Livestock Grazing Intensity Research Articles

The Effect of Grazing Intensity on Vegetation Coverage and Nitrogen Mineralization Kinetics of Steppe Rangelands of Iran (Case Study: Nodoushan Rangelands, Yazd, Iran)

Livestock grazing can affect the cycling of nutritional elements in soil by making changes to the vegetation coverage. This study aimed to investigate the effect of rangeland exploitation on vegetation coverage and nitrogen kinetics. To this end, three experimental sites of light, moderate, and heavy grazing in Nodoushan rangelands of Yazd province were selected. The vegetation properties were then measured through systematic random sampling method and three to five bases along the transect were sampled from the current year growth of the dominant plants in the region. The soil samples were collected from 0–15 cm depth in five replications and mixed together to obtain a single composite soil sample on each site. In the first stage, nitrogen (N), carbon (C), C/N, cellulose, hemicellulose, and lignin of the sampled plant as well as nitrogen, carbon, lime, soil texture, saturation moisture percentage, pH, and electrical conductivity (EC) of the soil were measured. As the soil properties did not differ for light and moderate grazing soils, different treatments were conducted on the dominant species of light and heavy grazing sites with 1% organic carbon added to the rangeland soil. Nitrogen mineralization treatments were selected based on vegetation changes that, with increasing livestock grazing intensity, changed the predominance of plant composition from Artemisia sieberi and steppe to percentage Artemisia sieberi and Peganum harmala. The treatments included control, 100% Artemisia sieberi, 75% Artemisia sieberi and 25% Peganum harmala, 50% Artemisia sieberi and 50% Peganum harmala, 25% Artemisia sieberi and 75% Peganum harmala, and 100% Peganum harmala. The soil samples were incubated for pure nitrogen mineralization in three replications of 3 months. The results of nitrogen mineralization revealed that the immobilization of the treated soil with higher Artemisia sieberi and lower Peganum harmala was done at a more rapid rate during the first week. The immobilization was slowly reduced by the third week and then followed a growing rate. Overall, the results show that an increase in grazing intensity was associated with a change in vegetation coverage toward Peganum harmala species, the biochemical characteristics of which elevated the levels of pure nitrogen mineralization in soil.

A scientific basis for promoting grassland ecosystemmultifunctionality by diversifying grazing livestock: A review

The grassland is the largest terrestrial ecosystem in the world. How to manage and maintain grassland ecosystem functionality is becoming a critical issue as grasslands face serious degradation under the increasing pressures of global change. Livestock grazing is one such pressure, and it is the most widespread land use on Earth. Here, we explore theories and empirical evidence regarding how diversifying grazing livestock species and breeds could potentially improve grassland ecosystem multifunctionality. First, livestock grazing has been known to affect grassland multitrophic biodiversity, and thereby ecosystem multifunctionality. Different livestock species, such as cattle and sheep, vary in their foraging mode, diet, trampling effect and movement as well as in the quantity, distribution, and chemical composition of their excreta deposited in grasslands. As a result, diversity in livestock grazers leads to a variety of disturbances, higher landscape heterogeneity and more varied niches for plants, insects and soil organisms to inhabit. Therefore, diversity in grazers promotes higher overall ecosystem biodiversity. Second, livestock is an important dispersal agent for plants because they reduce intraspecific competition, minimize loss of genetic diversity and mitigate inbreeding. This leads to a more viable and diverse plant population. Third, diverse livestock species in natural grassland ecosystems may ecologically replace large-bodied and extinct native herbivores, and they certainly directly increase herbivore diversity, in grassland ecosystems. Finally, when a variety of livestock species or breeds grazes in the same grassland, it can lead to complex multi-species interactions. These interactions can be attributed to different nutritional demands and selections, and they thus greatly enhance trophic complexity and ecosystem functioning. At its core, the theory of diversifying livestock grazing aims to choose herbivores with different morphological, physiological or behavioral characteristics to thereby exert diverse disturbance on grasslands, rather than a single stressor. These diversified groups of livestock could comprise animal species of different functional groups, such as grazers and browsers, different species of the same functional group, or even different breeds of the same species. The greater the morphological, physiological and behavioral differences among livestock, the more sustainable is the grazing. Further, this diversity can also be created by adjusting the relative abundance of each species or variety, or by adopting one of two grazing modes; where all livestock graze in the same grassland at the same time (i.e., mixed grazing), or at different times (i.e., alternate grazing). In conclusion, altering livestock species composition and grazing intensity may improve grassland ecosystem functioning. We suggest that the ecological effects of grazing by diversifying livestock species and breeds should be empirically tested across different grassland types worldwide, and each specific mode of diversifying livestock grazing should be explored in turn. Future studies should test the following key questions: (1) Can altering the proportion or grazing sequence of different livestock species help achieve optimal grazing by multiple livestock species? (2) How do introduced diverse livestock interact with native herbivores? (3) Can diverse livestock be used as a long-term ecological substitute for large wild herbivores to maintain grassland ecosystem functioning?

