Rangelands provide different ecosystem services to satisfy human needs. Although grazing management in southern Patagonia is mostly characterized by extensive continuous grazing, rotational grazing management may improve plant productivity and its associated microbiome. Arbuscular mycorrhizal (AM) symbioses play an important role in the functioning of arid rangelands. However, in most arid and semiarid grasslands, little is known about the environment-plant-symbiont interaction under different defoliation frequencies and contrasting growth conditions. In this context, the objective of the present study was to evaluate the response of Rytidosperma virescens native grass and the associated AM fungi under different defoliation frequency treatments (plants undefoliated, two clippings with 50-d intervals between defoliations, four clippings with 30-d intervals, and six clippings with 21-d intervals) and two growth conditions (field and greenhouse) in a 150-d experiment. Defoliation frequency with 21-d clipping intervals negatively affected plants and AM colonization. We found a negative linear relationship between AM colonization and removal of aboveground biomass and a positive relationship with root biomass and leaf area of R. virescens plants. We determined that the appropriate recovery period for rotational grazing systems should be at least 50 d (threshold) to optimize forage production and AM symbiosis during spring-summer seasons. Sustainable grazing management practices should be designed to improve or restore AM communities to maintain positive feedback with plant development.

Subtropical humid grazing lands represent a large global land use and are important for livestock production, as well as supplying multiple ecosystem services. Patch-burn grazing (PBG) management is applied in temperate grazing lands to enhance environmental and economic sustainability; however, this management system has not been widely tested in subtropical humid grazing lands. The objective of this study was to determine how PBG affected forage resources, in comparison with the business-as-usual full-burn (FB) management in both intensively managed pastures (IMP) and seminative (SN) pastures in subtropical humid grazinglands. We hypothesized that PBG management would create patch contrasts in forage quantity and nutritive value in both IMP and SN pastures, with a greater effect in SN pastures. A randomized block design experiment was established in 2017 with 16 pastures (16 ha each), 8 each in IMP and SN at Archbold Biological Station's Buck Island Ranch in Florida.

PBG management employed on IMP and SN resulted in creation of patch contrast in forage nutritive value and biomass metrics, and recent fire increased forage nutritive value. Residual standing biomass was significantly lower in burned patches of each year, creating heterogeneity within both pasture types under PBG. PBG increased digestible forage production in SN but not IMP pastures. These results suggest that PBG may be a useful management tool for enhancing forage nutritive value and creating patch contrast in both SN and IMP, but PBG does not necessarily increase production relative to FB management. The annual increase in tissue quality and digestible forage production in a PBG system as opposed to once every 3 yr in an FB system is an important consideration for ranchers. Economic impacts of PBG and FB management in the two different pasture types are discussed, and we compare and contrast results from subtropical humid grazing lands with continental temperate grazing lands.

Rangelands used for cattle grazing in Florida are typically managed under prescribed fire to increase forage production and nutritive value while preventing shrub encroachment. Sustainability of extensively managed, low-input native rangelands is highly dependent on nutrient cycling through plant litter decomposition, which is often constrained by limited N availability. We evaluated the effect of prescribed fire (Unburned vs. Burned), N addition (0 vs. 180 kg N ha^–1 yr^–1), and species composition (Palmetto [Serenoa repens Bartr.] [100% saw-palmetto], Palmetto-Grass [50–50% mixture of saw-palmetto and grasses], and Grass [chalky bluestem, Andropogon capillipes Nash.; lopsided indiangrass, Sorghastrum secundum {Elliott} Nash]) on aboveground plant litter decomposition and N and P mineralization using field incubated litterbags over 224 d in a split-split plot design with three replicates. Litter disappearance followed a single exponential decay model (P ≤ 0.01) and was mainly driven by plant litter chemical characteristics. At the end of the 224-d incubation, remaining plant litter was less in Palmetto (62%) compared with other treatments (∼72%), possibly due to more favorable chemical characteristics associated with Palmetto treatment (43, 65, and 112 C:N ratio; and 15, 20, and 25 lignin:N ratio for Palmetto, Palmetto-Grass, and Grass, respectively). Remaining N was less (greater N mineralization) in Palmetto (79%) compared with Palmetto-Grass treatment (92%) but was not different from Grass (P ≥ 0.12, 86% remaining N). Greater lignin and proportion of N bound to fiber observed at the end of incubation suggested increased C and N recalcitrance as a result of decomposition. Nutrient inputs through ash or N addition suppressed litter net P and N mineralization. These results suggest litter quality, particularly N concentration and C:N and lignin:N ratios, are the main drivers in nutrient cycling through plant litter decomposition in Florida rangelands.

