Vegetation restoration by seasonal exclosure in the Kerqin Sandy Land,Inner Mongolia

Grazing control has been reported to be effective for the control of desertification in semi-arid regions. However, economic reasons often make complete inhibition of grazing (complete exclosure) difficult to carry out. Grazing control has been applied to the Kerqin Sandy Lands, Inner Mongolia, China, by means of seasonal exclosure, whereby grazing is allowed from November to April. The harvesting of hay is also allowed once during September - October. The aim of the reported study was to evaluate the effectiveness of this seasonal exclosure on vegetation restoration. Species compositional data were obtained from 356 quadrats and ordinated by Detrended Correspondence Analysis (DCA). Ordination indicated that landform was the most important factor influencing the species composition of the vegetation. Regardless of landform and type of grazing control, however, vegetation coverage, vegetation height and species richness were higher at sites where grazing had been controlled, than at sites lacking any control. Perennial species were dominant at the former while annual species were dominant at the latter. Both shrub and tree species were quite rare at the sites where seasonal exclosure had been carried out. It is concluded that seasonal exclosure is sufficient to restore and maintain grassland vegetation in and around the study area. When shrubby or tree vegetation is needed for reasons such as fixing sands or preventing sand dune remobilization, complete exclosure is recommended.     

Forage nutritional characteristics and yield dynamics in a grazed semiarid steppe ecosystem of Inner Mongolia,China

In the steppe of Inner Mongolia, forage is the only source of feed for sheep. The forage intake of sheep can be characterized in both quantity and quality terms, which are determined by environmental and anthropogenic factors and grazing has a strong effect on steppe productivity and the grassland ecosystem. Evaluation of forage quality and quantity is therefore of critical importance. The effects of grazing intensity, interannual variability effects, and species composition on aboveground net primary productivity (ANPP) and forage nutritional characteristics were investigated in a controlled grazing experiment along a gradient of 7 grazing intensities (from non-grazed to very heavily grazed) over six years (2005–2010) on typical steppe in Inner Mongolia. Forage nutritional characteristics were defined by the nutritional value (concentrations of crude protein (CP), cellulase digestible organic matter (CDOM), metabolizable energy (ME) and neutral detergent fibre (NDF)) and the nutritional yield. The forage nutritional yield is a function of ANPP and the forage nutritional value. Forage nutritional value increased but ANPP and nutritional yields decreased with increasing grazing intensity. The inter-annual variation of ANPP, forage nutritional value and yield were weakly linked to the inter-annual variability of precipitation. However, ANPP and nutritional value also varied during the growing season, depending on the seasonal distribution of precipitation and temperature, which influence forage digestibility (CDOM) and metabolizable energy (ME), with higher CDOM and ME under high seasonal precipitation and low seasonal mean temperature. Forage nutritional value and yield, as well as ANPP, were predominantly determined by the dominant species rather than by species diversity. The results suggest that forage nutritional yield in the Inner Mongolian steppe is predominantly determined by the ANPP and only to a minor extent by forage nutritional value, and is predominantly determined by the dominant species and only to a minor extent by species diversity. Therefore, herbage productivity seems to be the most limiting factor in managing this steppe ecosystem as a feeding resource for livestock and to be the best ecological and environmental indicator for grassland management practices.     

Grazing in remnant woodland vegetation: changes in species composition and life form groups

Abstract. Grazing by domestic livestock in native woodlands can have major effects on ecosystem functioning by the removal of plant species that form important functional groups. This paper documents the changes in floristics in a large group of remnants of native woodland left after agricultural clearing in southwestern Australia. Species richness and diversity were significantly reduced in remnants and the proportion of exotic species increased. Detrended Correspondence Analysis (DCA) was used to identify floristic and environmental patterns among plots and identified two distinct groups based on grazing intensity. This indicated that the significance of the relationship between grazing effects and DCA floristic axes was greater than edaphic characteristics that normally influence floristic patterns. Floristic characteristics of sites that were influencing the position of plots on the ordination diagram included proportion of exotic species and proportion of native perennial shrubs and herbs. Numbers of species of native shrubs and perennial herbs were significantly reduced in grazed plots and numbers of exotic annual grasses and herbs were significantly higher. Other life form groups such as native perennial grasses and geophytes were not significantly affected by grazing. Reproductive strategies of perennial species showed a significant decrease in numbers of resprouters and a significant increase in numbers of facultative seeder/sprouters. Exclosure plots showed increases in number and cover of perennial shrubs and herbs after three years whereas number and cover of exotic species did not change. Time series DCA showed that the floristic composition of exclosure plots in grazed sites became closer to that of the ungrazed sites.     

