Livestock Biomass Research Articles

Spatial and temporal dynamics of agricultural residue resources in the last 30 years in China.

The availability and distribution of biomass resources are important for the development of the bioenergy industry in a region. Biomass resources are abundant in China; however, the raw material is severely deficient, which makes the Chinese bioenergy industry an embarrassment and a contradiction. Unclear reserves and distribution and changing trends of biomass resources are the reason for this situation. A collection coefficient model of Chinese agricultural residue resources was established and the spatial and temporal pattern dynamics of agricultural residue resources in the last 30 years were analyzed. The results show that agricultural residue resources increased in stages from 1978 to 2011, including a rapid increase from 1978 to 1999, a significant fall from 2000 to 2004, and a slow increase from 2004 to 2011. Crops straw and livestock manure are the main ingredients of agricultural residue resources with proportions of 53-59% and 31-38%, respectively. However, the former has gradually decreased, while the latter is increasing. This mainly resulted from the strategic reorganization of the Chinese agriculture structure and the rapid development of large-scale livestock breeding and agricultural mechanization. Large regional differences existed in Chinese agricultural residue resources, and three distribution types formed, including resource-rich areas in North China, Northeast and Inner Mongolia, resource-limited areas in Central and Southwest China, and resource-poor areas along Northwest and Southeast coasts. This pattern is a reverse of the distributions of climatic conditions, water resources, economic development, human resources, and technological levels. Finally, it can be predicted that livestock manure and biomass conversion technology at low temperature will play increasingly significant roles in bioenergy industry development.

Extreme Wildlife Declines and Concurrent Increase in Livestock Numbers in Kenya: What Are the Causes?

There is growing evidence of escalating wildlife losses worldwide. Extreme wildlife losses have recently been documented for large parts of Africa, including western, Central and Eastern Africa. Here, we report extreme declines in wildlife and contemporaneous increase in livestock numbers in Kenya rangelands between 1977 and 2016. Our analysis uses systematic aerial monitoring survey data collected in rangelands that collectively cover 88% of Kenya’s land surface. Our results show that wildlife numbers declined on average by 68% between 1977 and 2016. The magnitude of decline varied among species but was most extreme (72–88%) and now severely threatens the population viability and persistence of warthog, lesser kudu, Thomson’s gazelle, eland, oryx, topi, hartebeest, impala, Grevy’s zebra and waterbuck in Kenya’s rangelands. The declines were widespread and occurred in most of the 21 rangeland counties. Likewise to wildlife, cattle numbers decreased (25.2%) but numbers of sheep and goats (76.3%), camels (13.1%) and donkeys (6.7%) evidently increased in the same period. As a result, livestock biomass was 8.1 times greater than that of wildlife in 2011–2013 compared to 3.5 times in 1977–1980. Most of Kenya’s wildlife (ca. 30%) occurred in Narok County alone. The proportion of the total “national” wildlife population found in each county increased between 1977 and 2016 substantially only in Taita Taveta and Laikipia but marginally in Garissa and Wajir counties, largely reflecting greater wildlife losses elsewhere. The declines raise very grave concerns about the future of wildlife, the effectiveness of wildlife conservation policies, strategies and practices in Kenya. Causes of the wildlife declines include exponential human population growth, increasing livestock numbers, declining rainfall and a striking rise in temperatures but the fundamental cause seems to be policy, institutional and market failures. Accordingly, we thoroughly evaluate wildlife conservation policy in Kenya. We suggest policy, institutional and management interventions likely to succeed in reducing the declines and restoring rangeland health, most notably through strengthening and investing in community and private wildlife conservancies in the rangelands.

