• A survey-based assessment of cattle producers' adaptation to climate change in British Columbia, Canada

      Cox, M.; Gardner, W. C.; Fraser, L. H. (Society for Range Management, 2015-03)
      A quantitative analysis of the British Columbia, Canada cattle ranching community in light of global climate change provides insight as to how stakeholder needs and observations can be included in future planning. More than 63% of the 239 survey respondents believe that human activities are increasing the rate at which global climate changes occur, and 60% of 231 respondents adapted their management because of climate change. Cattle ranchers operating for less than 20 years were more likely to agree that human activities are increasing the rate of global climate change compared with those operating more than 40 years. This may reflect the fact that the concept of climate change has gained more public acceptance in the past 2 decades and would likely be perceived as a legitimate risk to an operation by those in this category in comparison with those who have been operating for a long period of time and tend to rely on experiential or embedded knowledge. Regional analysis showed that the most northerly region is more likely to have noticed change in climate compared with one of the most southern regions. With respect to operation of scale in terms of head of cattle, those ranches with more than 50 head of cattle identified water availability as a significant challenge to operations. Family succession planning was identified as a greater challenge for those operating their ranch for more than 40 years, compared with those operating less than 20 years. Adaptation to climate change included accessing available forage and providing a water source for cattle. Experiential and scientific knowledge will be crucial to future planning to reduce the vulnerability of the ranching industry and building adaptive capacity. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • A Temporal Analysis of Elephant-Induced Thicket Degradation in Addo Elephant National Park, Eastern Cape, South Africa

      Kakembo, V.; Smith, J.; Kerley, G. (Society for Range Management, 2015-11)
      Elephant-induced thicket degradation in the Addo Elephant National Park (AENP), Eastern Cape, South Africa, was assessed during 1973 and 2010 using multitemporal satellite imagery. Changes in the thicket condition, in relation to the AENP expansion, were analyzed using the Normalized Difference Vegetation Index, postclassification, and landscape metrics. The change detection of land-cover classes was analyzed by postclassification. Landscape-spatial metrics were used in order to gain an understanding of vegetation-fragmentation trends. Temporal changes in vegetation gradients in relation to water points and thicket conditions within the botanical reserves were also assessed. The thicket condition was noted to have deteriorated, as the AENP had expanded. An expansion of degraded vegetation away from the water points was identified during the study period. The thicket condition in botanical reserve 1 had fluctuated, whereas it remained constant in reserves 2 and 3. Landscape spatial-metric analyses revealed evidence of increased vegetation fragmentation, as new areas of the AENP had been opened for elephant activity. A progressive decline in intact thicket and an increase in degraded thicket were observed. Remote-sensing techniques can assist with thicket-clump restoration by applying "target monitoring" for the timeous identification of potential-degradation hotspots. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Aboveground vegetation and perennial grass seed bank in arid rangelands disturbed by grazing

      Bertiller, M. B.; Carrera, A. L. (Society for Range Management, 2015-01)
      Recruitment by seeds can be an important mechanism for recovery of plant communities following disturbance. Our objective was to assess the density and spatial patterning of perennial grass (highly preferred by herbivores) seeds in litter patches at locations with different aboveground vegetation structure in sites with different grazing history characteristic of the Patagonian Monte (Argentina). We asked whether structural differences in aboveground vegetation are reflected in the density and spatial patterning of perennial grass seeds in litter patches. We selected two study sites characteristic of the Patagonian Monte and within them three locations representing different vegetation states, resulting from different combinations of grazing and/or release from grazing history. At each location, we assessed the density of perennial grass seeds in litter patches at microsites beneath plant patches (canopy) and in interpatch areas without or with scattered vegetation (bare soil) at three dates during the reproductive and seed dispersal periods. The density of perennial grass seeds in litter patches was greater at canopy than at bare soil microsites, and the number of litter patches without seeds increased with decreasing total plant cover at both microsites. The density of perennial grass seeds in litter patches did not vary with differences in total plant cover or litter patch attributes at canopy microsites, while it was reduced with decreasing total plant cover at bare soil microsites. We concluded that differences in aboveground plant cover differentially affected the density of perennial grass seeds in litter patches at contrasting soil microsites. Thus potential microsites for perennial grass recruitment by seeds would increase from litter patches at bare soil microsites to litter patches at canopy microsites at locations with high and low aboveground plant cover, respectively. These issues should be considered for the sustainable management of these rangelands. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Abundances of coplanted native bunchgrasses and crested wheatgrass after 13 years

