Range and livestock production in the Monte Desert,Argentina

This article reviews and analyzes the available information on range and livestock production in the Monte Desert. Cow–calf operations, goats for meat, and sheep for wool are the dominant production systems under continuous grazing. Rest-rotational grazing systems improved the efficiency of the current cow–calf production. Forage resources are primarily composed of perennial grasses and woody species. Rain-use efficiency for the total vegetation ranged from 3.9 to 4.8 kg DM ha^?1 year^?1 mm^?1. Carrying capacity showed a broad range: 18.7, 4.5–64.5, and 21.6–89.3 ha AU^?1 in the north, central, and south portions of the Monte, respectively. Mean crude protein (CP) content of grasses varied from 8.4 to 10.3 (wet season) and 7.1–3.7% DM (dry season) in the central west and Patagonia, respectively. Grasses predominated in the cattle diet, while the sheep diet was highly diverse because they ate most of the available plant species, and there was no unanimity as to the fact that goats are strictly browsers. Livestock diseases have lower prevalence indices than those recorded in other areas of the country. The high variability in carrying capacity values could be attributed to differences in rangeland condition and to the different methods used for its estimation. The CP levels in forage could meet cattle requirements provided that a proper-stocking rate were used. The most promising species for land rehabilitation are Opuntia, Atriplex spp., Eragrostis curvula and Cenchrus ciliaris. Priorities for future research should include topics such as assessment of the carrying capacity for most of the areas and nutrient content of the components of livestock diet, the livestock intake values, the economic feasibility of the use of complementary feeds and the development of seeding technology for valuable forage resources as Trichloris crinita, among others.     

Pastoralists’ perceptions and realities of vegetation change and browse consumption in the northern Kalahari, Namibia

Pastoral production around artificial watering points in semi-arid environments affects the density and composition of plant communities. In the Kalahari desert of southwestern Africa, bush encroachment is often regarded as the major form of land degradation resulting from pastoral production around watering points. We investigated the OvaHerero pastoralists’ perceptions of the extent of vegetation change since the establishment of artificial watering points in the northern Kalahari desert of Namibia, and related this to ecological data on vegetation change. We determined the utility of woody vegetation to pastoralists’ livelihoods in terms of provision of construction material, fuel wood and browse. We quantified local knowledge of cattle browse consumption and correlated this with field data. We also assessed the purposes for which major livestock types were used. Our results showed that: (1) pastoral knowledge of bush encroachment and browse consumption was consistent with concurrently collected field data, (2) the current level of bush encroachment was perceived to be beneficial for pastoral production, and (3) cattle played an important role in the production of milk and milk by-products for domestic use, and served as a source of cash income, while sheep and goats were primarily kept for meat consumption. This result contrasts with historical studies that mainly portray cattle as a symbol of social status among OvaHerero pastoralists.     

Influence of livestock on the regeneration of fodder trees along ephemeral rivers of Namibia

Faidherbia albida and Acacia erioloba (Mimosoideae) are important fodder trees for livestock and wildlife along the westward flowing ephemeral rivers of the Namib Desert. Together with other, mainly woody vegetation, F. albida and A. erioloba line these rivers and present a linear oasis in a resource poor environment. For centuries nomadic to semi-nomadic inhabitants seasonally utilised the resources of these ephemeral rivers to survive in the otherwise harsh desert environment. In the past decades, more permanent settlements were established along these rivers, with small stock subsistence farmers making a living from the available resources. Livestock (mainly goats) usually moves freely around, feeding on the available vegetation.This study investigated the influence of free moving animals on the regeneration and recruitment of F. albida and A. erioloba along the Kuiseb ephemeral river. It was found that a large numbers of recently emerged seedlings were removed soon after germination. In addition, tree densities of adult versus juvenile individuals differed in areas with large numbers of livestock. The overall height increase and health of juvenile plants were influenced negatively by browsing livestock. In general, browsing pressure differed spatially and was higher close to the main water channel.     

Forage resource use by cattle or goats at an Indian protected area: Differences and implications for conservation

In India, increasing livestock populations exert pressure on protected areas (PAs) and surrounding rangelands. Differences in resource use by cattle and goats kept in local communities close to the Bandhavgarh National Park were assessed to conclude on expected environmental damage and to provide management implications. Within 5 months of dry period (subdivided into cool and hot dry season), 2 × 25 dairy goats and cattle were continuously observed during daylight. The time spent for various feeding-related activities and plant species and biomass ingested were recorded. This was accompanied by surveying and recording herders’ activities. Cattle and goats largely relied on woody plants. Goats spent time equally on browsing and grazing, increased leaf litter intake with time but rarely consumed crop residues. Goat herders often offered cut leaf-bearing branches. Cattle preferentially grazed, but also increasingly ingested leaf litter. Crop residues were offered instead of cut woody plants. Cattle herds were much less efficiently using the scarce forage resources for milk production than goat herds. However, as woody plants are important for PAs, particularly goat pasturing practices were detrimental to conservation. Desertification in PA surroundings may be prevented by combining improvements in general livestock management and specific feeding procedures, tree protection, and afforestation measures.     