Mitigating invasive annual grass impacts is critical to halting native rangeland conversion to fire-prone, annual grass-dominated communities and maintaining the ecosystem services provided by perennial plants. The herbicide indaziflam (Rejuvra, Bayer, Leverkusen, Germany) may allow managers to selectively deplete annual grass seed banks in plant communities that continue to support desirable perennial vegetation, but nontarget impacts are difficult to assess in the small plots typically used in herbicide trials, and the potential for impacts to the seed bank is not well understood. To assess the potential for nontarget impacts resulting from indaziflam treatment, we used modified-Whittaker multiscale vegetation plots to compare diversity (species accumulation) in three treatment plots (73 g ai ha^–1 indaziflam) and three control plots in sagebrush-grasslands near Pinedale, Wyoming that are invaded by cheatgrass (Bromus tectorum L.). We also assessed the density and richness of shallow (0- to 1-cm depth) and deep (1- to 5-cm depth) germinable seed banks in treatment and control plots by tracking seedling emergence from seed bank samples during a 20-wk greenhouse study. Vegetation data and seed bank samples were collected during the third growing season after treatment. Treatment did not impact aboveground species diversity, but this contrasted with the results of the seed bank assay; shallow and deep native seed bank density and shallow native seed bank richness were significantly reduced in treatment plots. All impacted species were detected in the aboveground plant community in treatment plots after herbicide application, suggesting that reduced native annual abundance may be temporary. Considering the potential for nontarget impacts to seed banks will help land managers accurately assess trade-offs when making treatment decisions.

Effective fire and grazing management practices are crucial to the restoration of prairie ecosystems, but prairie restoration efforts have only recently included bison (Bison bison) reintroduction. Given the novelty of such efforts and the importance of grazing in ecosystem dynamics, questions remain regarding how human activity and habitat management affect bison habitat selection. We radiocollared seven female bison at an enclosed restored grassland site in northern Illinois during 2014–2016 and developed resource selection models to evaluate the influence of land cover, fire management, and concentrated human activity on habitat selection by bison. To help managers target areas for future activities, we used the most-supported model to map predicted bison use across the study area. Our results indicated that bison habitat selection was primarily driven by the type of restoration conducted at a location, with strong selection for partially restored prairie and avoidance of nongrassland areas. These results are likely due to the expected high relative abundance of perennial grasses at partially restored prairie sites in our study area. Our research emphasizes the relationship between restoration approaches and grazers in prairie ecosystems and underscores the importance of including restoration practices in habitat selection research. Additionally, the map of predicted bison use highlights areas to focus further management and conduct vegetation surveys to ensure grazing is resulting in increased plant diversity and species richness.

We used ranch records and soil analyses to investigate the effects of cattle ranching on phosphorus (P) and nitrogen (N) balances in a humid, tallgrass savanna ecosystem in Tanzania. Over a 41-yr period between 1958 and 1999, the ranch supported an average of 10 435 cattle. These consumed an estimated 571 586 tons (t) of dry matter containing 692 t P and 6 230 t N. Of these nutrients, 162 t of P (23%) and 602 t of N (9.7%) were exported in animals leaving the ranch, while 222 t (32 %) P and 2 364 t of N (38 %) were transferred as excreta to the night corrals. The measured excesses of nutrients in the soil of the corrals were equivalent to 59% of all P and 19% of all N deposited in these areas over 41 yr. Total losses from the pastures amounted to 10.2% of P and 6.6% of N in the top 20 cm of tall grass savanna soil. These losses, especially of P, probably reduced the nutritional quality of the pastures and may have contributed to the reported decline in animal fertility. In addition, they may have promoted the spread of secondary woodland dominated by Vachellia (formerly Acacia) zanzibarica. Three general conclusions can be drawn from this study. First, humid tallgrass savannas on nutrient-poor soils are unsuitable for intensive livestock production. Second, over an extended period the loss of nutrients from cattle pastures can be ecologically significant. Ensuring the sustainability of grazing systems requires measures to counteract this loss, such as the use of shifting night corrals. Third, ranch records, while lacking the precision and detail possible in experimental studies, can provide valuable insights into long-term effects of ranching that would be difficult to obtain by other means.