A socio-hydrological comparative assessment explaining regional variances in suicide rate amongst farmers in Maharashtra, India

Abstract. Maharashtra is one of the states in India that has witnessed one of the highest rates of farmer suicides as proportion of total number of suicides. Most of the farmer suicides in Maharashtra are from semi-arid divisions such as Marathwada where cotton has been historically grown. Other dominant crops produced include cereals, pulses, oilseeds and sugarcane. Cotton (fibers), oilseeds and sugarcane providing highest value addition per unit cultivated area and cereals and pulses the least. Hence it is not surprising that smallholders take risks growing high value crops without “visualising” the risks it entails such as those corresponding to price and weather shocks.We deploy recently developed smallholder socio-hydrology modelling framework to understand the underlying dynamics of the crisis. It couples the dynamics of six main variables that are most relevant at the scale of a smallholder: water storage capacity (root zone storage and other ways of water storage), capital, livestock, soil fertility and fodder biomass. The hydroclimatic variability is accounted for at sub-annual scale and influences the socio-hydrology at annual scale. The model incorporates rule-based adaptation mechanisms (e.g., adjusting expenditures on food and fertilizers, selling livestocks) of smallholders when they face adverse conditions, such as high variability in rainfall or in agricultural prices. The model is applied to two adjoining divisions of Maharashtra: Marathwada and Desh. The former is the division with relatively higher farmer suicide rates than the latter. Diverse spatial data sets of precipitation, potential evaporation, soil, agricultural census based farm inputs, cropping pattern and prices are used to understand the dynamics of small farmers in these divisions, and to attribute farmer distress rates to soil types, hydroclimatic variability and crops grown.Comparative socio-hydrologic assessment across the two regions confirms existing narratives: low (soil) water storage capacities, no irrigation and poor access to alternative sources of incomes are to blame for the crisis, suggesting that smart indigenous solutions such as rain-water harvesting and better integration of smallholder systems to efficient agricultural supply chains are needed to tackle this development challenge.

Technical and Economic Analysis of a Cogeneration Plant Fueled by Biogas Produced From Livestock Biomass

This technical report illustrates an anaerobic digestion plant for the production of biogas designed to be powered by livestock biomass, combined with a 330 kWe CHP unit co-generator, installed in a cattle farm located in the province of Reggio Emilia. The plant consists essentially of a pre-treatment system of the effluents to the load, two anaerobic continuously stirred tank reactors and heated under mesophilic regime sheltered with gasometric coverings with double membrane; at the end of the process of fermentation, the digestate converges in a solid-liquid separation system with helical compression and a storage tank of the clarified fraction, sheltered with a covering for the containment of residual gaseous emissions into the atmosphere. The produced biogas is collected in gasometers placed above the tanks and, after desulfurization, dehumidification and cooling, it fuels the co-generator. The report is determined to illustrate the experimental results for the first 12 months of operation of the plant that confirmed, both in terms of energy and from a financial perspective, the efficiency of biogas plants fueled only by livestock effluents.

Relative availability of natural prey versus livestock predicts landscape suitability for cheetahsAcinonyx jubatusin Botswana

Prey availability and human-carnivore conflict are strong determinants that govern the spatial distribution and abundance of large carnivore species and determine the suitability of areas for their conservation. For wide-ranging large carnivores such as cheetahs (Acinonyx jubatus), additional conservation areas beyond protected area boundaries are crucial to effectively conserve them both inside and outside protected areas. Although cheetahs prefer preying on wild prey, they also cause conflict with people by predating on especially small livestock. We investigated whether the distribution of cheetahs’ preferred prey and small livestock biomass could be used to explore the potential suitability of agricultural areas in Botswana for the long-term persistence of its cheetah population. We found it gave a good point of departure for identifying priority areas for land management, the threat to connectivity between cheetah populations, and areas where the reduction and mitigation of human-cheetah conflict is critical. Our analysis showed the existence of a wide prey base for cheetahs across large parts of Botswana’s agricultural areas, which provide additional large areas with high conservation potential. Twenty percent of wild prey biomass appears to be the critical point to distinguish between high and low probable levels of human-cheetah conflict. We identified focal areas in the agricultural zones where restoring wild prey numbers in concurrence with effective human-cheetah conflict mitigation efforts are the most immediate conservation strategies needed to maintain Botswana’s still large and contiguous cheetah population.

