Interactions of grazing and rainfall on vegetation at Grootfontein in the eastern Karoo§

Rainfall and grazing are primary drivers of vegetation composition in the Nama-Karoo. Increased rainfall increases grassiness, to where Nama-Karoo transitions to grassland. Severe grazing treatments (e.g. continuous or summer-only) increase abundance of grazing-tolerant dwarf shrubs and annual grasses, and decrease perennial grasses. Grootfontein, which is ecotonal between the Nama-Karoo and Grassland Biomes, houses long-term grazing trials. The area has experienced higher-than-average rainfall in recent decades. Plant basal cover data from the 1960s and 2010s allow several hypotheses to be addressed: (1) historical severe grazing (until 1985) will limit subsequent grassiness (grazing legacy effect); (2) severe grazing will preclude increases in grassiness, independent of rainfall (herbivore trap effect); and (3) historically leniently-grazed sites will transition to grassland with increased rainfall (biome shift effect). Rainfall was lower from 1957–1966 (350 mm) than from 2003–2012 (490 mm). The grazing legacy effect was supported based on the abundance of Aristida diffusa, despite all sites becoming much grassier. The herbivore trap effect was not supported. The biome shift effect was supported in that shifts to grassland sometimes occurred. Results suggest that increasing rainfall has prompted a shift to much increased grassiness and decreased abundance of dwarf shrubs, and that grazing had a smaller secondary effect.     

Drivers and trajectories of social and ecological change in the Karoo,South Africa§

This review article explores past, present and possible future drivers of change in Karoo social-ecological systems. Biogeographically, the Karoo comprises the arid Succulent Karoo and Nama-Karoo biomes covering significant portions of the Northern Cape, Eastern Cape and Western Cape provinces and a smaller part of the Free State. Despite the Karoo’s specific environment and spatial importance nationally (covering some 30% of South Africa), no government structures address its needs holistically. Today it is a politically and economically marginalised region; perceptions of it as a desert easily morph into perceptions of it as deserted and ripe for exploitation for the benefit of external constituencies, whether in the name of astronomy, shale-gas and uranium mining or renewable energy. To manage the Karoo better for present and future generations, it is clearly desirable for social and natural scientists to work collaboratively, yet there is relatively little interdisciplinary work to date. Against this background this review article provides an overview of social and ecological changes historically and in the present, and offers some cautious reflections concerning climate change, changing land use and governance as key drivers affecting trajectories of change into the future.     

Review: Restricted and Programmed Feeding of Beef Cattle—Definitions,Application, and Research Results

Restricted and programmed feeding are two commonly used approaches to manage feed intake by cattle. Restricted feeding, which is most often applied to starting cattle on feed and to finishing cattle, takes various forms but generally includes any method of feed intake management with which intake is restricted relative to actual or anticipated ad libitum intake. Conversely, programmed feeding, which is most frequently used in growing programs, is a method in which net energy equations are used to calculate the quantities of feed required to meet the needs for maintenance and a specific rate of gain. Both restricted and programmed feeding have been shown to improve feed efficiency, perhaps in part because recent research data suggest that body energy gain by cattle increases in a diminishing manner with increasing energy intake. Nonetheless, commercial application of restricted and(or) programmed feeding is limited by concerns related to application in large vs small pens and potential negative effects of restriction and(or) programming on daily gain and carcass quality grade. Research findings suggest consistent improvements in feed efficiency, generally decreased daily gain, and generally lower carcass quality grade when intake is restricted from 5 to 15% relative to pair-fed ad libitum controls in finishing cattle. Application of restricted and(or) programmed feeding during growing periods followed by ad libitum feeding, however, seems to have little effect on subsequent performance and carcass quality grade. Although restricted feeding offers the advantages of simplified feed bunk management, advanced knowledge of feed milling needs, and potential environmental benefits, additional research and field-level fine tuning will be needed before widespread commercial application is likely.     

