• When art and science meet: Integrating knowledge of French herders with science of foraging behavior

      Meuret, M.; Provenza, F. D. (Society for Range Management, 2015-01)
      Landscapes are complex creative systems that continually transform due to ever-changing relationships among environments and organisms including human beings. During the past half-century, those who study these relationships and those who manage them have become increasingly isolated from one another in their attempts to understand and manage landscapes. As we have come to rely on experimental science to understand principles, we have diminished the importance of experiential knowledge in understanding and implementing practices. In this paper, we discuss convergence of the knowledge of herders from Southeastern France with the science of foraging behavior. We review insights of researchers gained through interviews with herders, surveys, and in situ recordings of the foraging behavior of closely herded sheep and goats. Though years of hands-on experience, herders have come to understand processes involved in food and habitat selection. Using a conceptual model of four steps, which represent four intertwined processes for a given herder-herd-fodder resource, we describe how herders 1) teach their animals to use the full range of forages, 2) train the herd to respect the boundaries of grazing areas, 3) modulate what they call the "temporary palatability scoring" of forages, and 4) establish daily grazing circuits to stimulate appetite and intake through meal sequencing. This knowledge is also valuable when the objective is to boost appetite for particular forages, such as coarse grasses, scrub, and invasive species. The practices of herders are consistent with scientific studies that show the importance of plant biodiversity for enabling animals to select nutritious diets and the significance of animal learning and culture on nutrition, production, and health. We conclude by highlighting implications for furthering the exchange between herders and scientists and by providing implications for managing grazing on pastures and rangelands, with or without shepherds and dogs, and targeting grazing on particular plants and habitats. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Weather affects grasshopper population dynamics in continental grassland over annual and decadal periods

      Jonas, J. L.; Wolesensky, W.; Joern, A. (Society for Range Management, 2015-01)
      Understanding the complex dynamics of insect herbivores requires consideration of both exogenous and endogenous factors at multiple temporal scales. This problem is difficult due to differences in population responses among closely related taxa. Increased understanding of dynamic relationships between exogenous and endogenous factors will facilitate forecasting and suggest nodes in the life cycle of economically important species susceptible to intervention by managers. This study uses an information-theoretic approach to examine the contributions of weather and density to model population densities and growth rates of nine common grasshopper species from continental U.S. grassland over 25 years. In general, grass-feeding species and total grass-feeders as a functional group were most closely associated with weather during the year before hatching. Increased variability in prior growing season precipitation was associated with increased densities of Mermiria bivittata, Opeia obscura, Phoetaliotes nebrascensis, and the grass-feeding guild. Melanoplus sanguinipes densities tended to be smaller following warm fall seasons, while Amphitoruns coloradus declined during the positive phase of the North Atlantic Oscillation or after warmer than average winters. Population growth rate dynamics of all grouped species combinations were best explained by models including variability in precipitation during the prior year growing season. Large-scale Pacific Decadal Oscillation (PDO) patterns were also associated with growth rate dynamics of the mixed-feeding species group. Density showed a negative relationship with population growth rates of five species. This study indicates the importance of parental and diapause environmental conditions and the utility of incorporating long-term, readily obtained decadal weather indices for forecasting grasshopper densities and identifying critical years with regard to grasshopper management--at least to the degree that the past will continue to predict the future as global climates change. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Tourism impacts on indigenous pastoral communities in China