A new zoogeography of domestication and agricultural planning in Southern Ghana

Animal behaviour is vital for livestock choices, but is less researched in West Africa than economic considerations. An animal geography framework is applied to the socio-economic context of livestock behaviour in coastal Ghana, assessing the shared 'actant' behaviour of people and animals, and the contribution of such a study to animal geography and agricultural knowledge. Data were gathered on cattle, sheep and goat behaviour and the impact of these on human livelihoods, perceptions and the socio-environmental context. Animal behaviour was more important in the choice of livestock species, but economic considerations were more important in the decision to acquire animals. Goats had more incidents with people in village centres than sheep and cattle. Cattle had more incidents in farmland and grassland than goats and sheep. Women and young people were more affected by livestock behaviour. These findings increase the understanding of livestock zoogeography and livelihood decisionmaking, and contribute to animal geography by documenting the relevance of individualised gender- and age-based human behaviour, as well as intra- and inter-species animal behaviour to a shared actancy perspective, and a more dynamic zoogeography.     

Influence of land use on the abundance of wildlife and livestock in the Kalahari,Botswana

Human land use such as pastoralism may be a key determinant of wildlife populations. We studied the influence of land use on wildlife and livestock in south-western Kalahari, Botswana, during the wet and dry seasons. We included two types of livestock areas and two types of wildlife protection areas. Wild and domestic mammals >0.2 kg were sampled by distance technique. Small mammals <0.2 kg were trapped and a vegetation survey was performed. Livestock and some medium-sized wildlife species were most abundant in livestock areas, while large-sized wildlife species were mainly restricted to wildlife areas. Most red-listed species were confined to the national park. The influence of land use on abundances changed moderately between seasons. However, cattle moved into wildlife areas during the wet season. Differences in species richness and diversity were most pronounced during the dry season. The trapping frequency of small mammals was highest in the national park. Differences in vegetation structure included sparser field layer and higher cover of an invasive shrub in livestock areas. Our study shows the importance of protected areas for many wildlife species in the Kalahari. It also shows the value of a multi-species approach for investigating the effects of land use on wildlife communities.     

Modeling the optimal grazing regime of Acacia victoriae silvopasture in the Northern Negev,Israel

Silvopasture, the planting of suitable tree species in pastures, can improve the sustainability and productivity especially in dry rangelands. While recent studies provide information on the effects of different tree compositions on biological productivity, water and soil protection, additional parameters such as fodder production by the trees or the impact of silvopasture on the grazing potential themselves have rarely been addressed. We determined fodder production in Acacia victoriae woodland and savanna by measuring annual vegetation and tree biomass growth. We developed mathematical models for calculating the vegetative biomass available for grazing. In order to get accurate estimation for the grazing capacity, we differentiated between the grazing and the browsing fodder availability, and adapted the model to the most abundant grazers in the Negev, goats and sheep. Grazing capacity for sheep and goats was twice bigger in A. victoriae woodland than in the adjacent sustainably managed shrubland and four times higher than in degraded shrubland. The mathematical model presented in this paper can be applied in order to plan and realize high yielding and sustainable silvopasture in arid environments resistant to degradation and desertification while providing adequate fodder reserves during drought years.     

Grazing itineraries and forage selection of goats in the Al Jabal al Akhdar mountain range of northern Oman

In view of the repeatedly reported overstocking of the high-altitude pastures on Al Jabal al Akhdar, northern Oman, plant species abundance, cover and frequency, and herbaceous mass yield were studied in ungrazed versus heavily grazed areas of this mountain range. In addition, plant species selection by goats along a gradient of 1000–2000 m and spatial extent of pasture areas were investigated after abundant rainfall and a subsequent 6-months dry spell by means of manual observation and GPS/GIS tools.The substantially higher species diversity and herbaceous mass yield in the ungrazed area illustrate the production potential of these mountain pastures or, respectively, the biodiversity and productivity loss resulting from continuous grazing. The concentration of goats' selection on only a dozen herbaceous and ligneous species favours pasture encroachment with poisonous shrubs such as Nerium mascatense in the lower and Dodonaea viscosa in the higher altitudes. Given the spatially limited extent of pasture areas, these are exposed to high stocking rates. Therefore, grazing and feeding schemes need to be developed which reduce livestock pressure on the pastures, taking into account local property rights, herding skills and the recovery potential of the vegetation, which heavily depends on unpredictable rainfall events.     