Study on the effects of different levels of grazing and exclosure on vegetation and soil properties in semi-arid rangelands of Iran

Livestock grazing is one of the main factors of vegetation and soil degradation in arid and semi-arid rangelands of Iran and causes changes in diversity, vegetation, litter and soil characteristics. Therefore, this study has been conducted aimed to examine the effects of exclosure and livestock grazing on vegetation and soil. For this purpose, two grazing areas of medium and high grazing intensity and two exclosure areas (Non-grazing livestock) with duration of 8 and 11 years were selected for sampling. Then, we identified plant species, percentage of coverage of each species, measurement of diversity indices, species similarity and soil chemical properties including electrical conductivity (mho), acidity, organic matter(%), organic carbon (%), nitrogen (%), phosphorus (mg/L) and bulk density (gr/cm³) in each area and they were compared using variance analysis. The results showed that exclosure significantly at 5% level reduced organic matter percentage, electrical conductivity and organic carbon percentage, but it caused a significant increase in soil bulk density at 1% level. Similarity of plant species due to the reduction of livestock grazing intensity and increasing exclosure duration. The results also indicate Livestock grazing increased Coverage of plant family such as Poaceae, Zygophyllacea in the area due to the increase of plant species such as Peganum harmala and Poa bulbosa (non-pleasant species of class III). Based on the results, despite increasing the diversity of plant species in the area over time, increasing diversity does not increase dominant species of the area, as well as companion species increased in the composition of vegetation. It concluded that exclusion has a significant effect on vegetation improvement, vegetation cover percentage, diversity, palatability and litter percentage in the region.     

Long‐term changes in the vegetation after the cessation of livestock grazing in Eucalyptus marginata (jarrah) woodland remnants

This paper documents changes in the floristic composition of Eucalyptus marginata Donn (jarrah) woodlands over 7 years of recovery from continual, intensive livestock grazing. In remnants of native woodland left after agricultural clearing, which have been subjected to livestock grazing, comparisons were made between the floristics of fenced exclosure plots and open plots that continued to be grazed. The vegetation in nearby remnants, which had not been subjected to livestock grazing, was also surveyed. An initial increase in annual exotic pasture species after grazing relief was only temporary and highly influenced by fluctuations in annual climatic patterns, particularly rainfall distribution and abundance. Subsequent years saw a decrease in exotic annuals in exclosure plots and an increase in native perennials, in a trend towards becoming more floristically similar to the ungrazed sites. Germination of overstorey species was observed in the exclosure plots, however, development of seedlings and saplings was sparse. Results indicate that for jarrah woodland in southwestern Australia, natural regeneration is possible after the removal of livestock, with the return (within 6 years) of native species richness to levels similar to those found in ungrazed vegetation. Re‐establishment of cover, however, appears to take longer. The floristic dynamics are described in terms of a nonequilibrium model. Two vegetation states exist, degraded remnants with an understorey dominated by annual species, and ungrazed vegetation with an understorey dominated by perennial shrubs and herbs. The former state is maintained by continual heavy grazing by livestock. Upon relief from grazing, the vegetation undergoes a transition towards floristic similarity to ungrazed vegetation. After 6 years, vegetation change in the exclosure plots appears to be continuing and therefore it is still in transition.     

