Arbuscular mycorrhizal fungi (AMF) are vital for maintaining ecosystem structure and functioning and can be affected by complex interactions between plants and herbivores. Information found in the literature about how ungulate grazing affects AMF is in general contradictory but might be caused by differences in grazing intensities (GIs) among studies. Hence we studied how different GIs affect the composition, diversity, and abundance of AMF communities in a semiarid steppe of Patagonia. We predicted that 1) total AMF spore abundance (TSA) and diversity would decrease only under intense-grazing levels and 2) AMF species spore abundance would depend on their life-history strategies and on the GI. To test our predictions, we compared AMF communities among nongrazed (NG), moderately grazed (MG, 0.1–0.3 sheep ha1), and intensely grazed sites (IG, > 0.3 sheep ha1). GI was the most important factor driving changes in TSA and diversity, regardless of host plant identity. TSA, diversity, and evenness significantly decreased in IG sites but were not affected by MG. AMF species spore abundance varied depending on their life-history strategies and GI. Families with high growth rates like Glomeraceae and probably Pacisporaceae showed the highest spore abundance in all sites but decreased under IG. Species with higher carbon demands like Gigasporaceae showed low spore abundance and frequency in NG and MG sites and were absent in IG sites. In contrast, species with low growth rates, but efficient carbon usage, like Acaulosporaceae, showed low spore abundance in all sites but increased in IG sites compared with NG or MG sites. We conclude that intensification of grazing reduces AMF diversity and abundance, with the likely loss of AMF benefits for plants, such as improved nutrient and water uptake and soil aggregation. Therefore, sustainable grazing systems should be designed to improve or restore AMF communities, particularly in degraded rangelands, like the Patagonian steppes. © 2019 Elsevier Inc.

Restoring arid regions degraded by invasive annual grasses to native perennial grasses is a critical conservation goal. Targeting site availability, species availability, and species performance is a key strategy for reducing invasive annual grass cover while simultaneously increasing the abundance of seeded native perennial grasses. However, the potential for establishing successful seedings is still highly variable in rangeland ecosystems, likely because of variable year-to-year weather. In this study, we evaluated the independent and combined inputs of tilling, burning, applying imazapic herbicide, and varying seeding rates on existing species and seeded native perennial grass performance from 2008 to 2012 in a southwestern Idaho rangeland ecosystem. We found that combining tilling, fire, and herbicides produced the lowest annual grass cover. The combination of fire and herbicides yielded the highest seeded species density in the hydrologic year (HY) (October − September) 2010, especially at higher than minimum recommended seeding rates. Although the independent and combined effects of fire and herbicides directly affected the growth of resident species, they failed to affect seeded species cover except in HY 2010, when weather was favorable for seedling growth. Specifically, low winter temperature variability (few freeze-thaw cycles) followed by high growing season precipitation in HY 2010 yielded 14 × more seeded perennial grasses than any other seeding year, even though total annual precipitation amounts did not greatly vary between 2009 and 2012. Collectively, these findings suggest that tilling, applying prescribed fire, and herbicides before seeding at least 5 × the minimum recommended seeding rate should directly reduce resident annual grass abundance and likely yield high densities of seeded species in annual grass − dominated ecosystems, but only during years of stable winter conditions followed by wet springs. © 2018

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. © 2019 The Society for Range Management

Shinnery oak (Quercus havardii) is a native clonal shrub that contributes to an imperiled biotic community in the southern Great Plains of North America. Nevertheless, there is little information on shinnery oak ecology and this lack of information hinders potential restoration of shinnery oak in areas where it has been eliminated. We provide findings from a study conducted to assess emergence and seedling survival from acorns collected in western Oklahoma in 2016. We observed that cold stratification treatments (i.e., acorns stored at 2°C for 2 weeks) and greater acorn size resulted in higher emergence. Although we found no effect of acorn size on seedling survival, we observed that shade reduced seedling survival (P < 0.005). Our study provides previously unknown information on several fundamental aspects of shinnery oak ecology and offers a baseline for restoration efforts by documenting successful shinnery oak emergence and factors associated with seedling survival. © 2019 The Society for Range Management

Rangeland dung beetles represent an important assemblage of insects for the Great Plains. In this study, we examine the effects of a postfire rangeland environment on a dung beetle assemblage in north-central Texas. We deployed baited pitfall traps to examine spring prescribed fire treatment, differences in vegetation visual obstruction, and dung density influence on dung beetle abundance and community composition. Using model-based multivariate methods, we did not find an influence of prescribed burning on the dung beetle assemblage. We report a negative influence of vegetation visual obstruction and no significant influence of dung density on dung beetle assemblages. These results suggest that prescribed fire may not negatively affect dung beetle species within the North American Great Plains; however, vegetation structure correlated to postfire rangeland environments may influence local beetle abundance. © 2018 Elsevier Inc.