      Fan, M.; Li, W.; Wei, G.; Luo, F. (Society for Range Management, 2015-01)
      In China, booming tourism is considered to be a win-win solution to fight both ecosystem degradation and poverty in pastoral areas. However, whether this alternative livelihood can reduce pressure on rangeland and improve livelihood of indigenous peoples has not yet been explored. To examine tourism's impacts on pastoral communities, we conducted field surveys at Inner Mongolia and Xinjiang and distributed questionnaires in 12 provinces including most of the grassland areas of China. On the basis of fieldwork and national survey data, we found that different types of operations have different impacts on livelihood and ecosystem in pastoral area. Pastoralists involved in tourism can increase the income of pastoral households during the summer tourism season, but that pastoralism still provides the main guarantee of a sustainable livelihood. However, along with the development of tourism, business enterprises from outside the pastoral area may replace local herders in tourism operations. As a result, a large area of rangeland may be lost to local herders, who only receive money if they rent their pastures or serve as laborers; unfortunately, many residents lack the training to perform better-paid roles. In addition, we found that pure tourism that replaces pastoralism does not necessarily protect the rangeland, as it brings a variety of environmental impacts and disrupts traditional use that the rangeland may be adapted to. On the basis of our findings, we recommend that tourism managed by local operators who also engage in pastoralism should become the main direction for economic development. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Stocking rate and grazing season modify soil respiration on the Loess Plateau, China

      Chen, J.; Hou, F.; Chen, X.; Wan, X.; Millner, J. (Society for Range Management, 2015-01)
      The influence of sheep grazing on carbon cycling in the midarid steppe of the Loess Plateau, Gansu, China, was investigated by measuring the CO2 exchange rate in pastures with a 7-year history of zero, light, moderate, and heavy grazing. Farming systems in the area are characterized by heavy grazing pressure and low vegetation productivity. The effect of stocking rate on soil respiration (Rs) was determined using field trials to investigate factors influencing spatial and temporal variation in Rs in August 2008 on two sites: summer grazed and winter grazed. Soil respiration is an important component of the carbon cycle in rangeland. Measurements included daily Rs, soil temperature, soil moisture, and root biomass. Daily Rs was also measured in late April and middle December 2008. The response of Rs to increasing stocking rate in August 2008 differed with site; on the summer-grazed site increased stocking rates reduced Rs (P < 0.02), whereas on the winter-grazed site, stocking rate had little effect on Rs. Path analysis revealed that on the summer-grazed site, soil moisture had the greatest influence on Rs, whereas on the winter site soil temperature was the most important factor; stocking rate had the least influence on Rs at both sites. The results highlight the importance of environmental variability in determining the effects of grazing on Rs. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Stand persistence and forage yield of 11 Alfalfa (Medicago sativa) populations in semiarid rangeland

      Misar, C. G.; Xu, L.; Gates, R. N.; Boe, A.; Johnson, P. S. (Society for Range Management, 2015-01)
      Livestock producers in the Northern Great Plains value alfalfa (Medicago sativa L.) for increasing forage production and quality in grazing lands. However, alfalfa persistence can be poor, especially under grazing. Demand exists for alfalfa that can establish and persist in semiarid grazing lands. A naturalized population of predominantly yellow-flowered alfalfa (Medicago sativa L. subsp. falcata [L.] Arcang.) was found growing and reseeding on private and public rangeland in northwestern South Dakota. This naturalized alfalfa population demonstrates persistence in this semiarid environment. A study, initiated in May 2006 at the Antelope Range and Livestock Research Station near Buffalo, South Dakota, evaluated stand persistence and forage yield of 11 alfalfa populations transplanted into mixed-grass prairie. Populations were pure falcata, predominantly falcata, hay-type sativa, or pasture-type sativa populations. Transplants were space planted on 1-m centers within three exclosures (35 × 35 m) divided into two sections, which were either mob grazed by cattle or protected from mob grazing. Mob grazing began in August 2007 and continued periodically through 2008 and 2009. Survival, plant height, plant canopy diameters, and biomass data were collected. Grazing, dry spells, and ice sheets subjected alfalfa plants to substantial stress. High mortality of grazed plants occurred during the 2008-2009 winter. Hay-type sativa and pasture-type sativa populations exposed to mob grazing had poor final survival (<19%) and forage yield in July 2010. However, pure falcata and most predominantly falcata populations had higher survival (>38%) and forage yield. Low mortality and high yield of protected plants indicated that accumulated stress from mob grazing weakened grazed plants, increasing environment-related mortality (e.g., winterkilling). Falcata-based populations persistent under mob grazing and adapted to the regional environment have potential for use in the Northern Great Plains. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Patch burn grazing management in a semiarid grassland: Consequences for pronghorn, plains pricklypear, and wind erosion