Grazing crops: implications for reproducing sheep

Integration of crops and livestock has been revitalised in Australia, initially as an opportunity to increase cropping within the high-rainfall grazing zones, and more recently, to improve enterprise diversification and profitability across the low-, medium- and high-rainfall, and mixed-farming zones. Young crops are highly digestible (>80% dry matter digestibility, DMD) with a high energy density (>12 MJ/kg DM) and, in much of southern Australia, fill a winter feed gap. The quality and time of feed availability also coincide with the high nutrient requirements of ewes in late pregnancy and lactation. In Western Australia and South Australia, young crops are available for lactating ewes and young growing lambs (autumn lambing). For the smaller proportion of growers who lamb later in winter, young crops are available for the last 1–2 months of pregnancy. In the later-lambing states of New South Wales and Victoria, crops may be grazed by ewes at any stage of pregnancy and lactation and/or by young lambs. In Tasmania, crops are more likely to be available during early–mid-gestation. Limited studies on feed budgeting with grazing crops have indicated that ewes can maintain or even increase liveweight, with a much lower level of feed on offer than would be required with traditional pastures (<500 kg DM/ha). This has the potential to increase whole-farm stocking rates and/or reduce fetal mortality, increase lamb birthweight and survival and improve lifetime production. Maintaining or increasing ewe liveweight during pregnancy and lactation may also result in heavier ewes the following year and higher ovulation rates. Pregnancy and lactation are also periods of increased susceptibility to metabolic disturbances. The composition of young crops increases this susceptibility. Pregnancy toxaemia, hypocalcaemia and hypomagnesaemia can influence ewe health and fetal survival. Chronic acidosis and excessive ammonia absorption from rapid introduction of pregnant ewes onto young crops may risk appetite loss and increase susceptibility to pregnancy toxaemia. Low magnesium and sodium combined with high potassium increases the risk of grass tetany. Most young crops (except canola) also have a tetany index >2.2, indicating a high risk of grass tetany. The elevated potassium also contributes to a high dietary cation–anion difference of approximately +49 mEq/100 g DM and this may cause metabolic alkalosis and hypocalcaemia. Pregnancy toxaemia, hypocalcaemia and grass tetany are all potential causes of increased ewe mortality. Pregnancy and/or lactation outcomes will also be influenced by a deficiency of trace elements. Grazing young crops in areas with a history of selenium, copper, iodine and cobalt deficiency will increase susceptibility to deficiency by increasing growth and feed intake. In conclusion, the grazing of young growing crops presents new opportunities for increased production and stocking rates in the mixed-farming zones. The value of this feed source is well recognised by some producers. While growing crops have a highly productive potential, they also come with an increased risk of a range metabolic disturbances and nutritional imbalances. These risks can be minimised by regular monitoring of livestock and crop biomass and the provision of mineral supplements.

Landscape suitability in Botswana for the conservation of its six large African carnivores.

Wide-ranging large carnivores often range beyond the boundaries of protected areas into human-dominated areas. Mapping out potentially suitable habitats on a country-wide scale and identifying areas with potentially high levels of threats to large carnivore survival is necessary to develop national conservation action plans. We used a novel approach to map and identify these areas in Botswana for its large carnivore guild consisting of lion (Panthera leo), leopard (Panthera pardus), spotted hyaena (Crocuta crocuta), brown hyaena (Hyaena brunnea), cheetah (Acinonyx jubatus) and African wild dog (Lycaon pictus). The habitat suitability for large carnivores depends primarily on prey availability, interspecific competition, and conflict with humans. Prey availability is most likely the strongest natural determinant. We used the distribution of biomass of typical wild ungulate species occurring in Botswana which is preyed upon by the six large carnivores to evaluate the potential suitability of the different management zones in the country to sustain large carnivore populations. In areas where a high biomass of large prey species occurred, we assumed interspecific competition between dominant and subordinated competitors to be high. This reduced the suitability of these areas for conservation of subordinate competitors, and vice versa. We used the percentage of prey biomass of the total prey and livestock biomass to identify areas with potentially high levels of conflict in agricultural areas. High to medium biomass of large prey was mostly confined to conservation zones, while small prey biomass was more evenly spread across large parts of the country. This necessitates different conservation strategies for carnivores with a preference for large prey, and those that can persist in the agricultural areas. To ensure connectivity between populations inside Botswana and also with its neighbours, a number of critical areas for priority management actions exist in the agricultural zones.