Herbaceous vegetation change in variable rangeland environments: The relative contribution of grazing and climatic variability

Abstract. A 44‐yr record of herbaceous vegetation change was analysed for three contrasting grazing regimes within a semi‐arid savanna to evaluate the relative contribution of confined livestock grazing and climatic variability as agents of vegetation change. Grazing intensity had a significant, directional effect on the relative composition of short‐ and mid‐grass response groups; their composition was significantly correlated with time since the grazing regimes were established. Interannual precipitation was not significantly correlated with response group composition. However, interannual precipitation was significantly correlated with total plant basal area while time since imposition of grazing regimes was not, but both interannual precipitation and time since the grazing regimes were established were significantly correlated with total plant density. Vegetation change was reversible even though the herbaceous community had been maintained in an altered state for ca. 60 yr by intensive livestock grazing. However, ca. 25 yr were required for the mid‐grass response group to recover following the elimination of grazing and recovery occurred intermittently. The increase in mid‐grass composition was associated with a significant decrease in total plant density and an increase in mean individual plant basal area. Therefore, we failed to reject the hypotheses based on the proportional change in relative response group composition with grazing intensity and the distinct effects of grazing and climatic variability on response group composition, total basal area and plant density. Long‐term vegetation change indicates that grazing intensity established the long‐term directional change in response group composition, but that episodic climate events defined the short‐term rate and trajectory of this change and determines the upper limit on total basal area. The occurrence of both directional and non‐directional vegetation responses were largely a function of (1) the unique responses of the various community attributes monitored and (2) the distinct temporal responses of these community attributes to grazing and climatic variation. This interpretation supports previous conclusions that individual ecosystems may exist in equilibrial and non‐equilibrial states at various temporal and spatial scales.     

Grazing intensity monitoring in Northern China steppe: Integrating CENTURY model and MODIS data

Steppe, an important belt to protect North China from dust storms, is vulnerable and has been degraded in recent decades because of climatic change and heavy grazing. In order to improve steppe management, this study presents a framework for the monitoring of grazing intensity in Xilingol steppe of middle Inner Mongolia, northern China, by integrating the CENTURY ecosystem model-based simulation and remotely sensed MODIS data-based inversion. The CENTURY model worked well after calibrations using field data 1991–1995 of Xilinhaote and Zhenglan Banner observation stations (the correlation coefficient between simulated and observed above ground biomass (AGB) is 0.85). In order to run CENTURY spatially, regional input were formulated including data such as temperature, precipitation, AGB and soil water content (SWC) at the beginning of growing season in 2002, vegetation cover and land use. The modeled AGB at the end of the growing season in 2002 was compared with that inverted from MODIS data. The spatial variation of grazing in the research area was estimated with an iterative adjusting method. Results showed that grazing is variable throughout the study area. Grazing intensity is high and concentrated in the southwest and middle of Abarger Banner, and is low and extensive on the south of Xilinhaote, west of West Ujumchin Banner and northwest of Keshiketeng Banner. This result is comparable with the field conditions. From this work, it can be concluded that human activities such as livestock grazing can be monitored at broad scales with the integration of ecosystem modeling and remote sensing approaches.     

Effect of cattle grazing on soil salinity and vegetation composition along an elevation gradient in a temperate coastal salt marsh of Samborombón Bay (Argentina)

Salt marshes of Samborombón Bay (Argentina) have been grazed sporadically at very low stocking rates, but in the last decade, grazing intensity increased due to agriculture expansion. We investigated the effect of cattle grazing on vegetation and soil salinity on the most extended Spartina densiflora community. This community develops along an elevation gradient where the frequency and duration of tidal flooding and soil salinity increased as elevation decreased. Vegetation and soil data were collected from a national park excluded to cattle grazing for 30 years and from an adjacent commercial livestock farm continuously grazed by cattle. As elevation level decreased, plant cover, richness and diversity of functional groups and species decreased. As we expected, grazing altered soil salinity and vegetation composition in different extent along the elevation gradient. Grazing changed vegetation structure more intensively in the high elevation level because it reduced the competitive exclusion exerted by S. densiflora, allowing the increase in floristic richness. Grazing increased soil salinity and the contribution of salt-tolerant species only in the medium but not in the low elevation level probably because the higher frequency and duration of tidal flooding counterbalanced the increase in evaporation promoted by biomass removal in the low respect to the medium elevation level. While grazing may cause positive impacts for plant conservation in the high elevation level, it may cause negative consequence for livestock production because of the reduction in forage quality along the entire elevation gradient.     

