Grantee Research Project Results
2000 Progress Report: Characterization of Ecological Integrity of Commercially Grazed Rangelands Using Remote Sensing-based Ecological Indicators
EPA Grant Number: R826112Title: Characterization of Ecological Integrity of Commercially Grazed Rangelands Using Remote Sensing-based Ecological Indicators
Investigators: West, Neil E. , Washington-Allen, Robert , Ramsey, R. Douglas
Institution: Utah State University
EPA Project Officer: Packard, Benjamin H
Project Period: November 1, 1997 through September 30, 1999
Project Period Covered by this Report: November 1, 1999 through September 30, 2000
Project Amount: $340,617
RFA: Ecosystem Indicators (1997) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Aquatic Ecosystems
Objective:
We are using 27 years of wet and dry season Landsat satellite imagery from (1972-1998); a GIS database of site biological, physical, and administrative characteristics and analysis tools; historical and current ranch management records; and a multiple-time by nested multiple-scale experimental design to establish causal links between ecological indicators diagnostic of land degradation and human management interventions to assess the ecological integrity of ecosystems within a semi-arid landscape subject to commercial grazing.Progress Summary:
The study area selected for this research was the Deseret Land and Livestock Ranch (DLL) located in the northeastern corner of the Utah panhandle. As previously reported, our first year (1997-1998) was spent primarily on tabular and spatial data acquisition and processing of satellite imagery. Our second year has been spent on additional tabular and spatial data acquisition, as well as processing and analyzing these data sets. Spatial data acquisition included additional Landsat satellite imagery, a 1998 Indian Resource Satellite scene of DLL, and site administrative/biophysical parameters. Administrative data acquisitions concerned private, state, and federal (BLM) ownership boundaries. Biophysical data acquisitions included the Rich County Soil survey and seven U.S. Geological Survey (USGS) 30 m x 30 m digital elevation model (DEM) quadrangles, which make up DLL.Tabular data acquisition included digital climate data for Woodruff and Deseret, UT (see Figure 1); climate stations from the Utah Climate Center; the digital soil survey of Rich County from the NRCS's Map Unit Interpretation Database (MUIR); digital ranch land management data from DLL, which included cow-calf mortality, weight gain, and weaning data from 1983-1997 as well as grazing management data; and grazing enclosure data from 1990-1998 collected from three study sites on DLL by Mark Ritchie of the Department of Fish and Wildlife, Utah State University (see the MUIR Web Site at www.statlab.iastate.edu/soils/muir/). Archived written tabular data were acquired from: (1) the Rich County Courthouse, Randolph, UT, concerning tax records on livestock numbers from 1970-1983; (2) the University of Utah Library's Special Collections concerning ranch management and livestock numbers from 1893-1903, 1925, 1933-1951; (3) Mr. William Hopkin, the DLL land manager, who provided a record of the history of 126 water sources on DLL; and (4) and federal agency field monitoring data and memos that were collected. Field survey data came from both NRCS land assessments (acquired from DLL's Gregg Simonds) and from the archives of the Bureau of Land Management's (BLM) Salt Lake City office. Some information was digitized from the Randolph Management Framework Plan (MFP) for Rich County, UT, and the accompanying BLM Final Environmental Impact Statement (EIS) on Grazing Management in the Randolph Planning Unit, Rich County, UT.
Figure 1. Precipitation data (1893-1996) at Deseret climate station within Deseret Land & Livestock Ranch, Woodruff, UT.
The Natural Resources Conservation Service's (NRCS) Rich County soil survey was digitized, attributed, and rubber sheeted. The vector coverage was rubber sheeted to a 1998 Indian Resource Satellite (IRS) UTM, Zone 12, NAD 27, scene and merged with the MUIR digital Rich County soil survey tabular data. From this merge, raster images of range sites, standing crop, and Universal Soil Loss Equation (USLE) variables (e.g., soil erosivity) were generated. Range sites are homogenous units, which are used as experimental unit/patches within a dryland landscape (Figure 2). The standing crop and Universal Soil Loss Equation (USLE) variables were used to calibrate the Soil Adjusted Vegetation Index (SAVI) values used. The IRS image also was used to adjust the administrative vector layers including the ranch and paddock boundaries. The seven USGS 30 m digital elevation model (DEM) quadrangles were mosaiced and processed, using a focal mean function to smooth out pits and line dropout regions, into a complete DEM of DLL.
Both calf weaning weights (Figure 3) calf mortality (Figure 4) at DLL are biological indicators whereby livestock metabolic responses serve as surrogate measures of range land trend from 1983 to 1998 on the entire DLL. Figure 2 suggests no change in range land condition, but Figure 3 suggests that improving conditions for growing cattle over time have led to a decrease in mortality (Figure 4).
Written tabular data, from DLL's land manager, Mr. William Hopkin, on the history of water sources was merged with the vector point coverage of water sources on DLL. This amounted to 126 water points out of an estimated 677 on DLL with a site history. We also developed a GIS-based biosphere analysis program in collaboration with DoD Strategic Environmental Research and Development Program (SERDP) scientists to analyze the water point data in relation to the time series of wet and dry season remotely-sensed imagery. From each standardized Landsat scene a SAVI image, a surrogate measure of plant cover, was generated. Changes in this index in relation to water points are determined and if present are possible indicators of degradation. We have submitted this manuscript to the Journal of Range Management and the program itself is available from the Web site www.nr.usu.edu/~tvn.