Soil organic carbon sequestration in agroforestry systems. A review

The increase in atmospheric carbon dioxide (CO2) concentrations due to emissions from fossil fuel combustion is contributing to recent climate change which is among the major challenges facing the world. Agroforestry systems can contribute to slowing down those increases and, thus, contribute to climate change mitigation. Agroforestry refers to the production of crop, livestock, and tree biomass on the same area of land. The soil organic carbon (SOC) pool, in particular, is the only terrestrial pool storing some carbon (C) for millennia which can be deliberately enhanced by agroforestry practices. Up to 2.2 Pg C (1 Pg = 1015 g) may be sequestered above- and belowground over 50 years in agroforestry systems, but estimations on global land area occupied by agroforestry systems are particularly uncertain. Global areas under tree intercropping, multistrata systems, protective systems, silvopasture, and tree woodlots are estimated at 700, 100, 300, 450, and 50 Mha, respectively. The SOC storage in agroforestry systems is also uncertain and may amount up to 300 Mg C ha−1 to 1 m depth. Here, we review and synthesize the current knowledge about SOC sequestration processes and their management in agroforestry systems. The main points are that (1) useful C sequestration in agroforestry systems for climate change mitigation must slow or even reverse the increase in atmospheric concentration of CO2 by storing some SOC for millennia, (2) soil disturbance must be minimized and tree species with a high root biomass-to-aboveground biomass ratio and/or nitrogen-fixing trees planted when SOC sequestration is among the objectives for establishing the agroforestry system, (3) sequestration rates and the processes contributing to the stabilization of SOC in agroforestry soils need additional data and research, (4) retrospective studies are often missing for rigorous determination of SOC and accurate evaluation of effects of different agroforestry practices on SOC sequestration in soil profiles, and (5) the long-term SOC storage is finite as it depends on the availability of binding sites, i.e., the soil’s mineral composition and depth. Based on this improved knowledge, site-specific SOC sequestering agroforestry practices can then be developed.

Determinants of Persistence and Tolerance of Carnivores on Namibian Ranches: Implications for Conservation on Southern African Private Lands

Changing land use patterns in southern Africa have potential to dramatically alter the prospects for carnivore conservation. Understanding these influences is essential for conservation planning. We interviewed 250 ranchers in Namibia to assess human tolerance towards and the distribution of large carnivores. Cheetahs (Acinonyx jubatus), leopards (Panthera pardus) and brown hyaenas (Hyaena brunnea) were widely distributed on Namibian farmlands, spotted hyaenas (Crocuta crocuta) had a narrower distribution, and wild dogs (Lycaon pictus) and lions (Panthera leo) are largely limited to areas near source populations. Farmers were most tolerant of leopards and least tolerant of lions, wild dogs and spotted hyaenas. Several factors relating to land use correlated consistently with carnivore-presence and landowner tolerance. Carnivores were more commonly present and/or tolerated where; wildlife diversity and biomass were higher; income from wildlife was higher; income from livestock was lower; livestock biomass was lower; in conservancies; game fencing was absent; and financial losses from livestock depredation were lower. Efforts to create conditions whereby the costs associated with carnivores are lowest, and which confer financial value to them are likely to be the most effective means of promoting carnivore conservation. Such conditions are achieved where land owners pool land to create conservancies where livestock are replaced with wildlife (or where livestock husbandry is improved) and where wildlife generates a significant proportion of ranch income. Additional measures, such as promoting improved livestock husbandry and educational outreach efforts may also help achieve coexistence with carnivores. Our findings provide insights into conditions more conducive to the persistence of and tolerance towards large carnivores might be increased on private (and even communal) lands in Namibia, elsewhere in southern and East Africa and other parts of the world where carnivore conservation is being attempted on private lands.

