• Habitat Selection by Free-Ranging Bison in a Mixed Grazing System on Public Land

      Ranglack, D. H.; Du, Toit, J. T. (Society for Range Management, 2015-07)
      Domestic livestock have replaced bison (Bison bison) on almost all the remaining rangelands of North America. One of the few places where bison and cattle (Bos taurus) comingle on shared rangelands is in the Henry Mountains (HM) of southern Utah. Ranchers there are concerned, however, that bison are selecting the same grazing areas that are needed by cattle. We used global positioning system telemetry on bison across the entire HM rangeland to determine which habitats are most important for bison throughout the seasonal cycle. Sexual segregation was also measured (using the segregation coefficient, SC) to determine if bison bulls exert localized impacts by congregating in certain habitats separate from cow/calf groups. The HM bison exhibited low levels of sexual segregation for both the breeding (SC = 0.048) and nonbreeding seasons (SC = 0.112). We found bison habitat use to be diverse and dynamic, with bison grazing effects distributed widely across habitats throughout the seasonal cycle. Patches of grassland, whether naturally occurring or created through burning or mechanical treatments, were favored regardless of their distance to water. Our findings should assist ranchers and agency personnel in moving forward with the integrated management of free-ranging bison and cattle on the HM rangeland, with implications for bison conservation on public lands elsewhere in the United States. © 2015 The Authors.
    • 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.
    • Litter Reduction by Prescribed Burning Can Extend Downy Brome Control

      Kessler, K. C.; Nissen, S. J.; Meiman, P. J.; Beck, K. G. (Society for Range Management, 2015-07)
      Downy brome (Bromus tectorum L.) is a highly successful invasive species primarily because it fills an open niche in native plant communities. It also produces large amounts of litter over time. We hypothesized that removing accumulated litter with a prescribed burn before applying herbicides would improve herbicide efficacy, extending the duration of control. In January 2012, two downy brome-infested sites were burned. In March 2012, postemergent applications of glyphosate, imazapic, and tebuthiuron were made in a split-plot design. Above-ground biomass was collected at 6, 18, and 27 months after treatment (MAT) to evaluate treatment effects. In nonburned areas, all herbicide treatments were similar to the control 27 MAT; however, burning combined with imazapic or tebuthiuron reduced downy brome biomass 27 MAT by 81% ± 4.6 SE and 84% ± 19.3 SE, respectively. Remnant species responded positively to burning and herbicide treatments. Native cool-season grass biomass increased after burning whereas native warm-season grass biomass increased following tebuthiuron treatments. The impact of litter on imazapic and tebuthiuron availability was also evaluated. Herbicide interception increased in a linear relationship with increasing litter. For every 50 g · m-2 increase in litter there was a 7% increase in the amount of herbicide intercepted, meaning that 75% of the applied herbicide was intercepted by 360 g · m-2 of litter. A simulated rainfall event of 5 mm, 7 days after application, removed a significant amount of herbicide. This indicates that in sites with surface litter, timely precipitation could be critical for herbicide efficacy; however, when burning was used to remove litter and was followed by herbicides with residual soil activity, downy brome control was extended. Due to downy brome's relatively short seed viability in the soil, extending herbicide efficacy to several years could help to reduce the soil seed bank. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Long-Term Trade-Offs among Herbage Growth, Animal Production, and Supplementary Feeding in Heavily Grazed Mediterranean Grassland

      Henkin, Z.; Ungar, E. D.; Perevolotsky, A.; Gutman, M.; Yehuda, Y.; Dolev, A.; Landau, S. Y.; Sternberg, M.; Seligman, N. G. (Society for Range Management, 2015-07)
      A 17-yr grazing trial was conducted in the eastern Galilee of Israel to quantify trade-offs among the responses of pasture and livestock productivity, duration of grazing, amount of supplementary feed, and profitability to higher stocking density during the growing season of a Mediterranean grassland. Treatments included two stocking densities and two grazing protocols. The stocking densities throughout the grazing period were 0.55 animal unit (AU)·ha-1, which is common in this region, and 1.1 AU·ha-1, which is considered high. The grazing protocols were continuous grazing throughout the grazing season and split-paddock grazing in which the herd grazed one subpaddock from the onset of grazing until the pasture was depleted, after which the herd was moved to the second ungrazed subpaddock. Under both protocols, heavier stocking density reduced standing biomass of the whole paddock at the end of the growing season by 43% and grazing duration during the subsequent dry season by 38% but increased the daily consumption of supplementary feed and the weaned live-weight production per unit area. Under continuous grazing the high stocking density of 1.1 AU·ha-1 was maintained throughout the grazing season for 17 consecutive yr with no detectable effect on productivity of the pasture, typical to the resilience of Mediterranean grasslands that have been grazed for thousands of years. The lower pasture biomass production was compensated by higher weaned calf production. At the current local prices, the heavier stocking density was close to the economically optimal stocking density for the pasture in the region. It is concluded that on Mediterranean grassland intensive use of the pasture with high stocking density during the growing season can be economically feasible in those cases where the feed requirement of the herd can be maintained throughout the growing season. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Restoration of Native Plants is Reduced by Rodent-Caused Soil Disturbance and Seed Removal

