Cheatgrass (Bromus tectorum L.) seedlings suffer mortality if they do not occupy safe sites that provide establishment requirements. Previous research demonstrated that fall cattle grazing has strong potential for reducing invasive annual grass species dominance in winter-dominated precipitation areas of the Intermountain West. Fall cattle grazing reduces the volume of safe sites through the removal of standing dead biomass in the fall and early winter, when cheatgrass can actively germinate. This study continued an assessment of cheatgrass seed bank characteristics under fall-grazing and grazing exclusion treatments initiated by a previous study. A seed bank assay was organized into a randomized complete block, repeated measure design to assess cheatgrass seed bank characteristics from 2014 to 2017 in central Nevada. Across years, fall-grazed areas had about half the assayed seed bank levels (3 432 ± 2 513 seeds · m^–2) of ungrazed areas (7 187 ± 1 569), (P <0.0001). There was also a difference among years with 2015 producing higher assayed numbers in both grazing treatments. Combined plotted data from this and the previous study indicated that after several years of fall-grazing treatments, removal of fall cattle grazing for only 1 yr can result in significant increases in cheatgrass seed bank size. Conversely, reapplication of fall cattle grazing can quickly decrease cheatgrass seed bank potential.

Substantial gaps exist between weed management researchers and practitioners with respect to prompt exchange of knowledge between the two groups, hindering the implementation of effective management to solve weed problems. We conducted a survey between 2016 and 2018 among weed management practitioners (n = 259) across diverse ecoregions on California rangelands and collected essential information from practitioners for bridging the research-implementation gap. The information included management costs, high-priority weeds, and spatial scales and temporal changes in weed management. The management cost had a mean of $5.12 ha–¹yr^–1 with a large variance implying the uncertainty of this information. The percentage of annual budget dedicated to weed management explained about 30% of the variation in this cost. Moreover, this annual per-unit area cost decreased with increasing management area. The average size of rangeland managed by survey respondents was 1 256 ha. The top three high-priority weeds statewide were yellow starthistle (Centaurea solstitialis), medusahead (Taeniatherum caput-medusae), and all thistles combined. Medusahead and some thistle species remained on the top list in each ecoregion. Respondents overwhelmingly (80.9%) noted changes in weed problems in the past 5–10 yr, specifically citing greater weed pressure and changes in weed species. A significantly higher proportion of respondents from agencies and private businesses reported changes in weed problems than those from universities and nongovernmental organizations (NGOs), further underscoring the gap between practitioners and researchers. A majority of the respondents (75.3%) indicated the record-setting California drought had a negative effect on weed management, reducing treatment efficacy and favoring weeds over desirable species. Overall, our findings illustrate increasing challenges in weed management on California rangeland. These challenges call for adaptive management-research programs to increase cost-effectiveness of weed management and to swiftly and effectively respond to dynamic weed problems on large spatial and long temporal scales.

Native pastures that present high botanical richness produce a variety of feed items for grazing herbivores. Diet selection takes place at the bite scale and, at a daily scale, the sum of bites composing the intake determines diet characteristics. The objective of this paper is to bring an original contribution to the understanding of diet selection in diverse foraging environments such as native Pampa grasslands. The issues are 1) to improve grazing management in Pampa ecosystems and 2) to evaluate the ability of native pastures to feed a herd in order to reduce supplementation and to improve the economic sustainability of extensive systems. We hypothesize that the information contained in the infrared spectra of plant samples corresponding to potential bites can be useful for establishing functional bite categories, which, in turn, can be used to understand and manage pastoral ecosystems. We analyzed the near-infrared spectrum (NIRS) of 1 515 bite samples gathered in 2012 using the continuous bite monitoring method applied to heifers continuously grazing on Pampa grassland at five grazing intensities (randomized block design with two replicates, applied since 1987). On the basis of the main wavelengths, a statistical classification of bite samples was produced and five classes were described: 1) small bites of wetland grasses and short grass; 2) medium bites of forbs and short grass; 3) small bites of short Poaceae and mixed species; 4) large bites on tussocks of Poaceae; and 5) extralarge bites on stiff tussock of Poaceae and Apiaceae. In order to evaluate the functional value of the classification, we tested its ability to take seasonal changes in pasture composition into account and to describe the variations in animal intake and performance in contrasted grazing conditions. We concluded that the NIRS is a good support for establishing functional classes of feed items that can be used to understand the foraging behavior and diet composition of grazing herbivores. Our approach was tested in Pampa grasslands grazed by cattle but should be applicable to a wide range of ecosystems, provided that chemical composition is more relevant for selection than feed item accessibility.

