• Estimating sagebrush biomass using terrestrial laser scanning

      Olsoy, P. J.; Glenn, N. F.; Clark, P. E. (Society for Range Management, 2014-03)
      The presence of sagebrush (Artemisia tridentata) in rangelands has declined due to the invasion of annual grasses such as cheatgrass (Bromus tectorum) and the feedback between these flammable grasses and wildfire frequency. Monitoring the change and distribution of suitable habitat and fuel loads is an important aspect of sagebrush management, particularly under future climate conditions. Assessments of sagebrush biomass are used to monitor habitat for critical wildlife species, determine fire risk, and quantify carbon storage. Field techniques such as destructive and point-intercept sampling have been used to determine sagebrush biomass, but both of these techniques can be expensive and time consuming to implement. Light detection and ranging techniques, including airborne laser scanning and terrestrial laser scanning (TLS) have potential for rapidly assessing biomass in sagebrush steppe. This study used TLS to estimate biomass of 29 sagebrush plants in Reynolds Creek Experimental Watershed, Idaho. Biomass was estimated using TLS-derived volume, then compared with destructive samples to assess the estimation accuracy. This accuracy level was then contrasted with the estimates obtained using point-intercept sampling of the same plants. The TLS approach (R2-=-0.90) was slightly better for predicting total biomass than point-intercept sampling (R2-=-0.85). Prediction of green biomass, or production, was more accurate using TLS-derived volume (R2-=-0.86) than point-intercept sampling (R 2-=-0.65). This study explores a promising new method to repeatedly monitor sagebrush biomass across extensive landscapes. Future work should focus on making this method independent of sensor type, scan distance, scan number, and study area. © 2014 The Society for Range Management.
    • Evaluating a state-and-transition model using a long-term dataset

      Perlinski, A. T.; Paige, G. B.; McClaran, M. P. (Society for Range Management, 2014-03)
      State-and-transition models (STMs) are used in natural resource management to describe ecological site scale response to natural and anthropogenic disturbances. STMs are primarily based for expert opinion and literature reviews, lacking analytical testing to support vegetation community dynamics, thresholds, and state changes. We developed a unique approach, combining ordination and permutation MANOVA (perMANOVA) with raw data interpretation, to examine vegetation data structure and identify thresholds for a STM. We used a long-term monitoring dataset for an ecological site on the Santa Rita Experimental Range, Arizona. Basal cover of perennial grasses and canopy cover of shrubs and cacti were measured on permanent transects beginning in 1957. Data were grouped by drivers identified by the STM including species invasion, grazing, drought, and mesquite treatment. Ordination by nonmetric multidimensional scaling described the structure of the data. PerMANOVA was used to test for differences between groups of sample units. Analyses of combined key species (Lehmann's lovegrass and mesquite Prosopis velutina Woot.") and nonkey species patterns demonstrated an irreversible transition and occurrence of a structural threshold due to Lehmann's lovegrass invasion, as well as a short-term reversible transition (restoration pathway) following mesquite treatment. Sensitivity analysis, in which key species were removed from the dataset, showed that the relative composition of nonkey species did not differ between states previously defined by the key species. This apparent disconnect between dynamics of key and nonkey species may be related to changes in the functional attributes that were not monitored during this time series. Our analyses suggest that, for this ecological site, transition to a Lehmann's lovegrass state occurs when basal cover of this species exceeds 1-2%, which often occurs within 6 yr of its arrival. Evaluation of the restoration pathway showed a recrossing of the threshold within 6 yr of treatment and when mesquite canopy cover exceeded 10%. © 2014 The Society for Range Management.
    • Evaluation of landscape-level grazing capacity for domestic sheep in alpine rangelands

      Mysterud, A.; Rekdal, Y.; Loe, L. E.; Angeloff, M.; Mobæk, R.; Holand, Ø.; Strand, G. -H. (Society for Range Management, 2014-03)
      Balancing the number of grazing animals with the level of plant resources is a core issue in grazing management. Complete, full-coverage vegetation surveys are often used for this purpose, but these are expensive undertakings. We have presented a method to downscale information from regional sampling surveys by poststratification using a land cover map derived from satellite-based measures of reflectance values. This approach opens new prospects for landscape-level evaluation of productivity. We applied this method to eight grazing districts (19-245 km2) in Setesdal Vesthei, Norway, in 2006. Sheep densities in three of eight grazing districts of Setesdal Vesthei fluctuated above the estimated grazing capacity. We fitted 43 sheep with Global Positioning System collars in two contrasting grazing districts in 2007-2008 to assess their selection of the land cover productivity classes in the map used for poststratification. In the area with high vegetation coverage, sheep selection increased in areas with an overall higher productivity, supporting the main basis of the approach. However, in the grazing districts with lower vegetation coverage, selection was higher for areas of overall low vegetation productivity. The likely explanation is the presence of small areas of snow bed vegetation with high-quality forage in areas with a generally rocky surface. Our study provides a first step toward a grazing capacity evaluation to achieve a sustainable management of sheep on alpine ranges of Scandinavia, and our approach is likely applicable to other open alpine ranges in the northern hemisphere. © 2014 The Society for Range Management.
    • Feed intake and performance of sheep grazing semiarid grassland in response to different grazing systems