      Gurney, C. M.; Prugh, L. R.; Brashares, J. S. (Society for Range Management, 2015-07)
      Granivory and soil disturbance are two modes by which burrowing rodents may limit the success of native plant restoration in rangelands. This guild of animals has prolific effects on plant community composition and structure, yet surprisingly little research has quantified the impact of rodents on plant restoration efforts. In this study, we examined the effects of seed removal and soil disturbance by the giant kangaroo rat (Dipodomys ingens) on native plant restoration in a California rangeland. Using experimental exclosures and stratifying restoration plots on and off rodent-disturbed soil, we assessed the individual and combined effects of seed removal and soil disturbance on seedling establishment of four native plant species. Across all species, biotic soil disturbance by kangaroo rats reduced seedling establishment by 19.5% (range = 1-43%), whereas seed removal reduced seedling establishment by only 6.7% (range = 4-12%). Rates of seed removal across species weakly paralleled kangaroo rat dietary preferences. These results indicate the indirect effects of burrowing rodents such as kangaroo rats on native seedling establishment via changes in soil properties may rival or exceed the direct effects of seed removal. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Stocking Rates and Vegetation Structure, Heterogeneity, and Community in a Northern Mixed-Grass Prairie

      Lwiwski, T. C.; Koper, N.; Henderson, D. C. (Society for Range Management, 2015-07)
      Currently, livestock management in the North American Great Plains aims for even use of forage, which creates a homogenous landscape. Reintroducing heterogeneity, defined here as the variation in vegetation structure and composition, to native North American rangelands is imperative to maintaining grassland biodiversity, and using a variety of cattle stocking rates on the landscape could accomplish this. We assessed effects of stocking rates on northern mixed-grass prairie vegetation structure, structural heterogeneity, and plant species diversity. The study took place in Grasslands National Park in Saskatchewan, Canada, using nine pastures (∼300 ha) that were grazed at a range of stocking rates from very low to very high for this region. Three of these pastures were ungrazed controls. We used generalized linear mixed models to describe effects of stocking rate on vegetation over 4 years, following the reintroduction of livestock grazing to this landscape after 15 years without grazing. We used a Mantel test to determine whether plant communities changed with varying stocking rates and over time. Effects of grazing on many response variables were cumulative and changed over time. Species richness in uplands increased with stocking rate and time, but richness decreased with stocking rate in lowlands. Heterogeneity generally increased with stocking rate and time in upland but not lowland habitats. While natural annual variability influenced many variables, the cumulative effects of grazing were still apparent. A variety of stocking rates could be used to maximize structural heterogeneity and provide a diversity of habitat structure at the landscape scale. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
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      Society for Range Management, 2015-07
    • 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.
    • Herd Size-Dependent Effects of Restricted Foraging Time Allowance on Cattle Behavior, Nutrition, and Performance