      Nafus, A. M.; Svejcar, T. J.; Ganskopp, D. C.; Davies, K. W. (Society for Range Management, 2015-03)
      Crested wheatgrass (Agropyron cristatum [L] Gaertm) has been seeded on more than 5 million hectares in western North America because it establishes more readily than native bunchgrasses. Currently, there is substantial interest in reestablishing native species in sagebrush steppe, but efforts to reintroduce native grasses into crested wheatgrass stands have been largely unsuccessful, and little is known about the long-term dynamics of crested wheatgrass/native species mixes. We examined the abundance of crested wheatgrass and seven native sagebrush steppe bunchgrasses planted concurrently at equal low densities in nongrazed and unburned plots. Thirteen years post establishment, crested wheatgrass was the dominant bunchgrass, with a 10-fold increase in density. Idaho fescue (Festuca idahoensis Elmer), Thurber's needlegrass (Achnatherum thurberianum (Piper) Barkworth), basin wildrye (Leymus cinereus [Scribn. & Merr.] A. Löve), and Sandberg bluegrass (Poa secunda J. Presl) maintained their low planting density, whereas bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Löve), needle-and-thread (Hesperostipa comata [Trin. & Rupr.] Barkworth), and squirreltail (Elymus elymoides [Raf.] Swezey) densities declined. Our results suggest that densities of native bunchgrasses planted with crested wheatgrass are unlikely to increase and that some species may only persist at low levels. The high recruitment of crested wheatgrass suggests that coplanting of some native bunchgrasses may be a viable way of avoiding crested wheatgrass monocultures when this species is necessary for rehabilitation or restoration. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Alternative Rangeland Management Strategies and the Nesting Ecology of Greater Prairie-Chickens

      McNew, L. B.; Winder, V. L.; Pitman, J. C.; Sandercock, B. K. (Society for Range Management, 2015-05)
      Population declines of grassland birds over the past 30 yr have followed the widespread implementation of intensive rangeland management practices that create homogenous grassland habitats. Patch-burn grazing (PBG) was tested as an alternative management technique that is ecologically similar to historically heterogeneous fire and grazing regimes and holds promise as a rangeland management tool that may benefit grassland wildlife. We conducted a 3-year study to compare nest-site selection and nest survival of greater prairie-chickens, an umbrella species for tallgrass prairie conservation, on private lands managed with PBG or intensive fire and grazing in the Flint Hills of Kansas. The goal of our field study was to evaluate the relationships among rangeland management practices, habitat conditions, and nesting ecology of greater prairie-chickens. Nest-site selection and nest survival of prairie-chickens were both directly related to vertical nesting cover, which was determined by the fire return interval of a pasture. Nesting habitat was affected little by stocking rate in PBG management regimes because preferred nest sites were unburned patches that were not grazed by cattle. Overall, the quantity and quality of nesting sites was improved under PBG management when compared with more intensive rangeland management regimes. Our results join a growing body of evidence that rangeland management strategies that mimic historical heterogeneous fire and grazing regimes benefit native species of prairie wildlife. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • An alternative rangeland management strategy in an agro-pastoral area in Western China