Converting rangelands to reserves: Small mammal and reptile responses 24 years after domestic livestock grazing removal

AbstractWith one million species threatened with extinction and more than a third of terrestrial Earth now devoted to crop or livestock production, many conservation organisations are acquiring land, destocking and converting them to national parks or conservation reserves. When pastoral properties are acquired, destocking is often the first management action. Species responses to destocking are varied and largely associated with changes in ground vegetation complexity. However, studies over short timeframes may fail to capture the often slow and episodic recovery post‐destocking, particularly in arid and semi‐arid ecosystems. In this study, we examined the response of small mammals and reptiles between 6 and 24 years since destocking in mallee (Eucalytpussp.) andCasuarinavegetation communities in semi‐arid Australia. As casuarina sites were closer to water than mallee, they were subject to higher domestic livestock grazing intensity, and higher grazing pressure from invasive goats and native kangaroos after livestock were removed. We related faunal abundance and diversity to time‐since‐destocking, fractional cover, rainfall and temperature and described compositional dynamics. We found that the vegetation types had distinct fauna communities and unique recovery trajectories. In mallee, reptile abundance and diversity increased with time‐since‐destocking but did not change in casuarina. Small mammal response to time‐since‐destocking was non‐linear and strongly influenced by rainfall. Overall, the mallee community showed signs of recovery, but recovery was less evident in the more degraded casuarina. We highlight that destocking ex‐pastoral properties is rarely a restoration ‘quick‐fix’ and land managers must deal with a complex legacy of impacts, when converting pastoral land to conservation reserves.

Responses of soil moisture to climate variability and livestock grazing in a semiarid Eurasian steppe

Soil water is vital for sustaining semiarid ecosystems. However, data on soil moisture have unlikely been continuously collected for a long time (e.g., >50 years), let alone under various combinations of climates and livestock grazing intensities. The objective of this study was to formulate and parameterize an ecohydrological model for predicting long-term variability of soil moisture, taking a typical Eurasian grassland located in northeast China as the testbed. The parameters were determined by extensive literature review, field reconnaissance, laboratory analyses of soil and grass samples, and model calibration using daily soil temperatures and soil moistures measured at four depths from 2014 to 2017. The model, driven by the daily climate data from 1955 to 2017, performed well in reproducing the measurements. Across the assessment years of 1960 to 2017, the daily soil moistures were predicted to vary from 0.02 to 0.38. Overall, the soil moistures at a shallower depth were smaller but had a wider range than those at a deeper depth, with a largest mean and a widest range around the 30 cm depth. Regardless of the depths, the soil moistures pulsed in beginning March and plateaued from May to September. Livestock grazing was precited to reduce top 1.5-cm soil moistures but increase moistures of the beneath soils. The optimal grazing intensity was determined to be around 3.0 cattle ha−1, above which wind erosion would become a concern. The grazing impacts on soil moisture were found to monophonically decrease with increase of evapotranspiration or annual precipitation of larger than 220 mm. For the years with an annual precipitation of less than 220 mm, such grazing impacts either increased or decreased with increase of precipitation, depending on the relative magnitude of evapotranspiration. Climate change will diminish soil moisture pulses in early spring, likely intensifying soil erosion by wind.

