Methodology for assessing trend in range condition is still evolving. This paper demonstrates use of Dice's community similarity coefficient, 2a/(2a + b + c), with communities present at 3 times and a notional community as a goal. Coefficients range from 0 (indicating a complete lack of similarity) to 1 (indicating complete similarity). Similarity is classed as low (0 - 0.25), moderate (0.26 - 0.50), high (0.51 - 0.75), or full (0.76 - 1). Study of time-goal coefficent graphs is suggested for deciding whether trend is up, down, or static. Defining goals and lack of statistical tests are major limitations. The goal concept and use of data standardization are discussed.

Managers and range scientists are interested in the response of such variables as forage production and animal performance to various environmental and management factors. Due to the inability to control many of the factors affecting range systems, production responses should include distributional information in addition to their expected values. Recent developments in the estimation of conditional probability distribution functions provide the range scientist with a practical procedure to more fully characterize variable responses. The conditional probability distribution approach is applied to an analysis of forage production data from the literature. An illustration of the procedure in range decision analysis derives distributional information on animal performance and net return under several different steer stocking levels.

Determination of live and dead herbage fractions from mixed herbage samples requires hand separation or specialized laboratory procedures. The constituent differential method is designed to determine the relative proportion of live and dead components in a mixture based on the difference in dry matter concentration between the components. Our objective was to evaluate several characteristics of the constituent differential method under field conditions in tallgrass and mixed grass vegetation. Estimation of live standing crop by this method is most sensitive to the dry matter content of the total mixture and the dead component but becomes less sensitive as the difference between these variables increases. Time-of-day was not usually associated with dry matter content of the herbage components if sampling began after the herbage was thoroughly dry to the touch. Suggested sample sizes in large experimental units for estimating dry matter content are 40-50 samples for herbage mixtures, 10 samples for live herbage, and 5 samples for dead herbage. In 4 field trials the average value for percent live herbage determined by hand separation and the constituent differential method differed by 1.6 percentage units, which was nonsignificant P>0.10). The constituent differential method is a relatively rapid and accurate method for determining live and dead herbage fractions.

A 9-year grazing trial was conducted to compare shortgrass vegetation and steer responses under intensive-early stocking (IES) at 2 stocking rates to season-long stocking (SLS). The stocking rates were (1) equal to SLS, with twice as many steers used for the first half of the SLS grazing season (2X-IES), and (2) greater than SLS. with 3 times as many steers used for the same period (3X-IES). The hypothesis tested was that SLS and 2X-IES would be similar and sustainable in terms of productivity and vegetation composition, whereas 3X-IES would be different and not sustainable. The 3 treatments were assigned to 6 pastures in a randomized-complete block. Grazing was initiated on or near 1 May each year and continued until about 15 July for IES and about 1 October for SLS. Steers were weighted at initiation of grazing and in mid-July, and SLS steers were weighed in October. Vegetation data were collected in July and October in each pasture from 10 randomly located plots. Species composition of grasses was estimated, and grasses and forbs were clipped separately to determine biomass availability. Steer total gain and average daily gain (ADG) under SLS and 2X-IES were equal (P>0.10) during the early season, but 3X-IES gain and ADG were less (P<0.05). Total-season gain was greater under SLS (P<0.05 than either IES treatment, but total- season ADG was equal to that under 2X-IES. Steer production per ha was equal under SLS and 2X-IES, but greater under 3X-IES (P<0.05). Western wheatgrass [Pascopyrum smithii (Rydb.) Löve] and buffalograss (Buchloe dactyloides (Nutt.) Engelm.) composition did not change over time under SLS and 2X-IES, but decreased and increased, respectively, under 3X-IES (P<0.05). Blue grama (Bouteloua gracilis (HBK.) Lag. ex Steud.) and annual grasses displayed initial composition differences (P<0.10) among grazing treatments, but not differential composition shifts over time (P>0.10). Grass and total biomass availability were reduced (P<0.10) over time by 3X-IES. The hypothesis was supported: SLS and 2X-IES were equal in terms of both livestock performance and vegetation responses, but livestock performance and biomass availability were reduced and vegetation composition changed under 3X-IES. Thus, 3X-IES was not sustainable. While SLS and 2X-IES appear biologically equal, using them simultaneously on separate land areas may reduce market variability risk by marketing twice per year.