Environmental perceptions and practices of livestock keepers on the Namaqualand Commons challenge conventional rangeland management

In South Africa, interventions in communal rangelands proposed by most agriculture-sector institutions are still dominated by the belief that communal herders have little technical skills and by the tenets of “the tragedy of the Commons”, assuming that individual livestock keepers are selfish, norm free, and aiming at maximising short-term offtake and that there is no consistent management of the commons. In this study we show that practices of a diversity of livestock keepers on the Leliefontein Commons of Namaqualand are at odds with this viewpoint: access to rangeland and its use are structured by collective norms and concerns regarding both the sharing of resources and their long-term sustainability. We also show that part of the management of the commons relies on grazing practices which involve tacit and formalised technical knowledge that can be described and modelled. Livestock keepers assess the heterogeneity of the grazing quality of the commons. They are aware of the toxicity and unpalatability of some plants, of the way this differs according to the amount ingested and the availability of other forage, and of the variations of these two factors over seasons of grazing. They classify grazing areas and decide on daily grazing routes according to a complex set of criteria. Carrying capacity of each area is not considered as a fixed parameter but rather as a variable dependant on rainfall. Seasonal movements between areas are designed accordingly. These findings offer a new perspective for research agendas on technical models and extension measures for communal rangeland management particularly in arid and semi-arid areas.     

Co-occurrence and potential for competition between wild and domestic large herbivores in a South American desert

Introduction of domestic ungulates may lead to interspecific competition with native herbivores, particularly if the species involved are of similar size and share similar foraging strategies due to a scarcity of trophic resources. This interaction has not been investigated in South American deserts in which guanaco (Lama guanicoe), the larger South American wild camelid and the most widely-distributed ungulate, co-occurs with several introduced ungulates (e.g. cattle, donkeys, sheep or red deer). We studied the occurrence and abundance patterns of guanacos, donkeys and cattle in desert areas of Argentina by dung sampling. Analyses of co-occurrence show no relationship in land use between guanaco and livestock when geographical effects are removed. Distribution and abundance models of the guanaco are strongly associated with sparse plant cover, rocky substrata and human-influence variables, guanacos appearing in areas furthest from villages. Nevertheless, while guanaco distribution is weakly related to feral livestock presence, their abundance is negatively associated with donkey presence. In contrast, livestock species appear closely associated with each other, being centred on areas of densest and most productive vegetation. These results are relevant for the management of extensive arid areas of South America, where guanacos co-occur with feral donkeys and frequently conflicts with humans activities.     

Archaeological evidence for pastoralist land-use and settlement in Namaqualand over the last 2000 years

Despite the extreme aridity of the region, there is good evidence that sheep were being herded in small numbers in Namaqualand up to 2000 years ago. Archaeological research at Spoegrivier Cave on the Atlantic coast confirms the presence of sheep at 2100 years ago. Increasing aridity in Namaqualand around 1300 years ago lead to the abandonment of the cave. Jakkalsberg on the banks of the Orange River in the Richtersveld was occupied around 1300 BP by people who were herding sheep rather than hunting game. People with sheep and goats were herding their livestock at Bethelsklip, in central Namaqualand, between 800 and 360 BP. The archaeological evidence clearly supports a long tradition of herding in the region. The question is whether these early herder groups are the ancestors of the Namaqua Khoekhoen pastoralists who occupied Namaqualand during historical times?Historical records from the 17 to 20th centuries testify to the seasonal transhumance of the Namaqua with cattle, sheep and goats between the Kamiesberg Mountains and the plains. On occasions pastoralist groups also moved to the interior plateau of Bushmanland to make use of the seasonal grasses after summer thunderstorms. Traditional land-use practices have a long history in the region and a study of these land-use patterns may assist in interpreting the archaeological record and in developing a sustainable land-use policy for the region.     