Climate Variability Rather Than Livestock Grazing Dominates Changes in Alpine Grassland Productivity Across Tibet

Alpine grasslands on the Tibetan Plateau, being vulnerable to environmental and anthropogenic changes, have experienced dramatic climate change and intensive livestock grazing during the last half-century. Climate change, coupled with grazing activities, has profoundly altered alpine grassland function and structure and resulted in vast grassland degradation. To restore degraded grasslands, the Central Government of China has implemented the Ecological Security Barrier Protection and Construction Project since 2008 across the Tibetan Autonomous Region. However, the relative effect of climate change and grazing activities on the variation in alpine grassland productivity is still under debate. In this study, we quantified how aboveground net primary production (ANPP) varied before (2000–2008) and after (2009–2017) starting the project across different alpine grasslands and how much variance in ANPP could be attributed to climate change and grazing disturbance, in terms of temperature, precipitation, solar radiation, and grazing intensity. Our results revealed that Tibet’s climate got warmer and wetter, and grazing intensity decreased after starting the project. Mean ANPP increased at approximately 81% of the sites, on average from 27.0 g C m–2 during 2000–2008 to 28.4 g C m–2 during 2009–2017. The ANPP positively correlated with annual temperature and precipitation, but negatively with grazing intensity for both periods. Random forest modeling indicated that grazing intensity (14.5%) had a much lower influence in controlling the dynamics of grassland ANPP than precipitation (29.0%), suggesting that precipitation variability was the key factor for alpine grassland ANPP increase across Tibet.

Impact of livestock grazing intensity on plant diversity of montane grassland in the northern Drakensberg, South Africa

Communal livestock grazing is expected to impact botanical composition and plant diversity of Drakensberg montane grasslands. Accordingly, a grazing gradient extending outward from kraals, and fence-line contrasts between communal rangeland and protected areas (Golden Gate Highlands National Park and Royal Natal National Park), were studied in the QwaQwa region of South Africa. Presence of a grazing gradient was confirmed by a decrease in the amount of cattle dung with increasing distance from kraals that was independent of altitude, solar radiation, slope, or soil physico-chemical properties. Canonical correspondence analysis confirmed that grazing intensity had a significant influence on botanical composition although most compositional variation was unexplained. Higher grazing intensities tended to negatively affect plant species richness and diversity, and the cover of perennial graminoids, but benefitted the abundance of dwarf shrubs and alien invasive species. Similar effects were apparent across each of the fence line contrasts. Despite a long history of livestock grazing, communal rangeland supported >320 indigenous species, illustrating some contribution to biodiversity conservation, but being compromised near kraals. An improved approach for study of the impacts of livestock grazing on plant diversity is suggested that would overcome the difficulties of assessing rare and threatened species using a community approach.

Effects of different livestock grazing intensities on plant cover, soil properties, and above and below ground C and N pools in arid ecosystems (Jiroft rangeland, Iran)

This study was conducted in Jiroft rangeland, Kerman, Iran to assess the effects of different livestock grazing intensities (low, moderate, heavy) on ecological factors, soil properties, and root and shoot carbon and nitrogen pools. In each plant sampling site, five points were selected and five quadrates (a total of 75 quadrats) were investigated. Soil surface samples were taken in quadrats (75 samples). Data analysis was carried out by analysis of variance (SPSS18.0). Findings indicated that canopy cover (46.23%) had the maximum level in the low grazing site. The diversity index was maximum in the overgrazed site (1.63), while the low grazing site had the minimum species diversity (1.27). In the three sites, the nitrogen and carbon pools were higher in the roots compared to the shoots. In the low grazing site, the plants' nitrogen and carbon pools were notably more than the heavy and moderate grazing sites. Potassium (612.87 mg kg-1), nitrogen (3.30 g kg-1), and organic carbon (39.20 mg kg-1) were considerably higher under heavy grazing conditions. However, the low grazing condition resulted in notable enrichment of phosphorus (11.44 mg kg-1). The soil nitrogen and carbon pool in the overgrazed site were higher. In spite of the fact that the soil nutrients in the heavy grazed site were higher because of livestock manure; we could not interpret it as greater soil fertility. Our results suggest that low grazing can be effective for managing plant community and soil quality in arid ecosystems.