      Hua, L.; Yang, S.; Squires, V.; Wang, G. (Society for Range Management, 2015-03)
      Governance plays a key role in rangeland management. In China, all rangeland, including pastoral land and agro-pastoral land, is owned by the State. Since 1980, use rights have been granted to households by the Chinese government extending the household contract responsibility system (HCRS). But in the agro-pastoral areas of northwestern (NW) China, the rangeland degradation is more severe than that in pastoral areas. The HCRS is difficult to implement because the limited and fragmented grazing land cannot be contracted to individual households. Thus the pastures in the agro-pastoral areas are grazed as communal pastoral land and the rate of rangeland degradation has accelerated as livestock numbers have grown. Several measures have been introduced in an attempt to reverse this degradation trend, but most failed. This paper reports a 5-year comparison of three rangeland management regimens, including the national "Protecting rangeland by restricting grazing" (PRRG) project under the individual HCRS (PRRG under IHCRS), the Allied Householders Contract Responsibility System (AHCRS) program funded by the World Bank/GEF, and the free grazing on common pasture as the control area (CA) at Mayinggou Village, Yongchang County, Gansu Province in NW China. The results showed significant differences (P < 0.05) between AHCRS and the other two regimens (PRRG under IHCRS and CA) in terms of biomass of palatable forages, cover, and plant diversity index of vegetation but no significant difference (P > 0.05) between PRRG under IHCRS and CA. Reducing the number of livestock in AHCRS also resulted in increased revenue from the livestock turn-off rate compared with that in PRRG under IHCRS and CA. Therefore, AHCRS is a better alternative management regimen for rangelands in agro-pastoral areas. AHCRS can solve the overgrazing problem, maintain or improve household income, and potentially ensure a long-term sustainable rangeland management regimen in agro-pastoral areas in NW China. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Anchor Chaining's Influence on Soil Hydrology and Seeding Success in Burned Piñon-Juniper Woodlands

      Madsen, M. D.; Zvirzdin, D. L.; Petersen, S. L.; Hopkins, B. G.; Roundy, B. A. (Society for Range Management, 2015-05)
      Broadcast seeding is one of the most commonly applied rehabilitation treatments for the restoration of burned piñon and juniper woodlands, but the success rate of this treatment is notoriously low. In piñon-juniper woodlands, postfire soil-water repellency can impair seeding success by reducing soil-water content and increasing soil erosion. Implementing anchor chaining immediately after seeding can improve establishment of seeded species by enhancing seed-to-soil contact and may improve restoration success by decreasing soil-water repellency through soil tillage. The objectives of this research were to 1) determine if anchor chaining in postfire pinyon-juniper woodlands diminishes soil-water repellency, and 2) determine meaningful relationships between soil-water repellency, unsaturated hydraulic conductivity [K(h)], and the establishment of seeded and invasive species. Research was conducted on two study sites, each located on a burned piñon-juniper woodland that had severe water repellency and that was aerially seeded. At each location, plots were randomly located in similar ecological sites of chained and unchained areas. At one location, anchor chaining considerably improved soil hydrologic properties, reducing the severity and thickness of the water-repellent layer, and increasing soil K(h) 2- to 4-fold in the first 2 yr following treatment. At this same location, anchor chaining increased perennial grass cover 16-fold and inhibited annual grass and annual forb cover by 5- and 7-fold, respectively. Results from the second site only showed improvements in soil K(h); other hydrologic and vegetative treatment responses were not significantly improved. Overall, this research suggests that anchor chaining has the potential to improve restoration outcomes, though additional research is warranted for understanding the direct impact of anchor chaining on soil-water repellency without the interaction of a seeding treatment. © 2015, Elsevier Inc. All rights reserved.
    • Avian habitat following grazing native warm-season forages in the mid-south United States

