Land managers need consistent terminology and classification frameworks to discuss the ecological status of the land. A common framework used in upland terrestrial systems is an ecological site description (ESD), in which systems are categorized by soils, vegetation, and topography. Creating ESDs in riparian areas must follow a different framework than upland systems because function of riparian systems is driven by hydrology. This study categorized riparian areas by hydrology using stream geomorphology and the Rosgen Stream Classification System. Stream cross sectional and longitudinal profile data were collected from 75 reaches from 19 streams in North Dakota from 2012 to 2018. Each reach (i.e., one full meander) was classified by channel type (E, C, B, F, and G), and stability class (stable and unstable). A stream parameter matrix was constructed using entrenchment ratio, width-to-depth ratio, sinuosity, slope, channel bed material, bank height ratio, and meander width ratio. A multiple response permutation procedure showed that the parameters differed on the basis of both channel type and stability class. An indicator analysis showed that entrenchment ratio, bank height ratio, and meander width ratio were the parameters most influential in separating the reaches by stability class. The strongest indicator stable reach was entrenchment ratio, but meander width ratio and bank height ratio were also significant indicators of stable and unstable reaches, respectively. The parameters used in this study to delineate channel type can be used to consistently discriminate between stable and unstable channels. This information may be a useful tool in describing the states and transitions of prairie stream development in riparian complex ESDs, validating the continued use of Rosgen Stream Classification System in ESD development.

Soil seed banks are a key component of ecological resilience as they provide a temporal reserve for plant species richness and diversity. Soil seed banks depend on on-site reproduction, seed longevity, and seed immigration for maintenance. When immigration of seeds is lost due to a change in land use or a disturbance, such as fragmentation, seed banks rely on on-site reproduction and longevity for maintenance. Within a fragment without seed immigration, seed banks become vulnerable to extinction debt leading to community disassembly over a long time scale. Therefore, we investigated how long-term fragmentation impacts community disassembly in seed banks. Seed bank samples were taken from grassland fragments (sod tables, n = 28) and from the surrounding area (matrix, n = 28). Seed banks were germinated, and emerging plants were identified. We found that community disassembly was not predictable in regard to species identity, and specialist (P < 0.001) and perennial (P < 0.001) species were lost from fragments. However, seed banks in fragments maintained a similar grass-to-forb ratio compared with the surrounding vegetation. Therefore, the ability of seed banks to provide ecological resilience may be limited after long-term fragmentation and land managers may need to reseed specialist species and perennials into grassland fragments.

More attention has been paid to the effects of diversity and dominance on community temporal stability rather than spatial stability in the main biome globally. Moreover, the maintenance mechanisms underlying the stability patterns of plant communities dominated by different plants in the Gobi Desert remain unknown. This article addresses the maintenance mechanism of plant community stability dominated by different plants in the Gobi Desert northwest of China. Four communities dominated by Sympegma regelii, Reaumuria songarica, Nitraria sphaerocarpa, and Gymnocarpos przewalskii, respectively, were selected in the national nature reserve, and a total of 240 quadrats, 20 × 20 m each, were established in the four communities. The correlations among species richness, species evenness, species diversity, community stability, and the biomass of dominant species were analyzed by linear regression model and structural equation model. The dominant species determined positively and directly the stability of the N. sphaerocarpa community, while diversity acted negatively in the maintenance of G. przewalskii community stability. However, species richness contributed mainly and positively to the maintenance of stability in the S. regelii community. Direct and negative effect of species richness and positive function of diversity were found in the maintenance of stability in the R. songarica community. Taken together, community stability is maintained by the divergent mechanisms in arid environment, which depends on the dominant species and diversity. The study could provide reference for the management of communities in the arid desert regions.