      Augustine, D. J.; Derner, J. D. (Society for Range Management, 2015-01)
      Management strategies that allow for spatiotemporal interactions between fire and herbivores can potentially achieve multiple management goals related to livestock production and wildlife conservation, but little is known about such interactions in semiarid grasslands where fire has traditionally been viewed as having few management applications. We studied patch burn grazing management in the shortgrass steppe of northeastern Colorado, comparing unburned pastures to pastures where 25% of the area was burned in October or November each year over 4 years. Our objective was to examine the interactive effects of patch burns and the subsequent response by pronghorn (Antilocapra americana) on plains pricklypear (Opuntia polyacantha) and wind erosion rates. We monitored abundance of plains pricklypear and wind erosion rates throughout the experiment and quantified seasonal pronghorn densities and postburn damage to plains pricklypear cladodes during the latter 2 years of the study. Pronghorn density was 26 times greater in winter and 7 times greater in spring on patch burns compared with unburned pastures. By late winter, densities of bitten or uprooted plains pricklypear cladodes were five times greater on patch burns compared with unburned pastures. Patch burns, as well as the subsequent response of pronghorn, reduced plains pricklypear density by 54-71% during the first year after the burns, and density remained suppressed for up to 6 years after burns. Wind erosion rates on patch burns were greater compared with unburned pastures but were two orders of magnitude lower than rates measured on fallow croplands in the region. Autumn patch burns can be a valuable means to suppress plains pricklypear and thereby increase grass available for livestock consumption in the shortgrass steppe. These outcomes can be achieved without increasing wind erosion in a manner that threatens long-term soil sustainability and without negative consequences for livestock weight gains.
    • Mapping and monitoring cheatgrass dieoff in rangelands of the Northern Great Basin, USA

      Boyte, S. P.; Wylie, B. K.; Major, D. J. (Society for Range Management, 2015-01)
      Understanding cheatgrass (Bromus tectorum) dynamics in the Northern Great Basin rangelands, USA, is necessary to effectively manage the region's lands. This study's goal was to map and monitor cheatgrass performance to identify where and when cheatgrass dieoff occurred in the Northern Great Basin and to discover how this phenomenon was affected by climatic, topographic, and edaphic variables. We also examined how fire affected cheatgrass performance. Land managers and scientists are concerned by cheatgrass dieoff because it can increase land degradation, and its causes and effects are not fully known. To better understand the scope of cheatgrass dieoff, we developed multiple ecological models that integrated remote sensing data with geophysical and biophysical data. The models' R2 ranged from 0.71 to 0.88, and their root mean squared errors (RMSEs) ranged from 3.07 to 6.95. Validation of dieoff data showed that 41% of pixels within independently developed dieoff polygons were accurately classified as dieoff, whereas 2% of pixels outside of dieoff polygons were classified as dieoff. Site potential, a long-term spatial average of cheatgrass cover, dominated the development of the cheatgrass performance model. Fire negatively affected cheatgrass performance 1 year postfire, but by the second year postfire performance exceeded prefire levels. The landscape-scale monitoring study presented in this paper helps increase knowledge about recent rangeland dynamics, including where cheatgrass dieoffs occurred and how cheatgrass responded to fire. This knowledge can help direct further investigation and/or guide land management activities that can capitalize on, or mitigate the effects of, cheatgrass dieoff. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Impacts of differing grazing rates on canopy structure and species composition in hulunber meadow steppe

