We evaluated the effectiveness of natural color aerial photography as a tool to improve detection, monitoring, and mapping of sulfur cinquefoil (Potentilla recta L.) infestations. Sulfur cinquefoil is an exotic perennial plant invading interior Pacific Northwest rangelands. Because sulfur cinquefoil produces distinctive pale yellow flowers, we timed aerial photography for early July, when the plant was at peak bloom. Photography was collected at 3 spatial scales (1:3 000, 1:6 000, and 1:12 000). A grid with 250-m spacing was superimposed over photographs of the entire study area using geographic information systems. At each grid intersection point (n = 80), we visually analyzed the photographs within a 404.7-m² (0.1 acre) circular plot, recorded sulfur cinquefoil presence, and estimated sulfur cinquefoil percent cover. Sample points on the grid were then located in the field using a global positioning system. Field data collected at each point included sulfur cinquefoil presence, percent cover, and stem density; and total vegetation composition and percent cover by life form. Results indicate that the accuracy of detecting sulfur cinquefoil increased from small to large scale. At the 1:3 000 scale, sulfur cinquefoil presence was correctly identified in 76.9% of the sites, whereas at the 1:6 000 and 1:12 000 scales, infestations were identified in 67.9% and 59.1% of the sites, respectively. Low-density infestations (< 1% cover) were detected at all scales. Accuracy of percent cover estimates ranged from 33.8% to 38.0% across scales. Although tree canopy hindered detection, our results indicate that aerial photography can be used to detect sulfur cinquefoil infestations in open forests and rangelands in the Intermountain West.

Hyperspectral 1-m-resolution remote sensing has the potential to reduce the time spent sampling and reduce spatial sampling errors found in traditional forage nutritive analysis over large areas. The objective of this study was to investigate if 1-m-resolution hyperspectral techniques are useful tools to provide reliable estimates of forage nitrogen (N), phosphorus (P) and neutral detergent fiber (NDF) in Yellowstone National Park. The vegetative communities investigated varied in the amount of canopy coverage and species diversity, and ranged from xeric, semiarid environments to mesic, wetland/riparian environments. A large number of simple ratio-type vegetation indices (SRTVI) and normalized difference-type vegetation indices (NDTVI) were developed with the hyperspectral dataset. These indices were regressed against N, P, and NDF values from ground collections. We found that 1) there were strong linear relationships between selected SRTVI and N (R² = 0.7), P (R² = 0.65), and NDF (R² = 0.87) nutritive values on an area basis (g·m⁻²); and 2) there were no strong linear relationships (R² < 0.3) between a variety of SRTVI and NDTVI and N, P, and NDF on a dry matter basis (g·g⁻¹ × 100). The lack of relationship is related to 1) the highly variable relationship between the dry matter biochemical signal and total plant biomass and water content and 2) the weakening of the biochemical signal from exposed soil in low-canopy situations, from nonphotosynthetic vegetation (bark, stems, and litter), and from different plant species.

This study was designed to determine the utility of a 1-m-resolution hyperspectral sensor to estimate total and live biomass along with the individual biomass of litter, grasses, forbs, sedges, sagebrush, and willow from grassland and riparian communities in Yellowstone National Park, Wyoming. A large number of simple ratio-type vegetation indices (SRTVI) and normalized difference-type vegetation indices (NDTVI) were developed from the hyperspectral data and regressed against ground-collected biomass. Results showed the following: 1) Strong relationships were found between SRTVI or NDTVI and total (R² = 0.87), live (R² = 0.84), sedge (R² = 0.77), and willow (R² = 0.66) biomass. 2) Weak relationships were found between SRTVI or NDTVI and grass (R² = 0.39), forb (R² = 0.16), and litter (R² = 0.51) biomass, possibly caused by the mixture of spectral signatures with grasses, sedges, and willows along with the variable effect of the litter spectral signature. 3) A weak relationship was found between sagebrush biomass and SRTVI or NDTSI (R² = 0.3) that was related to interference from sagebrush photosynthetic or nonphotosynthetic branch and twig material, and from the indeterminate spectral signature of sagebrush. This study has shown that hyperspectral imagery at 1-m resolution can result in high correlations and low error estimates for a variety of biomass components in rangelands. This methodology can thus become a very useful tool to estimate rangeland biomass over large areas.

