for clonal reproduction; and for production of buds. These buds can quickly sprout during snowmelt and grow into aerial shoots that may in turn produce flowers or spores. Rhizomes are also a key means of advance for pioneer species, which include plants colonizing a recently revealed snowfield's edge. Phenology is the science of the timing of biological events, and one consequence of climate change is that phenology can be offset. Therefore, rhizome physiology can be seen as a functional trait that is a coordinating mechanism for many phenological events in snowfield plants.In 2012 and 2014, we established geospatially referenced transects perpendicular to the lateral and leading edges of snowfields at Mt. Clements, Siyeh Pass and Piegan Pass at Glacier National Park [3]. We collected leaves for morphometric measurements from 1m 2 quadrats placed at 5m intervals along the 50m transects. Functional traits of plants differed significantly with distance from the snowfields. Morphometric traits of leaves collected along an environment gradient extending from the edge of the vast Mt. Clements snowfield to the top of the steep (35°) Mt. Clements moraine were measured with Image-J and dry weights were obtained [4]. Specific leaf area, (mm -2 /mg dry weight,) is an indirect measure of leaf density. Leaves with higher SLA generally have less densely packed cells. At the Mt. Clements moraine, community-weighted trait means of SLA decreased significantly with distance from the snow. Therefore, the leaves of the collective snowfield species were thinner, or less dense, near the snow where water availability was greater, and thicker, or with greater density, farth...