放牧对呼伦贝尔草地植物和土壤生态化学计量学特征的影响

放牧通过畜体采食、践踏和排泄物归还影响草地群落组成、植物形态和土壤养分,植物通过改变养分利用策略适应环境变化。通过分析呼伦贝尔草原放牧和围封样地中的群落植物和土壤的碳氮磷养分及化学计量比,探讨放牧对生态系统化学计量学特征和养分循环速率的影响机制。结果如下:(1)群落尺度上,放牧和围封草地植物叶片C、N和P的含量没有显著差异;但是在种群尺度上,放牧草地植物叶片N含量显著高于围封草地;(2)放牧草地土壤全C、全N、有机C、速效P含量,低于围封草地,硝态N含量高于围封草地;土壤全P和铵态N指标没有显著差异;(3)放牧草地植物C∶N比显著低于围封草地,植物残体分解速率较快,提高了生态系统养分循环速率。     

Grazing effects on herbage nutritive values depend on precipitation and growing season in Inner Mongolian grassland

Aims Grasslands are widely used for production of livestock, which depend on the nutritive value of herbage species. However, there are still large uncertainties as to how grazing, precipitation and growing season interactively affect herbage nutritive value.Methods Here, based on a grazing experiment with seven grazing intensities in an Inner Mongolian grassland since the year 2005, we analysed nutritive value of four dominant grass species from June to September in both a relatively wetter year (2008) and a drier year (2010). Herbage with high nutritive value is characterized by high concentration of crude protein, high concentration of cellulase digestible organic matter and low concentration of neutral detergent fibre.Important findings We found that (i) grazing significantly increased the nutritive value of Leymus chinensis, Agropyron michnoi and Cleistogenes squarrosa but had minor effects on the nutritive value of Stipa grandis. (ii) For all species, nutritive values were greater in the wetter year than in the drier year and were greatest in the early growing season (June) and lowest at the end of the growing season (September). Inter-annual and inter-seasonal variations in nutritive value were much greater for L. chinensis and A. michnoi than for C. squarrosa and S. grandis, suggesting higher water use efficiency for the latter two species. (iii) Grazing significantly decreased the drought resistance of three species, but not of S. grandis. (iv) Grazing significantly increased inter-month variation in nutritive value for L. chinensis and A. michnoi but had relatively minor or no effects on that of C. squarrosa and S. grandis. Therefore, grazing effects on species nutritive values showed strong inter-annual and seasonal patterns, and species-specific responses might be related to species traits (i.e. water use efficiency, digestibility). Our results have important implications for ecosystem management of arid and semi-arid grasslands under intense grazing and global climatic change.     

Manipulation of vegetation communities on the Abu Dhabi rangelands. I. The effects of irrigation and release from longterm grazing

The effect on vegetation communities of release from grazing by camels and goats has been investigated in the Baynunah region of Abu Dhabi emirate, in The United Arab Emirates, by the study of an exclosure established 11 years previously. Also the effect of sprinkle irrigation (in the absence of grazing) on the rangeland vegetation was investigated. Perennial species richness was significantly lower outside the exclosure compared with inside on both sand and gravel substrata. Annual species richness however was not significantly different. Perrenial percentage covers were lower outside the exclosure compared with inside, especially on sand substrata. The perennial grass Stipagrostis plumosa (L) showed the greatest difference in percentage cover in this respect. The species richness of annuals and perennials was not significantly different between irrigated and non-irrigated areas within the exclosure. The perennial percentage cover was much greater on sprinkle irrigated sand and gravel substrata. The perennial which benefited the most was Zygophyllum hamiense, Scweinf. Annual percentage cover was lower in irrigated quadrats. Suggestions are made about the effect of intensive grazing on the vegetation communities at Baynunah and on the effectiveness of irrigation as a tool for increasing the quality of the rangeland for livestock and wildlife.     