In 1974 we selected 8 pairs of gully headcuts on the Santa Rita Experimental Range. Mesquite (Prosopis velutina Woot.) on the watershed of 1 headcut of each pair was killed with diesel oil. Densities of perennial grasses and shrubs, shrub cover, surface erosion, headcut advance, and gully depth were recorded at 3-year intervals, 1974-1986. Four of the watershed pairs were in pastures grazed yearlong: 4 were in Santa Rita rotations. Each grazing schedule included 2 watershed pairs that were about 200 m higher in elevation than the other 2. In 1974, before mesquite was killed, perennial grass densities were low with little difference between assigned conditions. By 1977 perennial grass density was greater where mesquite was killed than on untreated watersheds and was greater at upper elevations. Lehmann lovegrass (Eragrostis Lehmanniana Nees.) made up almost all of the grass density increase at the upper elevation. Native perennial grasses, which were largely replaced by Lehmann lovegrass at the upper elevation, accounted for almost all of the gain at the lower elevation. Lower density (P less than or equal to 0.05) on low elevation rotation grazed watersheds in 1986 was the result of summer drouth in 1985 and 1986 that coincided with March-October grazing in 1986. Soil loss (mm) during each 3-year period was lower at headcut-soil surface grids where mesquite was dead. Advances in headcuts and changes in gully depth showed similar trends. On the 4 pairs of watersheds that were equipped to measure runoff, there was more total runoff per millimeter of rainfall where mesquite was alive than where mesquite was killed.

Stocking rates and grazing strategies may alter botanical composition of rangeland vegetation by altering frequency and intensity of defoliation of individual plant species. We used long-interval time-lapse photography to study frequency and intensity of defoliation of western wheatgrass (Pascopyrum smithii[Rydb.] A. Love) and blue grama (Bouteloua gracilis [H.B.K.] Lag. ex Steud.) tillers under continuous season-long and time-controlled short-duration rotation grazing by steers at 2 stocking rates. Frequency, intensity, and variability of defoliation of both grasses were similar under both grazing systems. Western wheatgrass tillers were grazed more frequently under heavy than under moderate stocking, and in 1990 more herbage was removed the second time a tiller was grazed under heavy stocking. Blue grama tillers were grazed more frequently under heavy than under moderate stocking in both years under rotation grazing, but only in 1990 under continuous grazing; more herbage was removed under heavy stocking the second time a tiller was grazed. Under heavy and moderate stocking, respectively, 19% and 36% of western wheatgrass tillers and 42% and 54% of blue grams tillers were ungrazed throughout the grazing season. Few western wheatgrass tillers were grazed more than twice, and few blue grams tillers were grazed more than once. Stocking rates have much greater potential than grazing systems for altering frequency and intensity of defoliation and subsequent changes in botanical composition of range plant communities. Results of grazing studies support this conclusion.

Globemallows (Sphaeralcea spp.) are native, drought-resistant forbs of interest for inclusion in seed mixtures for semiarid rangeland renovation. Little is known of their nutritional value for ungulates. We measured element concentrations in representative globemallow species and evaluated their adequacy for livestock nutrition. We also correlated forage selection by sheep (Ovis aries) with element concentrations. Alfalfa (Medicago sativa L.), crested wheatgrass [Agropyron cristatum (L.) Gaertn. X A. desertorum (Fisch.) Schult.], and 13 accessions of globemallows [S. coccinea (Pursh) Rydb., S. grossulariifolia (H. & A.) Rydb., S. munroana (Dougl) Spach., and S. parvifolia A. Nels.] were transplanted into replicated grazing trials in southern Idaho. Herbage was sampled and the pastures were grazed by sheep in the fall of 2 years and in the spring of the following 2 years. Concentrations of Ca and Mg in crested wheatgrass were lower than in forbs. Differences between seasons were greater than the differences among globemallow species. Forage selection ratios were positively associated with the N concentration of globemallow leaves and with the Ca:P ratio of globemallow stems but were negatively associated with stem Zn concentrations. Herbage from pastures containing crested wheatgrass with globemallows and/or alfalfa would meet the dietary element requirements of beef cattle (Bos taurus) and sheep.

An extensive food plot program maintained for 4 years on the National Red Dirt Wildlife Management Preserve of the Kisatchie National Forest, La., failed to produce improvements in southern pine-mixed hardwood forest range sufficient to affect quality of deer (Odocoileus virginianus) harvested by sport hunters. A combination of normal forest management practices plus maintenance of deer densities at relatively low levels was apparently sufficient for maintaining deer in good condition. Other than for public relations, the food plot program was not warranted based on biological effects.