We conducted historical reconstruction of environmental events relevant to DLL to develop a picture of landscape condition prior to the satellite image assessment period (1972-1998) and during the period for which paddock specific grazing management data were not available (1972-1979). We obtained cattle numbers from 1970-1983 from archived tax records held by the Rich County (Utah) Treasurer, located in Randolph, UT. These records pertained to taxes assessed in April of the same year on cattle, bulls, sheep, horses, and mules. The data for 1977 were missing.
Historical reconstruction showed that the ranch has been commercially grazed for 108 years; since 1891, primarily by sheep, and later primarily by cattle beginning in the early 1970s. The ranch has had four owners and thus four major management periods: 1891-1952, the William Moss/Walter Dansie period; 1953-1974, the Garff, Freed, and Robinson period; 1974-1983, the Joseph Hotung period; and 1983 to the present, the Church of Jesus Christ and Latter Day Saints (LDS). During the Moss/Dansie years, a 10-year drought occurred in conjunction with the depression of the 1930s. Letters and memos to soil conservation district and forest service district offices to the DLL's managers in that decade reveal that climate (harsh winters and drought years) drove the ranch's success; with drought being the primary concern and deer competition with sheep a secondary concern. There also were concerns about weed invasion (Bull, Canadian and Russian thistles) and grants for herbicide treatments (Unpublished data, Shawna Morrissey). Also notable, was that the range began to be fenced in during the mid- 1930s probably as a result of passage of the Taylor Grazing Act (1934), which led to formation of grazing districts. We also developed three maps that depict the trend of increasing paddock number with a subsequent decrease in paddock size from 1972-1998. From 1972-1978. there were 24 paddocks, 1979-1983 had 61 paddocks, and 1984-1998 had a 112.
Figure 3. Mean calf weaning weight, a biological indicator of rangeland health, from 1983 to 1998 on Deseret Land & Livestock Ranch. The plot suggests constant and stable weaning weights and thus stable forage conditions.
Figure 4. Calf mortality, a biological indicator of rangeland health, from 1983 to 1998 on Deseret Land & Livestock Ranch was calculated as the percentage of the crop which failed to be weaned. The plots suggests that mortality has declined in the 17- year period.
Figure 5. Statistical state space phase diagram of the dry season response from 1972 to 1998 of the soil-adjusted vegetation index(SAVI) for the sagebrush steppe portion of Deseret Land & Livestock Ranch, Woodruff, UT.
The satellite image data set from 1972-1998 (Table 1) was reprocessed because two problems were detected. The first problem concerned the original behavior of the data where seasonal images from 1972-1992 were converted to the SAVI images and the temporal trend examined. The overall SAVI trend for the wet and dry season imagery suggested (1) a decline in vegetational cover and (2) in 1982 a threshold had been apparently exceeded coinciding with a combination of increased stocking rate and drought. However, this phenomena showed no relationship with the Woodfruff climate data set and a somewhat circumstantial relationships with the Deseret climate data set.
Figure 5 shows a statistical state space phase diagram of the reanalyzed dry season response of the soil-adjusted vegetation index (SAVI) for the sagebrush steppe portion (eastern half) of DLL. This graphical method is a dynamical systems analysis or analysis of a time-evolving process of two state variables; the mean and the variance of SAVI from 1972-1997. Both the variance and the mean's temporal behaviors oscillate, thus in combination their behavior is cyclic. The cyclic behavior from 1972-1988 tends to be focused inward with lower mean and lower variance compared to the period from 1989-1997. This period is unfocused with higher SAVI means and variances than the period 1972-1988. Interpretation of the focusing and unfocusing oscillations would suggest that the sagebrush steppe rangeland on DLL follows an unstable limit cycle. Secondly, the oscillations appear qualitatively to be climatically driven in relation to La Ni?a (cooling of tropical Pacific currents) and El Ni?o (warming of tropical Pacific currents) where in northeastern Utah precipitation is below average during La Ni?a events and average to above average during El Ni?o events.
Table 1a. Characteristics of the wet and dry season Landsat
Multispectral Scanner (MSS) satellite imagery from 1972 - 1988 and 1990 and
1992.
Imagery is path 41/row 31 and path 38/row 31.
Table 1b. Characteristics of the wet and dry season Landsat Thematic Mapper (TM) satellite imagery from 1989, 1991, 1993 - 1997. Imagery is path 38/row 31.
Table 1c. Characteristics of the 1985 and 1986 annual data set of Landsat Multispectral Scanner (MSS) satellite imagery. Imagery is path 41/row 31 and path 38/row 31.
Future Activities:
We have yet to test the use of the Soil Surface Index (SSI) and the 12 landscape metrics as a means of discriminating change at the various scales at which we quantified SAVI. This is the final effort that needs to be made to complete the project.Journal Articles:
No journal articles submitted with this report: View all 28 publications for this projectSupplemental Keywords:
ecological health, condition, trend, landscape metrics., RFA, Scientific Discipline, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Water & Watershed, Ecosystem/Assessment/Indicators, Ecosystem Protection, State, Ecological Effects - Environmental Exposure & Risk, Environmental Monitoring, Ecology and Ecosystems, Watersheds, Ecological Indicators, agricultural watershed, ecosystem integrity, Midwestern Watersheds, Utah (UT), ecosystem indicators, terrestrial, commercial rangeland, aquatic ecosystems, GIS, synoptic monitoring, water quality, multiscale assessment, agriculture ecosystemsProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.