Impact of grazing regime on a Mongolian forest steppe

Question: What is the impact of grazing regime on plant species abundance, plant growth form, plant productivity and plant nutrient concentrations in a forest steppe? Location: Hustai National Park in the forest steppe region of Mongolia. Methods: On the Stipa steppe we applied three different grazing regimes by using; (1) one type of exclosure which excluded grazing by large mammalian herbivores, mainly takh (Przewalski horse), (2) another type of exclosure that excluded both large and small (Siberian marmots) mammalian herbivores, and (3) control plots which were freely grazed. We measured species frequencies, tiller densities, plant biomass and nitrogen concentrations of the vegetation. Results: Exclusion from grazing by takh and marmots significantly increased plant standing crop, but marmot grazing and full grazing did not show significant differences. Protection from grazing decreased forage quality, shown by a lower N-concentration of the standing crop. However, this was solely the result of the lower live-dead ratio of the vegetation. The frequency of the rhizomatous Leymus chinensis decreased under reduced grazing, as did the frequency of the total of rhizomatous species. The frequency of Stipa krylovii increased under reduced grazing, as did its basal areas, tiller density and tussock height. Conclusion: Reduced grazing leads to a lower abundance of rhizomatous species and an increase in tussock species.     

Vegetation and soil responses to livestock grazing in Central Asian grasslands: a review of Chinese literature

Grasslands in northern China and the Qinghai-Tibetan plateau are particularly important to both ecosystem functioning and pastoral livelihoods. Although there are numerous degradation studies on the effect of livestock grazing across the region, they are largely only published in Chinese, and most focus on single sites. Based on case studies from 100 sites, covering a mean annual precipitation gradient of 95–744 mm, we present a comprehensive, internationally accessible review on the impact of livestock grazing on vegetation and soils. We compared ungrazed or slightly grazed sites with moderately and heavily grazed sites by evaluating changes in two indicator groups: vegetation (plant species richness, vegetation cover, aboveground biomass, belowground biomass and root/shoot ratio) and soil (pH, bulk density, organic C, total N, total P and available P). Most indicators declined with intensified grazing, while soil pH, bulk density and belowground biomass increased. Available P showed no clear response. Variables within indicator groups were mostly linearly correlated at a given grazing intensity. Relative grazing effects on different indicators varied along specific abiotic gradients. Grazing responses of plant species richness, aboveground biomass, soil bulk density, total N and available P interacted with precipitation patterns, while grazing effects on belowground biomass were influenced by temperature. Elevation had impact on grazing responses of aboveground biomass and soil organic carbon. Complex grazing effects reflect both methodological inconsistency and ecological complexity. Further assessments should consider specific characteristics of different indicators in the context of the local environment.     

Livestock grazing affects vernal pool specialists more than habitat generalists in montane vernal pools

Questions

Do livestock grazing and seasonal precipitation structure species composition in montane vernal pools? Which grazing and precipitation variables best predict cover of vernal pool specialists and species with broader habitat requirements? Is vernal pool species diversity correlated with livestock exclosure, and at what spatial scales?

Location

Montane vernal pools, northeast California, USA.

Methods

Vegetation was sampled in 20 vernal pools, including pools where livestock had been excluded for up to 20 years We compared plant species composition, functional group composition and species diversity among sites that varied in grazing history and seasonal precipitation using CCA and LMM.

Results

Although vernal pool specialists were dominant in montane vernal pools, over a third of plant cover was comprised of species that occur over a broad range of wetland or upland environments. The species composition of vernal pool plant communities was influenced by both livestock grazing and precipitation patterns, however the relative effects of these environmental variables differed by functional group. Livestock exclosures favoured perennial vernal pool specialists over annual vernal pool specialists. In contrast, the cover of habitat generalists was more strongly influenced by seasonal precipitation than livestock grazing. At small spatial scales, species richness and diversity decreased as the number of years a pool had been fenced increased, but this relationship was not significant at a larger spatial scale.

Conclusions

Both livestock grazing and seasonal precipitation structure the montane vernal pool plant community. We found that livestock grazing promotes the cover of annual vernal pool specialists, but at the expense of perennial vernal pool specialists. Wetter vernal pools, however, support higher cover of wetland generalist species regardless of whether pools are grazed.     

