Terrestrial monitoring is generally stratified by LANDFIRE biophysical setting (BpS) groups. This remote sensing-derived layer is conceptually very similar to NRCS Ecological Sites. BpS represents the vegetation that may have been dominant on the landscape prior to Euro-American settlement. BpS is based on both the current biophysical environment and an approximation of the historical disturbance regime. BpS describe the following physical characteristics of a BpS environment: vegetation, geography, biophysical characteristics, succession stages, and disturbance regimes (and major disturbance types).
BpS is very useful because it represents variability in landscape potential as a continuous and consistent layer across the western US. Thus it can be applied for stratification across administrative boundaries and across all types of land. In contrast, other commonly-used layers such as NRCS Ecological Sites have gaps in certain areas or types of land that limit their usability for stratification. Even where BpS are mapped imprecisely (e.g., wrong BpS assigned to a single pixel), they still achieve the primary goal of stratification which is to reflect the heterogeneity of the landscape as a whole. For reporting, a different attribute such as ecological site verified by the soil pit will generally be used.
How to apply BpS for stratification
Strata are often a combination of individual BpS’s as well as BpS Groups (see map below). For example, a Wyoming Big Sage strata could be made up of the BpS Groups Wyoming Big Sage-Wheatgrass-4, Wyoming Big Sage-Indian Ricegrass-4, and Wyoming Big Sage-Rubber Rabbitbrush-4.
More background on individual BpS is available on the LANDFIRE website–particularly the Using BpS Descriptions document.
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