Spatial,temporal and attitudinal dimensions of conflict between predators and small-livestock farmers in the Central Karoo§

Conflict between predators and small-livestock farmers is a global phenomenon adversely impacting the preservation of wildlife, the well-being of livestock and human livelihoods. Such conflict is pervasive in the Karoo region of South Africa but its contemporary history and various causes remain poorly understood. In this study, we interviewed 77 small-livestock farmers in the Central Karoo between July 2014 and March 2015 to (1) assess the spatio-temporal distribution and severity of the reported predation problems with the main regional predators of livestock (black-backed jackal, caracal and baboon) and (2) describe the perceived reasons for changes in predator numbers. Farmers reported that serious predation problems have increased since the 1990s for all three predators. Jackal predation appears to have re-emerged, particularly since the 2000s, while baboon predation seems to have escalated rapidly since 2014 for select farmers. Farms with more rugged terrain were more likely to experience serious problems with baboons and caracal but ruggedness did not predict the year of onset of problems. Farmers perceive predator numbers to be increasing and attribute this trend to declining government support for predator management, changes in farming practices and the associated increase in suitable predator habitat, from which they can recolonise commercial farms.     

Linear structures in the Karoo,South Africa,and their impacts on biota§

Linear structures include fences, roads, railways, canalised water ways and power lines, all man-made. Fencing as a way of managing livestock began in the late 1800s, and by the early twentieth century was almost fully implemented throughout the Karoo sensu lato. The advent of these fences, and now in many instances, ‘game proof’ (～2 m high) and electric fences have impacted native flora and fauna in various ways. Roads influence the quality and quantity of vegetation along corridors throughout the Karoo, with impacts on wildlife through increased mortality, but also provide foraging opportunities. Road-side structures, such as transmission poles, offer nest sites and perches in otherwise treeless landscapes, benefiting certain avifauna. Railway lines create similar corridors, carrying ungrazed vegetation along them. Their associated structures – culverts and (historically) steel frame bridges – provide nest sites for birds and some mammals. Transmission cables and pylons along power lines have mixed benefits to conservation, providing bird nest and perch sites, but can also cause bird mortalities. Unquestionably, these linear structures have had marked effects on the biota of the Karoo, through their effects on wildlife and livestock movement and mortality, plant demography and the spread of native and alien species.     

Requirements and Forms of Classroom Tests at High School

As we all know, Testing is a fundamental component in the English language education. And it’s a complex job.Large-scaled criterion tests are carried out by some specialagencies and full-time personnel. The whole test processesare systematic work, which contains laying down test aims, working out test syllabus, designing and developing testpapers, scoring and analyzing test results. The whole scientificand modern processes ensure that testing has higher testreliability and validity and so on. But small-scaled tests, likeclassroom tests, have also their requirements and forms.1.A Classroom TestA Classroom test which is a kind of achievement test issmall-scaled, it has the testing demands and processes. But athigh school, a Classroom test is often operated and organized     

An overview of themes in the agrarian and environmental history of the Karoo since c.1800§

This article explores some themes in the agrarian and environmental history of the Karoo since 1800. It argues that environmental change cannot be understood without incorporating social, economic and political history. This is especially so in the case of the Karoo because the landscape and ecology was transformed by intensive commercial livestock production in the nineteenth and twentieth centuries. The scale and economic significance of sheep farming and wool production up to the 1960s is generally underestimated in histories of the Cape and South Africa. The article outlines the patterns of economic growth and also the technologies required, such as fencing and water provision. The environmental impact of intensive livestock farming was recognised from the late eighteenth century and new scientific approaches helped to define understandings of environmental change. Environmental degradation was at its height in the first half of the twentieth century; simultaneously, conservationist ideas were developed and gradually implemented. In the second half of the twentieth century, these approaches, together with socio-economic factors that led to lower levels of stocking, resulted in a stabilisation and even some environmental recovery.     