Understanding how energy infrastructure affects local biodiversity and soil characteristics is important for informing restoration and management. However, the rapid rate of modern oil and gas development is beyond the limit of current knowledge and mitigation strategies. In a mixed-grass prairie in western Oklahoma, we assessed the presence and directionality of biodiversity and environmental gradients associated with energy development in an observational framework. Specifically, we sampled arthropods, vegetation, soil temperature, and soil moisture on the edge of active oil well pads and at 1 m, 10 m, and 100 m away from the well pad. Though variable, the abundance and biomass of most arthropod orders was lower on the pad and 1 m away compared with 10 m and 100 m away, suggesting that the pad itself negatively influenced arthropods but that these effects were limited in spatial extent. However, vegetation structure and composition varied more extensively. Vegetation height, shrub cover, and warm season grass cover increased sixfold, threefold, and fourfold, respectively, from on the oil pad to 100 m away. Forb cover was 5× higher at 10 m from the well pad than on the pad, 1 m away, and 100 m away from the pad. Soil surface temperature was lower at sites farther from well pads, but we found no relationship between soil moisture and distance from well pad. Well pad effects on arthropods and soil temperature appear to be limited to the pad itself, though long-term changes in vegetation structure extend significantly beyond the well footprint and demand a better understanding of the effectiveness of restoration activities around well pads.

Pinyon-juniper ecosystems occur extensively across western North America, and at the landscape scale, variation in structure and composition is influenced by topographic position, soils, disturbance history, and local climate. The persistent pinyon-juniper woodland is a common structural form, and though they are known to be infrequent-fire systems, there is increasing interest in implementation of hazardous fuels reduction treatments in woodlands, especially in the wildland-urban interface. Few studies have quantified stand dynamics following fuels reduction treatments in persistent woodlands or compared treatment outcomes to conditions that develop under natural disturbance and successional processes. In 2004, we established a randomized, replicated study in woodlands of northern Arizona, and monitored stand dynamics and understory responses to determine how stand-level changes differed between common fuels reduction approaches. We compared the resulting structure with a conceptual state-and-transition model. Results showed that, over the 11 yr after treatment, juniper tree densities decreased by 8.4% and 0.9% but increased by 14.0% and 27.3% in Control, Burn, Thin, and Thin + Burn treatments, respectively. Pinyon tree densities decreased by 1.1% and 3.3%, increased by 12.2%, and decreased 7.9% in Control, Burn, Thin, and Thin + Burn treatments, respectively. All treatments showed fuel load reductions throughout the 11-yr study period and minimal rebound of tree recruitment toward pretreatment conditions. Prescribed fire alone (Burn) maintained persistent woodland conditions. Thinning treatments substantially reduced small tree densities and, with the addition of prescribed fire, produced losses of large trees. Thinning with prescribed fire (Thin + Burn) tended to produce conditions qualitatively unlike those described by our state-and-transition model. Evaluation of these commonly used fuels treatments against our state-and-transition model suggested that concerns regarding loss of ecological integrity may be warranted.

The many species of larkspur (Delphinium spp. L.) are among the most dangerous poisonous plants on rangelands in the western United States, causing death losses estimated at 2 – 5% (up to 15%) per year for cattle grazing in larkspur habitat. Other effects, such as altered grazing management practices and consequent lost forage quantity and quality, are significant but poorly understood. Current best management practice recommendations are based on seasonal avoidance, with little evidence that this is practical or effective. Our ongoing research has presented evidence that instead it may be possible to manage grazing such that all cattle eat some larkspur, but none eat a fatal dose. This raises the question of the potential response of larkspur to being grazed. In this study we examine the response of Geyer's larkspur (D. geyeri Greene) to two seasons of 25% or 75% aboveground plant mass removal. The 75% treatment led to significantly lower alkaloid concentrations (mg • g^{– 1}) and pools (mg per plant), while the 25% treatment had a lesser effect. Combined with lessons from previous studies, this indicates that Geyer's larkspur plants subject to aboveground mass removal such as may occur via grazing can be expected to become significantly less dangerous to cattle. We suggest that the mechanisms for this reduction are both alkaloid removal and reduced belowground root mass, as significant evidence indicates that alkaloids are synthesized and stored in the roots. These results continue to build support for our theory that the solution to the seemingly intractable challenge of larkspur poisoning lies not in avoidance but in the skill of managers and the wisdom of herds.

