Draft Report to the U.S. Forest Service Spring Mountains National Recreation Area

Executive Summary

The Nature Conservancy was contracted to map Fire Regime Condition Classes (FRCC) and associated products for approximately 1.25 million acres of the Spring Mountains in U.S. Forest Service (USFS), Bureau of Land Management (BLM), and private land management. FRCC is a measure of departure of vegetation structure-composition, and fire regimes between current and reference condition. The Nature Conservancy interpreted ecological site associations from three USDA Natural Resource Conservation Service soil surveys to 20 major vegetation types representing LANDFIRE biophysical settings (potential vegetation types) typical of Mojave Desert high elevation ranges. The natural range of variability (percentage of each succession class per biophysical setting) was either obtained from LANDFIRE or recalculated after adapting LANDFIRE computer models. Biophysical settings are the fundamental stratification of FRCC mapping. Subcontractor Spatial Solutions conducted remote sensing with field help from Conservancy staff from April to August 2008. Spatial Solutions refined associations of biophysical settings to unique ones and mapped succession and uncharacteristic vegetation classes per biophysical settings. The Nature Conservancy processed biophysical settings and current vegetation class geodata, and natural ranges of variability with the inter-agency software FRCC Mapping Tool. Four biophysical settings, including the very extensive creosotebush-white bursage and blackbrush systems, were in FRCC 3, 5 biophysical settings were in FRCC 2, and 11 in FRCC 1. Higher elevation and the lowest elevation biophysical settings (below creosotebush-white bursage) were generally less departed from the natural range of variability. A summary output table was also produced that identified vegetation classes per biophysical settings that were over-represented, similar, or under-represented compared to the natural range of variability. The summary output table is directly relevant to land management decisions.