photo of Colorado sagebrush shrubland landscape

Macro Review: Inter-Mountain Basins Big Sagebrush Shrubland

LANDFIRE mapped the Inter-Mountain Basins Big Sagebrush Shrubland (Big Sage Shrubland) Biophysical Setting (BpS) on nearly 52 million acres across 24 different map zones in the U.S. Twelve unique BpS models are used to represent this system throughout its range. Each unique model, known as a variant, is assigned to one or more map zones. Variants can differ by species composition, succession class structure, disturbance regimes or other characteristics. The purpose of this macro-review is to determine if the LANDFIRE Big Sage Shrubland model variants capture the ecological variation across the range of this BpS and to check for logical consistency within the variants. Your input is needed to answer key questions and to improve this widely used resource.

Review Instructions

Review the resources shown at the right and answer as many of the following questions as possible. Detailed information and supporting citations are encouraged.

Review Options

There are several options for providing your review comments. Choose the option that works best for you:

  1. Create a separate document with your comments, but be specific about which model(s) your comments apply to.
  2. Place comments directly in the relevant BpS document(s) using Track Changes.
  3. Compose an email with your comments, but again be specific about which model(s) your comments apply to.
  4. Contact Kori Blankenship to schedule a facilitated review via phone/webinar.

Submit all reviews to landfire@tnc.org

Key Questions
  1. Do the 12 variants that LANDFIRE has modeled for Big Sage Shrubland encompass the full range of ecological variation for this BpS? The comparison table, maps, and description documents provide detailed information about each variant.
  2. Within the range of the Big Sage Shrubland do the variants that LANDFIRE has modeled accurately reflect ecological differences? Would you change the variants in any way (e.g. lump or split zones)?
    • Big Sagebrush Steppe and Big Sagebrush Shrub are lumped in some zones, but not in others – see here. Are these lumps appropriate? If so, should they be lumped in other map zones?
      • In map zone 33, the Big Sagebrush Steppe BpS was lumped into the Big Sagebrush Shrub BpS. This means they have an identical model and only the Big Sagebrush Shrub BpS was mapped.
      • In map zones 29, 30, and 31, the Big Sagebrush Shrub BpS was lumped into the Big Sagebrush Steppe BpS. This means they have an identical model and only the Big Sagebrush Steppe BpS was mapped.
    • The variants for map zones 15/25, 28 and 33 have state-and-transition models with identical fire frequencies, but minor differences in non-fire transition frequencies – see here. There are also minor differences in the succession class structure (height/cover) between the variants – see here. Are these differences appropriate or should these variants be lumped?
    • The primary difference between the map zone 6 et al. and the map zone 18 variants is in the succession class mapping rules – see here. Are these differences appropriate or should these variants be lumped?
    • In map zones 21 and 22 Big Sage Shrubland was split into Wyoming Big Sage and Basin Big Sage types to represent differences in fire regime, floral components and habitat. Does this split seem appropriate? Should a similar split be applied to the rest of the Big Sage Shrubland range?
  3. Is the relationship between the Big Sage Shrubland variants logically consistent? For example, do the fire return intervals change in the direction you expect as you change variants north to south or east to west – see the fire regime map?
  4. What role if any does “mixed” severity fire play in this BpS across its range? Has mixed fire been used appropriately in the state-and-transition model for each variant? LANDFIRE defines mixed severity fire as a fire that topkills 25-75% of the dominant lifeform (e.g. shrubs in a shrubland). The ratio of high severity to mixed and low severity fires determines a BpS’s fire regime group classification. Some of the Big Sage Shrubland BpS are classified in low or mixed severity fire regime groups because they had too much mixed and low severity fire modeled relative to replacement severity.
  5. Do you any suggestions about the Big Sage Shrubland models not covered by the questions above?

What happens next?

Thanks for your review! The LANDFIRE team will review your comments as soon as possible and contact you with any questions. All comments and suggestions will be documented and made available to the public, but the LANDFIRE team will make the final decision on how review comments are incorporated into the revised BpS model set. Look for revised descriptions and models available online in 2016.