      Odadi, W. O.; Rubenstein, D. I. (Society for Range Management, 2015-07)
      We tested the influence of herd size on the effects of restricted foraging time on cattle (Bos indicus) foraging behavior, nutrition, and performance in a Kenyan savanna rangeland. Using a randomized block design, we compared weight gain, forage intake, diet selection, dietary crude protein (CP) and digestible organic matter (DOM), bite and step rates, distance travelled, and activity time budgets between steers allowed unlimited foraging time (DNG) in predator-free areas with those herded diurnally in predator-accessible areas in large (200 steers; LDG), medium (150 steers; MDG), or small (100 steers; SDG) herds and corralled at night. Daily weight gain was greater (P &lt; 0.01) in DNG (0.61 kg) or SDG (0.56 kg) than in LDG (0.19 kg) or MDG (0.29 kg) but did not differ (P = 0.591 ) between DNG and SDG. Likewise, daily organic matter intake was greater (P &lt; 0.05) in DNG (6.2 kg) or SDG (5.4 kg) than in LDG (3.7 kg) or MDG (3.7 kg) but did not differ (P = 0.288) between DNG and SDG. Grazing time was lower (P &lt; 0.01) in DNG (42.2%) than in LDG (71.3%), MDG (72.2%), or SDG (69.5%), while the reverse was the case for ruminating and/or resting time (47.1%, 12.1%, 11.9%, and 10.3% in DNG, LDG, MDG, and SDG, respectively). Bite rate was lower in DNG (13.1 bites · min-1) than LDG (21.0 bites · min-1; P = 0.068), MDG (27.7 bites · min-1; P = 0.13) or SDG (26.2 bites · min-1; P = 0.007). However, diet selection, CP, DOM, step rate, and distance travelled did not differ among treatments. Our findings demonstrate subdued negative effects of restricted foraging time when cattle are herded diurnally in small-sized herds. Application of this strategy could reduce the need for eliminating wild carnivores to facilitate unrestricted foraging time for cattle. © 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.
    • 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.
    • Improving Cattle Nutrition on the Great Plains with Shrubs and Fecal Seeding of Fourwing Saltbush

      Kronberg S. L. (Society for Range Management, 2015-05)
      Two in vitro trials were conducted for estimates of dietary percentage of fourwing saltbush (Atriplex canescens; FS) or winterfat (Krascheninnikovia lanata; WF) for improved dietary digestibility when cattle graze mature cool-season grass. Three in vitro trials were conducted to estimate percentage of FS and WF seeds that could survive passage through the bovine gastro-intestinal tract (GIT) with potential for fecal seeding. Mixtures of FS and mature smooth bromegrass (Bromus inermis; SB) or WF and SB had greater apparent digestibility than SB alone (P &lt; 0.0001). There were positive linear relationships (r2 ≥ 0.93) between the amount of each shrub in digested mixtures and digestibility. Similar relationships were observed with mixtures of FS and mature Altai wildrye (Leymus angustus). Germination of Dakota FS seeds in the first trial, incubated for 24 or 48 h, was 55% and 47%, respectively, with no difference in germination of seeds for the 24- and 48-h incubations (P = 0.26), but more seeds germinated if incubated versus not (P ≤ 0.002). Germination of Utah FS seeds, which were incubated for 24 or 48 h with high-, medium-, or low-quality forage, averaged 9% and 8%, respectively. Length of incubation, forage quality, and their interaction did not influence germination (P ≥ 0.45). Germination of nonincubated Utah FS seeds was 21% and greater than for incubated seeds (P = 0.004). Average germination of WF seeds was 0.6% and 0.1% for 24- and 48-h incubations, respectively, with incubation length, forage quality, and their interaction not significant (P ≥ 0.31). Nonincubated WF seeds had greater germination (42%) than incubated seeds (P &lt; 0.0001). Results from the third trial were confirmatory for Dakota FS seed. FS and WF can improve diet quality of grazing cattle in late summer through winter, and some FS seeds have potential for fecal seeding. © 2015, Elsevier Inc. All rights reserved.
    • On-Ranch Grazing Strategies: Context for the Rotational Grazing Dilemma