      Yan, R.; Xin, X.; Yan, Y.; Wang, X.; Zhang, B.; Yang, G.; Liu, S.; Deng, Y.; Li, L. (Society for Range Management, 2015-01)
      In this study, the impacts of cattle grazing with differing grazing rates on species composition, canopy structural traits, standing crop of canopy biomass, and plant species diversity were examined in a meadow steppe of the Hulunber grasslands, Northeastern China. Six stocking-rate treatments (0, 0.23, 0.34, 0.46, 0.69, and 0.92 AU.ha-1) with three replicates were established, and observations were conducted from 2009 to 2011. Our findings demonstrate that short-term grazing substantially altered the species composition and relative dominance, standing crop of aboveground biomass, and canopy structural traits, whereas no significant changes in species diversity and evenness occurred in response to different-rated grazing in this meadow steppe, which has a long-term evolutionary grazing history and high-resources availabilities. We found that perennial graminoid significantly decreased, while forbs and annuals increased at the same time, with increasing grazing intensity and duration; canopy height and coverage decreased substantially with increasing stocking rates, whereas significant changes in plant density occurred only at heavy grazing in the second and third years; and significant negative linear relations were found between the standing crop of biomass and grazing intensity in each individual year or for 3 years on average. Significantly highest species richness and canopy dominance occurred only at the intermediate grazing rate in the third year, and intermediate grazing intensity also maintained a highly constant standing crop of canopy biomass in the 3 years, all being in accordance with the intermediate disturbance hypothesis. Our findings imply that monitoring changes in species composition, canopy traits, and standing crop of biomass in grassland communities can provide important references for assessing current grazing management scenarios and conducting timely adaptive practices to maintain the long-term ability of grassland systems to perform their ecological functions. © 2015 Published by Elsevier Inc. on behalf of Society for Range Management.
    • Fire and nitrogen alter axillary bud number and activity in purple threeawn

      Russell, M. L.; Vermeire, L. T. (Society for Range Management, 2015-01)
      Belowground accumulation of vegetative buds provides a reservoir of meristems that can be utilized following disturbance. Perennial grass bud banks are the primary source of nearly all tiller growth, yet understanding of fire and nitrogen effects on bud banks is limited. We tested effects of fire and nitrogen addition on bud banks of purple threeawn (Aristida purpurea Nutt.), a perennial C4 bunchgrass. Fire (no fire, summer fire, fall fire) and nitrogen addition (0,46, 80 kg·ha-1) treatments were assigned in a completely randomized, fully factorial design and axillary buds were evaluated on two similar sites in southeastern Montana 1 and 2 years after fire. Permanently marked plants were assessed for live tiller production, and randomly selected tillers were sampled to determine active and dormant buds per tiller. Fire and nitrogen had opposite effects on axillary buds. Summer and fall fire reduced active buds by 42% relative to nonburned plots. Adding nitrogen at 46 or 80 kg.ha-1 increased active buds per tiller 60% compared with plots with no nitrogen addition. The number of dormant buds per tiller was similar across fire treatments and levels of nitrogen. Fire and nitrogen had interacting effects on total buds at the tiller level. Without nitrogen addition, fall and summer fire reduced total buds per tiller about 70%. Nitrogen had no effect on total buds per tiller for nonburned plants. However, total number of buds per tiller was greater with nitrogen addition following fall fire and increased with each increase in nitrogen following summer fire. Results indicate fire effectively controls purple threeawn through bud bank reduction and that nitrogen can stimulate bud production. Interacting effects of fire and nitrogen on buds reveal a potential source of inconsistency in nitrogen effects and a possible method of facilitating recovery of fire-sensitive bunchgrasses after fire. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Fecal-FT-NIRS as a noninvasive tool for assessing diet quality of mediterranean deer