CH4 and N2O emissions from different varieties of forage rice (Oryza sativa L.) treating liquid cattle waste

To evaluate global warming potential (GWP) on livestock waste treatment and biomass production in rice field, methane (CH4) and nitrous oxide (N2O) fluxes from forage rice fields planted with 4 different cultivars (Oryza sativa L. cv. Hamasari, Leafstar, Kusahonami and Takanari) were measured. Each of the cultivars were subjected either to basal fertilization alone (control plots) (84kgNha−1), or to basal fertilization plus topdressing with liquid cattle waste or LCW (treatment plots) (567kgNha−1). Liquid cattle waste application to the rice field resulted in peak CH4 fluxes ranging from 22.0 to 32.1mgm−1h−1 during flooded conditions and large N2O fluxes ranging from 526 to 8591μgm−1h−1 after midsummer drainage and final drainage. The GWP of the control plots was between 1358 and 3872kgCO2eqha−1, while the treatment plots ranged between 4503 and 8426kgCO2eqha−1 and more than 60% of the GWP was from the N2O emission in treatment plots. In both the control and treatment plots, the lowest GWPs per ton of above-ground biomass were found to be from the Leafstar cultivar, which had a higher aboveground biomass than other cultivars; 117kgCO2eqt−1 from the control and 257kgCO2eqt−1 from the treatment plots. Thus, both forage production and suitable disposal of the LCW may be able to be achieved concomitantly with lower levels of GWP by cultivation of Leafstar in our field.

Spatio‐temporal variation in large herbivore pressure in Norway during 1949‐1999: has decreased grazing by livestock been countered by increased browsing by cervids?

AbstractDuring recent decades, rough livestock grazing has decreased markedly on unimproved land (i.e. natural and semi‐natural habitats) across most of Europe, whilst the number of wild cervids has increased. However, we still know little about the overall changes in the herbivore pressure and how herbivore regimes vary between biogeographic regions. We have quantified the spatio‐temporal variation in herbivore pressure indirectly by estimating the metabolic biomass of large herbivores in mountain, coastal and inland municipalities of Norway every 10th year during 1949‐1999. We quantified how much livestock biomass has decreased, whether this corresponded to increasing cervid biomass, and whether the proportion of grazing relative to browsing has changed within the herbivore community. Total metabolic biomass of livestock and cervids (MBAtotal) decreased from 126 kg/km2 in 1949 to 107 kg/km2 in 1999 (∼85% of MBAtotal in 1949). Changes differed markedly between regions. Herbivore pressure in the coastal region nearly halved from 1949 to 1999, while the decrease was minor in the inland and mountain regions. Livestock grazing more than halved, whereas the metabolic biomass of cervids increased by 276% from 1949 to 1999. Cervids dominated the community of large herbivores on unimproved land in Norway in 1999 (54% of MBAtotal). Livestock dominated in the mountain (52% of MBAtotal) and in the coastal region (54% of MBAtotal) in 1999, while cervids dominated in the inland region (67% of MBAtotal). Most herbivore foraging consisted of grazing in 1949 (89% at a national scale). This proportion was reduced to 54% by 1999. Percent browsing was especially high (> 90%) in several municipalities in southeastern Norway in 1999. The increase of wild cervids is exceptional in a historical perspective, and managers have to adapt to wild cervids being the major ecosystem engineers in many landscapes.