      Harper, C. A.; Birckhead, J. L.; Keyser, P. D.; Waller, J. C.; Backus, M. M.; Bates, G. E.; Holcomb, E. D.; Brooke, J. M. (Society for Range Management, 2015-03)
      Native warm-season grasses (NWSG) currently are being promoted for livestock forage and biofuels feedstock in the Mid-South. However, there are no published data on how NWSG managed with livestock in the Mid-South may affect habitat for wildlife. We conducted a study to evaluate habitat for grassland songbirds and northern bobwhite (Colinus virginianus) in response to two cattle grazing treatments in NWSG pastures across three sites in Tennessee, 2010 and 2011. We evaluated vegetation composition and structure along with invertebrate availability during the primary nesting season for grassland songbirds and the typical brood-rearing season for the northern bobwhite. Grazing treatments included full-season (May to August) grazing and early-season (30 days beginning in May) grazing, after which subsequent growth was taken as a biofuel harvest postdormancy. Forage treatments included big bluestem/indiangrass mixture, switchgrass, and eastern gamagrass. Vegetation composition was dominated by the planted forages in all pastures. All forage types and both grazing treatments provided suitable structure for grassland songbirds and bobwhite during the primary nesting season. Full-season grazing maintained suitable structure through the brooding period, with greater openness at the ground level and angle of obstruction, as well as optimal vegetation height (<60 cm). Structure within early-season grazing treatments became dense after cattle were removed with less openness at ground level than what brooding bobwhites typically use. Invertebrate biomass was sufficient in all forage types and grazing treatments to support bobwhite broods. We recommend livestock producers in the Mid-South use full-season grazing that maintains grass height of approximately 40 cm in production stands of NWSG to maximize benefits for grassland birds and northern bobwhite. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Behavioral Responses at Distribution Extremes: How Artificial Surface Water Can Affect Quail Movement Patterns

      Tanner, E. P.; Elmore, R. D.; Fuhlendorf, S. D.; Davis, C. A.; Thacker, E. T.; Dahlgren, D. K. (Society for Range Management, 2015-11)
      Supplementing wildlife populations with resources during times of limitation has been suggested for many species. The focus of our study was to determine responses of northern bobwhite (Colinus virginianus; Linnaeus) and scaled quail (Callipepla squamata; Vigors) to artificial surface-water sources in semiarid rangelands. From 2012-2014, we monitored quail populations via radio telemetry at Beaver River Wildlife Management Area, Beaver County, Oklahoma. We used cumulative distribution functions and resource utilization functions (RUFs) to determine behavioral responses of quail to water sources. We also used Program MARK to determine if water sources had any effect on quail vital rates. Our results indicated that both northern bobwhite and scaled quail exhibited behavioral responses to the presence of surface-water sources. Northern bobwhite selected for areas < 700 m and < 650 m from water sources during the breeding and nonbreeding season, respectively. However, the nonbreeding season response was weak ( =-0.06, SE = < 0.01), and the breeding season ( = 0.01, SE = 0.02) response was nonsignificant on the basis of RUFs. Scaled quail selected for areas < 650 m and < 250 m from water sources during the breeding and nonbreeding season, respectively. The breeding season RUF ( =-0.31, SE = 0.07) indicated a stronger response for scaled quail than bobwhite. Conversely, there was no direct effect of surface water on quail vital rates or nest success during the course of our study. Although water may affect behavioral patterns of quail, we found no evidence that it affects quail survival or nest success for these two species. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Big Game and Cattle Influence on Aspen Community Regeneration Following Prescribed Fire

      Walker, S. C.; Anderson, V. J.; Fugal, R. A. (Society for Range Management, 2015-07)
      Aspen (Populus tremuloides Michx.) is a major component of Intermountain forest ecology and relies on periodic disturbance, such as prescribed fire, to perpetuate. On the Manti-LaSal National Forest in central Utah, both big game and cattle depend on forage growing on forested lands, which has contributed to intense conflict. Understanding the effects of browsers on recently burned aspen stands is critical to managing the regeneration of these communities. This study measured the effects of cattle and big game foraging on regenerating aspen communities. Three study sites were selected from a 142-ha prescribed burn conducted in an aspen-conifer stand on the Ferron District of the Manti-LaSal National Forest in 1989. Each of the three study sites was subdivided into four areas and randomly assigned one of the following treatments: big game and cattle exclusion (No Use), big game exclusion (Cattle Use), cattle exclusion (Big Game Use), and open access (Dual Use). Vegetation was sampled in 1991-1994, 1999, and 2005. Density, biomass, height, nested frequency, and cover of aspen suckers were measured. Nested frequency and cover were measured for all other species encountered. Aspen cover, density, and biomass showed a significant year-by-treatment interaction (P < 0.05). Aspen and understory regeneration responded similarly to No Use, Cattle Use, and Big Game Use. Dual Use resulted in lower (P < 0.05) aspen regeneration and more annual, weedy species in the understory. In 2005, Dual Use aspen cover (4%) was lower (P < 0.05) than the other three treatments: Big Game Use (25%), Cattle Use (31%), and No Use (34%). Controlled burning to regenerate aspen will be most successful under light stocking rates for both big game and cattle to allow suckers to develop beyond the browse line (>2 meters). © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Biological Soil Crust Response to Late Season Prescribed Fire in a Great Basin Juniper Woodland

