USGS:Biology Biological Informatics Program Vegetation Characterization Program National Vegetation Classification Standard (NVCS)

National Vegetation Classification Standard (NVCS)

Current Status

The Classification System is an FGDC standard through the physiognomic (first 5 levels). Work continues through the USGS-NPS Vegetation Mapping Program, in association with USGS/BRD (CBI), USGS/BRD (GAP), EPA (EMAP), U.S. Fish and Wildlife Service, National Park Service, NatureServe, The Nature Conservancy, Ecological Society of America (Vegetation Section), and the FGDC Vegetation Subcommittee on the floristic levels (lower 2 levels) of the standard. The lower levels of the Classification have several thousand cover types and associations to date. Work will continue for an indefinite period as new classes are proposed and existing classes are refined or aggregated.

Standardized National Vegetation Classification System (1994); protocol document for the USGS-NPS Vegetation Mapping Program

The Federal Geographic Data Committee's Information on National Vegetation Classification Standard, Version 1 (1997)

The Federal Geographic Data Committee's Information on The National Vegetation Classification Standard, Version 2 (2008)

Newly developed training and outreach tools for the NVC

An brief explanation of the relationship of the 2008 Revised NVCS and earlier work history documented on this site. - 10/22/2008

The previous NVC standard was adopted in 1997 (FGDC 1997) and the hierachy did not incorporate biogeography, but structure and phenology were emphasized at the highest levels. Officially the 1997 standard, the alliances and associations were not formally adopted, but the work on them has been supported through a variety or projects and NatureServe has worked intensively on those levels. NatureServe has maintained the hierarchy and serves that data through NatureServe Explorer.

The new standard will bring over much of the content of the existing types, especially at the association level, but the hierachy is different enough that alliances will change. Groups and macrogroups in the new hierarchy will be closes to what you are interested in. The new structure incorporates biogeography indirectly through species composition shifts. So the new alliances will be informed by the existing alliances, but likely to split and be grouped. In fact that is likely to be the last level that settles down after the reworking from above and below. Associations should be most stable with changes occurring over time as new field data and analyses are run.

There will be much work done in the next year towards getting the initial content of the new hierachy compiled, so depending on your timeline you may want to start with the old hierachy and then switch or start work with the newly drafted hierachy as it comes together.

NatureServe "Terrestrial Vegetation of the United States"

Specifications and Requirements

• The system must be based on a sound scientific approach that is a logical progression from historical methods
• The approach must be repeatable and based on standard field and data analysis methods
• The system should be broadly accepted both nationally and internationally
• The system must classify existing biological associations that repeat across the landscape
• The classification units must be ecologically meaningful.
• The classification must be mappable from imagery.
• The classification system must be hierarchically organized such that it can be applied at multiple scales.
• The system must identify classification units that are appropriately scaled to meet objectives for biodiversity conservation, as well as resource and ecosystem management needs.
• The system must be flexible and open ended such that it will allow for additions, modifications and continuous refinement.
• The system must be well documented.
• The system should be able to be cross-walked between other frequently used systems.

Illustrated example of a classification, through association level

A. PHYSIOGNOMY

System: Terrestrial/Aquatic - (hydrological regime)

Class - Woodland - (spacing & height of dominant form)

Subclass - Evergreen Woodland - (morphological & Phenological similarity)

Group - Temperate Evergreen Needle-leaved - (climate latitude, growth form, leaf form)

Formation - Evergreen needle-leaved forest with conical crowns - (mappable units)

B. FLORISTICS

Alliance (or cover type) - Abies lasiocarpa Forest (dominant species)

Association (or community) - Abies lasiocarpa/Vaccinium scoparium [Subalpine fir/Grouseberry] (subdominant or associated species with similar ecological processes)

Abies lasiocarpa/Vaccinium scoparium forest

USGS Home :: Geology :: Geography :: Water