Demographic hurdles to persistence in Acacia peuce (F. Muell.): Effects of resources,fire and browsing on a threatened keystone tree species from arid Australia

We use a 31 year dataset to assess the effects of resources (rainfall, soil, relief) and disturbance (cattle browsing and fire) on regeneration and growth in a long-lived tree Acacia peuce from arid inland Australia. Temporal and spatial resource availability had an overwhelming effect on recruitment and stand density; but cattle browsing and fire limited sapling growth and stand persistence, respectively. Seedling establishment over the 31 years was effectively confined to a single prolonged high rainfall phase. Cattle browsing in productive (run-on) patches kept saplings short; while long-fenced and low cattle-use (run-off) patches provided spatial escape opportunities for sapling growth. Fire caused the death of standing plants, but it did not stimulate recruitment, and was therefore an additional limiting factor for stand persistence. Our study provided further support for the central role of prolonged large rainfall events for regeneration in long-lived arid trees, but it also emphasised how disturbance can strongly limit stand regeneration. Overall, we expect that desert trees such as Acacia peuce that are characterised by slow population dynamics will be adversely affected by climate change due to increasingly rare recruitment. Minimisation of disturbance factors will be an increasingly important requirement for the long-term persistence of this species.     

The food habits of goats on rangelands with different amounts of fourwing saltbush (Atriplex canescens) cover

Esophageally fistulated goats were released in a microphyll desert scrub habitat with 14.6% or 46.2% aerial cover of Atriplex canescens (induced by removal of all shrubs except A. canescens, with livestock grazing exclusion for 10 years) to determine the seasonal forage species selected by the goats. The shrub removal strongly influenced the goats’ feeding habits. The goats grazing the Atriplex-dominated site consumed 4.5 times more A. canescens than the goats on the untreated (control) pasture during all seasons. Shrubs were used heavily during all seasons by goats in both pastures, with higher percentages (75.5–82.8%) in the diets of goats grazing the control pasture than in the diets of goats grazing the Atriplex-dominated area (62.5–68.5%). No differences were found between seasons. The goats in the Atriplex-dominated pasture ate more grass than the goats grazing the control area and used more perennial graminoids during the summer (15.0%) and spring (18.3%) than the goats on the control area (6.0–7.0%). Forbs were an important component of diets. It was concluded that the successful revegetation of the treated pasture affected the goats’ feeding strategy, with an increase in the use of A. canescens, forbs and grasses in all seasons.     

Diets of mammalian herbivores in Australian arid, hilly shrublands: seasonal effects on overlap between euros (hill kangaroos), sheep and feral goats, and on dietary niche breadths and electivities

The diets of euros or hill kangaroos (Macropus robustus), domestic sheep (Ovis aries) and feral goats (Capra hircus) in hilly, shrub rangeland in southern Australia were examined in a 12-year study. Levels of dietary overlap between these herbivores, their foraging in relation to resource availability, and the potential for competition in different conditions were also examined. The diet of euros was based around grasses. In dry seasons some shrubs were also eaten but in severe drought grass formed more than 80% of their diet. While grass was important to sheep in wetter conditions, they ate much shrub in dry conditions. Feral goats had broad diets but their preference for browse was high. In drought, euros had only a modest dietary overlap with sheep and goats. Data for dietary niche breadths and electivities pointed to only limited competition between the herbivores.     

Diet of a fossorial rodent (Octodontidae), above-ground food availability,and changes related to cattle grazing in the Central Monte (Argentina)

Overgrazing by livestock has caused desertification in the Monte, where ctenomyids and livestock share grasses as main food items. The diet of Ctenomys eremophilus, above-ground food availability and changes related to cattle grazing are analyzed in the arid plain of Mendoza, Argentina. The most available categories were grasses, followed by low shrubs and tall shrubs. Tuco-tucos showed dietary generalism, ate mainly above-ground plant parts, preferred grasses and avoided shrubs at both grazed and ungrazed sites. Plant cover, grass diversity and availability decreased under livestock grazing, which was reflected in the diet by a lower percentage of grasses, a shift toward low shrubs and higher number of frequently used resources. Tuco-tucos in the grazed paddock compensated for lower consumption of vegetative plant parts by increasing the use of Prosopis flexuosa pods stored inside burrows. Moreover, greater dietary variation among individuals suggests foraging restricted to the items closest to burrow holes. These feeding tactics would allow them to reduce above-ground foraging as a response to high raptor predation risk due to increased bare soil. The plant recovery detected during the rest period, favoured by moderate stocking rate and rotational grazing system, would allow coexistence of tuco-tucos and cattle.     

Does large herbivore removal affect secondary metabolites,nutrients and shoot length in woody species in semi-arid savannas?

