Plant functional traits and microbes vary with position on striped periglacial patterned ground at Glacier National Park,Montana

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.

     

Plant functional types and climate along a precipitation gradient in temperate grasslands, north-east China and south-east Mongolia

Using data from three field surveys along a precipitation gradient of temperate grasslands in north-east China (the Northeast China Transect, NECT) and south-east Mongolia, the spatial distribution of six plant functional types (PFTs): C₃ species, C₄ species, grasses, shrubs, forbs and succulents and their relationships with climate were analysed. The spatial distribution of different PFTs varies in different regions and in different grassland types of the study area. The species richness in each PFT also has different relationships with climate (significantly or not). Generally, the number of C₃ species, C₄ species, grasses and forbs have positive relationships with precipitation and aridity. Shrubs have negative relationship with precipitation and aridity. Succulents were found to have no relationship with precipitation and aridity. Shrubs, grasses and forbs have stronger relationships with precipitation than C₃ and C₄ species. The relationships between C₃ species, forbs and aridity are more significant than with precipitation. On a regional basis, the combined effect of precipitation and temperature, the aridity, is more significantly correlated with the distribution of C₃ species and forbs, which are more dominant in the study area, than with C₄ species, grasses and succulents.