Vegetation of zonal patterned‐ground ecosystems along the North America Arctic bioclimate gradient

Abstract

Question: How do interactions between the physical environment and biotic properties of vegetation influence the formation of small patterned‐ground features along the Arctic bioclimate gradient? Location: At 68° to 78°N: six locations along the Dalton Highway in arctic Alaska and three in Canada (Banks Island, Prince Patrick Island and Ellef Ringnes Island). Methods: We analysed floristic and structural vegetation, biomass and abiotic data (soil chemical and physical parameters, the n‐factor [a soil thermal index] and spectral information [NDVI, LAI]) on 147 microhabitat relevés of zonal‐patterned‐ground features. Using mapping, table analysis (JUICE) and ordination techniques (NMDS). Results: Table analysis using JUICE and the phi‐coefficient to identify diagnostic species revealed clear groups of diagnostic plant taxa in four of the five zonal vegetation complexes. Plant communities and zonal complexes were generally well separated in the NMDS ordination. The Alaska and Canada communities were spatially separated in the ordination because of different glacial histories and location in separate floristic provinces, but there was no single controlling environmental gradient. Vegetation structure, particularly that of bryophytes and total biomass, strongly affected thermal properties of the soils. Patterned‐ground complexes with the largest thermal differential between the patterned‐ground features and the surrounding vegetation exhibited the clearest patterned‐ground morphologies. Conclusions: Characterizing the composition and structure of small‐scale plant communities growing on distinctive microhabitats within patterned‐ground complexes was necessary to understand the biological and physical controls of vegetation on patterned‐ground morphology. Coarser‐scale vegetation units, referred to here as ‘zonal patterned‐ground vegetation complexes’ (groups of patterned‐ground plant communities within zonal landscapes), were useful for landscape and regional‐level comparisons and for extrapolation of information collected at plot scales to larger regions. Vegetation maps of the representative landscapes in each subzone were needed for extrapolation. Different growth characteristics of plants growing in northern and southern parts of the gradient have an important effect in stabilizing highly frost‐active soils. A conceptual diagram summarizes the interactions between vegetation and patterned‐ground morphology along the Arctic climate gradient.

Living strategy of cold-adapted fungi with the reference to several representative species

“…EMF resulted from analysis of root tips and soil clones in Arctic revealed their extremely high richness (Bjorbaekmo et al 2010; Geml et al 2012), comparing with previous estimation based on surveys of above-ground ECM sporocarps. A large number of OTUs were detected in Arctic, with 137 OUTs on the roots of Dryas octopetala along a latitudinal gradient from Southern Norway to Svalbard (Bjorbaekmo et al 2010), 73 ECM basidiomycete OTUs in soils on Svalbard (Geml et al 2012) and 224 OTUs in the roots of three co-occurring species in the Low Arctic (Walker et al 2011). …”

Artificial Neural Network Modeling of High Arctic Phytomass Using Synthetic Aperture Radar and Multispectral Data

“…Previous studies in the High Arctic have noted the fine-scale topographic and moisture controls of the ice-wedge polygon and frost crack dominated landscape [8,14]. Vegetation in polar semi-desert areas is often limited to the margins of the polygons, where wind speed is reduced and sufficient moisture and nutrients are present to allow growth; these features therefore leave large patches of bare ground.…”

“…In addition to the obvious limitations of air and soil temperature, there are a number of factors that serve as controls on vegetation growth in the high arctic, including soil moisture [8,9], available nutrients [10,11], topography [12,13], microtopography [8,12,14], and soil type [14]. The variation and distribution of these different environmental controls results in a very heterogeneous vegetation cover, with very different vegetation ecosystems sometimes in close proximity to one other.…”

Ice-age megafauna in Arctic Alaska: extinction, invasion, survival

“…Today, the vegetation of the North Slope is a Low Arctic tundra mosaic encompassing Bioclimatic Subzones C, D, and E (CAVM Team, 2003;Walker et al, 2011). Sedge/grass and moss wetlands occupy the northern edge of the Coastal Plain, while sedge, moss, and dwarf-shrub wetlands are abundant further inland.…”