Spatial Utilization and Microhabitat Selection of the Snow Leopard (Panthera uncia) under Different Livestock Grazing Intensities

AbstractThere is increasing conflict between snow leopards and humans in many protected areas, the main driver of which is the overlap in spatial utilization between snow leopards and livestock. Understanding the spatial utilization and microhabitat selection of snow leopards in areas featuring different levels of livestock grazing is important to better understand and resolve this conflict, but such studies are rare. Here, we conducted line transect and plot surveys in low- and high-grazing-disturbance areas (LGDAs and HGDAs) in Wolong National Reserve, southwestern China. We compared snow leopard spatial utilization and microhabitat characteristics between LGDAs and HGDAs. Results showed that snow leopards had aggregated distribution in both LGDAs and HGDAs, but the distribution of snow leopards in HGDAs was more centralized than in LGDAs. Herb cover and height in LGDAs were greater than in HGDAs. We fit a resource selection function (RSF) that showed that snow leopards preferentially selected higher elevation, smaller basal diameter of shrubs, and lower height of herbs in LGDAs. In contrast, there were no significant microhabitat factors in our snow leopard RSF in HGDAs. Our results indicate that high-intensity grazing tends to reduce the habitat types available to and preferential selectivity of habitat by snow leopards. We recommend that livestock grazing should be controlled to restore the diversity of the alpine ecosystems in Wolong Nature Reserve. Our findings also highlight the need for evaluating the impact of livestock grazing on rare animals in alpine environments (e.g., snow leopard) in other areas facing similar issues.

Diet Overlap Between Livestock and Wild Herbivores in the Greater Himalaya

Understanding the niche usage and dietary habits of wild ungulate populations is crucial to monitoring their response to livestock grazing and changes in habitat quality. Livestock grazing is common throughout the Himalaya and may reduce available forage for wild ungulates, but few studies have assessed the impact of livestock grazing on the diets of wild herbivores in the Greater Himalaya. We assessed forage availability and used microhistological analysis to compare the diet composition of livestock (domestic goats and sheep) and 2 wild herbivores (blue sheep Pseudois nayaur and musk deer Moschus sp.) in the Uttarkashi district of Uttarakhand, India. We calculated the diet preference and niche breadth of each species and the diet overlap between each pair of species. Our results suggest that musk deer may browse trees more than previously understood. In addition, blue sheep consumed fewer graminoids in the autumn than has been previously published. The seasonal increase in shrub and herb consumption by blue sheep during the winter may be amplified and shifted to earlier in the year as a result of reduced graminoid availability after intensive livestock grazing. We recommend monitoring livestock numbers in the study area and limiting livestock to current numbers to avoid further reducing forage availability.

Four millennia of vegetation and environmental history above the Hyrcanian forest, northern Iran

Past vegetation, fire, and climate dynamics, as well as human impact, have been reconstructed for the first time in the highlands of the Gilan province in the Alborz mountains (above the Hyrcanian forest) for the last 4,300 cal yrs bp. Multi-proxy analysis, including pollen, spores, non-pollen palynomorphs, charcoal, and geochemical analysis, has been applied to investigate the environmental changes at 2,280 m a.s.l., above the Hyrcanian forest. Dominant steppe vegetation occurred in the study area throughout the recorded period. The formation of the studied mire deposits, as well as vegetation composition, suggest a change to wetter climatic conditions after 4,300 until 1,700 cal yrs bp. Fires were frequent, which may imply long-lasting anthropogenic activities in the area. Less vegetation cover with a marked decrease of the Moisture Index (MI) suggests drier conditions between 1,700 and 1,000 cal yrs bp. A high proportion of Cichorioideae and Amaranthaceae, as well as the reduction of trees, in particular Fagus and Quercus, at lower elevations, indicate human activities such as intense livestock grazing and deforestation. Soil erosion as the result of less vegetation due to dry conditions and/or human activities can be reconstructed from a marked increase of Glomus spores and high values of K and Ti. Since 1,000 cal yrs bp, the increasing MI, as well as the rise of Poaceae and Cyperaceae together with forest recovery, suggest a change to wetter conditions. The occurrence of still frequent Cichorioideae and Plantago lanceolata along with Sordaria reflect continued intense grazing of livestock by humans.

