Ecological units of the Northern Region: Subsections

Abstract

Landscape Characteristics: Mountain front foothills, moraines, fans, and terraces that formed in calcareous shales overlain by till, outwash, alluvium, and terrace deposits. The landscape has been modified by glaciation. Elevations range from 3,400 to 6,000 feet. Drainage density is low to moderate.Climate: Mean annual precipitation ranges from 12 to 20 inches, about half falling as snow. The soil temperature and moisture regimes are frigid and typic ustic. Chinook winds are frequent. Potential Vegetation: Wheatgrass-fescue-needlegrass Relationships of Dominant MapUnit Components: Landform Geology Soil Taxa Foothills/moraines Till Haploborolls/ Ustorthents Fans/terraces Calcareous outwash Argiborolls/Calciborolls Disturbance and Land Use: The primary natural disturbance is fire. Land use is predominantly livestock grazing. 331Db Montana Isolated Mountain Ranges Landscape Characteristics: Mountainsides, foothills, terraces, moraines, and fans that formed in Tertiary volcanics and mixed sedimentary rocks. Continental glaciation influenced these mountain ranges. Elevations range from 2,500 to 5,500 feet. Drainage density is moderate.Climate: Mean annual precipitation ranges from 16 to 30 inches, about 70 percent falling as snow. The soil temperature and moisture regimes are frigid (cryic at higher elevations) and typic ustic. Chinook winds are common.10 Potential Vegetation:Douglas-fir forest at higher elevations with foothills prairie on foothill and lower elevations.

Post-fire recovery of Wyoming big sagebrush shrub-steppe in centeral and southeast Montana

“…Sampling was conducted over a broad swath of eastern Montana (Figure 1) from a westernmost site within the Bighorn Basin Section, Bighorn Intermountain Basin Subsection (342Ad, Bailey 1995, Nesser et al 1997 (Bailey 1995).…”

Grazed Stubble Height as a Criterion for Controlling Sediment Production From Grazing Lands

“…This study was conducted from 1997 through 1999 on the Bandy Research Ranch, approximately 80 km (50 mi) northeast of Missoula, Montana, near Highway 200 ( Figure 1). Situated at the southern end of the Swan Mountain Range, the study area has from 890 to 2,000 mm (35 to 80 in) of precipitation annually, 60 percent of it falling as snow from November through April (Nesser et al, 1997). More than 40 percent of the remaining precipitation falls as rain during June.…”

Application of Logic and Decision Models in Sustainable Ecosystem Management

“…To meet multi-resource needs for integrated ecosystem assessment, we designed a logic model for ecosystem sustainability (and related desired conditions) with NetWeaver, based on core monitoring themes, sub-elements, and related performance measures as described in the USFS Northern Region Land Management Monitoring and Evaluation Framework [22]. The design addressed five basic categories of information at the broadest level: aquatic/watershed integrity of subwatersheds (6 th level hydrologic unit code) [11,12], terrestrial integrity of ecological subsections [15], fire danger within subwatersheds, social opportunity spectrum within subwatersheds, and economic integrity of National Forests.…”

“…Consequently, spatial evaluations of this information need to be made within large landscape units to ensure adequate sampling within a mapped stratum. For these reasons, ecological subsections [15], which delineate areas with similar geology, landform, and regional climatic attributes and are typically 100 to 200 km 2 in size, were used to summarize FIA data in this study. Subwatersheds (which typically range from 4,000 to 12,000 ha) are commonly used to assess watershed condition and other resource conditions [11,12,13] and were used as the cartographic base to evaluate aquatic and social opportunity topics.…”