      Warren, S. D.; St. Clair, L. L.; Johansen, J. R.; Kugrens, P.; Baggett, L. S.; Bird, B. J. (Society for Range Management, 2015-05)
      Expansion of juniper on U.S. rangelands is a significant environmental concern. Prescribed fire is often recommended to control juniper. To that end, a prescribed burn was conducted in a Great Basin juniper woodland. Conditions were suboptimal; fire did not encroach into mid- or late-seral stages and was patchy in the early-seral stage. This study evaluated the effects of the burn on biological soil crusts of early-seral juniper. Fire reduced moss cover under sagebrush and in shrub interspaces. Mosses were rare under juniper; their cover was unaffected there. Lichens were uncommon under juniper and sagebrush and therefore not significantly impacted there. Their cover was greater in shrub interspaces, but because the fire was spotty and of low intensity, the effects of burning were minimal. Compared with unburned plots, the biomass of cyanobacteria was diminished under juniper and sagebrush; it was reduced in the interspaces in both burned and unburned plots, presumably in response to generally harsher conditions in the postburn environment. Nitrogen fixation rates declined over time in juniper plots and interspaces but not in sagebrush plots. Although fire negatively affected some biological soil crust organisms in some parts of the early-seral juniper woodland, the overall impact on the crusts was minimal. If the intent of burning is to reduce juniper, burning of early-seral juniper woodland is appropriate, as most affected trees were killed. Control of sagebrush can likewise be accomplished by low-intensity, cool season fires without eliminating the crust component. Intense fire should be avoided due to the potential for greater encroachment into the shrub interspaces, which contain the majority of biological soil crust organisms. Burning early-seral juniper may be preferred for controlling juniper encroachment on rangeland. © 2015, Elsevier Inc. All rights reserved.
    • Cattle responses to a type of virtual fence

      Umstatter, C.; Morgan-Davies, J.; Waterhouse, T. (Society for Range Management, 2015-01)
      Interest in developing more flexible fencing technology to improve pasture and rangeland management is increasing. The objective of this study was to test the efficacy of a new virtual fencing product and measure impact on behavior, thus potentially allowing positive development of virtual fence systems. The Boviguard (Agrifence, Henderson Products Ltd., Gloucester, UK) invisible fence is now commercially available, consisting of cow collars, a battery-based transformer, and an induction cable laid on the ground or buried in the ground. As the Boviguard collar comes close to the induction cable, a warning sound is triggered and if the animal continues to move closer, an electrical stimulus is triggered. We tested this novel system on 10 cows wearing global positioning system (GPS) collars to pinpoint location and activity sensors to gather behavioral data. Two separate exclusion zones were created consecutively in different areas of a test field, with alternate periods of control, with no fence activity, and virtual fence activation. The system successfully prevented the animals from crossing the virtual fence line. No changes in general activity or lying behavior were found. There were significant changes in the pattern of use of the rest of the field area when the fencing system was activated. When only the unactivated cable was left on the ground in a final control period, the visual cue alone deterred animals from entering the exclusion area. The trial showed the effectiveness of a collar-based electrical stimuli system. This approach to virtual fencing could provide solutions for management systems where moving fences frequently is required, such as for strip grazing, nature conservation management of specific areas and habitats, and grazers of land where physical fences are not preferred or feasible. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Challenges of Establishing Big Sagebrush (Artemisia tridentata) in Rangeland Restoration: Effects of Herbicide, Mowing, Whole-Community Seeding, and Sagebrush Seed Sources