Grassland greening on the Mongolian Plateau despite higher grazing intensity

AbstractChanges in land management and climate alter vegetation dynamics, but the determinants of vegetation changes often remain elusive, especially in global drylands. Here we assess the determinants of grassland greenness on the Mongolian Plateau, one of the world's largest grassland biomes, which covers Mongolia and the province of Inner Mongolia in China. We use spatial panel regressions to quantify the impact of precipitation, temperature, radiation, and the intensity of livestock grazing on the normalized difference vegetation indices (NDVI) during the growing seasons from 1982 to 2015 at the county level. The results suggest that the Mongolian Plateau experienced vegetation greening from 1982 to 2015. Precipitation and animal density were the most influential factors contributing to higher NDVI on the grasslands of Inner Mongolia and Mongolia. Our results highlight the dominant effect of climate variability, and especially of the precipitation variability, on the grassland greenness in Mongolian drylands. The findings challenge the common belief that higher grazing pressure is the key driver for land degradation. The analysis exemplifies how representative wall‐to‐wall results for large areas can be attained from exploring space–time data and adds empirical insights to the puzzling relationship between grazing intensity and vegetation growth in dryland areas.

Disassembled Food Webs and Messy Projections: Modern Ungulate Communities in the Face of Unabating Human Population Growth

The human population grows inexorably. When Charles Darwin explored the southern cone of South America in 1830, fewer than 1.2 billion people inhabited Earth. When Ehrlich’s Population Bomb appeared in 1968 there were ~3.5 billion. We approach eight billion today, and biospheric impacts do not abate. We’ve affected most life forms through climate modification, harvest, erasure and fragmentation of habitat, disease, and the casting of alien species. Given the lack of abatement in human population growth, herein we focus on the modalities of ecological disruption – direct and indirect – that mitigate the changing role of ungulates in landscapes. Much of what was once generally predictable in terms of pattern and process is no longer. Offshore climatic events have strong onshore consequence, as exemplified by toxic algal blooms in the Patagonian Pacific. These have diminished the harvest of fish and likely resulted in fisherman using dogs to hunt huemul (Hippocamelus bisulcus), the most endangered large terrestrial mammal of the Western Hemisphere. Similarly, human economies foment change in the Himalayan realm and Gobi Desert by increasing numbers of cashmere-producing goats, and where dogs that once followed tourists or guarded livestock they now hunt a half dozen threatened, endangered, and rare ungulates including kiang (Equus kiang) and chiru (Pantholops hodgsonii), saiga (Saiga tatarica) and takin (Budorcas taxicolor), spread disease, and displace snow leopards (Panthera uncia). In North America’s Great Basin Desert, one hundred years of intense livestock grazing created a phase shift by which changed plant communities enabled mule deer (Odocoileus hemionus) colonization. An altered predator-prey system ensued with the arrival of pumas (Panthera concolor). Patterns of resilience postulated by Hollings (1973) become more difficult to witness in the absence of humans as our domination of earth destabilizes systems beyond return points. These include ungulates both in and out of protected areas. Consequently, only messy projections of future community reorganization seem reasonable whether related to food webs or assembly rules that once governed ungulate communities of the very recent past.

Salix herbacea L. (Salicaceae) in the Maramures massif of the Ukrainian Carpathians

Salix herbacea is a relict plant species related to the circumpolar arctic-alpine element of the Holarctic group. The aim of the study was to clarify the data on the distribution of S. herbacea within the Maramures massif of the Ukrainian Carpathians, since this species is reported by different authors for the massif without specific geographical and habitats descriptions. Field studies were conducted in the Maramures massif on the slopes of Pip Ivan Marmarosky (1936 m a.s.l.) and Rapa (1872 m a.s.l.) mountains in 2017–2019. The S. herbacea distribution chorology was analyzed on the basis of the inventory of UU, KW, KWHA, LW, Herbarium of the Carpathian Biosphere Reserve and Herbarium of the Biology and Ecology Department of the Vasyl Stefanyk Precarpathian National University collections. We have found S. herbacea confined to cliffs on a rocky tourist path between the peaks of Pip Ivan Marmarosky and Rapa mountains in Rakhiv district of Transcarpathian region (Zakarpattia oblast). Moreover, these rocky formations were colonized by tall grasses such as Calamagrostis villosa, Poa pratensis, and Festuca picturata. Also was found the occurrence of Holarctic and Alpine-Carpathian species Vaccinium uliginosum, Potentilla aurea, Pulsatilla alba, Thamnolia vermicularis, and Cetraria islandica. The occurrence of these species was caused by decreasing livestock grazing intensity during the past years in this area. The exact location and phytocoenological conditions of the site, which is endangered and requires additional conservation measures, were outlined. The necessity of these measures to preserve the habitat of S. herbacea on the Maramures massif was stressed out.