      Roche, L. M.; Cutts, B. B.; Derner, J. D.; Lubell, M. N.; Tate, K. W. (Society for Range Management, 2015-05)
      Considerable debate remains over the efficacy of rotational grazing systems to enhance conservation and agricultural production goals on rangelands. We analyzed responses to grazing management questions in the Rangeland Decision Making Surveys of 765 California and Wyoming ranchers in order to characterize on-ranch grazing strategies and identify variables influencing strategy adoption. Two-thirds of respondents practice on-ranch rotational grazing strategies, indicating ranchers do experience benefits from rotation which have not been documented in experimental comparisons of rotational and continuous grazing systems. Limited on-ranch adoption of intensive rotational strategies (5% of respondents) indicates potential agreement between research and management perceptions about the success of this particular strategy for achieving primary livestock production goals. Over 93% of all rotational grazer respondents were characterized as using extensive intragrowing season rotation with moderate (few wk to mo) grazing period durations, moderate (2.4-8 ha·animal unit) livestock densities, and growing season rest periods. Variables associated with ranchers' grazing preferences included a mixture of human dimensions (goal setting, views on experiment and risk tolerance, information networks), ranch characteristics (total number of livestock, land types comprising ranch), and ecoregions. We also found that the majority of grazing systems research has largely been conducted at spatial and temporal scales that are orders of magnitude finer than conditions under which on-ranch adaptive grazing management strategies have been developed. Resolving the discrepancies between the grazing systems research and management knowledge base will require substantive communication and novel approaches to participatory research between scientists and managers. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Success of Seeding Native Compared with Introduced Perennial Vegetation for Revegetating Medusahead-Invaded Sagebrush Rangeland

      Davies, K. W.; Boyd, C. S.; Johnson, D. D.; Nafus, A. M.; Madsen, M. D. (Society for Range Management, 2015-05)
      Millions of hectares of Wyoming big sagebrush (Artemisia tridentata Nutt. subsp. wyomingensis Beetle &amp; Young) rangeland have been invaded by medusahead (Taeniatherum caput-medusae [L.] Nevski), an exotic annual grass that degrades wildlife habitat, reduces forage production, and decreases biodiversity. Revegetation of medusahead-invaded sagebrush plant communities is necessary to restore ecosystem services. Disagreement, however, exists over whether to seed native or introduced perennial species to revegetate communities after controlling medusahead. Though native species generally do not establish as well as introduced species, interference from co-seeded introduced species has often been attributed to the limited success of natives. The potential for seeding natives to revegetate communities after medusahead control is relatively unknown because they have been largely co-seeded with introduced species. We compared the results of seeding native and introduced perennial species after controlling medusahead with prescribed burning followed with an imazapic herbicide application at five sites. Perennial bunchgrass cover and density were 5- and 10-fold greater in areas seeded with introduced compared with native species 3 years post seeding. Furthermore, exotic annual grass cover and density were less in areas seeded with introduced compared with native species. Seeded introduced and native shrubs largely failed to establish. High perennial bunchgrass density (15 individuals · m-2) in areas seeded with introduced species in the third year post seeding suggests that the succession trajectory of these communities has shifted to becoming perennial dominated. Average perennial bunchgrass density of 1.5 individuals · m-2 with seeding native species will likely not limit medusahead and appears to already be converting back to exotic annual grass-dominated communities. These results suggest that seeding introduced compared with native species after medusahead control will likely be more successful. Our results also imply that if natives are selected to seed after medusahead control, additional resources may be necessary to recontrol medusahead and repeatedly sow native species. © 2015, Elsevier Inc. All rights reserved.
    • Managing Medusahead (Taeniatherum caput-medusae) on Rangeland: A Meta-Analysis of Control Effects and Assessment of Stakeholder Needs

      James, J. J.; Gornish, E. S.; DiTomaso, J. M.; Davy, J.; Doran, M. P.; Becchetti, T.; Lile, D.; Brownsey, P.; Laca, E. A. (Society for Range Management, 2015-05)
      Invasive plant response to control efforts is strongly modified by site-specific factors, treatment timing, and environmental conditions following treatment, making management outcomes challenging to predict. Systematic reviews, which involve quantitative synthesis of data, can address this challenge by identifying general patterns of treatment effects across studies and quantifying the degree to which these effects vary. We conducted a systematic review of medusahead (Taeniatherum caput-medusae [L.] Nevski) control treatments that couples a meta-analysis on control data with an assessment of stakeholder needs to identify critical medusahead management knowledge gaps. With the meta-analysis we generated effect size estimates of how combinations of herbicide, burning, seeding, and grazing impacted medusahead on rangeland dominated by either annual or perennial vegetation. All combinations of treatments in both rangeland systems provided significant short-term control of medusahead, although treatment effects were highly transient on perennial rangeland, particularly for seeding treatments. Stakeholders listed grazing as a preferred management tool, and on annual rangeland an almost twofold reduction in medusahead abundance was achieved by timing high stocking rates to match phenological stages when medusahead was most susceptible to defoliation. Insufficient data were available to evaluate effects of grazing on medusahead on perennial rangeland. On the basis of these data and our stakeholder survey, four major information needs emerged, including the need to better understand 1) seedbank response to burning and herbicide treatments, 2) how to optimize grazing animal impacts on medusahead given ranch enterprise constraints, 3) costs and benefits of control and risk of practice failure, and 4) impacts of adaptive management treatments conducted on larger scales and at longer time intervals. Addressing these knowledge gaps should help overcome key ecological and economic barriers inhibiting implementation of medusahead and other invasive plant management programs on rangeland and provide a positive step toward conserving the critical ecosystem services these systems provide. © 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.
    • Long-Term Protection from Heavy Livestock Grazing Affects Ponderosa Pine Understory Composition and Functional Traits