      Dickhoefer, U.; Hao, J.; Bösing, B. M.; Lin, L.; Gierus, M.; Taube, F.; Susenbeth, A. (Society for Range Management, 2014-03)
      Effects of grazing management systems (GS) on biomass production and nutritional quality of rangeland vegetation in semiarid regions are extensively studied; however, limited information is available regarding their effects on diet digestibility and feed intake of grazing livestock. We therefore analyzed digestibility of ingested organic matter (dOM), organic matter intake (OMI), and live weight gain (LWG) of sheep in a grazing experiment established in the Inner Mongolian steppe of China, where two GS were tested for six different grazing intensities (GI) from very light to heavy grazing. For the continuous grazing system, sheep grazed the same plots each year, and for the alternating system, grazing and hay making were alternated annually between two adjacent plots. In July, August, and September 2009 and 2010, feed intake and live weight of sheep were determined. The GS did not affect dOM (P-=-0.101), OMI (P-=-0.381), and LWG of sheep (P-=-0.701). Across both GS LWG decreased from 98 g-·-d-1 for GI1 to 62 g-·-d-1 for GI6 (P-<-0.001; R2-=-0.42). There were no interactions between GS and GI for all measured parameters (P-≥-0.061), indicating that alternating grazing did not compensate for negative effects of heavy grazing even after 4 yr of grassland use. In summary, our study showed that irrespective of GI, alternating grassland use does not improve dOM, OMI, and hence, LWG of sheep. However, it might enhance revenues and ecological sustainability in the long term when compared to the common practice of continuous grazing at very high stocking rates. © 2014 The Society for Range Management.
    • Herder observations of rangeland change in Mongolia: Indicators, causes, and application to community-based management

      Bruegger, R. A.; Jigjsuren, O.; Fernández-Giménez, M. E. (Society for Range Management, 2014-03)
      Local observations of ecological change are important in developing tools for rangeland management and filling in gaps where quantitative data are lacking. Traditional ecological knowledge (TEK) is a potential source of information that can complement scientific knowledge. It may also allow policy makers and scientists to suggest responses that will be locally relevant, and therefore effective on the ground. We conducted 40 surveys with the use of closed-ended questionnaires followed by open-ended qualitative questions with herders in two soum (administrative districts), located in the steppe and forest steppe of Mongolia. Respondents were asked about their observations of rangeland change and its causes in the last 20 yr. Across the study areas, a strong majority (75%) of all herders reported that rangeland condition was much worse than 20 yr ago. Herders in both soum reported increases in undesirable plant species, declines in species richness, and the disappearance or decreasing abundance of specific desirable plant species. Comparing the two soum, more herders in the forest-steppe site (90%) reported that rangeland condition was much worse than reported by herders in the steppe site (65%). In qualitative responses to open-ended questions, herders identified multiple indicators of and causes behind degradation, including very heavy grazing. In a large, sparsely populated country like Mongolia, herders' observations may serve as an early warning of rangeland change, provide insights into causes of change, and identify key uncertainties. Community-based rangeland management organizations (CBRMs) could help to translate herder observations into action by participating in formal monitoring based on herder-identified indicators and implementing changes in management in response to observed change. However, herders cannot address all issues that might be contributing to troubling ecological trends without higher-level policy coordinating rangeland monitoring and herder movements at regional and national scales. © 2014 The Society for Range Management.
    • Human infrastructure and invasive plant occurrence across rangelands of Southwestern Wyoming, USA