Anthropogenic nitrogen emissions during the Holocene and their possible effects on remote ecosystems

[1] Reactive nitrogen (Nr = NH3-N + NOx-N) is an important atmospheric pollutant, contributing to acidification, eutrophication and biodiversity changes in ecosystems. This study estimates Nr emissions from anthropogenic sources on a global scale since the advent of agriculture ∼8000 B.C., using a simple model based on the development of human population and per capita factors of Nr emissions originating from livestock production, biomass burning (biofuel use and forest and savannah burning), and other anthropogenic sources (humans and pets, N-fertilizer use, and fossil fuel combustion). The estimated global cumulative anthropogenic emissions of Nr to the atmosphere are ∼17.4 Pg N (8.6 Pg NH3-N and 8.8 Pg NOx-N) for 8000 B.C. through the year 2000 A.D., with 28% of this amount emitted during 1850–2000 A.D., 42% during 1–1850 A.D., and 30% during the previous 8000 years. Forest and savannah burning represent the major cumulative flux of both NH3-N and NOx-N (3.5 and 5.8 Pg, respectively). Livestock production and biofuel burning are responsible for emissions of 3.3 and 1.2 Pg NH3-N, respectively, while the application of synthetic fertilizers contributes 0.26 Pg NH3-N. The different duration of biofuel and fossil fuel use (10,000 versus ∼150 years) causes the higher cumulative NOx-N emissions from biofuel than from fossil fuel use (1.9 versus 1.1 Pg). The cumulative Nr emissions on a land area basis are 1.3 and 3.0 Mg N ha−1 globally and in Europe, respectively. Since an estimated 60% of Nr emitted in Europe is also deposited there, the average cumulative anthropogenic Nr deposition would be ∼1.8 Mg N ha−1, representing ∼30% of the current N pools in forest and alpine meadow soils of European glaciated areas (i.e., soils of similar age as the emissions). Despite large uncertainties in the model (13.7–30.5 Pg N over the last 10,000 years), the relative temporal distributions of total cumulative Nr emissions vary within relatively narrow ranges for different assumptions, with 70%–84% of the emissions occurring prior to 1850 A.D. We conclude that the majority of the total cumulative Nr flux from anthropogenic sources over the last 10,000 years occurred in the preindustrial period and could have increased soil N pools of some remote ecosystems much earlier than is currently assumed.

Pastoral resource access and utilization: Quantifying the spatial and temporal relationships between livestock mobility, density and biomass availability in southern Kenya

The relationships between pastoralists, livestock, and the environment in dryland Africa are complex. Over the last half-century dominant narratives have portrayed pastoralists and their livestock as being responsible for ‘over grazing’ and ‘degradation’ without attention to how resource availability and cattle mobility are spatially distributed and temporally variable. The objective of this study is to test hypotheses on the nature, magnitude, and extent of the spatially and temporally explicit interactions between the density and distribution of pastoral cattle and resource availability. The study relies on coupling remotely sensed vegetation indices with cattle Global Positioning Systems (GPS) collar data for a pastoral community in southern Kenya. Data are temporally stratified in order to account for seasonal effects. Across seasons, there is a positive relationship between cattle mobility and resource availability with the trend more pronounced during drier periods, reflecting a strategy of increased resource access. The relationship between cattle density and vegetation reveals a strategy of increased resource utilization during wetter periods. The spatiality of high-density areas differs by season, revealing that cattle intensively utilize different parts of the landscape at different times. Areas closest to the household are consistently impacted by cattle across all seasons. These findings have implications on how the savanna vegetation may be impacted as trends towards sedentarization and reduced pastoral mobility continue. Copyright © 2010 John Wiley & Sons, Ltd.

