Prescribed fire is commonly used to initiate redberry juniper (Juniperus pinchotti Sudw.) suppression, and herbivory by goats presents a potentially effective mechanism to prolong the efficacy of the reclamation treatment. Monoterpenes in redberry juniper leaves serve as a barrier to effective herbivory, but fire has the potential to reduce this barrier through reversion of aboveground growth to juvenile tissue. Traditional optimal defense theory predicts that because of the assumed fitness value of vegetative regrowth, plant secondary chemicals will be higher in this tissue than mature growth. This study was designed to measure the monoterpene concentration and composition from redberry juniper foliage sampled from 3 different ages of plant tissue. Prescribed fire was used to create 3- and 11-month regrowth juniper foliage, and mature growth of juniper was sampled as a control. Total monoterpene levels were lowest in the 3-month regrowth (P = 0.018). Monoterpene concentration and composition was similar for the 11-month and mature foliage. Concentration of terpinen-4-ol (P = 0.001) and alpha-terpineol (P = 0.007), identified as particularly aversive monoterpenoids to goats, was lowest in the 3-month regrowth but increased to levels found in mature leaves by 11 months of age. There was a trend in changes in composition of total oil as relative concentrations of monoterpene hydrocarbons (a-pinene, b-pinene/sabinene) decreased and monoterpene alcohols and oxygenated monoterpenes increased. These results identify a short period of time following a burn during which monoterpene levels in regrowth are low. This suggests a period of vulnerability in plant biochemical defenses that has the potential to be utilized by strategic herbivory by goats for more effective juniper management. 

Human communities in the Intermountain West depend heavily on subalpine rangelands because of their importance in providing water for irrigation and forage for wildlife and livestock. In addition, many constituencies are looking to managed ecosystems to sequester carbon in plant biomass and soil C to reduce the impact of anthropogenic CO2 on climate. This work builds on a 90-year-old grazing experiment in mountain meadows on the Wasatch Plateau in central Utah. The purpose of this study was to evaluate the influence of 90 years of protection from grazing on processes controlling the input, output, and storage of C in subalpine rangelands. Long-term grazing significanty reduced maximum biomass in all years compared with plots within grazing enclosures. For grazed plots, interannual variability in aboveground biomass was correlated with July precipitation and temperature (R2 – 0.51), while there was a weak correlation between July precipitation and biomass in ungrazed plots (R2 – 0.24). Livestock grazing had no statistically sinificant impacts on total soil C or particulate organic matter (POM), although grazing did increase active soil C and decrease soil moisture. Grazing significantly incrased the proportion of total soil C pools that were potentially mineralizable in the laboratory, with soils from grazed plots evolving 4.6% of total soil C in 1 year while ungrazed plots lost 3.3% of total soil C. Volumetric soil moisture was consistently higher in ungrazed plots than grazed plots. The changes in soil C chemistry may have implications for how these ecosystems will respond to forecast climate change. Because grazing has resulted in an accumulation of easily decomposable organic material, if temperatures warm and summer precipitation increases as is anticipated, these soils may become net sources of CO2 to the atmosphere creating a positive feedback between climate change and atmospheric CO2.

Studies of Anderson and Scherzinger’s forage conditioning hypothesis have generated varied results. Our objectives were: 1) to evaluate late summer/early fall forage quality of crested wheatgrass (Agropyron desertorum [Fisch. ex Link] J. A. Schultes), bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Löve), Idaho fescue (Festuca idahoensis Elmer), bottlebrush squirreltail (Elymus elymoides [Raf.] Swezey), Thurber’s needlegrass (Achnatherum thurberianum [Piper] Barkworth), and basin wildrye (Leymus cinereus [Scribn. Merr.] A. Löve) from ungrazed paddocks and paddocks grazed at vegetative, boot, and anthesis; and 2) test hypotheses that postgrazing regrowth yields were correlated with soil moisture content when grazing occurred. Crop-year precipitation for 1997 and 1998 was 134% and 205% of average. Crude protein (CP) and in vitro dry matter digestibility (IVDMD) of ungrazed grasses displayed expected declines in quality. Among ungrazed grasses, late summer/ early fall CP was 5.7% in 1997 and 3.6% in 1998; IVDMD was 47% and 41%, respectively. Late summer/early fall forage quality was elevated by vegetative, boot stage, or anthesis grazing. The phenologically youngest regrowth always ranked highest in CP and IVDMD. Among grasses, respective 1997 CP and IVDMD means were 9.0% and 55% for regrowth following anthesis grazing. No regrowth followed anthesis grazing in 1998, but CP and IVDMD means from boot stage treatments were 5.5% and 47%, respectively. With CP measures, a species by treatment interaction occurred in 1997, but species reacted similarly in 1998. Vegetative, boot stage, and anthesis grazing in 1997 caused respective late summer/early fall standing crop reductions of 34%, 42%, and 58%; and 34%, 54%, and 100% reductions in 1998. Forage conditioning responses were lower for bluebunch wheatgrass and crested wheatgrass than other grasses. Soil moisture content was a poor predictor of regrowth yields. Managed cattle grazing can successfully enhance late season forage quality. 