Black-tailed prairie dogs (Cynomys ludovicianus) have high dietary overlap with livestock, which can cause forage-centric conflicts between agriculture and conservation. Research suggests prairie dogs can enhance forage quality, but trade-offs between quality and quantity throughout the growing season remain unclear, as well as the degree to which increased forage quality is caused by altered species composition versus altered plant physiology. To assess the effects of prairie dog herbivory on forage in a northern mixed-grass prairie, we collected samples on prairie dog colonies and at sites without prairie dogs during June, July, and August 2016 - 2017 for forage quality, and August 2015 - 2017 for herbaceous biomass. To isolate mechanisms affecting forage quality, we collected both composite samples of all herbaceous species and samples of western wheatgrass (Pascopyrum smithii [Rydb.] Á. Löve). Across years and plant sample types, crude protein, phosphorus, and fat were 12-44% greater and neutral detergent fiber was 6-10% lower on prairie dog colonies than at sites without prairie dogs. The effects of prairie dogs on forage quality persisted throughout the season for western wheatgrass samples (all treatment*time p-values ≥ 0.4). Across years, aboveground herbaceous biomass did not differ significantly between prairie dog colonies and sites without prairie dogs (on-colony: 933 ± 156 kg/ha, off-colony: 982 ± 117 kg/ha). The effects of prairie dogs on herbaceous biomass were significantly influenced by spring precipitation. In years with dry springs, herbaceous biomass was lower on colonies than sites without prairie dogs and this pattern was reversed in years with wet springs. Our results demonstrate season-long enhanced forage quality on prairie dog colonies, indicating that multiple mechanisms are shaping forage quality in this system, including altered species composition, phenological growth stage, and soil condition. Across years, enhanced forage quality may help to offset reductions in forage quantity for agricultural producers. © 2018 The Society for Range Management

The composition of the greenline plant community is linked to the stability of riparian ecosystems. Cool season exotic grasses are invading native plant communities across the northern Great Plains, potentially compromising streambank stability and increasing the risk of erosion within riparian ecosystems. To determine how the species composition of the greenline community impacts stream type and the risk of streambank erosion, thirty five reaches across five watersheds were sampled to determine the dominant greenline vegetation. At each reach, a cross-section was sampled to determine stream type, greenline vegetation, and risk of streambank erosion. Channel types were delineated using Rosgen's classification of natural rivers. Canopy cover and composition was assessed using the line point intercept method along a 30.5 m transect in the greenline community. Plants recorded were grouped by their wetland indicator status for the central Great Plains. The Bank Erosion Hazard Index (BEHI) was used to assess the streams risk of erosion by calculating the difference between the bank height and bank full height, average plant rooting depth and density, bank angle degree, and the dominant texture of the bank material. Bank height ratio (BHR) was assessed as a measure of streambank stability and floodplain connectivity. A Nonmetric Multidimensional Scaling ordination was performed to analyze plant community influences. Analysis of the data determined that the most stable stream types (E and C channels), lower BEHI scores, and stable bank height ratios were associated with high amounts of litter and facultative wet species. In comparison, unstable F channels were associated with early successional species and bare ground. Sites with the higher BEHI scores were associated with greenlines comprised of upland and facultative upland and saline tolerant species. Late successional facultative wetland species were found to provide the most protection to intermittent streambanks. © 2018 The Society for Range Management

