A series of 6 daylight observations was made each summer and again each winter over 2 years to map cattle distribution on a California foothill pasture. Sixty animals were used in the study with no animals appearing in. 1 observation series. During daylight hours, small herds of cows containing between 14 and 16 animals were scan-sampled and videotaped every 15 minutes. A global positioning system was used to record the position of the camera to aid in accurately locating individual animals. Animal locations and individual identifications were then entered into a geographic information system (GIS) by on-screen digitizing using color orthophotographs. Animal positions were determined to be within 5 m of their true location. Association software, ASSOC1, was used to analyze animal positions to determine cattle subgroups and herd units. This position-based grouping was compared with observation-based grouping by researchers. Direct observation also identified dominant herd members. Older animals, up to 16 years of age, were generally dominant over younger animals, and subgroups tended to be composed of animals of similar age. The size of naturally occurring subgroups was between 3 and 6 animals. Some animals exhibited independence in their actions and behaviors compared with subgroup members. ASSOC1 produced grouping results consistent with direct observations. However, accurate interpretation of the ASSOC1 results depended on direct observational data. ASSOC1 identified close association patterns in 3 of the observations that defined the dominant animals in the herd. Forage availability and thermoregulatory needs influenced the distance between associated subgroup members. Distance between animals decreased when animals sought shade in summer or shelter in winter. Computer analysis of spatial data from GPS collars may be able to determine the social structure and identify dominant animals in herd situations. Incorporating knowledge of cattle social behavior should improve management of cattle on the range.

The objective of this study was to identify and model environmental and management factors associated with cattle feces deposition patterns across annual rangeland watersheds in the Sierra Nevada foothills. Daily cattle fecal load accumulation rates were calculated from seasonal fecal loads measured biannually on 40 m2 permanent transects distributed across a 150.5 ha pasture in Madera County, Calif. during the 4 year period from 1995 through 1998. Associations between daily fecal load per season, livestock management, and environmental factors measured for each transect were determined using a linear mixed effects model. Cattle feces distribution patterns were significantly associated with location of livestock attractants, slope percentage, slope aspect, hydrologic position, and season. Transects located in livestock concentration areas experienced a significantly higher daily fecal load compared to transects outside of these concentration areas (P < 0.001). Percent slope was negatively associated with daily fecal load, but this association had a significant interaction with slope aspect (P = 0.02). Daily fecal load was significantly lower during the wet season compared to the dry season (P = 0.002). Daily fecal loading rates across hydrologic positions were dependent upon season. Our results illustrate the opportunities to reduce the risk of water quality contamination by strategic placement of cattle attractants, and provide a means to predict cattle feces deposition based upon inherent watershed characteristics and management factors.

Seasonal herbaceous production was measured beneath tree canopies of blue oak (Qutwcus douglush' Hook & Am.), interior live oak (Quercus w&&e&i DC), and digger pine (pinus scrbiufeua Dougi.), and in adjacent open grassiand during 2 drought years (1986-87 and 1987-88) at the San Joaquin Experimental Range, California. Early and mid-growing season herbrceous production was variable, with no increase in production beneath the canopies the first year and a 60 to 150 kg/ha increase the second year compared to the herbage produced in open grassland. Peak standing crop was about 1,000 kg/ha greater beneath blue oak canopies than in open grassiand in both years. Peak standing crop beneath interior live oak canopies was about 700 and 1,000 kg/ha greater than in open grassland the first and second years of the study, respectively. Peak standing crop beneath digger pine canopies was about 500 kg/ha greater the first year and similar the second year to that of the open grassland.

On Caiilomia's winter a~ud r8ngdanda precipitation controls the beginning and end of the growing season while temperature Lirgely controls se8sonai growth tmtes within the growing season. Post-germination accumulated degree-days (ADD) account for the length of the growing season and variation of daily temperature. Simple correlations of ADD and herbage yield or resultant livestock gains were determined at 5 locations in ammal type range in northern California. Degree day values were determined by summing daily degree-days from the beginning of the growing season after germinating rainfail until the ciipphrg or weigh dates. Accumulated degree-days accounted for 74 to 91% of the variation in seasonal herbage yield while accumuiated days (AD) accounted for 64 to 86% of the variation. Together, ADD and AD accounted for 94 and 8696, respectively, of the variation in stocker cattle weights. Regression coefficients relating ADD to herbage yield appear to predict maximum site productivity. A procedure for estimating a seasonai herbage yield profile based on key growth curve intlection points and using shnple field observations with 3 clipping dates and ADD is proposed.

Effects of recreational pack stock grazing on mountain meadows in Yosemite National Park were assessed in a 5-year study. Yosemite is a designated wilderness, to be managed such that its natural conditions are preserved. Studies were conducted in 3 characteristic meadow types: shorthair sedge (Carex filifolia Nutt.), Brewer's reed grass (Calamagrostis breweri Thurber), and tufted hairgrass [Deschampsia cespitosa (L.) Beauv.]. Horses and mules grazed experimental plots at intensities of 15 to 69% utilization for 4 seasons. In all 3 meadows, grazing caused decreases in productivity. The mean reduction after 4 years of grazing was 18% in the shorthair sedge meadow, 17% in the Brewer's reed grass meadow, and 22% in the tufted hairgrass meadow. Grazing also caused shifts in basal groundcover (usually a reduction in vegetation cover and increase in bare soil cover), and changes in species composition. Productivity and vegetation cover decreased as percent utilization increased, while bare soil cover increased as utilization increased. Changes in species composition were less predictably related to differences in grazing intensity. Passive management of grazing is insufficient in wilderness areas that are regularly used by groups with recreational stock. Wilderness managers need to monitor meadow conditions and the grazing intensities that occur. Our study suggests that biomass and ground cover are more sensitive indicators of grazing impact than species composition. Managers must make decisions about maximum acceptable levels of grazing impact and then develop guidelines for maximum use levels, based on data such as ours that relates grazing intensity to meadow response.