      Tellado, S.; Orpez, R.; Muñoz-Cobo, J.; Azorit, C. (Society for Range Management, 2015-01)
      In order to assess the diet quality of two Mediterranean deer species we developed and validated a Fourier transform near-infrared diffuse reflectance spectroscopy methodology on feces (Fecal-FT-NIRS) for the determination of acid detergent fiber (ADF), neutral detergent fiber (NDF), lignin, C:N ratio, and enzymatic digestibility of organic matter (EDOM). We used rumen contents and fecal samples from 149 red deer (Cervus elaphus hispanicus) and 111 fallow deer (Dama dama) from southeast Spain (n = 520 observations). Spectra from the feces were related with rumen conventional chemical analysis through chemometric regression with partial least-squares (PLS). Specific predictive equations from red and fallow deer data separately were generated, as well as merged equations after pooling all deer samples. All the predictive equations had a high linearity with high correlation coefficients (r = 0.8 - 0.99). The selected equations had a reliable accuracy considering the root-mean-square errors of prediction (RMSEP), calibration (RMSEC), and cross-validation (RMSECV) in relation to the range of values for which the NIRS calibration was set for each parameter. Broad-based equations from combined samples were demonstrated as being useful for all nutritional parameters determination in red and fallow deer simultaneously. Equations obtained for the red deer data were also successfully applied to fallow deer and vice versa for NDF, ADF, C:N, and lignin determination, while for EDOM assessment the specific equations for each species were more accurately applied. Once validated, the Fecal-FT-NIRS technique can be considered as a suitable noninvasive tool for monitoring deer diet quality variations in Mediterranean environment. This method has the possibility to overcome interspecific barriers of direct fecal analysis by using rumen digesta as its reference method. © 2015 Society for Range Management. Published by 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.
    • 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.
    • Weather constrains the influence of fire and grazing on nesting greater prairie-chickens

      Hovick, T. J.; Dwayne, Elmore, R.; Fuhlendorf, S. D.; Dahlgren, D. K. (Society for Range Management, 2015-03)
      Grasslands are highly imperiled as a result of widespread conversion for agriculture and alteration from human development. Remaining grasslands are susceptible to mismanagement, development and fragmentation, and variable weather associated with global climate change. Understanding the response of declining grassland species to these challenges will be important for informed conservation and management. We assessed Greater Prairie-Chicken (Tympanuchus cupido) survival and nest site selection in tallgrass prairie characterized by interacting fire and grazing disturbance and oil and gas infrastructure. We found that Greater Prairie-Chicken survival was most affected by weather variability (expressed in our models as solar radiation) while most other variables had little influence. Focal disturbance did not affect survival directly, but vegetation height, which is greatly influenced by fire and grazing processes, was positively associated with nest survival. Greater Prairie-Chickens chose nesting locations that maximized time post fire while minimizing tree cover and distance to leks. Future conservation efforts for Greater Prairie-Chickens should focus on variable fire regimens that create areas of residual biomass to increase vegetation height and potentially reduce the effects of solar radiation while decreasing woody vegetation that is avoided by nesting females. However, even the best management practices may prove to be futile in the southern Great Plains if climate change continues to create unfavorable nest survival conditions. Management that creates and maintains suitable nesting sites through the use of interacting fire and grazing should maximize the potential for high reproduction in years when local weather variables are favorable. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Time of grazing effect on subsequent-year standing crop in the Eastern Nebraska Sandhills

      Stephenson, M. B.; Schacht, W. H.; Volesky, J. D.; Eskridge, K. M.; Bauer, D. (Society for Range Management, 2015-03)
      Rotational grazing methods provide range managers opportunities to alter the time when grazing occurs on pastures in consecutive years. The effect of time of grazing on subsequent-year standing crop was evaluated within four pastures (42 ± 1 ha) rotated annually within a deferred rotation using a modified Williams design that included mean times of grazing within different pastures from 16 May to 14 June, 13 June to 20 July, 20 July to 29 August, and 27 August to 7 October (i.e., stages of grazing A, B, C, and D, respectively). Subsequent-year standing crop of different plant functional groups was collected from 2001 to 2008 at four topographic positions (i.e., north slopes, south slopes, dune tops, and interdunes) in mid-June and mid-August harvests. During the mid-June harvest, standing crop of subsequent-year warm-season grasses was 51 ± 24 to 117 ± 41 kg·ha-1 greater (P &lt; 0.1) when grazing occurred during stage A compared with when grazing occurred during stages B and C on north- and south-facing slopes and at the pasture level. During the mid-August harvest on south-facing slopes, subsequent-year warm-season grass standing crop was 265 ± 105 and 341 ± 113 kg·ha-1 greater (P &lt; 0.03) when grazing occurred during stage A compared with stages B and C, respectively. Overall, grazing on pastures during stage A tended to provide greater amounts of subsequent-year standing crop for warm-season and cool-season graminoids at specific topographic positions. Given that the effect of time of grazing on subsequent-year standing crop varied among topographic positions for different functional groups, a deferred grazing rotation provides a viable management tool to alter the yearly sequence of grazing on pastures to avoid negative effects of grazing Nebraska Sandhills vegetation at critical times in consecutive years. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Monitoring the impact of grazing on rangeland conservation easements using MODIS vegetation indices