Two studies were conducted to evaluate the effectiveness of low-moisture blocks (LMB) and conventional dry mixes (CDM) for supplementing minerals to cattle on rangeland and to modify grazing patterns. In study 1, cows were fed LMB or CDM on moderate or difficult foothill terrain in Montana during autumn and winter. Cows consumed more CDM in moderate terrain than difficult terrain, but intake of LMB was similar in both terrain types. Using global positioning system (GPS) telemetry data, visits to supplements were defined as collared cow positions within 10 m of placement sites. More cows visited LMB (74%) than CDM (56%). More cows visited supplements (LMB and CDM pooled) when placed in moderate rather than difficult terrain. Cows spent more nonresting time within 100 and 200 m of LMB than CDM. In study 2, CDM and LMB designed to supplement minerals (LMB-M) were compared when cows were also fed LMB designed to supplement protein (LMB-P). Comparisons were made with cows grazing rangeland and with cows fed hay. Intake of LMB-P and CDM was less when cows grazed rangeland than when they were fed hay. Cows consumed less LMB-P when LMB-M was available. More cows visited LMB-M than CDM, and cows visited LMB-M more frequently than CDM. The LMB formulations designed to supplement minerals work well with formulations designed to supplement protein. Both LMB and CDM met estimated deficits of minerals in the forage based on supplement intake (g day-1) and forage evaluations, but cows visited LMB more consistently than CDM. Low-moisture blocks appear to be more attractive to cows than CDM and should be more useful to modify grazing patterns on rangeland. 

This study investigated the role that a public land grazing permit buyout would have on ranching operations and conserving private land open space in the Rocky Mountain region of the western United States. Loss of grazing permits could serve as a pivotal factor in expediting private land fragmentation if ranching operations are enticed to sell their land due to loss of economic viability. This type of program inadvertently could be detrimental to overall ecosystem health and have unintended economic, ecological, and cultural consequences for the administering agencies and grazing permittees. The goal of this study was to provide sociodemographic profiles of landowners to better understand social motivations for ranching, implications of permit removal, ongoing conservation activities, and possible policy solutions. We assessed likely participation levels, demographic attitudes, and reasons for participation in a proposed grazing permit buyout program. This paper is based on data collected from a mail survey of 2 000 permittees in the Rocky Mountain States (39% response rate), and data collected from qualitative personal interviews. These interviews assessed motivations for participation, potential costs, and search for unforeseen consequences related to a proposed buyout program. We interviewed 49 individuals (33 ranchers, 16 agency personnel), which enabled us to describe likely outcomes and previously unmentioned items for consideration related to a proposed buyout program. Interview data were analyzed and broken into two major themes: motivation for participation in a buyout and potential consequences. Our study indicated that overall participation in potential buyout would be relatively low (17%); however, the associated financial, ecological, and administrative costs could be substantial. We note several unanticipated motivations for possible participation in this type of program, as well as possibly unrecognized impacts for administering agencies and permittees. 

Minimizing nonpoint source nutrient pollution is important to the sustainability of grazing lands. Increased nutrient loads have reduced water quality in Lake Okeechobee in south Florida, prompting establishment of a Total Maximum Daily Load (TMDL) that will require large reductions in phosphorus (P) runoff into the lake. A significant portion of this reduction must come from beef cattle ranches, the major land use in the region. A large-scale research project, consisting of a 420-ha array of 8 improved summer and 8 semi-improved winter pastures, was established from 1998-2003 to investigate the influence of beef cattle stocking rate on nutrient loads in surface runoff. Each pasture type had two replicates of four different cattle stocking rates including a control with no cattle and stocked pastures with low, medium, and high stocking rates (1.3, 1.0, 0.6 ha AU-1 [animal unit] in summer pastures; 2.1, 1.6, and 0.9 ha AU-1 in winter pastures). Cattle stocking rate did not affect nutrient concentrations or loads in surface runoff during the study period. Average annual P discharges were 1.71 kg ha-1 from summer pastures and 0.25 kg ha-1 from winter pastures. Average total P concentrations in runoff were 0.63 mg L-1 for summer pastures and 0.15 mgL-1 for winter pastures. Differences in runoff P were related to differences in soil P test results, a difference believed to be due to prior fertilization practices. Our findings show that reducing cattle stocking rates on beef cattle pastures is not an effective practice for reducing nutrient loads, and that accumulation of P in soil from historical fertilization has an overriding influence on P loads in surface runoff. Results indicate that reducing the overall volume of surface discharges would be a more effective strategy than altering cattle stocking practices to reduce nonpoint runoff of P from cattle pastures in this region. 

Developing sustainable ranch management systems requires integrated research that examines interrelations among ecological and economic factors. In south central Florida, where phosphorus (P) loading is an overriding environmental concern, we established an interdisciplinary experiment to address the effects of cattle stocking density and pasture type on P loading and other ecological and economic factors in subtropical Florida ranchlands through a partnership including ecologists, agricultural faculty, agency personnel, and producers. Here we present an overview of all project components detailed in 3 accompanying papers in this issue of Rangeland Ecology Management. We describe the experimental design, which included 2 replicates of 4 different cattle stocking density treatments (control, low, middle, and high [0, 15, 20, and 35 cow-calf pairs per pasture]) maintained on 8 improved summer pastures (– 20 ha each), and 8 seminative winter pastures (– 32 ha each) from 1998 to 2003. Stocking densities did not significantly affect P loads and concentrations in surface runoff, soil chemistry, or soil nematode communities, but did affect cattle production and economic performance. Cattle production was greater at the high than at the middle or low stocking density; economic performance declined significantly with decreasing stocking density (break-even was 1.89 kg-1 for high and 2.66 kg-1 for low density). Pasture type significantly affected environmental factors; average P runoff from improved summer pastures (1.71 kg P h-1 y-1) was much greater than from seminative winter pastures (0.25 kg P ha-1 y1), most likely because of past P fertilizer use in improved pastures. We integrate results from all the papers within the context of a conceptual model and a P budget, and emphasize that management practices targeted at specific environmental factors on beef cattle ranches, such as nutrient loading, must include consideration of economic impacts and broader ecosystem implications.