Livestock grazing impacts components of the breeding productivity of a common upland insectivorous passerine: Results from a long‐term experiment

Abstract The intensity of pastoral management in areas of High Nature Value farming is declining in some regions of Europe but increasing in others. This affects open habitats of conservation concern, such as the British uplands, where bird species that benefit from low‐intensity grazing may be most sensitive to such polarization. While experimental manipulations of livestock grazing intensities have improved our understanding of upland breeding bird responses in the short term, none have examined the long‐term impacts of altered management on reproductive success. Using a replicated landscape‐scale experiment that started in 2003, we investigated the effects of four grazing treatments (intensive sheep; low‐intensity sheep; low‐intensity mixed sheep and cattle; and no grazing) on the breeding productivity of meadow pipits Anthus pratensis, the most common upland passerine. Surveys were carried out systematically during early (2003 and 2004) and late (2015 and 2016) sampling periods of the experiment to compare the short‐ and long‐term effects of grazing treatments on breeding density and productivity of pipits specifically, but also on the overall bird community. Pipit breeding density was lowest under low‐intensity sheep grazing while the highest egg‐stage nest survival was observed in the same treatment, although no significant treatment effects were detected on overall nest survival or fledgling output. There were no significant differences in treatment effects between the sampling periods on any breeding variable, but overall nest survival was lower in the later sampling period across all treatments. Breeding bird species richness differed between treatments in the later sampling period, with highest species richness in the ungrazed treatment. Synthesis and applications. Livestock grazing management can have different outcomes for different upland birds. Our results showed that, with time, meadow pipit breeding productivity tended to be higher when sheep grazing intensity was reduced and/or mixed with cattle, and lower when livestock were removed, but not significantly so. Removal of grazing, however, can significantly increase bird species richness. The long‐term experiment showed an overall decline in fledglings regardless of grazing treatments, potentially a result of increased predator numbers harboured by nearby developing woodland, highlighting the importance of considering wider landscape processes in grazing management decisions.

Relatively undisturbed African savannas - an important reference for assessing wildlife responses to livestock grazing systems in European rangelands

In this study, we analyze and compare wildlife response patterns to livestock grazing systems in distinct grassland ecosystems in central Europe and sub-Saharan Africa. The main hypothesis is that relatively undisturbed African savannas can function as reference for a more sustainable management of highly transformed central European rangelands. We conducted four camera trap surveys (case studies) in three countries (Germany, Namibia and Tanzania) to observe communities of medium-sized and large mammals on pastures adjacent to protected areas (Lower Oder Valley National Park and Westhavelland Nature Park in Germany, Etosha National Park in Namibia, and Serengeti National Park in Tanzania). Within each case study, we comparatively examined a scenario where livestock was present and a scenario where livestock was absent (within-site comparison). A cross-regional phenomenon in all four case studies was that regardless of the different grazing system, presence of livestock was associated with a significant reduction in total wildlife activity (relative capture frequency, RCF) and a shift in daily activity towards night hours in various wildlife species. We found a region-specific difference in the daily activity patterns of livestock (less active during night in Africa). The comparison of phylogenetically closely related wildlife species/species groups or those with similar ecological functions in European and African wildlife communities reveals common response patterns (e.g. within-site change in RCF of medium-sized canids and suids), as well as region-specific differences (e.g. within-site change in RCF of small browsers). Results from Serengeti Region are an indicator of the extreme transformation of the landscape and pronounced human-wildlife conflicts. Results from Etosha Region reveal significantly lower RCFs of predominantly large ungulate species associated with livestock grazing. Similar and moderate response patterns of wildlife to different livestock grazing systems in Germany (rotational vs. “naturalistic” grazing) lead to a critical evaluation of the benefit of “naturalistic grazing”. Pronounced differences in the responses of wildlife communities to livestock grazing systems in Africa reveal a broad range of measurable effects. In Europe, differences between wildlife responses to less and more intense livestock grazing are expressed via a limited range of measurable effects. Our findings highlight the importance of less disturbed African ecosystems for the development of effective management strategies in more transformed geographical regions.