Short-term responses of rehabilitating coastal dune forest ground vegetation to livestock grazing

We investigated the responses of the ground vegetation in a 17‐year‐old coastal dune forest plant community to four levels of experimentally applied livestock grazing (three grazing levels and one ungrazed control) from May 1994 to March 1996. The effects of grazing were apparently subordinate to site‐specific intrinsic vegetation change and there were some indications that rainfall interacted with grazing level. Grazing had some apparent but no significant effects on plant species composition, significantly affected plant species richness over time, and significantly increased the range of species richness and vegetation cover values as well as the relative abundance and numbers of plant species with erect growth forms. Vegetation cover changed significantly over time, independently of grazing. Our results point to two important, easily measured mechanisms for the conservation management of coastal dune forests – the interaction of disturbance type with plant growth form and the increase of variation in community structural variables under disturbance. These mechanisms, although they potentially have wide application and predictive power, have not been studied adequately.     

Mediating Water Temperature Increases Due to Livestock and Global Change in High Elevation Meadow Streams of the Golden Trout Wilderness

Rising temperatures due to climate change are pushing the thermal limits of many species, but how climate warming interacts with other anthropogenic disturbances such as land use remains poorly understood. To understand the interactive effects of climate warming and livestock grazing on water temperature in three high elevation meadow streams in the Golden Trout Wilderness, California, we measured riparian vegetation and monitored water temperature in three meadow streams between 2008 and 2013, including two “resting” meadows and one meadow that is partially grazed. All three meadows have been subject to grazing by cattle and sheep since the 1800s and their streams are home to the imperiled California golden trout (Oncorhynchus mykiss aguabonita). In 1991, a livestock exclosure was constructed in one of the meadows (Mulkey), leaving a portion of stream ungrazed to minimize the negative effects of cattle. In 2001, cattle were removed completely from two other meadows (Big Whitney and Ramshaw), which have been in a “resting” state since that time. Inside the livestock exclosure in Mulkey, we found that riverbank vegetation was both larger and denser than outside the exclosure where cattle were present, resulting in more shaded waters and cooler maximal temperatures inside the exclosure. In addition, between meadows comparisons showed that water temperatures were cooler in the ungrazed meadows compared to the grazed area in the partially grazed meadow. Finally, we found that predicted temperatures under different global warming scenarios were likely to be higher in presence of livestock grazing. Our results highlight that land use can interact with climate change to worsen the local thermal conditions for taxa on the edge and that protecting riparian vegetation is likely to increase the resiliency of these ecosystems to climate change.     

Climate change and variability impacts on grazing herds: Insights from a system dynamics approach for semi‐arid Australian rangelands

Grazing livestock are an important source of food and income for millions of people worldwide. Changes in mean climate and increasing climate variability are affecting grasslands' carrying capacity, thus threatening the livelihood of millions of people as well as the health of grassland ecosystems. Compared with cropping systems, relatively little is known about the impact of such climatic changes on grasslands and livestock productivity and the adaptation responses available to farmers. In this study, we analysed the relationship between changes in mean precipitation, precipitation variability, farming practices and grazing cattle using a system dynamics approach for a semi‐arid Australian rangeland system. We found that forage production and animal stocking rates were significantly affected by drought intensities and durations as well as by long‐term climate trends. After a drought event, herd size recovery times ranged from years to decades in the absence of proactive restocking through animal purchases. Decreases in the annual precipitation means or increases in the interannual (year‐to‐year) and intra‐annual (month‐to‐month) precipitation variability, all reduced herd sizes. The contribution of farming practices versus climate effect on herd dynamics varied depending on the herd characteristics considered. Climate contributed the most to the variance in stocking rates, followed by forage productivity levels and feeding supplementation practices (with or without urea and molasses). While intensification strategies and favourable climates increased long‐term herd sizes, they also resulted in larger reductions in animal numbers during droughts and raised total enteric methane emissions. In the face of future climate trends, the grazing sector will need to increase its adaptability. Understanding which farming strategies can be beneficial, where, and when, as well as the enabling mechanisms required to implement them, will be critical for effectively improving rangelands and the livelihoods of pastoralists worldwide.     

