photo of eastern Washington shrub-steppe landscape

Macro Review: Inter-Mountain Basins Big Sagebrush Steppe

LANDFIRE mapped the Inter-Mountain Basins Big Sagebrush Steppe (Big Sage Steppe) Biophysical Setting (BpS) on nearly 39 million acres across 20 different map zones in the U.S. Eight 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 Steppe 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 eight variants that LANDFIRE has modeled for Big Sage Steppe 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 1/7/9, and 8 have identical state-and-transition models, but they have differences in the succesion class structure (height/cover) – see here – and some descriptive differences. Are these differences appropriate, or should these variants be lumped?
    • The variants for map zones 6 et al., 18, and 28 have identical state-and-transition models, but they have differences in the succesion class structure (height/cover) – see here – and some descriptive differences. Are these differences appropriate, or should these variants be lumped?
    • The variants for map zones 20 and 29/30/31 have identical disturbance transitions in their state-and-transition models, but they have slight differences in the succession class age ranges and succession class structure (height/cover) – see here – as well as some descriptive differences. Are these differences appropriate, or should these variants be lumped?
  3. Is the relationship between the Big Sage Steppe 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 Steppe 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 Steppe 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.