      Brabec, M. M.; Germino, M. J.; Shinneman, D. J.; Pilliod, D. S.; McIlroy, S. K.; Arkle, R. S. (Society for Range Management, 2015-09)
      The loss of big sagebrush (Artemisia tridentata Nutt.) on sites disturbed by fire has motivated restoration seeding and planting efforts. However, the resulting sagebrush establishment is often lower than desired, especially in dry areas. Sagebrush establishment may be increased by addressing factors such as seed source and condition or management of the plant community. We assessed initial establishment of seeded sagebrush and four populations of small outplants (from different geographies, climates, and cytotypes) and small sagebrush outplants in an early seral community where mowing, herbicide, and seeding of other native plants had been experimentally applied. No emergence of seeded sagebrush was detected. Mowing the site before planting seedlings led to greater initial survival probabilities for sagebrush outplants, except where seeding also occurred, and these effects were related to corresponding changes in bare soil exposure. Initial survival probabilities were > 30% greater for the local population of big sagebrush relative to populations imported to the site from typical seed transfer distances of ∼320-800 km. Overcoming the high first-year mortality of outplanted or seeded sagebrush is one of the most challenging aspects of postfire restoration and rehabilitation, and further evaluation of the impacts of herb treatments and sagebrush seed sources across different site types and years is needed. © 2015 Published by Elsevier Inc.
    • China's Rangeland Management Policy Debates: What Have We Learned?

      Gongbuzeren; Li, Y.; Li, W. (Society for Range Management, 2015-07)
      In China, three major rangeland management policies have caused dramatic social, economic, and ecological changes for pastoral regions in the past 30 yr: the Rangeland Household Contract Policy (RHCP), Rangeland Ecological Construction Projects (RECPs), and the Nomad Settlement Policy (NSP). The impacts of these policies are greatly debated. In this paper, we conduct a systematic review of academic perspectives on the impacts of the three policies and the causes of ineffective and negative effects. The findings demonstrate that academics increasingly report negative impacts of RHCP on the ecosystem, animal husbandry, pastoralist livelihoods, and pastoral society. An increasing number of scholars, although not the majority, attribute the negative impacts to improper policy itself rather than incomplete implementation. Regarding the RECPs, most academics believe that policies have improved the rangeland ecosystem but with obvious negative impacts on pastoralist livelihoods and pastoral society; they attribute the problems to incomplete policy implementation. For the NSP, most academics report positive impacts on pastoralist livelihoods and animal husbandry, although recent researchers have identified negative impacts on pastoral society and the ecosystem. Although they are not in the mainstream, more and more academics attribute the negative impacts to improper policy. Finally, we apply the concept of coupled social-ecological systems (SES) to further analyze the outcomes of these three policies and propose a more flexible and inclusive land tenure policy that recognizes the diverse local institutional arrangements; an integrated RECP framework that considers coadaptation between social and ecological systems; and facilitating voluntary choice in nomad settlement and developing innovative approaches to provide social services for pastoralists who would like to remain in pastoral areas. As these three policy approaches are applied in rangeland management and pastoral development worldwide, this paper may provide useful implications for future policy development in pastoral regions on a global scale. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Contrasting Mechanisms of Recovery from Defoliation in Two Intermountain-Native Bunchgrasses