The cover of Festuca gracillima (coirón fueguino), a native tussock grass that dominates grass steppes of Southern Patagonia and Tierra del Fuego, has diminished under continuous sheep grazing. This loss is a concern, because it also reduces forage availability in winter, biodiversity, and soil stability. In the present study, the hypothesis that tussock grass birth and mortality rates are balanced only under moderate-grazing or exclusion regimes was tested with two 5-year records of demographic data obtained from 3 sheep grazing regimes: exclosure (no grazing), low (0.0348 AU·ha⁻¹·y⁻¹, where AU represents animal units equivalent to the consumption of a 450-kg cow), and high (0.1043 AU·ha⁻¹·y⁻¹). Tussocks were outlined in photographs and marked in the field at two 5-year intervals. The initial total number of plants for the 3 grazing regimes (n = 358) increased to 384 plants at the end of the 10-year period. No recruitment from seed was observed; plant number changed as a balance of yearly rates of tussock mortality (1.48%), amalgamation (0.75%), and subdivision (2.04%). Intensely grazed populations showed greater (2.13%) mortality rates than ungrazed (1.20%) or moderately grazed (0.78%) populations. Tussocks in intensely grazed populations were smaller (167 cm²·plant⁻¹) than those in moderately grazed (197 cm²·plant⁻¹) or ungrazed (300 cm²·plant⁻¹) populations. Transition matrices showed eigenvalues of 0.701 (high grazing), 0.794 (exclosure), and 0.876 (low grazing). All growth rates of demographic models were negative; the largest rate of population decrease was found under high-intensity grazing, for which projections show that half the tussocks would be lost in 37 years. Under low-intensity grazing and exclosure, a similar tussock loss would take place in 87 and 74 years, respectively. Results show 1) the importance of vegetative processes for tussock demography, 2) the extremely slow dynamics of population changes, and 3) that tussocks may suffer increased mortality as a consequence of subdivision or fragmentation, a process that can be viewed as a small-scale example of the generalized effect of patch subdivision under grazing.

Tree establishment can have multiple effects on the production and biodiversity of rangelands. In mixed (C3–C4) grasslands, winter deciduous trees could favor cold-season species in the understory, improving forage availability in the most critical time of the year. Yet, they could also promote local extinctions and invasions, risking native biodiversity. We evaluate the effect of poplar planting on the structure, composition, and diversity of native grasslands in the Flooding Pampas of Argentina using a network of 9 pairs of adjacent nonafforested and afforested stands (age: 23–25 years, density: 625–1 111 plants ha⁻¹) located in different topographic positions. Phytosociological surveys, basal cover measurements, and tree volume were performed at all stands. Live plant cover was 42% lower under poplars (P < 0.05). Litter cover followed an opposite trend leaving bare soil proportions unchanged with afforestation. Afforested stands had a higher proportion of C3 species compared with nonafforested ones. Little evidence of local extinctions or invasions with afforestation was found. Poplar understories had significantly higher nonnative species cover but similar numbers and lower species diversity (Shannon–Weaver index) yet similar species richness when compared with their nonafforested counterparts. Beyond the diversification of ranch outputs, deciduous tree plantations in the Flooding Pampas can offer a good forage source in their understory that complements nonafforested natural grasslands in quality and seasonality.

Enhancing desired species establishment and persistence is central to rehabilitating invasive plant–infested rangeland. We hypothesized that nonnative desired species (alfalfa [Medicago sativa L., var. Arrow], intermediate wheatgrass [Thinopyrum intermedium {Host} Barkworth & D.R. Dewey], and crested wheatgrass [Agropyron cristatum {L.} Gaertn., var. Hycrest]) increase as desired species richness within seeding mixture increases, and spotted knapweed (Centaurea maculosa Lam.) decrease as desirable species richness increases. We simultaneously tested the degree of niche differentiation among desired species. Experiments consisted of 7 seeding monocultures and combinations. Treatments were monocultures of each desired species (3 plots), all combinations of 2 desirable species (2 250 seeds·m⁻² per species; 3 plots), and 1 plot containing all 3 desirable species (1 500 seeds·m⁻² per species). Monocultures or mixtures were replicated 4 times by seeding each treatment with four background densities of spotted knapweed (1 250, 2 500, 3 750, and 7 500 seeds·m⁻²; 7 treatments × 4 background densities = 28 plots). Analysis included regression with the 7 desired species monocultures or mixtures as a fixed effect and spotted knapweed sowing density as a continuous effect. All desired species established had either low or no negative influence on their neighbor, and differed in niche after 7 years of growing in association. Increasing richness of desired species led to increased productivity. Spotted knapweed density and biomass were low across all monocultures and mixtures at the productive site because shade and litter of desired species reduced light availability to the rosette-forming invasive weed. Combining crested wheatgrass and alfalfa provided lower spotted knapweed density and biomass more than did monocultures or grass mixtures because these 2 species appeared to occupy complementary niches. Increased niche occupation by nonnative desirable species may increase resource use and productivity, thus minimizing establishment and dominance of unwanted invasive plants during rehabilitation on arid, marginally productive rangeland sites.