The composition of the soil seedbank and its role in ecosystem dynamics and rehabilitation potential in the arid Tankwa Karoo Region,South Africa§

Very few soil seedbank studies have been conducted in South Africa, especially in arid rangelands. Insight into the soil seedbank could therefore improve assessment of rangeland dynamics and enhance rehabilitation efforts. This study aimed to characterise the soil seedbanks in various vegetation types of the Tankwa Karoo National Park, an arid environment in South Africa. At 43 sites soil was sampled twice at the end of spring and the end of autumn, and the composition and structure of aboveground vegetation were described at the peak growth period in spring. Seeds were isolated from the soil samples by means of flotation in a salt solution, seedbank species composition was obtained by seedling germination, and the vegetation was investigated using a line-point survey method. Overall seed density was 8 034 seeds m^?2 of which 55% was viable, and the common life-forms were therophytes and chamaephytes. Species richness and diversity were lower in the seedbank compared with those of the vegetation, and the two vegetation spheres were 25% similar. While seedbank composition suggested poor veld condition, there was enough seed density and viability for future regeneration and rehabilitation initiatives. However, this may be impeded by the absence of many perennial species in the soil seedbank.     

Seroprevalence and risk factors for leptospirosis in cattle,sheep, and goats at consorted rearing from the State of Piauí, northeastern Brazil

Leptospirosis is an endemic disease in Latin America, caused by pathogenic bacteria of the genus Leptospira. It is considered one of the main causes responsible for the negative economic impact on global livestock by causing reproductive problems. The research aimed to determine the prevalence of leptospirosis in cattle, sheep, and goats at consorted rearing in the micro-region of Teresina, Piauí state, northeastern Brazil, as well as to identify prevalent serovars and risk factors associated with seroprevalence. Serum samples were analyzed in 336 sheep, 292 goats, and 253 cattle using microscopic agglutination test (MAT). Overall, 378 samples were positive to MAT, with seroprevalence of 42.9%. The prevalences in cattle, sheep, and goats were 50.5, 40.5, and 34.6%, respectively. All herds presented at least one seropositive animal; the Hardjo/Wolffi serovar association was the most common in cattle and Icterohaemorrhagiae in goats and sheep. Beef production (OR?=?4.9), cattle herd over 35 animals (OR?=?4.0), feeding on pasture (OR?=?6.4), weir and/or stream as water source (OR?=?2.1), and no veterinary services (OR?=?2.9) were risk factors for cattle infection. For sheep, intensive management system (OR?=?5.3), suspended slatted facilities (OR?=?2.2), more than 20 sheep in reproductive age (OR?=?1.9), and absence of deworming (OR?=?3.5) were the risk factors, while for goats, the identified risk factors were sheep herd over 52 animals (OR?=?1.9) and no veterinary services (OR?=?1.8). We conclude that the infection was spreading in consorted herds in this region. Thus, it would be interesting and important to conduct educative activities to farmers on the economic impacts of this disease and the need of preventive and control strategies mainly focused on sanitary measures and animal handling.     

Zika virus – emergence,evolution, pathology,diagnosis, and control: current global scenario and future perspectives – a comprehensive review

This review converses the Zika virus which has attained global concern due to its rapid pandemic potential and impact on humans. Though Zika virus was first isolated in 1947, till the recent large-scale outbreak which occurred in Micronesia, in 2007, the virus was placed into the innocuous pathogen category. The World Health Organization on 1 February 2016 declared it as a ‘Public Health Emergency of International Concern.’ Of the note, American as well as Pacific Island strains/isolates is relatively closer to Asian lineage strains. The African and American strains share more than 87.5% and 95% homologies with Asian strains/isolates, respectively. Asian strains form independent clusters, except those isolated from China, suggesting relatively more diversity than African strains. Prevention and control are mainly aimed at the vector population (mosquitoes) with Aedes aegypti being the main species. Surveys in Africa and Asia indicated seropositivity in various animal species. However, so far its natural reservoir is unknown. There is an urgent need to understand why Zika virus has shifted from being a virus that caused mild illness to unforeseen birth defects as well as autoimmune-neurological problems. Unfortunately, an effective vaccine is not available yet. Availability of cryo-electron microscopy based on 3.8 Å resolution revealing mature Zika virus structure and the probable virus attachment site to host cell would provide critical insights into the development of antiviral treatments and vaccines.     