      Strahan, R. T.; Laughlin, D. C.; Bakker, J. D.; Moore, M. M. (Society for Range Management, 2015-05)
      Making accurate predictions of plant community responses to grazing management is a major objective of rangeland ecology. Metrics such as species composition are site specific, whereas others such as functional groups and functional traits can be generalized across different rangeland types. We analyzed long-term (1912-1941) shifts in the understory community at five sites in a ponderosa pine (Pinus ponderosa P. &amp; C. Lawson var. scopulorum Engelm.) forest when protected from heavy livestock grazing. We examined differences in total basal cover, species composition, species richness, functional group composition, and community-weighted mean (CWM) functional traits between heavily grazed and ungrazed areas in four time periods (1912, 1920, 1930, 1940). Total understory basal cover was greater in ungrazed than heavily grazed areas in 1920 but not in later time periods. Understory species composition diverged by 1930 and continued to differ in 1940. Functional group composition differed from 1920 onwards. In 1920 and 1930, C3 graminoids declined more in relative abundance in heavily grazed than ungrazed areas. By 1940, forbs accounted for much more of the cover in heavily grazed than ungrazed areas. During the study period, CWM specific leaf area and foliar Nmass declined by 8% and 11%, respectively, in ungrazed quadrats, while CWM leaf dry matter content increased 8%. Leaf traits, but not maximum height or seed mass, demonstrated consistent and predictable responses to protection from heavy grazing. Herbaceous understory species with leaf traits that allow for slower resource acquisition became more abundant in response to protection from heavy grazing. Our results indicate that managers should expect to observe more rapid changes in functional group composition and leaf functional traits than in species composition and species richness following protection from heavy livestock grazing. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Tidal Suppression Negatively Affects Soil Properties and Productivity of Spartina densiflora Salt Marsh

      Jacobo, E. J.; Rodriguez, A. M.; Fariña, C. M.; Paggi, Y. (Society for Range Management, 2015-05)
      In order to intensify cattle utilization, embankments were constructed to avoid tidal ingressions in Samborombon Bay, Argentina, The objective of this study was to evaluate the effect of tidal suppression and cutting frequency of a salt marsh dominated by Spartina densiflora Brongn. Two paddocks of a commercial cow-calf operation farm, one prevented from tidal flooding and another exposed to overflow from natural tidal pattern (control), were the main plots of the nested design. The experiments were carried out during a dry (2008- 2009) and a wet growing season (2012-2013). Two defoliation frequencies, simulating light and moderate grazing pressure, were performed in the subplots nested within each main plot. Soil organic matter and N content were lower and soil structural instability index was much higher in the embankment than in the control treatment. Soil salinity during the dry growing season was higher in the embankment than in the control treatment. Bare soil was higher under embankment treatment and high defoliation frequency exacerbated this response. Relative contribution of Spartina densiflora was lower under embankment than control treatment and the changes of floristic composition depended on the growing season. Aboveground net primary production (ANPP) in the wet growing season was almost 70% higher than in the dry growing season. Embankment reduced ANPP and high defoliation increased ANPP with respect to low defoliation frequency in the control paddock, to a much higher extent in the wet season. Dry matter digestibility of S. densiflora was not affected by treatments. Crude protein was higher in control paddocks under high frequency. Our results showed that tidal suppression by embankment was not effective to increase productivity and forage value of S. densiflora saltmarsh but caused soil and structural changes that may negatively alter ecosystem processes of this vulnerable grassland of high importance for biodiversity conservation. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.