The efficiency of livestock production in shortgrass steppe may be increased by grazing fourwing saltbush (Atriplex canescens [Pursh] Nutt)-dominated rangeland in late fall and/or early spring, but there is a paucity of information concerning stocking rates and animal gains. The objective of this study was to compare the effects of light and moderate stocking rates on weight gains of heifers grazing twice-replicated 16-ha pastures in late fall (November to mid-January) from 1996 to 1998, and in early spring (April to mid-May) from 1996 to 1999. Stocking rates for late fall (light: 1.3–1.5 ha · animal unit month⁻¹ [AUM⁻¹] vs. moderate: 0.8–1.0 ha · AUM⁻¹) and early spring (light: 3.7–4.0 ha · AUM⁻¹ vs. moderate: 2.3–2.5 ha · AUM⁻¹) were achieved using 5 (for light grazing) and 8 (for moderate grazing) Hereford heifers, with initial average weights of 405 ± 5.7 (mean ± 1 SE) kg for the late fall grazing period and 267 ± 3.8 kg for the early spring grazing period across the study years. Average daily gain was 58% greater for light (0.65 ± 0.06 kg · head⁻¹ · d⁻¹) compared to moderate (0.41 ± 0.05 kg · head⁻¹ · d⁻¹) stocking rates in the late fall grazing period, and 115% greater with light (0.59 ± 0.06 kg · head⁻¹ · d⁻¹) than with moderate (0.27 ± 0.07 kg · head⁻¹ · d⁻¹) stocking rates in the early spring grazing period. Beef production did not differ between stocking rates for either the late fall (16.4 ± 3.9 vs. 17.4 ± 4.5 kg gain · ha⁻¹, light vs. moderate stocking rates) or early spring (9.6 ± 2.7 vs. 7.6 ± 4.8 kg gain · ha⁻¹) grazing periods. We suggest that land managers employ light stocking rates during both grazing periods to obtain adequate individual animal gains without sacrificing gains per unit land area. Lengthening the grazing season in the shortgrass steppe should be economically desirable to land managers because feed costs could be lowered and animal gains obtained through minimal input.

Integrating use of seeded perennial cool-season grass pastures with native rangeland can increase available forage and provide a high plane of nutrition for grazing livestock. Our objective was to compare performance of yearling beef heifers grazing native rangeland with those grazing an integrated system that included seeded forages. Twice-replicated, 3-ha pastures seeded to either ‘Rosana’ western wheatgrass (Pascopyron smithii [Rydb.] A. Love), ‘Luna’ pubescent wheatgrass (Elytrigia intermedia [Host] Nevski), or ‘Hycrest’ crested wheatgrass (Agropyron cristatum [L.] Gaertn. ssp. desertorum [Fisch. ex Link] A. Love) were grazed in spring, whereas twice-replicated, 3.24-ha pastures seeded to either ‘Alkar’ tall wheatgrass (Thinopyrum ponticum [Podp.] ZW Liu & RC Wang), ‘NewHy’ hybrid wheatgrass (Elymus hoffmannii KB Jensen & KH Asay), ‘Bozoisky’ Russian wildrye (Psathyrostachys juncea [Fisch.] Nevski.), or ‘Prairieland’ Altai wildrye (Leymus angustus [Trin.] Pilger) were grazed in autumn. Native rangeland was grazed during summer in the integrated system and spring, summer, and autumn in the rangeland treatment. Heifers exhibited greater weight gains on seeded pastures than on native rangeland in spring and autumn of most years. In 2 out of 3 years, heifers that grazed native rangeland during spring gained more (P = 0.012 for gain head⁻¹ and P = 0.021 for gain head⁻¹ day⁻¹) while grazing native rangeland during summer than heifers that grazed seeded pastures in spring. Spring   summer gains averaged (mean ± SE) 0.56 ± 0.01 kg·head⁻¹·d⁻¹ and 73.1 ± 1.6 kg·head⁻¹. Livestock managers need to consider their livestock marketing and management strategies when using seeded pastures for seasonal grazing.

