Common (Translated Scientific) Name: Boreal Grassland & Shrubland Formation

Colloquial Name: Boreal Grassland & Shrubland

Hierarchy Level:  Formation

Type Concept: Poleward of the temperate grassland are minor areas of Boreal Grassland & Shrubland, dominated by mesomorphic perennial grasses and forbs, with shrubs of varying dominance. Mosses and lichens play a larger role than in other grasslands. This type is associated with cold semi-arid to moist climates, with extended cold winters and short mild summers, and geographically occurs mixed with boreal forests and wetlands. The climate generally favors establishment of forest vegetation; thus, the absence of forest vegetation is a result of local conditions related to water regime, soil parameters, or disturbance regimes. There are lengthy periods of freezing temperatures with the coldest month isotherm of -3°C, and the growing season generally averaging less than 100 days, occasionally interrupted by nights of below-freezing temperatures. Snow may be present for extended periods (7-10 months) and soils are frozen in winter. Annual precipitation is 38-50 cm (15-20 inches). The northern and southern boundary of these boreal grasslands may be similar to that of boreal forest, but the reasons for the presence of grassland and shrubland rather than forest typically reflects water regime, soil characteristics, disturbance regime, and local climate that prevent tree growth. This formation is found in the northern mid-latitude regions of North America and Eurasia, extending through much of the boreal region between 55° and 70°N latitude.

Diagnostic Characteristics: Mesomorphic perennial grasses and shrubs are the most common growth forms in this formation, with a variable amount of perennial forbs. Trees are scattered to minimally present (typically <10% cover) in the northern mid-latitude regions of North America and Eurasia, extending from cool-temperate regions into the boreal region between 55° and 70°N latitude.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Clarification of the growth forms, distribution and extent, and ecological processes that control boreal shrublands and grasslands is needed. Examples of vegetation from western boreal include: (1) Betula nana and/or Salix glauca shrublands and Festuca altaica grasslands in cold air-influenced valleys and high-elevation areas below the alpine; (2) Elymus trachycaulus grassland or Amelanchier alnifolia / Leymus innovatus / Arctostaphylos uva-ursi scrub on warm aspects, often on coarse-textured materials; and (3) Post-fire disturbance vegetation that can be dominated by willows and may exclude tree regeneration.

Similar NVC Types: No Data Available

note: No Data Available