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Information Relating to Supplemental Data Collection/NRI MapsRange and Pasture Technical Note Number MT-28If you encounter any problems with the file provided on this page, please contact Technical Resources at 406-587-6822.
A printer-friendly versions of this technical note is available
in
Adobe Reader format. January 1994. For the 1982 National Resources Inventory (NRI) conducted by SCS in Montana, supplemental data was collected at those inventory points falling on rangeland to aid in the completion of the inventory and to support additional analysis of the NRI data collected on rangeland. Among the supplemental data elements collected on each rangeland point were individual species composition by weight information. Subsequent to the NRI the supplemental rangeland data was loaded into the Montana State University (MSU) computer for analysis by SCS. At about this same time, MSU staff developing the Montana Agricultural Potentials System (MAPS) geographic information system (GIS) requested the inclusion of the rangeland data, along with other NRI data, into MAPS to expand the interpretive value of that system. The rangeland data was subsequently edited to reflect changes made in the rangeland data as a result of the 1987 NRI. Having the edited rangeland information in MAPS permitted the generation of the attached rangeland species distribution maps. The species distributions maps were generated to aid range specialists in Montana update SCS Technical Range Site Descriptions. However, it was thought the maps could be of use to others involved in rangeland related activities. Consequently the maps were published in this SCS Technical Note. The species distribution maps include all range sites and all condition classes identified during the 1982 NRI. Thresholds, in terms of relative composition by weight were arbitrarily selected to represent expected "dominance thresholds" useful in interpreting the distribution and ecological role of the various grass species as they occur across the state. A primary sample unit (PSU) within the NRI was randomly located and usually 160 acres in size. Three points were randomly located within the PSU, unless the PSU was smaller than 160 acres. When a point "fell" on rangeland, appropriate data was recorded some of which was used to generate the maps from the MAPS GIS. The cell size of MAPS is approximately 2 miles by 3 miles. Any one point or several points within a PSU falling within a MAPS cell meeting the selection parameters shows as a "hit" (black rectangle) on the maps. The NRI encompassed only nonfederal lands. Consequently the maps reflect plant species distribution on nonfederal lands. One should keep this in mind when interpreting the maps. Large concentrations of Federal land are not reflected such as the National Forests, The CMR National Wildlife Refuge and occasionally large concentrations of Bureau of Land Management administered lands. The following maps show grass species distribution by percent composition by weight (CBW) classes for all SCS range sites and ecological condition classes: (Based upon 1982 NRI data.)
If you have any questions, please contact: Ronald Nadwornick,
State Resource Conservationist < Back to Range and Pasture Technical Notes Last Modified: 08/19/2008 |
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