Plateau pikas (Ochotona curzoniae) often clip tall plants near active burrow entrances to detect and avoid predators. This clipping behavior influencing plant communities near active burrow entrances has not been well documented. A field experiment was conducted to investigate the effects of this clipping behavior on plant communities across three sites in the Qinghai-Tibetan Plateau by comparing plant communities near active burrow entrances with communities near abandoned burrow entrances. This study showed that the clipping behavior decreased plant community height and increased plant cover and species richness of the community and had no effect on plant community biomass across three sites or at each site. This study further showed that clipping behavior decreased the plant biomass of the graminoid group and had no effect on the plant species richness of the graminoid group, whereas it increased the plant biomass and plant species richness of the forb group across the three sites or at each site. These findings suggest that a general pattern concerning the effect of the clipping behavior can increase plant species richness and decrease the grazing quality of alpine meadows near active burrow entrances.

Plant aboveground biomass (AGB) is a useful metric to assess ecosystem functioning, and its sensitivity to changing environmental conditions provides insight into potential global change impacts. Allometric estimates of AGB using vegetation characteristics such as plant cover or height provide nondestructive biomass proxies for repeated measurements but can introduce uncertainty to estimates. We estimated the relationship between both plant cover and a cover·height index and AGB for 15 plant species from six sites to identify the most reliable approach to estimate biomass nondestructively in semiarid eastern Australian rangelands. Estimates were made by grouping species at four different levels of specificity, to test whether generic estimates were more robust than grouping species based on life history and morphological characteristics. Estimates were then tested on a 1.5-m² plot at each site for validation. In all cases, models were highly significant (P < 0.001) with adjusted R² values ranging from 0.42 to 0.96 for cover models and 0.38 to 0.98 for cover·height index models. We found the addition of height improved model fits in four groups while reducing model fits in two groups. The error around AGB estimates for cover·height index–based models ranged from –66.8 to 4% (absolute mean 35%). Cover-based models had errors between –13.4% and 53% (absolute mean 14.2%). For cover-based estimates of AGB in validation plots, grouping plants by plant functional types (PFTs) increased accuracy (absolute mean error 17.3%) compared with estimates using data from all 15 species (absolute mean of 65.2%). Overall cover was a useful surrogate to estimate AGB (with the exception of one site, accuracy ranged from –2.3% to 11.5%), while height (thought to be a surrogate for canopy characteristics) provided benefit in a few circumstances. We suggest that future research should test additional nondestructive proxies and group species based on PFTs to improve AGB estimates using allometry.