Protected-area sagebrush steppe ecosystems are few in number and increasingly important to the North American conservation network as sagebrush steppe faces growing threats from land use, climate change, and invasive species. We analyzed the distribution and abundance of native perennial and invasive annual plants to better understand patterns of plant invasion within two protected areas: John Day Fossil Beds National Monument (JODA), located in central Oregon, and Craters of the Moon National Monument and Preserve (CRMO), located in southeast Idaho. We used multivariate analysis to examine vegetation monitoring datasets and illuminate geographic variation in plant cover along gradients of well-known aspects of resistance to plant invasion (elevation, exposure [slope and aspect], precipitation and proximity to disturbance). Topographically mediated resistance to invasion appeared to manifest in the park with greater topographic variability (JODA), while increased elevation was more strongly associated with resistant sites in the park, which spanned a greater elevational gradient (CRMO). Factors that may mitigate moisture-mediated resistance also differed between sites. Slope and aspect were factors of apparent resistance for bunchgrass communities in JODA, while high crop year precipitation appeared to benefit medusahead (Taeniatherum caput-medusae [L.] Nevski) and the weedy native subshrub broom snakeweed (Gutierrezia sarothrae [Pursh] Britton & Rusby) over bunchgrasses and Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young). Increased elevation and distance to disturbed areas were the most important factors of resistance in forb-rich communities at CRMO, with the invasive annuals cheatgrass (Bromus tectorum L.), tumblemustard (Sisymbrium altissimum L.), and Descurainia spp. Webb & Bethel. invading in low elevations and in close proximity to roads or agricultural fields. Such complexity underscores the idiosyncratic nature of the manifestation of resistance and the need for place-based empirical studies to provide information for guiding protected-area management.

Invasion of exotic annual grasses (EAG) and increased wildfire have led to an emphasis on managing rangeland plant communities for resistance to invasion and resilience to disturbances. In sagebrush steppe and similar rangelands, perennial bunchgrasses and particularly their roots are hypothesized to be primary contributors to resistance and resilience. We asked how bunchgrass root abundance relates to annual grass invasion and aboveground indicators of bunchgrass vigor that are more readily measured, such as plant height. We used a standardized US Department of Agriculture protocol for root measurement in 445 excavations made in 2016 – 2018 across a topographically and ecologically varied region of sagebrush steppe burned in the 2015 Soda fire in the Northern Great Basin, United States. Nearly all (99%) bunchgrasses, including seedlings, had deeper roots than the surrounding annual grasses (mean depth of annuals = 6.8 ± 3.3 cm), and 88% of seedlings remained rooted in response to the “tug test” (uprooting resistance to ∼ 1 kg of upward pull on shoot), with smaller plants (mean height and basal diameters < 20 cm and < 2 cm, respectively) more likely to fail the test regardless of their root abundance. Lateral roots of bunchgrasses were scarcer in larger basal gaps (interspace between perennials) but were surprisingly not directly related to cover of surrounding EAG. However, EAG cover increased with the size of basal gaps and decreased with greater basal diameter of bunchgrass (in addition to prefire EAG abundance), albeit with a low r². These results provide some support for 1) the importance of basal gaps and bunchgrass diameters as indicators of both vulnerability to annual grass invasion and bunchgrass root abundance and 2) the need for more detailed methods for root measurement than used here in order to substantiate their usefulness in understanding rangeland resistance and resilience.

Treatments in big sagebrush (Artemisia tridentata Nutt.) are often implemented to improve habitat conditions for species such as greater sage-grouse (Centrocercus urophasianus). These treatments aim to increase the availability of forbs and invertebrates critical to juvenile and adult sage-grouse during the breeding season. However, information regarding the response of forbs in treated sagebrush are often conflicting, dependent on the type of sagebrush community treated and time after treatment. In addition, there is little information on the response of invertebrates to treatments, particularly herbicide treatments in Wyoming big sagebrush (A.t. ssp. wyomingensis Beetle & Young) communities. We evaluated the response of forbs and invertebrates in Wyoming big sagebrush that had been mowed or aerially treated with tebuthiuron compared with untreated reference areas. We also compared forb and invertebrate dry matter (DM) between treated plots and locations used by brood-rearing females. Forb and invertebrate DM in mowed and tebuthiuron treatments did not differ from untreated plots up to 4 yr after treatment and were equal to or less than locations used by brood-rearing grouse up to 2 yr after treatment. Our findings corroborate best available science that suggest treating Wyoming big sagebrush may not increase food availability for sage-grouse.