Livestock and kangaroo grazing have little effect on biomass and fuel hazard in semi-arid woodlands

Using livestock grazing as a tool to manage biomass and reduce fuel hazard has gained widespread popularity, but examples from across the globe demonstrate that it often yields mixed, context-dependent results. Grazing has potential to deliver practical solutions in systems where grazing reduces not only biomass but also reduces fuel hazard by altering vegetation connectivity or composition. We assessed the extent to which recent rainfall, rabbit and kangaroo grazing and recent and historic livestock grazing alters and accounts for variation in above-ground biomass, biomass composition and fuel hazard ratings across three broad communities in eastern Australia. We used nested linear models to assess biomass in three vertical vegetation strata, that matched the strata assessed in the Overall Fuel Hazard Assessment guide (i.e. litter/surface fuel; groundstorey vegetation/near surface fuel; and midstorey vegetation/elevated fuel) and Ordinal Logistic Regression to assess categorical fuel hazard ratings. Only recent kangaroo grazing reduced groundstorey biomass across all communities. Kangaroo grazing altered litter mass and significantly reduced surface fuel hazard in one community. Recent livestock grazing did not reduce fuel hazard, and despite significantly reducing half of our measures of biomass, these were not practical reductions. For instance, livestock grazing significantly reduced litter mass, however our model predicts that doubling our assessment of livestock grazing intensity only reduces total litter mass by 0.8%, or 8 kg per hectare in landscapes where average litter loads ranged from 3600 to 12,600 kg per hectare. Furthermore, long-term livestock grazing increased shrub biomass and in one community this increased elevated fuel hazard. There were few effects of rabbits. The effects of rainfall on biomass were up to an order of magnitude greater than any effects due to grazing, despite sampling during relatively average rainfall conditions. Our data suggest that management practices that seek to use livestock grazing to reduce biomass or its connectivity in these systems will not achieve practical reductions in biomass and or fuel hazard.

Effects of livestock grazing intensity on soil arbuscular mycorrhizal fungi and glomalin-related soil protein in a mountain forest steppe and a desert steppe of Mongolia

Arbuscular mycorrhizal fungi (AMF) are important components of the grassland ecosystems in terms of plant phosphorus uptake and accumulation of glomalin-related soil protein (GRSP). Though Mongolian grasslands are seriously degraded by livestock grazing, the effects of grazing on soil AMF and GRSP remain unclear. Here, we examined community composition and diversity of AMF as well as amount of GRSP at three different grazing intensities: lightly grazed (LG), moderately grazed (MG), and heavily grazed (HG) under two different types of grassland, mountain forest steppe at Hustai and desert steppe at Mandalgobi. The diversity and biomass of AMF-host and non-AMF plants strongly affected the overall AMF community composition and its diversity. When we separately analyzed the factors affecting soil AMF diversity at Hustai and Mandalgobi, decrease in the shoot biomass of Poaceae plants at Hustai and decreases in the species number and shoot biomass of AMF-host plants at Mandalgobi were significantly correlated with AMF diversity. GRSP decreased with increasing grazing intensity, which was significantly correlated with soil pH and total root biomass at Hustai. The decrease in plant biomass caused by grazing thus led to GRSP reduction. Our results showed that change in soil AMF community caused by livestock grazing were associated with change in the biomass and diversity of functional vegetation groups such as Poaeceae, AMF-host and non-AMF plants, indicating the importance to focus on such functional vegetation groups to evaluate the effect of grazing on AMF.

Effects of land-use change on community diversity and composition are highly variable among functional groups.