Forage kochia (Bassia prostrata [L.] A.J. Scott) is a perennial, halophytic Chenopodiaceae shrub adapted to semiarid rangelands and steppes. It is noted for its ability to produce edible forage in saline environments, but the effect of salinity on its nutritive value has not been determined. Therefore, this study evaluated the dose-response of increasing salinity on the forage quality of forage kochia and Gardner's saltbush (Atriplex gardneri [Moq.] D. Dietr., a chenopod forage shrub indigenous to the United States). Individual plants were evaluated in hydroponics for 28 days at 0, 150, 300, and 600 mM NaCl. Salt from accumulated ions, minerals, and forage nutritive value were determined using ground shoot samples. Analysis of forage nutritive value is problematic in plants with high salt concentrations, so neutral detergent fiber (NDF) and in vitro true digestibility (IVTD) were also predicted on an ash-corrected dry matter (DM) basis (NDF_corrected and IVTD_corrected). Forage kochia exhibited a dose-response for salt concentration, IVTD_corrected, and crude protein (CP) as salinity increased. Salt concentrations increased to 19% of DM at 600 mM NaCl, which may reduce voluntary intake by ruminants grazing forage kochia. Results indicated that uncorrected IVTD estimates were inflated as forage kochia IVTD_corrected decreased from 65% to 56% with the major change between 300 and 600 mM NaCl. Crude protein did not differ between two forage kochia cultivars but decreased from 26% to 15% between 0 and 600 mM NaCl, whereas Gardner's saltbush CP decreased by only five percentage points as salinity increased. Nonetheless, despite the greater CP sensitivity to salinity level, forage kochia salt concentration was less and digestibility and metabolizable energy (ME) were greater than Gardner's saltbush. Overall, salinity reduced the forage quality of forage kochia, though not as dramatically as for Gardner's saltbush, thus supporting use of forage kochia to improve the forage base of saline rangelands.

Diet overlap estimation among species is important to understand interspecific interactions. Through these interactions, one species may extinguish others through competition or adapt through mechanisms such as resource partitioning. The introduction of domestic herbivores in a native assemblage may introduce competition for resources with wild herbivores. In southern Patagonian steppes, guanaco (Lama guanicoe) populations are increasing after a drastic demise during the past century. This is occurring in protected areas and extensive ranching areas for sheep, and in the latter ranchers have rising concerns regarding competition. In this observational study, we measured diet overlap, food selection and preferences, and niche width for guanaco and sheep to compare use of food resources during the summer season. Feces were analyzed through microhistological technique to determine sheep and guanaco diets. Diets of guanaco and sheep were dominated by tussock grass (Festuca gracillima, sheep > 60%, guanaco > 50%), the most abundant plant species. Although food niche widths, measured through Levin's Index, were narrow, guanaco presented the broadest niche (P < 0.001). Of the 17 identified plant species present in guanaco and sheep diets, 5 were always selected by both ungulates and 1 was always avoided at the four study sites. Overlap between diets was high (> 0.90), evidencing potential competition. In addition, diet overlap coupled with our results of small variation in use and selectivity of food resources suggest the absence of resource partitioning. Therefore, both species might share resources or coexist, possibly due to high availability or spatial distribution of food resources and guanaco resilience to cope with numerically dominant competition from sheep. These findings offer new insight into the understanding of these species' interactions. It is also a management challenge to emerging wild and domestic herbivores interactions, as well as livestock production concerns at large.

The Lebanese Baladi goat dairy production sector suffers from food availability problems due to the dependence on natural rangelands and the scarcity of crop residues and forage pastures, leading to lower production. Thus, the nutritional values of the pastures were evaluated in an observational study where 48 Baladi lactating goats were selected and kept within a farm in Qâa er Rîm located in the region of Zahleh, Lebanon. Animal responses in feeding behavior were measured on four different circuits of natural rangelands (NR1, NR2, NR3, and NR4) surrounding the farm site, during a period of ≈75 d (from April to mid-June). Observations and measures consisted of evaluating the rangeland's botanical composition, selective feeding and analysis of forage nutritional values, recording of daily foraging dynamic, and estimation of daily intake. Natural rangelands revealed a large botanical diversity that changed according to season and altitude: From NR1 to NR4, as summer season advanced and animals were moved to higher altitudes, bushes increased, whereas grasses retreated. In parallel, mean diet nutritional value decreased; dry matter (DM) content increased, as well as acid detergent fiber and neutral detergent fiber contents, while crude protein levels decreased. The animals, however, adapted their feeding dynamics on the rangelands accordingly: With the advancement of summer time, total duration of grazing day was increased in order to compensate for longer resting periods at noon and longer walking periods in higher altitudes, without a decrease in total feeding duration. On the other hand, animals were able to adjust their feeding regimen to the available plant species by increasing their daily intake of 0.56 kg/d between NR1 and NR3 and by substituting grasses with shrubby species; a shift from 25% to 28% to 53% to 54% DM in the animals' diet. These adaptive behavioral responses explain the capacity of Baladi goats to survive in their harsh environment and even tolerate feeding perturbations.