The Northern bobwhite quail (Colinus virginianus) is an important gamebird among hunters that has been experiencing a nationwide decline for > 50 yr. In West Texas, one of the last regions to experience this downward trend, research on bobwhite populations has focused on habitat variables and, increasingly, on parasitic infection. In bobwhite, two of the most common parasites are the caecal worm (Aulonocephalus pennula) and eyeworm (Oxyspirura petrowi). To better document the state of bobwhite populations in the Rolling Plains Ecoregion, trapping, summer rooster counts, fall covey counts, and parasitic infection assessments were conducted in three counties during 2018. These efforts were compared with previous years for a longitudinal perspective. In 2018, bobwhite populations experienced a widespread decline, although some counties surveyed fared slightly better than others. More effort was required to trap fewer total bobwhite, and fewer roosters and coveys were counted than in previous years. In addition, in 2018, parasitic infection levels of caecal and eyeworms were higher than or similar to levels in previous years. Additional research is necessary to understand which factors influence bobwhite populations in allopatric locations and over time.

The Common Agricultural Policy supports the use of free-ranging cattle herds to control woody encroachment and fire hazards in Europe. There is, however, little empirical evidence about the effectiveness of extensive grazing to preserve open landscapes in the Mediterranean Basin. In this work, we evaluated the effects of extensive beef cattle grazing on the vegetation structure in a Mediterranean ecosystem using a twofold framework: 1) analyzing temporal changes in the forest, shrub, and grassland cover in areas under different grazing pressures for 16 yr (1993–2009) and 2) studying diet selection to assess the impact of cattle on the local Mediterranean vegetation. Our landscape structure analyses revealed a remarkable change in land cover over the study period. However, woody community dynamics seemed to be more related to natural vegetation succession than to cattle effects. Extensive grazing seemed to preserve grasslands but only at high stocking rates. On the other hand, the diet analyses supported the lack of a role for cattle in encroachment control. Beef cattle diets were based on herbaceous plants (59%) with lower contribution of woody ones (41%). Cattle only showed a significant preference (P < 0.05) for few woody species (Erica multiflora, Olea europaea, Quercus ilex, and Rosmarinus officinalis), mostly at high-density stocking rates. Hence, our results support the idea that extensive cattle grazing alone exerts a negligible effect on shrub encroachment and thus on the risk of fire in the studied Mediterranean area. We urge a redesign of current research to truly integrate extensive cattle grazing as High Nature Value farming in European policies to successfully meet its putative goals, such as shrub encroachment control and wildfire risk prevention.

Variability in aboveground herbaceous biomass and its quality were studied in response to three different stocking densities during a 2-yr grazing experiment with sheep on a montane summer pasture in the Chinese Altay. We determined herbaceous cover and aboveground biomass in 16 paddocks of 0.25 ha each. Vegetation cover showed high spatial variation, prompting us to implement a randomized block design. Forage intake of one male sheep per paddock was quantified four times per grazing season by collection of total feces and estimation of diet digestibility. Sheep weight was recorded every 3 wk. Aboveground herbaceous dry mass (DM) was characterized by pronounced annual variation. Biomass quality declined with progressing season and increasing sheep density. Daily organic matter intake per sheep ranged from 0.7 to 1.4 kg, which was paralleled by a biomass removal of 710–1 560 kg DM/ha at densities of 8–24 sheep/ha. At 8 sheep/ha, animals gained weight throughout each grazing period, whereas weight losses of 40–100 g/d occurred at higher densities. These results challenge the presently followed concept of a fixed stocking density for summer pastures in Altay Prefecture, Xinjian, China. Such practice may result in low herbage allowances and thus deficient sheep nutrition in one year, as well as underutilization of forage resources in another. Flexible adjustment of stocking densities is also advisable for montane pastures where spatiotemporal variability, although less pronounced than in desert steppes of the Altay foothills, is nonetheless highly relevant.

We used an Atlantic grassland system on the Iberian Peninsula to ascertain whether monthly climate variability explains variation in monthly aboveground net primary production (ANPP) and to test whether climate-ANPP relationships depend on grazing regime. In 2005, large herbivores (beef cattle, dairy sheep, and horses) were excluded through fencing three 2 500-m² plots, each located in a different location; adjacent grazed plots of equal size were established. ANPP was measured monthly during the next three growing periods (2006–2008), and locally measured climate data were obtained from a public database. Because between-site variation in annual ANPP was not significant, we used data averaged across sites to test for the effect of monthly climate variability on monthly ANPP by means of dynamic regression. Enhanced ANPP was found after grazing abandonment, probably due to the sudden dominance of productive graminoids. Variation in monthly rainfall did not contribute to explain monthly ANPP under grazing or grazing exclusion. Simultaneous mean monthly air temperature explained monthly ANPP under grazing. By contrast, the effect of temperature on ANPP under grazing exclusion was delayed by 1 mo. We suggest that this delay can be explained by the development of a thick organic layer (litter) that insulated the soil in the grazing exclusion plots. However, changes in floristic composition and, consequently, in phenology might also have contributed to the differential response.