      Manier, D. J.; Aldridge, C. L.; O'Donnell, M.; Schell, S. J. (Society for Range Management, 2014-03)
      Although human influence across rural landscapes is often discussed, interactions between the native, natural systems and human activities are challenging to measure explicitly. We assessed the distribution of introduced, invasive species as related to anthropogenic infrastructure and environmental conditions across southwestern Wyoming. to discern direct correlations as well as covariate influences between land use, land cover, and abundance of invasive plants, and assess the supposition that these features affect surrounding rangeland conditions. Our sample units were 1-000 m long and extended outward from target features, which included roads, oil and gas well pads, pipelines, power lines, and featureless background sites. Sample sites were distributed across the region using a stratified, random design with a frame that represented features and land-use intensity. In addition to land-use gradients, we captured a representative, but limited, range of variability in climate, soils, geology, topography, and dominant vegetation. Several of these variables proved significant, in conjunction with distance from anthropogenic features, in regression models of invasive plant abundance. We used general linear models to demonstrate and compare associations between invasive plant frequency and Euclidian distance from features, natural logarithm transformed distances (log-linear), and environmental variables which were presented as potential covariates. We expected a steep curvilinear (log or exponential) decline trending towards an asymptote along the axis representing high abundance near features with rapid decrease beyond approximately 50-100 m. Some of the associations we document exhibit this pattern, but we also found some invasive plant distributions that extended beyond our expectations, suggesting a broader distribution than anticipated. Our results provide details that can inform local efforts for management and control of invasive species, and they provide evidence of the different associations between natural patterns and human land use exhibited by nonnative species in this rural setting, such as the indirect effects of humans beyond impact areas. © 2014 The Society for Range Management.
    • Knapweed hay as a nutritional supplement for beef cows fed low-quality forage

      Bohnert, D. W.; Sheley, R. L.; Falck, S. J.; Nyman, A. A. (Society for Range Management, 2014-03)
      Advancing our ability to use invasive plants for producing commodities is central to the agricultural industry. Our objective was to evaluate Russian knapweed (Acroptilon repens "L." DC.) as a winter feed supplement for ruminant livestock. In Experiment 1, we utilized three ruminally cannulated steers in a completely randomized design to compare the ruminal degradation characteristics of alfalfa and Russian knapweed. In the second experiment, Russian knapweed and alfalfa were compared as protein supplements using 48 midgestation, beef cows (530-±-5 kg) offered ad libitum hard fescue (Festuca brevipila Tracey) straw in an 84-d study. Treatments included an unsupplemented control and alfalfa or Russian knapweed provided on an iso-nitrogenous basis. In Experiment 1, the rate and effective degradability of neutral detergent fiber was greater for alfalfa compared with Russian knapweed (P-≤-0.02). Ruminal lag time for NDF (period before measurable disappearance began) was greater for knapweed (P-=-0.03). Soluble nitrogen, rate of N degradation, rumen degradable N, and effective degradability of N were all greater for alfalfa compared with Russian knapweed (P-<-0.01). In Experiment 2, supplementation increased (P-<-0.01) cow weight gain and BCS compared to the unsupplemented control with no difference between alfalfa and Russian knapweed (P-=-0.47). There was no difference (P-=-0.60) in the quantity of straw offered between the unsupplemented cows and supplemented groups, but alfalfa fed cows were offered approximately 11% more (P-=-0.03) than Russian knapweed-fed cows. Total DM offered to cows was greater (P-<-0.01) for supplemented compared with unsupplemented cows with no difference noted between alfalfa and Russian knapweed (P-=-0.79). Russian knapweed is comparable to alfalfa as a protein supplement for beef cows consuming low-quality forage. Using Russian knapweed as a nutritional supplement can help solve two major production problems; managing an invasive weed, and providing a feedstuff that reduces an impediment in livestock production systems. © 2014 The Society for Range Management.
    • Long-term vegetation change provides evidence for alternate states in silver sagebrush