Invasive Lantana camara (L. camara) is one of the key drivers of social-ecological and environmental change. Understanding its distribution is critical in determining its impact on the environment and livelihoods and in developing sustainable remediation and rehabilitation strategies. In this study we demonstrate the first comparative assessment of Landsat 8 Operational Land Imager (OLI) and Sentinel-2 Multispectral Instrument (MSI) satellite data in detecting and mapping of invasive L. camara from other land cover types (i.e., built up, fields/bare patches, grassland, and shrub) in semiarid rangeland ecosystems of South Africa. Discriminant analysis (DA) classification technique was used to detect and characterize the spatial distribution of L. camara using Landsat 8 OLI and Sentinel-2 derivatives (i.e., spectral bands, indices, and combined variables). Comparatively, the results show that Sentinel-2 data were able to detect and map L. camara with a high overall accuracy (78.4%) than Landsat 8 OLI, which yielded an accuracy of 65.5%. Further, Student's t-test statistical analysis results showed that Sentinel-2 outperformed Landsat 8 (P < 0.05, Student's t < 0.233) in mapping L. camara from other land cover types. High performance from Sentinel-2 data indicates the relevance and potential of characterizing and profiling invasive species with the new-generation sensors, a previously daunting task, with broadband multispectral sensors.

One of the primary conservation threats surrounding sagebrush (Artemisia spp.) ecosystems in the Intermountain West of the United States is the expansion and infilling of pinyon pine (Pinus edulis, P. monophylla) and juniper (Juniperus spp.) woodlands. Woodland expansion into sagebrush ecosystems has demonstrated impacts on sagebrush-associated flora and fauna, particularly the greater sage-grouse (Centrocercus urophasianus). These impacts have prompted government agencies, land managers, and landowners to ramp up pinyon-juniper removal efforts to maintain and restore sagebrush ecosystems. Accurately quantifying and analyzing management activities over time across broad spatial extents still poses a major challenge. Such information is vital to broad-scale planning and coordination of management efforts. To address this problem and aid future management planning, we applied a remote sensing change detection approach to map reductions in pinyon-juniper cover across the sage-grouse range and developed a method for rapidly updating maps of canopy cover. We found total conifer reduction over the past several yr (2011–2013 to 2015–2017) amounted to 1.6% of the area supporting tree cover within our study area, which is likely just keeping pace with estimates of expansion. Two-thirds of conifer reduction was attributed to active management (1.04% of the treed area) while wildfire accounted for one-third of all estimated conifer reduction in the region (0.56% of the treed area). Our results also illustrate the breadth of this management effort—crossing ownership, agency, and state boundaries. We conclude by identifying some key priorities that should be considered in future conifer management efforts based on our comprehensive assessment.