      Mukherjee, J. R.; Jones, T. A.; Adler, P. B.; Monaco, T. A. (Society for Range Management, 2015-11)
      Grazing tolerance of dominant native species may determine the fate of rangeland ecosystems, and using native plant populations with good grazing tolerance in restoration seedings may improve ecosystem resilience, especially when domestic herbivores are present. We examined interspecific and intraspecific differences in shoot biomass and defoliation tolerance for two semiarid, perennial cool-season bunchgrasses native to the Intermountain West, USA, Pseudoroegneria spicata and Elymus wawawaiensis, on the basis of four functional traits (specific leaf area [SLA], plant basal area, tiller number, and tiller mass). We applied two treatments, control and boot-defoliation, where the latter included defoliation at the early-reproductive ("boot") stage, the phenological stage most vulnerable to herbivory, while the control treatment did not. We tested two contrasting hypotheses (i.e., that boot-defoliation tolerance is increased through either increases in SLA or through more favorable tiller demography). For shoot biomass, both grasses were less productive under the boot-defoliation treatment than for the control, but E. wawawaiensis displayed higher boot-defoliation tolerance than P. spicata. Interpopulation variation occurred in all four functional traits for P. spicata, but there were no such variation for E. wawawaiensis. The tiller demography hypothesis better explained boot-defoliation tolerance in both species, and neither SLA nor plant basal area was correlated with shoot biomass for either treatment. Of the traits measured, high tiller number served as the primary mechanism for shoot biomass and boot-defoliation tolerance in P. spicata, while tiller number and tiller mass were both important predictors of both shoot biomass and boot-defoliation tolerance. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Controls of Carrying Capacity: Degradation, Primary Production, and Forage Quality Effects in a Patagonian Steppe

      Golluscio, R. A.; Bottaro, H. S.; Oesterheld, M. (Society for Range Management, 2015-05)
      Rangeland carrying capacity depends on aboveground net primary production (ANPP) and on the sustainable harvest index (HIsust), the portion of ANPP that livestock can consume without undermining the production capacity of the system. At a regional scale, the observed harvest index (HIreal) increases with ANPP, but at a landscape scale the pattern is less clear, and controls of HIreal and HIsust are unknown. We analyzed the landscape patterns of variation of HIreal and HIsust across gradients of ANPP, pastoral value of vegetation (PV), and degradation. In 15 plots of a 2 753-ha paddock in a western Patagonian grass-shrub steppe, we estimated ANPP, consumption, forage pastoral value, and degradation. To estimate degradation we used PV weighed by forage cover because it was negatively correlated with a combination of ecosystem traits formerly linked to grazing-induced degradation. We calculated HIreal (consumption/ ANPP) and HIsust (consumption removing 40% of aerial biomass of the key species/ANPP). We choose Festuca pallescens as the key species because of its high abundance and moderate preference. As the paddock was grazed with low stocking rate to maximize among-plots selection, HIreal was lower than HIsust. As in regional models, HIsust and HIreal increased with ANPP within the paddock (R2 = 0.33 and 0.30, respectively). Multiple regressions showed that HIreal increased with ANPP and degradation, while HIsust increased with ANPP but decreased with degradation (R2 = 0.64 and 0.77, respectively). This suggests that at stocking rates lower than carrying capacity, sheep choose highly productive stands and, at a given level of ANPP, they prefer degraded stands. In contrast, carrying capacity increases with productivity and decreases with degradation. Management systems based on HIsust may result in severe biomass removal of species more preferred than the key species (Poa ligularis), and it is necessary to include strategies to preserve their individuals and populations. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Demographic Changes Drive Woody Plant Cover Trends - An Example from the Great Plains

      Berg, M. D.; Sorice, M. G.; Wilcox, B. P.; Angerer, J. P.; Rhodes, E. C.; Fox, W. E. (Society for Range Management, 2015-07)
      Woody plant encroachment - the conversion of grasslands to woodlands - continues to transform rangelands worldwide, yet its causes and consequences remain poorly understood. Despite this being a coupled human-ecological phenomenon, research to date has tended toward ecological aspects of the issue. In this paper, we provide new insight into the long-term relationships between human demographics and woody plant cover at the landscape scale. We used time-series aerial imagery and historical census data to quantify changes in population, land ownership patterns, and woody cover between 1937 and 2012 in three different settings in central Texas, USA. Woody cover closely paralleled population in a semi-urban watershed (R2 = 0.81) and two separate clusters of rural watersheds (R2 = 0.88 and 0.93), despite exhibiting very different directional trends over time in each setting. Woody cover also closely tracked average farm size in each rural watershed cluster (R2 = 0.57 and 0.90). These results highlight a tight coupling between demographic trends and the extent of woody plant cover. Such human factors may explain a great deal of woody plant cover patterns in other global rangeland systems with similar historical contexts and serve as a predictive proxy of landscape trends. Accordingly, policy recommendations should consider these demographic factors, and future woody plant encroachment research should explicitly include human dimensions. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Drought Influences Control of Parasitic Flies of Cattle on Pastures Managed with Patch-Burn Grazing