      Kachergis, E.; Rocca, M. E.; Fernández-Giménez, M. E. (Society for Range Management, 2014-03)
      A key goal in land management is to prevent ecosystem shifts that affect human well-being. Like other types of sagebrush shrublands, large areas dominated by the common but little-studied mountain silver sagebrush may have shifted to a less productive shrub-dominated alternate state under heavy livestock grazing in the 19th century. The goals of this study are to 1) describe long-term vegetation change in a silver sagebrush mountain park and 2) evaluate evidence that these changes constitute alternate states. We examined vegetation change over the last 57 yr in California Park, Colorado, USA, using monitoring data from 15 permanent transects at six sites. We analyzed change in species composition over time and related it to management and climatic drivers using nonmetric multidimensional scaling. We found that management practices influenced species composition. Spraying herbicides resulted in decreases of sagebrush and a dominant, unpalatable forb (Wyethia amplexicaulis), but sagebrush recovered. Spraying also triggered a temporary increase in native palatable grasses and forbs. Native grasses have since decreased again, coinciding with increases in the cattle stocking rate and elk population. The nonnative pasture grass Phleum pratense has increased to become one of the dominant grasses in 2010. Sagebrush and herbaceous understory dynamics were not consistent with a shrub-dominated alternate state: changes were gradual and not persistent. However, historic Wyethia dominance and the widespread increase in the nonnative grass Phleum were persistent and may represent alternate states. We used these findings to update a state-and-transition model of high-elevation silver sagebrush shrubland dynamics for land management decision making. Our analysis differentiated gradual, nonpersistent changes from potentially irreversible changes, as is necessary for identifying alternate states that are important for land management and ecosystem function. The gradual but persistent increase in the nonnative grass Phleum reinforces others' observations that even incremental changes may lead to irreversible shifts. © 2014 The Society for Range Management.
    • Near infrared spectroscopy and fecal chemistry as predictors of the diet composition of white-tailed deer

      Jean, P. -O.; Bradley, R. L.; Giroux, M. -A.; Tremblay, J. -P.; Côté, S. D. (Society for Range Management, 2014-03)
      Overbrowsing by white-tailed deer (Odocoileus virginianus Zimmermann) on Anticosti Island (Canada) created a need to develop efficient methods for estimating their foraging patterns. We tested the ability of near infrared (NIR) spectra of feces and of fecal chemical properties to predict diet composition of different individuals. We first used a principal component-based discriminant analysis to sort the NIR spectra of fecal samples (n-=-102) obtained from two groups of captive deer that had been fed two different diets. The diets differed only in their relative abundance of balsam fir (Abies balsamea "L." P.Mill.) and white spruce (Picea glauca "Moench" Voss.) foliage. The calibrated model allowed us to assign 28 of 30 validation fecal samples (93.3 %) to the correct diet. In a second study, we attempted to estimate the proportion of coniferous, deciduous, herbaceous, and lichenous forages in diets of free-ranging white-tailed deer, as determined by fecal microhistology. Both NIR spectra and chemical properties of feces were used as predictors of diet composition. NIR spectra were analyzed using partial least-squares regression (PLSR), whereas fecal chemical properties were analyzed using mixed-linear regressions (MLRs). The PLSR models were robust (R2-=-0.89; ratio of prediction to deviation-=-3.2) for predicting the amount of coniferous fragments, but not for predicting the relative amounts of balsam fir, white spruce, and deciduous and lichenous fragments within feces. MLR models revealed a positive relationship (47% variance explained) between acid detergent lignin (ADL) and coniferous fragments within feces. ADL and cellulose explained 24% of variance in deciduous fecal fragments, whereas ADL alone explained 22% of variance in balsam fir fecal fragments. These results suggest that NIR spectroscopy and fecal chemical properties have several applications on Anticosti Island, such as measuring the degree of variation in diets within a given home range or determining dietary conifer intake during winter. © 2014 The Society for Range Management.
    • Perception and management of spatio-temporal pasture heterogeneity by hungarian herders

      Molnár Z. (Society for Range Management, 2014-03)
      The goal of our study was to document traditional steppe herders' perception and management of spatial and temporal heterogeneity of forage availability of their seminatural pastures. Ninety-two herders living in the Hortobágy saline steppe, Hungary, Central Europe were interviewed, and participatory observation was used to understand herding and habitat improvement techniques. The herders recognized 47-66 habitat types (mostly grassland types), and listed at least 90 plant species important for grazing. They have a nuanced knowledge of the intra- and interannual variations of forage quality and quantity. They perform very strong and well-planned herding practices. Daily spatial pattern of grazing is, however, often opportunistic and flexible, but has a more-or-less regular year-round cycle, in which marshes and stubbles provide forage in drought periods. Reciprocal learning and continuous communication between the herder and his driving dogs and livestock strongly influence grazing pattern. Herders manage and improve different habitats of their pastures differently by traditional and, less frequently, modern methods. The main method is grazing supplemented by manuring, burning, and removal of spiny weeds. Traditional knowledge of herders could be effectively used in evidence-based conservation and pasture management of European saline steppes; e.g., the reintroduction of some old herding techniques (opportunistic pasture use, grazing of marshes, and burning). Herders' knowledge could also help the fine-tuning and local adaptation of European agri-environmental regulations (e.g., how to balance subsidies for hay-making and grazing in saline steppes). More research is needed, however, on the ecological effects of different traditional grazing techniques, e.g., rotation, manuring, and burning. In general a more complex socio-ecological understanding of the internal and external factors affecting adaptation of the Hortobágy herders to changing environment, society, and European Union policies is needed. © 2014 The Society for Range Management.
    • Root biomass and distribution patterns in a semi-arid mesquite savanna: Responses to long-term rainfall manipulation