      Tsalyuk, M.; Kelly, M.; Koy, K.; Getz, W. M.; Scott, Butterfield, H. (Society for Range Management, 2015-03)
      Monitoring the effects of grazing on rangelands is crucial for ensuring sustainable rangeland ecosystem function and maintaining its conservation values. Residual dry matter (RDM), the dry grass biomass left on the ground at the end of the grazing season, is a commonly used proxy for rangeland condition in Mediterranean climates. Moderate levels of RDM are correlated with soil stability, forage production, wildlife habitat, and diversity of native plants. Therefore RDM is widely monitored on rangeland conservation properties. Current ground-based methods for RDM monitoring are expensive, are labor intensive, and provide information in the fall, after the effects of grazing have already occurred. In this paper we present a cost-effective, rapid, and robust methodology to monitor and predict RDM using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data. We performed a time series analysis of three MODIS-based vegetation indices (VIs) measured over the period 2000-2012: Normalized Difference Vegetation Index (NDVI), Leaf Area Index (LAI), and Fraction of Photosynthetically Active Radiation (FPAR). We examined the correlation between the four VIs and fall RDM measured at The Nature Conservancy's Simon Newman Ranch in central California. We found strong and significant correlations between maximum VI values in late spring and RDM in the fall. Among the VIs, LAI values had the most significant correlation with fall RDM. MODIS-based multivariate models predicted up to 63% of fall RDM. Importantly, maximum and sum VIs values were significantly higher in management units with RDM levels in compliance with RDM conservation easement terms compared with units out of compliance. On the basis of these results, we propose a management model that uses time series analysis of MODIS VIs to predict forage quantities, manage stocking rates, and monitor rangeland easement compliance. This model can be used to improve monitoring of rangeland conservation by providing information on range conditions throughout the year. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Management regimen and seeding rate modify seedling establishment of leymus Chinensis

      Liu, G. X.; He, F.; Wan, L. Q.; Li, X. L. (Society for Range Management, 2015-03)
      Broadcasting of Chinese wild rye, Leymus chinensis seeds (without plowing) is the long-standing recommendation for reseeding degraded grasslands in Northern China. However, no experimental assessments have been made to determine which management options, including presow harrowing, postsow cutting, nitrogen fertilizer, and seeding rate, may influence the establishment of L. chinensis seedlings after broadcasting. We conducted a 2-year field study that quantified the relative impacts of these factors on seedling emergence, survival, and growth on a degraded short-grass steppe site at SaiBei, Hebei Province, China. Broadcast seeding of L. chinensis after harrowing resulted in the highest seedling emergence (16.4%), seedling survival (62.5%), and plant height (8.5 cm) compared with the other management regimens assessed. By Year 2, survival was 10 times greater in plots where harrowing had been implemented. This finding was especially important because of the drought conditions that occurred during the study period. The lowest seeding rate (400 seeds m-2) was linked with 15% seedling emergence and average heights of 7.3 cm at the end of the 2 years. It is our recommendation that seedling establishment is optimized when harrowing is used for initial soil preparation and seed dispersal. Harrowing improved seed-soil contact, increased the number of seed safe sites on the soil surface, and reduced competition from the already existing sward. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Long-term forage and cow-calf performance and economic considerations of two stocking levels on chihuahuan desert rangeland

