| Patrick E. Clark, Mark S. Seyfried, and Bob Harris |
| Authors are range scientist and soil scientist, USDA Agricultural Research Service, 800 Park Blvd., Plaza IV, Suite 105, Boise, Ida. 83712 and remote sensing/GIS analyst, University of Idaho, 800 Park Blvd., Plaza IV, Suite 105, Boise, Ida. 83712. |
Abstract |
| Rangeland plant communities of the Intermountain West differ in their ecology and management requirements. Successful management of extensive areas at plant community-level resolution first requires an efficient, cost-effective means of plant community classification and mapping. We evaluated the influence of image acquisition date and satellite imaging system on the accuracy of plant community maps created from multispectral satellite imagery of Reynolds Creek Experimental Watershed (RCEW) (234 km2) in southwestern Idaho. Maps delineating 6 native and 2 non-native Intermountain plant communities were created from Landsat 5 TM and SPOT 3 HRV data using a maximum likelihood classification procedure. Map accuracy was assessed using ground reference points. Maps created from satellite data acquired during dry-down (early August) had higher overall accuracy (x– = 70.5%) than from data acquired during peak growth (early June) (x– = 54.4%). Overall accuracy of maps generated by Landsat (x– = 60.1%) and SPOT (x– = 65.5%) were statistically similar. Given their broad spatial coverages (3,600 to 31,450 km2 scene-1, respectively), moderate resolutions (20 to 30 m pixels, respectively), and potential to provide high classification accuracies, the SPOT 3 HRV and Landsat 5 TM satellite systems were well-suited for classifying plant communities in the Reynolds Creek Watershed and similar areas of the Intermountain West. Practical procedures for plant community classification and map accuracy assessment are presented for use by natural resource managers. |
| Key Words: Cover type, maximum likelihood, multispectral, rangeland, remote sensing, satellite imagery, supervised classification, vegetation. |