Interseeding alfalfa into rangelands has been assessed for decades as a method of range improvement to increase forage production and forage quality for livestock. Research was initiated in 2001 to examine the long term effects of interseeding yellow-flowered alfalfa (Medicago sativa ssp. falcata) on northern mixed-grass rangelands. Forage production and forage quality parameters were assessed on sites interseeded in 1965, 1987, and 1998 and compared to adjacent native rangelands. Live aboveground biomass for the 1965, 1987, and 1998 interseeded sites was 68, 143, and 42% higher, respectively, compared to their native control areas. Alfalfa aboveground biomass accounted for 1 489 of the 2 969 kg·ha⁻¹ live biomass harvested from the 1965 interseeded site, 1 940 of the 2 744 kg·ha⁻¹ on the 1987 interseeded site, and 796 of the 2 322 kg·ha⁻¹ on the 1998 interseeded site. Increased soil N resulting from N fixation by the alfalfa significantly increased the crude protein (CP) content of several native species, whereas the alfalfa itself provided forage with 16 to 18% CP. Alfalfa had higher protein degradability and provided higher concentrations of calcium (Ca), potassium (K), and magnesium (Mg) than the native rangeland grasses. This research has shown that the practice of interseeding yellow-flowering alfalfa into rangelands is sustainable over decades and will increase forage production and improve nutritive value of forage in the northern Great Plains.

The University of California Cooperative Extension surveyed rangeland owners and managers who attended California's Ranch Water Quality Planning (RWQP) Short Course in 1995–2002. The survey evaluated the effectiveness of this industry-supported voluntary program by evaluating indicators for short course impacts, including 1) rancher participation in the short courses, 2) completion of nonpoint source self-assessments, 3) completion of ranch water quality plans, and 4) implementation of best management practices (BMPs). This report describes the RWQP short course and ranch water quality plan content including the nonpoint source pollution self-assessment and monitoring. Questionnaires were mailed to 777 short course participants on 5 August 2002 (Round 1). A second survey (Round 2) was mailed to nonrespondents on 7 April 2003. Round 1 and 2 surveys resulted in a 52.9% total adjusted response rate. Citing privacy issues, 28 respondents refused to complete the survey. Round 1 respondents had a significantly higher rate of BMP implementation, but Round 2 respondents invested more personal funds in BMPs. There was a significant relationship (P < 0.001) between plan completion and implementation of BMPs. While the majority of the respondents completed ranch water quality plans and self-assessments, and implemented BMPs, less than 50% of the respondents implemented a monitoring program. Fifty percent of the respondents raised beef cattle, and the majority managed ranches less than 5 000 acres in size. The results of this survey suggest that industry-initiated, voluntary programs supported by education are effective in helping rangeland owners and managers address nonpoint source pollution on their properties. In addition, social surveys are a viable method for landowners to confidentially self-document identified pollution sources and BMP implementation, and to avoid formal reporting to regulatory agencies.

In Kajiado District, Kenya, ranches held communally by Maasai are being subdivided into individually owned parcels. Livestock owners know that herds on parcels that are too small cannot be viable, but the decline in the capacity of parcels to support livestock has not been quantified. We used ecosystem modeling to represent the effects of subdivision as Maasai group ranches were divided into 196, 10, 5, 3, and 1 km² parcels. Within the spatially explicit, process-based Savanna ecosystem model, we used maps that constrained the movements of livestock to be within parcels. We also modeled cooperative grazing associations, giving groups of herders access to parcels composed of dispersed or contiguous 1 km² parcels. Vegetatively productive areas had higher carrying capacities when isolated because resident animals did not compete with animals moving in seasonally from other areas. In a ranch of low but heterogeneous productivity, we saw a steady decline in capacity under subdivision, until 25% fewer livestock could be supported on the ranch of 1 km² parcels relative to the intact ranch. On a ranch with both low productivity and heterogeneity, 20% fewer livestock were supported when parcels were still 10 km². The most productive ranch studied saw small population changes with subdivision. Participation in grazing associations was helpful in the ranch intermediate in productivity and heterogeneity, but not other ranches. Subdivision of Kajiado lands might be inevitable, but our results show the relative benefits to stakeholders if land owners and policy makers act to maintain open or flexible access to individually held parcels.

