Invalid Unit Specified
S18 Temperate & Boreal Grassland & Shrubland Subclass

The U.S. National
Vegetation Classification
Type Concept Sentence: Temperate & Boreal Grassland & Shrubland is dominated by mesomorphic grasses and shrubs, with or without scattered trees (and trees typically <10% cover), ranging from temperate coastal to inland lowland and montane grasslands and shrublands, with a strongly seasonal climate and at least some frost to extended cold seasons.
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Common (Translated Scientific) Name: Temperate & Boreal Grassland & Shrubland Subclass
Colloquial Name: Temperate & Boreal Grassland & Shrubland
Hierarchy Level: Subclass
Type Concept: Temperate & Boreal Grassland & Shrubland occurs in areas of moderately dry to wet, continental, coastal and Mediterranean climates, and is most abundant in North America, Eurasia (the steppes), South America, and parts of Southern Africa and Australia. The vegetation varies from grasslands of open to dense bunch or sod grasses, often with scattered shrubs or trees, to low (<2 m) open to dense shrublands and sclerophyllous or soft chaparral scrub, and trees absent to scattered (<10% cover). Xeromorphic growth forms are largely absent; the surface layer has a thin to thick litter and duff layer, posed in contrast to desert grassland and scrub, where the surface layer may be bare or contain a biological crust. Structure is a single, major grass or shrub stratum, or a mix of the two, typically exceeding 10-20% cover. There are a number of drivers that can preclude establishment of forest vegetation in these climates; including climatic characteristics, water regime (droughty habitats), and fire and flooding disturbances.
Diagnostic Characteristics: Temperate & Boreal Grassland & Shrubland is dominated by mesomorphic grasses or grasses and shrubs, with or without scattered trees (and trees typically <10% cover), ranging from temperate to coastal and inland lowland and montane grasslands and shrublands, with a strongly seasonal climate, with at least some frost and with extended strong cold seasons.
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: Desert grasslands are treated in 3. Desert & Semi-Desert Class (C03) based on the typical presence or abundance of xerophytic woody growth forms and, less commonly, the presence/abundance of ephemeral plants. Review of herbaceous growth forms is needed to determine if there are forms that more clearly distinguish desert grasslands from temperate grasslands. As Dixon et al. (2014) and others suggest, there may be good ecological reasons to treat upland tropical tree savannas, with up to 40% tree cover, trees <8 m tall, and a substantial graminoid layer, as part of 2. Shrub & Herb Vegetation Class (C02), and we allow for that option here. By contrast, in non-tropical regions, we place tree savannas with woodland and forest.
Similar NVC Types:
S01 Tropical Grassland, Savanna & Shrubland, note:
S15 Temperate & Boreal Forest & Woodland, note: Temperate & Boreal Grassland & Shrubland (S18) tree cover is <10%.
S11 Cool Semi-Desert Scrub & Grassland, note: Temperate & Boreal Grassland & Shrubland (S18) typically lacks the microphyllous leaved shrubs, more open and short grasses, and dry soils of cool semi-desert formation (S11), but dry grasslands, such as shortgrass prairies in North America, may have many similarities to cool semi-deserts.
S04 Temperate & Boreal Open Rock Vegetation, note: Temperate & Boreal Grassland & Shrubland (S18) contains many rocky river and lake shoreline types.
Physiognomy and Structure: The vegetation varies from grasslands of open to dense bunch or sod grasses, often with scattered shrubs, to low (<2 m) open to dense shrublands and sclerophyllous or soft chaparral and drought-deciduous scrub. Xeromorphic growth forms are largely absent, and the surface layer contains a thin to thick litter and duff layer in contrast to desert grassland and scrub, where the surface layer may be bare or contain a biological crust. Structure is a single, major grass or shrub stratum, or a mix of the two, with mesomorphic tree cover typically <10%, rarely with bare ground (Whittaker 1975). The range of variation in upland formations corresponds to Mediterranean, Temperate, Boreal, and Coastal climatic gradients.
Floristics:
Dynamics: No Data Available
Environmental Description: The vegetation occurs in areas of moderately dry to wet, continental, coastal, and Mediterranean climates (moderately dry, warm-temperate, maritime climates with little or no summer rain). A number of drivers can preclude establishment of forest vegetation in these climates, including climatic characteristics, water regime (droughty soils), and fire and flooding disturbances.
Geographic Range: This subclass occurs in the middle latitudes (between 25° and 60° to -0°N and S latitude) of both hemispheres, and is most abundant in North America, Eurasia (the steppes), South America, and parts of Southern Africa and Australia. Specific latitudes depend upon the continent on which they are located.
Nations: CA, US
States/Provinces:
Omernik Ecoregions:
Plot Analysis Summary:
Confidence Level: High
Confidence Level Comments:
Grank: GNR
Greasons:
Name:Database Code:Classification Code:
Class 2 Shrub & Herb Vegetation C02 2
Subclass 2.B Temperate & Boreal Grassland & Shrubland S18 2.B
Formation 2.B.4 Temperate to Polar Scrub & Herb Coastal Vegetation F005 2.B.4
Formation 2.B.2 Temperate Grassland & Shrubland F012 2.B.2
Formation 2.B.3 Boreal Grassland & Shrubland F028 2.B.3
Formation 2.B.1 Mediterranean Scrub & Grassland F038 2.B.1
Concept Lineage:
Predecessors:
Obsolete Names:
Obsolete Parents:
Synonomy: = Temperate Grassland Biome (Woodward 2008)
Concept Author(s): Hierarchy Revisions Working Group, Federal Geographic Data Committee (Faber-Langendoen et al. 2014)
Author of Description: D. Faber-Langendoen
Acknowledgements:
Version Date: 17Oct2014
References:
  • Faber-Langendoen, D., T. Keeler-Wolf, D. Meidinger, C. Josse, A. Weakley, D. Tart, G. Navarro, B. Hoagland, S. Ponomarenko, J.-P. Saucier, G. Fults, and E. Helmer. 2015c. Classification and description of world formation types. General Technical Report RMRS-GTR-000. USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO.
  • MacKenzie, W. H., and J. R. Moran. 2004. Wetlands of British Columbia: A guide to identification. Land Management Handbook No. 52. Research Branch, British Columbia Ministry of Forests and Lands, Victoria, BC. 287 pp.
  • Mitsch, W. J., and J. G. Gosselink. 2000. Wetlands. Third edition. John Wiley & Sons, Inc., New York. 920 pp.
  • National Wetlands Working Group. 1997. Wetlands of Canada. C. D. A. Rubec, editor. Ecological Land Classification Series No. 24. Environment Canada, Ottawa, and Polyscience Publications, Inc., Montreal. 452 pp.
  • Whittaker, R. H. 1975. Communities and ecosystems. Second edition. Macmillan Publishing Co., New York. 387 pp.
  • Woodward, S. 2008. Grassland biomes. Greenwood Press, Westport, CT.