Arctic patterned-ground ecosystems: A synthesis of field studies andmodels along a North American Arctic Transect

摘要

Arctic landscapes have visually striking patterns of small polygons, circles, andhummocks. The linkages between the geophysical and biological components of thesesystems and their responses to climate changes are not well understood. The"Biocomplexity of Patterned Ground Ecosystems" project examined patterned-groundfeatures (PGFs) in all five Arctic bioclimate subzones along an 1800-km trans-Arctictemperature gradient in northern Alaska and northwestern Canada. This paper provides anoverview of the transect to illustrate the trends in climate, PGFs, vegetation, n-factors,soils, active-layer depth, and frost heave along the climate gradient. We emphasizethe thermal effects of the vegetation and snow on the heat and water fluxeswithin patterned-ground systems. Four new modeling approaches build on the theme thatvegetation controls microscale soil temperature differences between the centers andmargins of the PGFs, and these in turn drive the movement of water, affect the formationof aggradation ice, promote differential soil heave, and regulate a host of system propertiesthat affect the ability of plants to colonize the centers of these features. We concludewith an examination of the possible effects of a climate warming on patterned-groundecosystems.