In order to understand how the effects of land-use change vary among taxa and environmental contexts, we investigate how three types of land-use change have influenced phylogenetic diversity (PD) and species composition of three functionally distinct communities: plants, small mammals, and large mammals. We found large mammal communities were by far the most heavily impacted by land-use change, with areas of attempted large wildlife exclusion and intense livestock grazing, respectively, containing 164 and 165 million fewer years of evolutionary history than conserved areas (~40% declines). The effects of land-use change on PD varied substantially across taxa, type of land-use change, and, for most groups, also across abiotic conditions. This highlights the need for taxa-specific or multi-taxa evaluations, for managers interested in conserving specific groups or whole communities, respectively. It also suggests that efforts to conserve and restore PD may be most successful if they focus on areas of particular land-use types and abiotic conditions. Importantly, we also describe the substantial species turnover and compositional changes that cannot be detected by alpha diversity metrics, emphasizing that neither PD nor other taxonomic diversity metrics are sufficient proxies for ecological integrity. Finally, our results provide further support for the emerging consensus that conserved landscapes are critical to support intact assemblages of some lineages such as large mammals, but that mosaics of disturbed land-uses, including both agricultural and pastoral land, do provide important habitats for a diverse array of plants and small mammals.

Recent grazing reduces reptile richness but historic grazing filters reptiles based on their functional traits

Abstract Grazing by mammalian herbivores can alter vegetation structure and composition. It can therefore affect critical habitat features used by native wildlife for shelter, feeding, and breeding. This can have variable effects, which advantage or disadvantage particular species, depending on habitat requirements. We tested the relative effects of recent and historic livestock grazing and recent rabbit and kangaroo grazing on all reptiles, and on specific groups of reptiles based on three functional traits: habitat preference (semi‐arboreal, terrestrial, fossorial), activity pattern (diurnal, nocturnal), and primary foraging habitat (tree, litter, open). We used structural equation modelling to assess the direct and indirect impacts of mammalian herbivores (livestock, and free‐ranging kangaroos and rabbits) on reptile richness at 108 semi‐arid woodland sites in eastern Australia. We used a trait‐based approach to classify reptiles according to their: (a) habitat preference, (b) activity pattern, and (c) foraging preference. We recorded 42 reptile species from 1,736 specimens caught over 13,824 trap nights. Sites grazed by rabbits were associated with greater richness of semi‐arboreal species. Kangaroo grazing had virtually no effects on total richness or richness within trait groups. The effects of recent and historic livestock grazing differed among reptile trait groups. Increasing intensity of recent livestock grazing reduced the richness of most reptile groups directly, and indirectly suppressed the positive effect of native plant richness on reptile richness. The effects of historic livestock grazing, however, filtered reptiles based on their traits, reducing the richness of tree‐shrub foraging reptiles only. Increasing woody cover had direct suppressive effects on all reptiles, but particularly open foragers and terrestrial species. Overall, the effects of recent livestock grazing were stronger than those of plant richness or woody cover. Synthesis and applications. We demonstrate how grazing by all herbivores, both domestic and free‐ranging, needs to be managed according to seasonal conditions in order to meet the conservation needs of semi‐arid reptiles within landscapes dominated by livestock.

Quantifying Grazing Intensity Using Remote Sensing in Alpine Meadows on Qinghai-Tibetan Plateau

Remote sensing data have been widely used in the study of large-scale vegetation activities, which have important significance in estimating grassland yields, determining grassland carrying capacity, and strengthening the scientific management of grasslands. Remote sensing data are also used for estimating grazing intensity. Unfortunately, the spatial distribution of grazing-induced degradation remains undocumented by field observation, and most previous studies on grazing intensity have been qualitative. In our study, we tried to quantify grazing intensity using remote sensing techniques. To achieve this goal, we conducted field experiments at Gansu Province, China, which included a meadow steppe and a semi-arid region. The correlation between a vegetation index and grazing intensity was simulated, and the results demonstrated that there was a significant negative correlation between NDVI and relative grazing intensity (p < 0.05). The relative grazing intensity increased with a decrease in NDVI, and when the relative grazing intensity reached a certain level, the response of NDVI to relative grazing intensity was no longer sensitive. This study shows that the NDVI model can illustrate the feasibility of using a vegetation index to monitor the grazing intensity of livestock in free-grazing mode. Notably, it is feasible to use the remote sensing vegetation index to obtain the thresholds of livestock grazing intensity.