Western juniper (Juniperus occidentalis spp. occidentalis Hook.) expansion into sagebrush steppe plant communities in the northern Great Basin has diminished shrub-steppe productivity and diversity. Chainsaw cutting of western juniper woodlands is a commonly applied practice for removing tree interference and restoring understory composition. Studies reporting understory response following juniper cutting have been limited to early successional stages. This study assessed successional dynamics spanning 13 years following tree cutting. Total herbaceous standing crop and cover increased significantly in the CUT. Total standing crop was 10 times greater in the CUT vs. WOODLAND. Herbaceous standing crop and cover, and densities of perennial grasses in the CUT did not change between 1996 and 2004 indicating that by the 5th year after cutting, remaining open areas had been occupied. In the early successional stages, perennial bunchgrasses and Sandberg's bluegrass were dominant. By the 5th year after treatment, cheatgrass had supplanted Sandberg's bluegrass and was codominant with perennial bunchgrasses. In 2003 and 2004, perennial bunchgrasses dominated herbaceous productivity in the CUT, representing nearly 90% of total herbaceous standing crop. A pretreatment density of 2–3 perennial bunchgrasses m⁻² appeared to be sufficient to permit natural recovery after juniper control. Perennial bunchgrass density peaked in the 6th year after treatment and the results suggested that 10–12 plants m⁻² were sufficient to fully occupy the site and dominate herbaceous composition in subsequent years. In the CUT, juniper rapidly reestablished from seed and from the presence of seedlings not controlled in the initial treatment. The shifts in herbaceous composition across years suggests that long term monitoring is important for evaluating plant community response to juniper control and to develop appropriate post treatment management to promote continued site improvement.

The economic and ecological benefits and control costs of western juniper (Juniperus occidentalis Hook) management on rangelands are evaluated using a discrete-time, dynamic economic model developed to depict 4 representative ranches in the John Day region of north-central Oregon. The model's optimization criterion is to maximize the net present value of profits through decisions regarding herd size and composition, cattle sales, and the manipulation of forage production through juniper management practices. Projections are made regarding the impacts of economically optimal juniper management on wildlife populations, stream flows, and erosion levels. Results consistently showed that juniper management options resulted in larger equilibrium herd sizes and greater economic returns. Erosion levels were substantially lower in scenarios that contained juniper management options. Economically optimal juniper management decisions led to increased quail and elk populations, but generally resulted in decreased deer populations. The results indicate there are both economic and ecological benefits from controlling western juniper on Oregon rangelands.

Habitat management guidelines for greater sage-grouse, Centrocercus urophasianus, have been formulated, in part, based on studies of nest site selection. However, these guidelines may not represent conditions when the female initiates nesting because sampling occurs posthatch (> 30 days after nest initiation) to avoid disturbing incubating females. In 2002, we investigated differences in 22 habitat variables at initiation and hatch. Sampling was at 30 randomly selected active nests marked in 2001. There was no significant difference in structural or cover data (P > 0.05). Grass height and percent grass cover differed (P < 0.05) based on timing of sampling. Grass heights at the nest bowl and at 1 m from the edge of the nest bowl were 10 and 9 cm at initiation and 16 and 13 cm at hatch, respectively. Percent grass cover increased from 4% to 6% cover from initiation to hatch. Sampling occurred in a dry year; differences in grass heights and percent cover may be more pronounced in years of normal precipitation. Preliminary results indicated current habitat sampling techniques conducted posthatching adequately described selection of structural components of shrub height, visual obstruction, and percent cover of shrubs, bare ground, litter, and forbs at the nest site at initiation. Data need to be verified for other study areas and under different climatic conditions.

The point sample method has been a standard plotless method for measurement of ground cover on rangelands since it was introduced by Levy in 1927. The instrument most commonly used to do point sampling is the point frame. Since its introduction, the point frame has undergone numerous modifications to improve efficiency and ease of use. This article introduces a laser point frame (LPF) that was designed by the Agricultural Research Service for measurement of ground cover and utilizes lasers in place of conventional metal pins. A comparative pilot study was conducted on a shortgrass prairie in northern Colorado to compare data collected using a magnetic point frame (MPF) with data collected using the LPF. Cover by species was measured from identical plots using 100 points per plot for each point frame, and sampling times were recorded for each plot. Correlations between cover data collected using the MPF and the LPF were relatively high (r² = 0.62–0.81). Total average vegetative cover measured with the MPF was 35%, compared with 40%, using the LPF. Cover of total grasses, C₄ grasses, C₃ grasses, and litter, were significantly greater with the LPF method. Total sampling time per 100 points was almost half using the LPF compared with the MPF. The LPF was easy to use, efficient for measurement of cover, and is a potential replacement for conventional point frames.