      Scasta, J. D.; Engle, D. M.; Talley, J. L.; Weir, J. R.; Fuhlendorf, S. D.; Debinski, D. M. (Society for Range Management, 2015-05)
      We compared the influence of patch-burn grazing to traditional range management practices on abundance of the most economically injurious fly parasites of cattle. Horn flies (Haematobia irritans), face flies (Musca autumnalis), stable flies (Stomoxys calcitrans), and horse flies (Tabanus spp.) were assessed at study locations in Oklahoma and Iowa, USA, in 2012 and 2013. Experiments at both locations were spatially replicated three times on rangeland grazed by mature Angus cows. Grazing was year-long in Oklahoma and seasonal in Iowa from May to September. One-third of patch-burn pastures were burned annually, and traditionally managed pastures were burned completely in 2012 but not at all in 2013. Because of significant location effects, we analyzed locations separately with a mixed effects model. Horn flies and face flies were below economic thresholds with patch-burn grazing but at or above economic thresholds in unburned pastures in Iowa. Pastures in Iowa that were burned in their entirety had fewer horn flies but did not have fewer face flies when compared with no burning. There was no difference among treatments in horn fly or face fly abundance in Oklahoma pastures. Stable flies on both treatments at both locations never exceeded the economic threshold regardless of treatment. Minimizing hay feeding coupled with regular fire could maintain low stable fly infestations. Horse flies at both locations and face flies in Oklahoma were in such low abundance that treatment differences were difficult to detect or explain. The lack of a treatment effect in Oklahoma and variable year effects are the result of a drought year followed by a wet year, reducing the strength of feedbacks driving grazing behavior on pastures burned with patchy fires. Patch-burning or periodically burning entire pastures in mesic grasslands is a viable cultural method for managing some parasitic flies when drought is not a constraint. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Evaluating Winter/Spring Seeding of a Native Perennial Bunchgrass in the Sagebrush Steppe

      Boyd, C. S.; Lemos, J. A. (Society for Range Management, 2015-11)
      Sagebrush (Artemisia tridentata Nutt.) plant communities in the Great Basin region are being severely impacted by increasingly frequent wildfires in association with the expansion of exotic annual grasses. Maintaining native perennial bunchgrasses is key to controlling annual grass expansion, but postfire restoration of these species has proven difficult with traditional fall drill-seeding. We investigated the potential for winter/spring seeding bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Love) in southeast Oregon. In 2011-2013, 500 seeds were planted in fall, or weekly from March through early May in 1·m-2 plots using a randomized block design with 5 replications. Germination was estimated using buried bags, and emergent seedlings were counted weekly from March to June. Germination and emergence varied strongly between years and by within-year timing of planting. With adequate precipitation, percent germination was high (up to 100%) regardless of timing of planting and emergence density decreased (P ≤ 0.05) with advancing winter/spring planting date in drier years. Emergence density was high (approaching 300 plants/m-2) with adequate precipitation but varied strongly across planting weeks for winter/spring plantings. Percent survival of emergent seedlings to harvest (July) was approximately 25-50% lower (P ≤ 0.05) for fall-planted seeds in all years; survival of winter/spring seedlings was 80-100% with no discernable pattern between planting weeks. Our results indicate that winter/spring seeding of perennial bunchgrasses is biologically feasible in years with adequate precipitation but fall seeding was more consistently successful. Additional research is needed to determine environmental factors driving within-year variation in demographics for winter/spring planted seeds. © Published by Elsevier Inc. On behalf of Society for Range Management.