Several recent studies have hypothesized that postgermination/preemergence soil freezing can have a major negative impact on spring emergence of seeded perennial grasses in the Intermountain western United States. In this experiment, we measured germination and emergence of 4 fall-seeded perennial grasses at 15 sites in southeastern Oregon, north-central Nevada, and southwestern Idaho in 2 different yr. We used hydrothermal germination and seedbed microclimatic models to estimate planting date effects on germination and preemergence mortality and evaluated these simulations relative to measured germination and seedling emergence in the field. There were clear indications that both germination and emergence were responsive to site-year effects, but premature fall germination before winter freezing events was not a factor in emergence rates. In all cases, planting was sufficiently late in the fall to avoid significant postgermination/preemergence freezing injury for the sites and years tested. Emergence was weakly correlated to seedbed favorability in the late winter and spring after the principal period of soil freezing. Our data show that for the 2 yr of this study, we can only account for a relatively small portion of any abiotic effects on spring emergence. General inferences about planting date effects, however, may have been limited by arid conditions during the 2-yr field study relative to long-term climate normals.

Ranchers in the western United States have long managed working landscapes prone to drought and wildfires. As the frequency and intensity of climate change impacts increase, ranchers will be front-line workers in the climate crisis—both adapting to climate impacts and managing landscapes with mitigation potential. This Forum paper first summarizes recent peer-reviewed research on ranchers and climate change in the western United States and then offers conceptual clarification of climate change adaptation based on this empirical research. Many ranchers remain unconvinced by climate science and express skepticism about long-term and anthropogenic climate change, though this may change as climate extremes intensify. Researchers working with ranchers often avoid climate change terminology, instead focusing on impacts, especially drought. Ranchers adjust their land and livestock management practices, as well as livelihood strategies, to cope with weather variability. Ranchers identify increasing management flexibility and diversifying ranch income as key adaptation strategies. While studies often focus on how to transition ranchers from reactive and toward proactive adaptation planning, few ranchers are actively planning for climatic change. Yet in this ranching context, many practices that begin as reactive coping strategies become longer-term adaptations as the impact, such as drought or recurrent wildfire smoke, persists. As ranchers observe positive outcomes of short-term adaptations or are unable to return to previous strategies, reactive coping strategies become proactive. We provide a conceptual clarification of adaptation in ranching systems, forwarding adaptation as a process, inclusive of a continuum from coping actions to more transformative adaptation strategies. Centering ranchers' experiences, perceptions, and responses related to climate change can help land managers, agricultural advisors, and policy makers increase the pace and scale of adaptation and mitigation in range systems.

Rangelands are the dominant ecosystems in the Tibetan Plateau and the most critical livestock production resources. However, a large quantity of rangelands has degraded in North Tibet, with declined forage yield and invaded unpalatable weeds. Thus, identifying potential degradation is essential to manage rangelands sustainably in the future. In this study, we aimed to use an environmentally sensitive area index (ESAI) that integrated the conditions of vegetation, soil, climate, and management to assess rangeland degradation in North Tibet and identify the major drivers of degradation by the random forest model. The ESAI contained 16 indicators of the selected four categories, which were input by layers from geographic information system data. The results revealed that 33% of the study area was susceptive to rangeland degradation, in which alpine desert-steppes in the west, with the highest mean ESAI scores of 1.38, were the most sensitive areas. According to the degrees of degradation, only 9% of rangelands in the east had low mean values of ESAI (< 1.22), which were mostly located in the alpine meadow. The importance ranking for rangeland degradation based on the random forest model indicated that the highest importance was vegetation cover type, followed by grazing intensity and aridity with more than 60% mean decrease accuracy. Besides, field measurements showed that the adjusted correlation coefficient of multiple regression of four vegetation degradation indicators was 0.86, illustrating that the assessment as a proxy for rangeland degradation sensitivity is feasible. This study provides an important approach to evaluating potential rangeland degradation. Therefore, the assessment model is recommended for regional-level decision makers to manage rangeland degradation with full consideration of local physical conditions.

Usable space for northern bobwhite (Colinus virginianus) has been reduced across South Texas rangelands because of the spread of non-native, invasive grasses. A native grass, tanglehead (Heteropogon contortus), has also rapidly expanded its dominance in South Texas within the past 25 yr. It has formed high-density monocultures, similar to non-native grasses, which are associated with losses of herbaceous diversity and bare ground, both key components of bobwhite habitat. The objectives of our research were to 1) determine selection-avoidance of invasive grass cover by bobwhites and 2) determine effects of invasive grass cover on vegetation characteristics.