Optimal Design of Biomass Utilization System for Rural Area Includes Technical and Economic Dimensions

In order to design optimal biomass utilization system for rural area, OMNIBUS (The Optimization Model for Neo-Integrated Biomass Utilization System) has been developed. OMNIBUS can derive the optimal system configuration to meet different objective function, such as current account balance, amount of biomass energy supply, and CO2 emission. Most of biomass resources in a focused region e.g. wood biomass, livestock biomass, and crop residues are considered in the model. Conversion technologies considered are energy utilization technologies e.g. direct combustion and methane fermentation, and material utilization technologies e.g. composting and carbonization. Case study in Miyakojima, Okinawa prefecture, has been carried out for several objective functions and constraint conditions. Considering economics of the utilization system as a priority requirement, composting and combustion heat utilization are mainly chosen in the optimal system configuration. However gasification power plant and methane fermentation are included in optimal solutions, only when both biomass energy utilization and CO2 reduction have been set as higher priorities. External benefit of CO2 reduction has large impacts on the system configuration. Provided marginal external benefit of more than 50,000 JPY/t-C, external benefit becomes greater than the revenue from electricity and compost etc. Considering technological learning in the future, expensive technologies such as gasification power plant and methane fermentation will have economic feasibility as well as market competitiveness.

Using rain-use efficiency to explore livestock production trends in rangelands in the Transkei, South Africa

We qualitatively describe the condition of communally managed rangelands in the Transkei, South Africa, using GIS and high resolution near-infrared imagery. Using livestock census data from 28 magisterial districts in the Transkei, we explored the trends in livestock biomass from 1923–1998. The area had been subjected to intensive herbivory by domestic livestock during that period, and the high livestock biomass had been blamed for the perceived degradation or 'overgrazing' of the region. Our assessment used the concept rain-use efficiency (RUE) (kg dry matter ha−1 mm−1) to determine whether there is evidence of change in the efficiency of the system to produce domestic livestock. We calculated RUE from annual livestock numbers and the mean annual rainfall for each district. We found no evidence of a decline in rain-use efficiency between the two assessment periods (1923–1944, 1945–1998). There was evidence of a shift in the ratio of sheep to goats between 1923 and 1998, with goat numbers increasing (greater than twofold) relative to sheep in eight districts. This trend may be associated with changes in the structure of vegetation. We conclude that this region is not showing evidence of system run down that affects domestic livestock production.

P406 エネルギー・マスフローを考慮した畜産廃棄物利活用システムの設計

P406 エネルギー・マスフローを考慮した畜産廃棄物利活用システムの設計

Sustainable Rangeland Grazing in Norse Faroe

The introduction of domestic livestock, particularly sheep, and rangeland grazing by Norse settlers to Faroe during the ninth century has generally been described as a major pressure on a sensitive landscape, leading to rapid and widespread vegetation change and contributing to land degradation. This view has, however, been developed without consideration of Norse grazing management practices which may have served to minimize grazing impacts on landscapes as well as sustaining and enhancing vegetation and livestock productivity. These alternative scenarios are considered using a historical grazing management simulation model with Faroese climate and vegetation inputs and given archaeological, historical and palaeoenvironmental parameters. Three contrasting rangeland areas are investigated and, based on the maximum number of ewe/lamb pairs the rangeland could sustain, modeling suggests that utilizable biomass declined with the onset of grazing activity, but not to a level that would cause major changes in vegetation cover or contribute to soil erosion even under climatically determined poor growth conditions. When rangeland areas partitioned into what are termed hagi and partir are modeled, grazing levels are still within rangeland carrying capacities, but productivities are variable. Some rangeland areas increase biomass and livestock productivities and biomass utilization rates while other rangeland areas that were too finely partitioned were likely to suffer substantial decline in livestock productivity. Partitioning of rangeland is a likely contributor to long-term differentiation of landscapes and the relative success of settlements across Faroe beyond the Norse period.