We hypothesised that exclusion of long-term browsing leads to decreased nutrient concentrations, increased carbon-based secondary metabolites (CBSMs) and decreased shoot length in woody plants in semi-arid savannas. To test this, we sampled four deciduous woody species in a large-scale, long-term exclusion experiment. We found a tendency for large herbivore exclusion to either decrease nitrogen or increase tannin in two tree species. Phosphorus and total polyphenol responses indicated complex interactions with herbivore assemblage. Shoot length decreased under exclusion in two species, while a similar tendency existed in the remaining species. Therefore, we found limited support for our predictions that exclusion of browsing results in reduced nitrogen or increased CBSMs, but moderate support for decreased shoot length in semi-arid savannas. Dichrostachys cinerea, a fast-growing, aggressive invader in savannas, displayed C-limitation with removal of large herbivores because both shoot length and CBSMs decreased. In conclusion, effects of long-term browsing on deciduous trees in semi-arid savannas depend on the plant species, specific nutrients or CBSMs measured and the composition of the herbivore assemblages. Because elephant densities in the study area were high and most responses were associated with their exclusion, we conclude that elephants are important drivers of browse quality in the study area.     

策勒绿洲外围不同地下水埋深下主要优势植物的分布和群落特征

对塔克拉玛干沙漠南缘策勒绿洲外围地下水埋深与主要优势植物分布和群落特点的研究结果表明,植物的分布和群落特征受地下水埋深变化的影响。但群落的组成成分和生物多样性受到地貌特征和地下水埋深的双重影响。群落的差异性和间断性大于群落的连续性和相似性。群落分布随地下水埋深的变化与其他荒漠地区在大的空间演替规律上相一致,但在群落类型、特别是低水位地段群落演替序列上有明显不同。随着地下水埋深的变化,植物群落依次为:低水位的骆驼刺群落,较低水位的柽柳群落,中低水位的柽柳、胡杨群落,较高水位的芦苇群落,高水位的苦豆子群落,其中地下水埋深6.0 m以上地段是植物群落类型、种类组成和生物多样性都较为丰富的地区。绿洲外围植物中柽柳具有最大的环境资源利用比率,对环境的适应性最强。     

A continental analysis of correlations between tree patterns in African savannas and human and environmental variables

This study analyses possible relationships between natural processes taking place in savannas and the tree patterns found in savannas. This can lead to new hypotheses about which processes are driving savanna physiognomy. To do so tree patterns were quantified for African savannas from historical aerial photographs applying frequently used landscape metrics. Also, additional data for these areas were collected to quantify the processes taking place at these locations. Correlations between tree pattern indices and explaining factors were analysed. We found a negative trend between tree cover and density of sheep and goats, but no relationship between tree cover and density of cattle, suggesting that small livestock have an effect on tree cover, but that larger livestock (or obligate grazers) do not. Also, a positive correlation between human population density and tree cover was found. Possible explanations for the found relations are discussed. Subsequent ways to analyse the latter correlation are discussed, and the potential of the presented historical database of aerial photographs is highlighted.     

Does land use matter in an arid Environment? A case study from the Hoanib River catchment, north-western Namibia

The effect of intensive grazing and browsing of domestic stock and wildlife on the number of species and abundance of vegetation was investigated in the Hoanib River catchment, north-western Namibia. The seasonal abundance of ground cover, bare earth, canopy cover, annual grass, perennial grass and annual forbs were measured in each of the focus-study areas. In three of the focus areas where the ranges of both domestic stock and wildlife were restricted either by fencing or water availability, impact on the vegetation was greatest. The final focus area was a more ‘open range’ system that allowed for the free movement of wildlife. Under these conditions the species abundance and availability of browsing and grazing was greater than the other focus areas during both the wet and dry seasons. However, very little difference in abundance and availability of vegetation was observed between focus areas in both seasons regardless of landuse. There is generally a low abundance of perennial grasses and browse species affording the ecosystem little resistance and resilience to disturbance caused by grazing and drought.     

Effects of grazing and climate change on sandy grassland ecosystems in Inner Mongolia

To understand the effects of grazing activities and climate change on sandy grassland ecosystems in northern China, a livestock field grazing and enclosure experiment was conducted from 1992 to 2006 in Horqin Sand Land, Inner Mongolia. The results showed that sustained heavy grazing resulted in serious degradation of the vegetation; moderate grazing can maintain vegetation stabilization; and light grazing can promote rapid restoration of degraded vegetation. The livestock productivity was the highest in the moderate grazing grassland, and sustained heavy grazing resulted in rapid decrease of the livestock productivity. Heavy grazing can cause a retrogressive succession of grassland vegetation, whereas moderate and light grazing may promote progressive succession of plant species. The effects of changing climate on succession processes were not significant in the short term; a warm-humid climate is favorable to restoration of degraded vegetation, whereas a sustained warm-drought climate may result in degradation of grassland vegetation. Heavy livestock grazing should be stopped for the sustainable use of grassland; the proper grazing intensity for sandy grassland is two to three sheep or sheep equivalents per hectare in Inner Mongolia.