Native colonial and large ungulate herbivores infrequently coexist on contemporary landscapes but frequently would have in the past, and understanding these interactions is important for conservation in working landscapes—those lands managed for biological and economic objectives. Although many factors contribute to grassland bird declines, consistent and long-term removal of native herbivores from western grasslands promotes homogenous landscapes that are now uniformly grazed by cattle (Bos taurus). This shift in grassland disturbance patterns limits habitat availability for specialized grassland species. We investigated vegetation and bird community dynamics in pastures grazed by domestic cattle and a native colonial herbivore, the black-tailed prairie dog (Cynomys ludovicianus). The study occurred in the northern mixed-grass prairie of the United States on four experimental pastures stratified by the proportion of prairie dog occupancy to create an ecological gradient. Vegetation and bird surveys were conducted from 2012 to 2015 on and off prairie dog colonies. Vegetation and bird communities were not different along the experimental pasture gradient but did differ relative to location on versus off town. Prairie dogs induced changes in the plant community with midstatured grasses like side-oats grama (Bouteloua curtipendula) and green needlegrass (Nassella viridula) being associated with off-colony sites while on-colony sites were associated with disturbance-tolerant species such as fetid marigold (Dyssodia papposa). The bird community responded to changes in vegetation structure resulting from prairie dogs with grasshopper sparrows (Ammodramus savannarum) being more abundant off colonies in areas with greater vegetation structure, while bird species with more complex life histories, such as the upland sandpiper (Bartramia longicauda), were associated with both on − and off − prairie dog colonies. Our findings demonstrate the importance of maintaining spatial heterogeneity in working landscapes and show that native colonial herbivores can help achieve this in the presence of herbivory by domestic cattle. © 2018 The Society for Range Management

Despite the fact that the northern bobwhite (Colinus virginianus Linnaeus; hereafter, bobwhite) is one of the most well-studied and widely distributed wildlife species in North America, we know little about how bobwhite respond to oil and gas infrastructure. We investigated the impacts of oil and gas development on space use of bobwhite using a multiseason approach. We captured and monitored bobwhite in the breeding season (1 April–30 September, n = 135 individuals) and nonbreeding season (1 October–31 March, n = 30 coveys) and modeled their habitat selection in a resource-utilization function (third order, within home range selection) and resource-selection function (second order, home range selection) format. Generally, energy infrastructure effects on bobwhite were neutral, but breeding season bobwhite did select for areas near low-traffic roads (β = − 0.31 ± 0.15 SE). In the nonbreeding season, coveys selected for areas within their home range with a limited viewshed (i.e., areas with limited visibility of anthropogenic structures; β = − 0.03 ± 0.02 SE). Selection differed between sexes for well pads (t = − 2.12, P = 0.04) but was otherwise similar. At the level of home range selection, bobwhite exhibited a preference for areas with a low density of oil and gas wells and a high density of low-traffic roads during both the breeding and nonbreeding seasons (breeding: βwell = − 0.14 ± 0.02, βroad = 0.26 ± 0.27; nonbreeding: βwell = − 0.08 ± 0.03, βroad = 0.16 ± 0.03). As a generalist species, bobwhite appear to be largely tolerant of energy infrastructure and associated disturbances at moderate levels of development but may be sensitive to high densities of oil and gas pads. © 2018 The Society for Range Management

Current methods for determining plant age of shrub species require destructive sampling and annual growth ring analysis on the primary stem. Although individual plant ages can frequently be determined in this manner, the method is time consuming and of limited value for plants that have lost stem wood from stem splitting and rot. Nondestructive methods for estimating big sagebrush (Artemisia tridentata Nutt.) plant age would be useful in assessing stand age structure and population dynamics at variable spatial scales. The purpose of this study was to test a suite of traits for potential use in estimating mountain big sagebrush (Artemisia tridentata ssp. vaseyana [Rydb.] Beetle) age. We evaluated traits including plant height, crown area, subcanopy litter depth, percent crown mortality, bark furrow depth, bark fiber length, circumference and diameter of plant basal stem, and circumference of secondary and tertiary branches. We measured and harvested basal cross-sections from 163 plants of varying sizes from five locations in central and south-central Utah. Plant age was determined from annual growth rings. Linear regression analyses revealed that stem diameter (r2 = 0.507 P < 0.0001) was the most highly correlated variable with plant age across all sites, followed by stem circumference (r2 = 0.474 P < 0.0001), secondary branch circumference (r2 = 0.360, P < 0.0001), tertiary branch circumference (r2 = 0.405, P < 0.0001), and bark fiber length (r2 = 0.373, P < 0.0001). Results support previous findings that stem girth has value for estimating mountain big sagebrush plant age and that this trait is a better indicator of age than any other tested traits. Although the relationship between stem diameter and plant age was significant, substantial stem size variability associated with plants of the same approximate age indicates that the method is most appropriate when precise age estimates are not required. This technique was developed specifically for mountain big sagebrush, but it is expected that it can be adapted for other sagebrush taxa. © 2019 The Society for Range Management