      Thomas, M. G.; Mohamed, A. H.; Sawalhah, M. N.; Holechek, J. L.; Bailey, D. W.; Hawkes, J. M.; Luna-Nevarez, P.; Molinar, F.; Khumalo, G. (Society for Range Management, 2015-03)
      Forage and cow-calf productivity on two lightly and two conservatively grazed pastures were evaluated over a 15-year period (1997-2011) in the Chihuahuan Desert of south-central New Mexico. Spring-calving Brangus cows were randomly assigned to pastures in January of each year. Pastures were similar in area (1 098 ± 69 ha, mean ± SE) with similar terrain and distance to water. Utilization of primary forage species averaged 27.1 ± 3.0% in lightly stocked pastures and 39.4 ± 4.0% on conservatively stocked pastures. No differences in perennial grass standing crop (163.5 ± 52.2 kg·ha-1) and calf weaning weights (286.1 ± 2.6 kg) were detected (P &gt; 0.10) between light and conservative treatments. Lightly grazed pastures yielded greater (P &lt; 0.05) kg of calf weaned·ha-1 and calf crop percent than conservatively grazed pastures in 1998 due to complete destocking of conservatively grazed pastures during that slight drought (i.e., rainfall was 75% of normal in 1998). After the initial 5 years of study (1997-2001), all pastures were destocked for 4 years (2002-2005) due to drought as rainfall was only 50% or less of normal. Pastures were then restocked for another 6 years (2006-2011). Postdrought, the percentage change in perennial grass standing forage crop (kg·ha-1) was -4.0 and -14.4 ± 2.5 % (P &lt; 0.09) in the light and conservative grazed pastures across the 6 years, respectively. While conservative stocking rates may provide higher net financial returns than light stocking rates during nondrought years as there were more AU per pasture, potential losses from cattle liquidation during short-term (i.e., 1-year) droughts could nullify this advantage. Results suggest that light grazing use of forage is a practical approach for Chihuahuan Desert cow-calf operations to minimize risk of herd liquidation during short-term drought. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Honey mesquite (prosopis glandulosa) seedling responses to seasonal timing of fire and fireline intensity

      James Ansley, R.; Kramp, B. A.; Jones, D. L. (Society for Range Management, 2015-03)
      Fire-resistant woody species have invaded many grassland and savanna ecosystems worldwide. Adults of many of these species are fire resistant because they resprout following fire; however, seedlings may be vulnerable to fire. Here we quantify effects of seasonal timing of fire and fireline intensity on seedling mortality response to fire in honey mesquite (Prosopis glandulosa Torr.), a native woody legume that has increased in abundance in southern Great Plains, USA grasslands. Scarified mesquite seeds were planted in plots with either mid-grass or tall-grass fuels in each of 2 years (Cohorts 1 and 2). Plots were burned in winter when seedlings were 10 or 22 months old or late summer when they were 17 months old. In the mid-grass fuel type, seedling mortality was greater (P ≤ 0.05) in summer-burned, 17-month-old seedlings (85%) than in winter-burned, 10-month-old seedlings (35%), suggesting summer fire may be important in limiting seedling establishment under lower-grass, fine-fuel conditions. The tall-grass fuel type yielded similar mortality responses to summer (89% and 79%) and winter (77% and 66%) fires in Cohorts 1 and 2, respectively (differences not significant at P ≤ 0.05). The study found a positive relationship between fireline intensity and seedling mortality, especially when only winter fires were included in the regression (r2 = 0.96). Summer fire may be most useful in lower-grass fuel amounts and may accomplish the same level of seedling mortality without the need for lengthy grazing deferral to accumulate sufficient grass fine fuel for a successful winter fire, as seedling mortality from winter fire depends on fireline intensity. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.