One-seed juniper (Juniperus monosperma [Englem.] Sarg.) encroachment into grassland habitats is facilitated by a diverse group of frugivores. To test seed germination after gut passage, we collected pellets or scats containing mature seeds from four frugivore groups: passerine (perching) birds, lagomorphs (hares and rabbits), mesocarnivores (coyotes and foxes), and porcupines. For comparison of germination success, we also evaluated seeds from intact, nondigested one-seed juniper cones. We conducted germination trials under three different scenarios: 1) imbibed bare seeds (a measure of potential germination); 2) seeds still encased within a frugivore deposited pellet or scat matrix or still in a nondigested cone; and 3) matrix-free seeds that had gone through the matrix germination trials and then were freed from the matrix (a simulation of seeds that become dislodged from scats or pellets). In the bare seed trials, germination was highest (70.8% ± 7.4%) for seeds digested by mesocarnivores and was 63.9% ± 5.7% for porcupines, which was higher (P < 0.05) than germination of seeds from bird pellets (33.3% ± 7.7%). Germination of seeds from all frugivores, including lagomorphs (51.4% ± 7.2%), was higher (P < 0.05) than for seeds encased in cones (9.7% ± 3.2%). The germination percentage of seeds still encased in frugivore pellets or scats was highest for birds (40.1 ± 4.2) and was significantly lower (P < 0.05) for other frugivores. Seeds freed from all frugivore deposition matrices showed a second pulse of germination activity, especially seeds from lagomorph pellets. Germination success differences can influence the nature of one-seed juniper woodland infill and encroachment into bordering grasslands, which can lead to loss of soil health, lower grass biomass production, and a diminishment of habitat quality for grassland-dependent wildlife species.

Degradation of alpine meadows on the Qinghai-Tibetan Plateau is an important issue for ecological science, policy making, and the welfare of local herders. Destruction of alpine meadows results from degeneration of vegetation and soil systems and from the mechanical decoupling of the environment, grassland, livestock, and herders and, subsequently, discordance among these subsystems. In this study, systematic integration of restoration techniques based on the grassland agroecosystems coupling theory was developed for the management and restoration of degraded alpine meadows. To test the effectiveness of these integrated restoration techniques, we conducted restoration trials that included grazing management, enclosed, fertilization, overseeding, and sward ripping by evaluating the ecosystem coupling of soil, plant and livestock, and ecosystem functions. The results of this study suggest that comprehensive restoration practices include grazing and agronomy techniques (fertilizer, overseeding, and sward ripping) that result in the greatest level of ecosystem coupling, while the single restoration practice leads to poorly coupled ecosystems. Restoration practice changes in ecosystem functionality are positively related to changes in ecosystem coupling. Our results highlight the importance of diversified restoration practices for facilitating ecological coupling and functioning in the degraded alpine meadow. The restorative scheme also bridges the gap between restoration theory and practice by providing guidelines for herders and policy makers for the urgent task of restoring degraded alpine meadows.

A field study in Randall County, Texas, was conducted to determine how soil bulk density and plant cover change over time in response to deferment following a high-density, high-intensity, short-term grazing/ trampling event. Green Sprangletop (Leptocloa dubia Kunth.) and Kleingrass (Panicum coloratum L.) were broadcasted at 4.5 kg ha^–1 pure live seed (PLS) on former cropland that had a partial stand of WW-Spar Bluestem (Bothriochloa ischaemum L.). A high-density, high-intensity trampling event was achieved with twenty-four 408-kg Bos taurus heifers occupying four 0.10-ha plots (97 920 kg live weight ha^–1) for 10 h, with four adjacent 0.10-ha control plots left untrampled. Canopy and basal cover were determined by plant functional group using the Daubenmire method after rainfall events of > 0.254 cm, and a 5.08 × 7.62 cm core was collected to determine soil bulk density. Strips of supplemental plant material were applied in March to test the effects of 100% soil cover on seedling recruitment. Trampled treatments had 30% less vegetative cover (P < 0.01) and average soil bulk densities that were 0.20 g cm^–3 higher (P < 0.01) than untrampled plots post trampling. Bulk density decreased with deferral until there were no significant differences between treatments (240 d). However, WW-Spar basal cover increased in both treatments, with no differences between treatments. Trampling did not affect seedling recruitment, but supplemental cover increased seedling density on three of five subsequent sampling dates (P < 0.05). Canopy cover of warm season perennial grasses in trampled treatments surpassed that of the untrampled treatments during the early growing season of 2016 (P < 0.01) but were no different after mid-June. Hydrologic function can be maintained with high stock densities by providing adequate deferment to reestablish sufficient cover and allow natural processes to restore porosity.