The evolution of the natriuretic peptides – Current applications in human and animal medicine

Although natriuretic peptides have played an important role in the fluid homeostasis of vertebrates for over several million years, their importance has only been noticed in the last few decades. Yet, the family of natriuretic peptides have since their discovery, drawn the attention of a broad spectrum of physicians and researchers involved in the maintenance of fluid homeostasis, including marine biologists, basic scientists, physicians and veterinarians.While all natriuretic peptides share a common phylogenetic background, due to differences in receptor-binding affinities, they have evolved into different hormones with clear distinct functions.B-type natriuretic peptide (BNP) is the most studied member of the natriuretic peptide family, and together with its cleavage equivalent amino-terminal proB-type natriuretic peptide (NT-proBNP) these peptides have emerged as important cardiovascular serum markers. However, since their introduction, physicians involved in human or animal medicine have faced common but also different challenges in order to optimally interpret the diagnostic and prognostic value of these novel cardiovascular biomarkers.     

Long-term changes in land use,land cover and vegetation in the Karoo drylands of South Africa: implications for degradation monitoring§

We used several large data sets at a range of temporal and spatial scales to document the land-use/land-cover change (LULCC) dynamics of the semi-arid Succulent Karoo and Nama-Karoo biomes of South Africa. More than 95% of the Karoo is comprised of land classified as Natural, which has been relatively stable since 1990. Over the last 100 years cultivation, as well as the number of domestic livestock, has declined significantly in both biomes. Protected areas have increased since 1980 to comprise nearly 8% of the Succulent Karoo biome, although they only cover 1.6% of the Nama-Karoo biome. There has been a significant recent increase in renewable energy installation applications, which cover 4% of the Karoo drylands. The trend in vegetation productivity (NDVI; 1982–2015) is unchanged over 90% of both biomes, while nearly 10% of the Karoo has shown a significant increase in NDVI trend. An analysis of repeat photographs shows that vegetation cover has either remained unchanged or has increased at most locations. Although the Karoo drylands appear less degraded than they were in the mid-twentieth century, on-going monitoring at different temporal and spatial scales is essential to evaluate the future impact of LULCC on these semi-arid environments.     

Influence of single applications of nitrogen on white clover nitrogen fixation in autumn and winter dairy pastures in south‐west Victoria,Australia

Abstract

Effects of nitrogen (N) (0, 15, 30, 45 and 60 kg N ha^?1) applied at five different times during autumn and early winter on the N fixation of Trifolium repens L. (white clover) in Lolium perenne L. (perennial ryegrass) / white clover pastures were examined (Experiment 1). Effects of applying different N fertilisers (e.g. urea and ammonium nitrate) at 45 kg N ha^?1 in autumn, with and without phosphorus (P), potassium (K) and sulphur (S) on N fixation were also tested (Experiment 2). In Experiment 1, percentage N derived from the atmosphere (percent Ndfa) by white clover varied between 87% and 91% in the period after (24 to 36 days) N application. Increasing rates of N and time of application did not influence percent Ndfa. The amount of N fixed by white clover ranged from 0.8 to 3.7 kg N ha^?1 in the period after N application. Increasing rates of applied N produced a significant (P<0.05) linear increase in the amount of N fixed. In Experiment 2, percent Ndfa and amount of N fixed (1.9 to 4.1 kg N ha^?1) were unaffected by different N fertilisers, with and without P, K and S, in the period after (37 days) fertiliser application. For both experiments, fertiliser N increased dry matter yield while having no effect on white clover composition. It is concluded that single applications of N during the autumn and early winter benefit pasture growth without adversely affecting white clover N fixation or clover composition. This finding, however, will require further investigation.