A large statewide historical database involving livestock numbers, vegetation cover, precipitation, air temperature, and drought frequency and severity allowed us to explore relationships between climate and rangeland livestock grazing levels and livestock productivity from 1920 to 2017. Trends in vegetation cover and livestock grazing levels from 1984 to 2017 were also explored. Our climate time series was divided into two periods, 1920–1975 and 1976–2017, based on an apparent accelerated increase in mean annual air temperatures that began in the mid-1970s. Both mean annual precipitation (MAP) and mean annual air temperature (MAT) differed (P ≤ 0.05) between the two periods. MAP and MAT were 9.6% and 3.4% higher in period 2 compared with period 1, respectively. From the 1920s to 2010s the livestock grazing level and weaned calf numbers fell 30% and 40%, respectively, despite a significant increase in MAP. Long-term declines in livestock grazing levels and in weaned calf numbers were significantly (P ≤ 0.05) correlated with increasing MAT (r = –0.34 and r = –0.43, respectively). No long-term trends (1984–2017) in woody or perennial herbaceous cover were detected at the level of the entire state of New Mexico. Woody plant cover dynamics for New Mexico were not related to livestock grazing levels. However, at the county level we detected a 2% increase in woody plant cover coupled with a 9% decrease in cattle animal units between 2000 and 2002 and 2015 and 2017 for 19 select counties well distributed across New Mexico. Increases in woody plant cover varied greatly among counties and were higher for eastern than western New Mexico. Both global and New Mexico data show the climate warming trend is accelerating. Our findings have relevance to several other parts of the world because New Mexico occurs at midlatitude, has varied topography and climatic conditions, and several different range vegetation types.

Rangeland ecosystems and their roles in providing ecosystem services are vulnerable to changes in climate, CO₂ concentration, and management. These drivers forcing widespread changes in rangeland ecosystem processes and vegetation dynamics create two-way interactions and feedback loops between biogeochemistry and vegetation composition. To support spatial simulation and forecasting in the global rangelands, the G-Range global rangelands model couples biogeochemical submodels from the CENTURY soil organic matter model with dynamic populations' submodels for herbs, shrubs, and trees. Here is presented a model description for G-Range, including novel elements of G-Range and implementation of CENTURY code. An initial evaluation of G-Range at global and site scales follows. G-Range outputs for net primary productivity (NPP) and vegetation cover (herbs, shrubs, trees, bare ground) were evaluated against global MODIS layers at global and site scales, and aboveground and belowground NPP were compared with field data from globally distributed sites. Most model outputs evaluated were within the range of a priori benchmarks for tolerable absolute or relative error (two benchmarks per output, at two scales, for five outputs of NPP and vegetation cover). Trade-offs in model fit among variables, datasets, and scales indicated practical constraints on improving model fit with respect to the selected evaluation datasets, especially field NPP versus MODIS NPP. The relative effects of multiple drivers of rangeland vegetation change were the greatest sources of uncertainty in model outputs. G-Range is best suited to scenario analysis of large-scale and long-term impacts of climate, CO₂, and management on rangeland ecosystem processes and vegetation, as well as ecosystem services, such as production of forage and browse and carbon sequestration.

Rangelands comprise a large component of the terrestrial land surface and provide critical ecosystem services, but they are degrading rapidly. Long-term rangeland monitoring with detailed, nonsubjective, quantitative observations can be expensive and difficult to maintain over time. Unmanned aerial vehicles (UAVs) provide an alternative means to gather unbiased and consistent datasets with similar details to field-based monitoring data. Comparing summer 2017 UAV images with long-term plot measurements, we demonstrate that rangeland vegetation cover changes can be accurately quantified and estimate an increase in total absolute shrub/subshrub cover from 34% in 1935 to > 80% in 2017 in central Arizona. We recommend UAV image-based rangeland monitoring for land managers interested in a few specific and dominant species, such as the foundation species, indicator species, or invasive species that require targeted monitoring. Land managers can identify and continuously monitor trends in rangeland condition, health, and degradation related to specific land use policies and management strategies.