Carbon sequestration and soil restoration potential of grazing lands under exclosure management in a semi‐arid environment of northern Ethiopia

Exclosures are used to regenerate native vegetation as a way to reduce soil erosion, increase rain water infiltration and provide fodder and woody biomass in degraded grazing lands. Therefore, this study assessed the impact of grazing exclosure on carbon sequestration and soil nutrients under 5 and 10 years of grazing exclosures and freely grazed areas in Tigray, northern Ethiopia. Carbon stocks and soil nutrients increased with increasing grazing exclusion. However, open grazing lands and 5 years of grazing exclosure did not differ in above‐ and belowground carbon stocks. Moreover, 10 years of grazing exclosure had a higher (p < 0.01) grass, herb and litter carbon stocks compared to 5 years exclosure and open grazing lands. The total carbon stock was higher for 10 years exclosure (75.65 t C ha^‐1) than the 5 years exclosure (55.06 t C ha^‐1) and in open grazing areas (51.98 t C ha^‐1). Grazing lands closed for 10 years had a higher SOC, organic matter, total N, available P, and exchangeable K + and Na + compared to 5 year's exclosure and open grazing lands. Therefore, establishment of grazing exclosures had a positive effect in restoring degraded grazing lands, thus improving carbon sequestration potentials and soil nutrients.     

Changes in species diversity and canopy cover in steppe vegetation in Inner Mongolia under protection from grazing

This study describes changes in species diversity and canopy cover in relation to variation in livestock grazing in a semi-arid area in Inner Mongolia, China. Canopy cover for each species was recorded 2 and 3 years after cessation of livestock grazing, as well as in an area with continued grazing. Total species richness, alpha diversity, beta diversity and canopy cover were analysed. Sixty species were recorded during the study; 25 of them were annuals. The total number of species was the same, 52, in the grazed and the protected area, but species richness and alpha diversity per plot were lower in the area protected from grazing. The beta diversity showed little difference between the protected area and the grazed control. The total canopy cover was highest in the protected area, but the cover of annuals was higher in the grazed area. In CA ordination, the difference between treatments increased with time of protection. However, in the short period covered by this study it was difficult to separate the effects of protection from grazing and fluctuation in weather conditions, particularly of precipitation.     

Long-Term Effects of Black-Tailed Prairie Dogs on Livestock Grazing Distribution and Mass Gain

The conservation and management of black-tailed prairie dogs (Cynomys ludovicianus) have been contentious issues in grasslands of central North America for much of the past century, primarily because of the perception that they compete with livestock for forage. Studies quantifying the magnitude of competition between prairie dogs and cattle are difficult to conduct because of the large spatial and long temporal scales needed to quantify how competition varies in response to interannual variation in precipitation and prairie dog abundance. We examined variation in mass gains of yearling steers in shortgrass steppe of northeastern Colorado, USA, with and without prairie dogs from 2008–2019, a period that encompassed a full cycle in prairie dog abundance from a nadir following plague-induced population collapse, to peak abundance following population recovery, to plague-induced population lows again. Analyses of cattle grazing distribution with global positioning system (GPS)-collars revealed preferential grazing on colonies following a period of unusually high vegetation production, and preferential grazing off colonies following a period of rapid vegetation senescence, but these patterns were not clearly related to cattle mass gains. Across all 12 years of the study, average daily mass gain (ADG) during the growing season was 0.97 kg/steer/day in pastures where prairie dogs were controlled annually, and 0.95 kg/steer/day in pastures where they were not. Average daily mass gain was a quadradic function of precipitation and a linear function of prairie dog occupancy within a pasture, with a generalized linear mixed model predicting an 8.0% decrease in ADG as prairie dog occupancy increased from 0 to 60% of a pasture with average growing-season precipitation. We did not detect a significant interaction between precipitation and prairie dog occupancy, but one limitation of our study is that the only drought year (2012) occurred when prairie dogs occupied low percentages (10–25%) of the study pastures. Prairie dogs had a small but detectable negative effect on cattle mass gains during the growing season in shortgrass steppe. The magnitude of this effect can be used by managers in combination with market conditions and the spatial extent of prairie dog colonies to estimate economic effects of prairie dogs on livestock operations. © 2021 The Wildlife Society. This article is a U.S. Government work and is in the public domain in the USA.