We hypothesized the effects of tanglehead on bobwhite would be negative and similar to the effect of non-native grasses in the region. We recorded covey locations via helicopter surveys in December 2014 and 2015, with field measurements of bobwhite habitat at covey and random locations taken each spring. We measured grass and forb species richness, herbaceous vegetation height, woody-plant cover, tanglehead canopy cover, and non-native grass canopy cover at all covey detections and an equal number of random locations. We developed continuous selection ratios using Simple Saddlepoint Approximations to determine habitat selection by bobwhites. We also used quantile regression, at the 10th, 50th, and 90th quantiles, to determine relationships between invasive grass cover and vegetation factors. Bobwhites avoided areas of high canopy cover (> 20%) of all invasive grasses measured. We found negative relationships between native and non-native invasive grass cover and forb and grass species richness, as well as bare ground, and a positive relationship with herbaceous vegetation height at all quantiles modeled. Our results demonstrate the negative effects of increased tanglehead cover on native rangeland habitats, which aligns with similar non-native invasive grasses. Further expansion by tanglehead has the potential to significantly reduce usable space for bobwhites in South Texas.

In semiarid regions of the western United States, there is heightened interest in tree removal to increase water availability for other uses such as forage growth and groundwater recharge. This study was conducted in central New Mexico to determine the effects of heavy infrequent defoliation of chemically thinned juniper woodland (Juniperus monosperma) on soil moisture. Each of three cattle-grazing exclosures (CD, FG, and KI) was instrumented: 1) beneath trees with a set of three soil moisture probes (0–25, 25–50, and 50–75 cm depth) and one soil temperature probe under live trees (control) and dead trees (herbicide-treated); and 2) between trees with one soil moisture and one soil temperature probe in control and herbicide-treated intercanopy plots. Each plot had three clipped and three unclipped subplots. Mean daily maximum surface soil temperature was highest (17.19°C) in intercanopy, intermediate (16.13°C) under herbicide-treated, and lowest (14.90°C) under control trees. Topsoil moisture (0–25 cm depth) was different among treatment combinations from late July to early September 2006. Thus, the control unclipped combination had the highest topsoil moisture while the herbicide-treated unclipped combination had the lowest topsoil moisture. Comparing other depths, control unclipped plots had higher soil moisture in the middle layer (25–50 cm) and bottom layer (50–75 cm) than at the top from late August to early November 2006. Results imply that clipping on chemically thinned juniper woodlands does not increase soil moisture at any depth, yet macropore flow and water absorption on deep soil layers, underneath live trees, might help to store soil moisture for longer periods in water-limited environments.

Past research has documented livestock grazing patterns and dynamics across pastoral landscapes. We used spatial locations of domestic range sheep (Ovis aries) obtained from Global Positioning System collars to study habitat selection on summer mountain habitat North of Scofield Reservoir Utah, United States. Data were collected between the months of July to September 2020. We developed a resource selection function to determine the influence of slope, distance to water, aspect, ruggedness, elevation, and vegetation types on habitat selection by sheep while grazing on summer mountain habitat. We found sheep selected for sites closer to water, with more gentle terrain, higher in elevation, and north-facing slopes. Vegetation types were less predictive, ostensibly due to the lack of species composition information in available geographic information system layers and the possibility of sheep being herded to avoid areas of overuse. Although it is often assumed that sheep use slopes more than their heavier and larger cattle counterparts, overall they tended to avoid steep slopes compared with all other predictor variables. This information on selection for higher elevations and avoidance of steep slopes can be used to improve livestock management practices including flock management that increases sheep foraging patterns and energy efficiency.

Kentucky bluegrass (Poa pratensis, POPR) is a dominant invader of the northern Great Plains, but little is known about its impact on seedbanks. We quantified patterns of seedling emergence from samples of litter, thatch, and mineral soil collected from invaded grassland sites, hypothesizing that POPR would be the dominant emergent species, but that composition of seedling populations would differ between the layers with a higher incidence of native species in mineral soil. POPR accounted for 84% of the emergent seedlings, and curves, fit with a Hill model, indicated that 50% of cumulative emergence was reached after 40.5 d. Rank-abundance diagrams were highly skewed and strongly dominated by POPR but indicated differences among litter, thatch, and soil layers. POPR accounted for 94.3%, 71.9%, and 69.9% of emergent seedlings from litter, thatch, and soil layers, respectively. More POPR seedlings emerged from litter material than the other layers. Management of POPR by fire or grazing should consider their possible effects on seed production, distribution, and longevity of buried seeds.