      Ansley, R. J.; Boutton, T. W.; Jacoby, P. W. (Society for Range Management, 2014-03)
      Expansion of woody plants in North American grasslands and savannas is facilitated in part by root system adaptation to climatic extremes. Climatic extremes are predicted to become more common with global climate change and, as such, may accelerate woody expansion and/or infilling rates. We quantified root biomass and distribution patterns of the invasive woody legume, honey mesquite (Prosopis glandulosa), and associated grasses following a long-term rainfall manipulation experiment in a mixed grass savanna in the southern Great Plains (United States). Root systems of mature trees were containerized with vertical barriers installed to a depth of 270 cm, and soil moisture was manipulated with irrigation (Irrigated) or rainout shelters (Rainout). Other treatments included containerized, precipitation-only (Control) and noncontainerized, precipitation-only (Natural) trees. After 4 yr of treatment, soil cores to 270 cm depth were obtained, and mesquite root length density (RLD) and root mass, and grass root mass were quantified. Mesquite in the Rainout treatment increased coarse-root (->-2 mm diameter) RLD and root mass at soil depths between 90 cm and 270 cm. In contrast, mesquite in the Irrigated treatment increased fine-root (-<-2 mm diameter) RLD and root mass between 30 cm and 270 cm depths, but did not increase total root mass (fine-+-coarse) compared to the Control. Mesquite root-to-shoot mass ratio was 2.8 to 4.6 times greater in Rainout than the other treatments. Leaf water stress was greatest in the Rainout treatment in the first year, but not in subsequent years, possibly the result of increased root growth. Leaf water use efficiency was lowest in the Irrigated treatment. The increase in coarse root growth during extended drought substantially increased mesquite belowground biomass and suggests an important mechanism by which woody plant encroachment into grasslands may alter below ground carbon stocks under climate change scenarios predicted for this region. © 2014 The Society for Range Management.
    • Vegetation responses to Pinyon-Juniper treatments in Eastern Nevada

      Provencher, L.; Thompson, J. (Society for Range Management, 2014-03)
      Comparisons of tree-removal treatments to reduce the cover of single-leaf pinyon (Pinus monophylla Torr. and Frém.) and Utah juniper (Juniperus osteosperma Torr. Little), and subsequently increase native herbaceous cover in black sagebrush (Artemisia nova A. Nelson), are needed to identify most cost-effective methods. Two adjacent vegetation management experiments were initiated in 2006 and monitored until 2010 in eastern Nevada to compare the costs and efficacy of various tree reduction methods. One Department of Energy (DOE) experiment compared a control to five treatments: bulldozing imitating chaining ($205-·-ha-1), lop-pile-burn ($2-309-·-ha-1), lop-and-scatter ($1-297- ·-ha-1), feller-buncher and chipper ($4-940-·- ha-1), and mastication ($1-136-·-ha-1), whereas a second Bureau of Land Management (BLM) experiment compared one-way chaining ($205-·-ha-1) to a control treatment. Chaining and bulldozing resulted in the least reduction of tree cover among the treatments. In the DOE experiment, forb cover only decreased in the mastication treatment. Litter increased in all methods. Slash cover was lowest in the control and lop-pile-burn treatments, intermediate in the feller-buncher and mastication treatments, and highest in the bulldozing and lop-and-scatter treatments. By 2010, forb cover and the combined cover of dead shrubs and trees were increased and decreased, respectively, by chaining in the BLM experiment. Nonnative annual grass and biotic crust were absent or uncommon before and after treatment implementation. In both experiments, tree removal resulted in a nonsignificant increase in perennial grass cover even 4 yr post-treatment. An ecological return-on-investment (EROI) metric was developed to compare perennial grass cover and tree cover per unit area cost of each active treatment. By 2010, chaining or bulldozing, followed by mastication, showed the highest EROI for improving perennial grass and decreasing tree cover. Mastication is recommended for restoration of smaller tree-encroached areas, whereas land managers should reconsider smooth chaining, despite its negative perceptions, for rapid and cost-efficient restoration of large landscapes obligates. © 2014 The Society for Range Management.