Effects of grazing intensity on small mammal population ecology in wet meadows

Summary Livestock grazing is common management practice in wet grasslands. However, knowledge of its effects on small mammals is limited. We studied the influence of grazing intensity on small mammals in general and field voles Microtus agrestis in particular in two Danish wet meadows, 1998–2000. Generally, grazing livestock had a negative effect on the peak biomass of small mammals, and the negative effect increased with grazing intensity, irrespective of whether pens were grazed by cattle or by sheep. More detailed analyses, however, revealed that an intermediate grazing intensity (approximately 400 kg ha −1 as maximum livestock biomass) actually seemed to benefit small mammals. This grazing intensity generally held small mammal biomasses and field vole population sizes that were similar to or larger than those on the ungrazed control, and markedly larger than those on the more heavily grazed pens. Additionally, field voles in the intermediate grazing intensity had more foetuses. Though a number of parameters may contribute to the observed patterns, we suggest that these primarily are caused by the livestock removing vegetation cover, thereby influencing the number and size of patches with high, dense vegetation in the vicinity of grass that is rejuvenated by grazing.

Competition between domestic livestock and wild bharal Pseudois nayaur in the Indian Trans‐Himalaya

Summary The issue of competition between livestock and wild herbivores has remained contentious. We studied the diets and population structures of the mountain ungulate bharal Pseudois nayaur and seven species of livestock to evaluate whether or not they compete for forage. The study was conducted in the high altitude Spiti Valley, Indian Trans‐Himalaya. We compared resource (forage) availability and bharal population structures between rangelands differing in livestock density. Forage availability was estimated by clipping the standing graminoid biomass in sample plots. Livestock and bharal population structures were quantified through annual censuses. Seasonal diets of livestock were studied by direct observations, while those of bharal were quantified through feeding signs on vegetation. We found that livestock grazing causes a significant reduction in the standing crop of forage. Graminoid availability per unit livestock biomass was three times greater in a moderately grazed rangeland compared with an intensively grazed one. There was considerable diet overlap among the herbivore species. In summer, bharal, yak Bos grunniens, horse Equus caballus, cow Bos indicus, and dzomo (yak–cow hybrids) fed predominantly on graminoids, while donkey E. asinus, sheep Ovis aries, and goat Capra hircus, consumed both graminoids and herbs. The summer diet of bharal was a subset of the diets of three livestock species. In winter, depleted graminoid availability caused bharal, yak and horse to consume relatively more herbs, while the remaining livestock species fed predominantly on graminoids. Diet overlap was less in winter but, in both seasons, all important forage species in the bharal diet were consumed in substantial amounts by one or more species of livestock. Comparison of the population structures of bharal between two rangelands differing in livestock density by c. 30% yielded evidence of resource competition. In the intensively grazed rangeland, bharal density was 63% lower, and bharal population showed poorer performance (lower young : adult female ratios). Synthesis and applications. High diet overlap between livestock and bharal, together with density‐dependent forage limitation, results in resource competition and a decline in bharal density. Under the present conditions of high livestock density and supplemental feeding, restricting livestock numbers and creating livestock‐free areas are necessary measures for conserving Trans‐Himalayan wild herbivores. Mediating competitive effects on bharal through supplemental feeding is not a feasible option.

Prey selection by the Indian tiger (Panthera tigris tigris) in Nagarjunasagar Srisailam Tiger Reserve, India

Summary Very little is known about prey selection by the Indian tiger Panthera tigris tigris in tropical dry deciduous forests or in wild herbivore-depleted habitats with high livestock pressures. We undertook a short-term study in a large south Indian tiger reserve and examined two intensive study areas (SA's) from October 1998 – June 1999. In each area, herbivore sightings were recorded, scats were collected, and wild prey and livestock kills documented. Chital, wild boar and sambar were the most abundant among the wild herbivores in the study area. Scat analysis revealed wild boar ( Sus scrofa ) being the most common prey followed by chital ( Axis axis ) and sambar ( Rusa unicolor ). Livestock comprised less than 7% of diet intake. Here, the tigers consumed a lower mean prey mass (56.3 kg) than in other reserves. Our study suggests that in tropical dry deciduous forests with low natural prey density, smaller prey species, and high livestock biomass, tigers preferentially kill smaller prey and generally avoid livestock predation.