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Grazing practices affect the soil and vegetation of grasslands, which further influence the provision of ecosystem services and the productivity of grasslands. We determined the ecosystem resilience of a mesic grassland under three grazing management systems in the Pakkies area, (30°33′08″ S, 29°25′22″ E), South Africa: cooperative (continuously grazed since 2017), commercial (rotationally grazed for >20 years), and communal (continuously grazed for >20 years) farms. This was carried out by measuring the penetration resistance and infiltration, soil nutrients, forage quality contents for livestock, veld condition, plant species composition and richness, and functional diversity. The soils had a higher penetration resistance in the continuously grazed communal farm, while water infiltration was highest in the continuously grazed cooperative farm. The plant species and functional diversity were greater in the rotationally grazed commercial farm than in the continuously grazed communal and cooperative farms. The continuously grazed cooperative farm had the highest veld condition score (97%), while the rotationally grazed commercial and the continuously grazed communal farms had 82% and 56% veld condition scores, respectively. The forage quality and soil nutrients were generally similar among all farms. The lower plant diversity observed with continuous grazing may indicate that the ecological system was not as resilient concerning this type of grazing. However, for forage quality, soil nutrients and veld condition, continuous grazing was resilient, which indicates that rotational grazing may not be better than continuous grazing for livestock production in this specific region. As long as a minimum level of ecological resilience can be retained, continuous grazing can sustain effective animal production, particularly for small-holder farmers. [ABSTRACT FROM AUTHOR]

Mine closure in the Witwatersrand Goldfields of South Africa has resulted in an acid mine drainage (AMD) legacy that is difficult to manage and costly to address. As a short-term measure, three large high-density sludge (HDS) plants were erected that treat 185 megalitres of AMD per day (ML/day), at great cost to taxpayers. Longer-term solutions are sought, as the salt load to the Vaal River System is unacceptable. Long-term modelling was used to assess whether the untreated and HDS-treated AMD could be used for irrigation and to determine the scale of the potential opportunity. The Goldfields waters are not very acidic, and simulations indicate it should be feasible to utilise even the untreated water for irrigation, especially if growers commit to applying limestone to their fields. HDS treatment lowers the corrosivity and trace element concentrations, and because the water is gypsiferous, double cropping will precipitate more than a third of the salts in solution as gypsum in the soil profile, thereby reducing salt load to the water environment. The potential irrigated area depends on the cropping system; it is about 9000 ha for rotational cropping and 30,000 ha for supplemental maize irrigation. It is prudent to seriously consider irrigation as a potential long-term water management option for the Goldfields AMD. [ABSTRACT FROM AUTHOR]

The concept of the piosphere is important in rangeland management, wildlife management, desertification. Piosphere research describes the changes in soil, biota and fauna as a function of distance from water sources utilized by grazing animals. Piosphere research has provided a better understanding of how grazing pressure can affect local environments. We conducted a bibliometric analysis to describe the progress of piosphere knowledge between 1915 and 2018. This is the first comprehensive bibliometric analysis of piosphere research, and it provides insights on future challenges, research challenges, and knowledge gaps. Google Scholar was used to identify 875 publications from 68 countries and 10 different languages. Our analyses showedthat research article was the most frequent publication type and piosphere was the most frequent keyword. Australia was first in the number of publications followed by South Africa and USA. Ivan Thrash is the most contributed author with 11 publications. The most frequently cited article is 'Responses of Mediterranean grassland plants to grazing and protection' in The Journal of Ecology. Herbivores, vegetation, soil, livestock, wildlife, and ecological were the most frequent research areas of piosphere investigations. English was the major and dominant language of piosphere publications. Rapid growth was found in piosphere research since the 1990s, enlivened by advances in statistics, remote sensing, GIS, and programming. We recommend that future research should investigate knowledge gaps such as grazing system relationships to piosphere patterns, economic analysis of watering point development and closure, and the implications of climate change and new piospheres. [ABSTRACT FROM AUTHOR]

Globally, the determinants of rangeland dynamics and sustainability have been debated for decades. This study sought to explain the drivers of rangeland ecosystems in semi-arid South Africa by examining the vegetation and soil conditions around animal drinking water points, and their implications for sustainable management and paradigm debates. For this purpose, we selected three land use systems (continuous-communal livestock farms, rotational-commercial livestock farms, and continuous-game reserves), with the livestock farms having either high or low stocking rates. Soil organic carbon (OC), bulk density (p < 0.05), and soil compaction (p < 0.0001) varied greatly at land scales, being greater in the communal farms or game reserves than the commercial farms. Within the communal farms, sites with high stocking rates showed higher (p < 0.05) soil OC and bulk density than sites with lower stocking rates, but in the commercial farms, sites with high stocking rates had lower soil OC. Above ground grass biomass, and the abundance of highly desirable grass species were greater (p < 0.001) in the commercial farms and game reserves. Our results conclude that equilibrium elements, importantly animal density and diversity, seemed to play a major role in soil and vegetation dynamics. We also observed variations in edaphic factors and rainfall across the land use systems and over seasons (rainfall). We assume that these non-equilibrium elements may also influence rangeland ecosystems. To confirm this, however, we recommend future studies to include comparable measures of the vegetation and soil, and their relations with edaphic and temporal long-term rainfall variability across the land use systems. [ABSTRACT FROM AUTHOR]

• Rotational grazing has little effect on vegetation NDVI, bare soil or woody plant cover. • Holistic planned grazing practitioners are self-aligned with rotational grazing. • Results corroborate findings from multiple farm-scale experimental trials. • Stocking rates or livestock type were unrelated to vegetation responses. The consensus from world-wide experimental studies is that rotational grazing management has little effect on enhancing vegetation cover and animal productivity relative to conventional management. Critics of these studies claim that experimental trials fail to capture the complexity of adaptive management decisions that bring about long-term vegetation changes at the landscape scale. Thus, we surveyed 48 working farms nation-wide in South Africa to test the hypothesis that rotational grazing sustains higher animal numbers while increasing grass cover and reducing bare ground and woody plant cover. A subset included 23 fence-line comparisons between farm neighbors or paddocks with a similar fire regime but with grazing management varying from continuous to ultra-high density grazing, and we coupled this with remotely-sensed vegetation indices. Results from 48 farms under consistent management for 15 ± 0.8 years (mean ± standard error), revealed that farm stocking rates were relatively higher than those recommended by agricultural extension services at 59 ± 12% (F a r m s - R e c o m m e n d e d F a r m s * 100 ± standard error) and that adherence to high density rotational grazing management did not affect this. For fence-line contrasts, the change (Δ) in each management or explanatory variable (stocking rate, stock density and proportion of grazers versus all livestock) across the fence was expressed using Hedge's g effect size as Δ = a - b a × 100 where (a) is the farm with the highest grazing density and (b) is its neighbour. As intended, the comparisons yielded a 85 ± 5% relative difference in grazing densities but revealed non-significant differences in normalised difference vegetation indices (NDVI), fractional bare ground, grass and woody plant cover at 82% of fence-lines. The absolute magnitude of fence-line differences in stocking rate (30 ± 7%) and grazer percentage (55 ± 16%) also had no consistent effect on vegetation cover. This regional analysis of working farms corroborates findings from multiple experimental studies on rotational grazing and adds weight to it by including a diversity of rotational grazing intensities. Evidence in this study was not compatible with commonly observed negative effects of high stocking rates on vegetation cover, implying that the relatively high stocking rates were within the carrying capacity of farms studied. Further, the previously untested hypothesis that rotational grazing alters woody plant cover was not supported in our study. Based on these and the findings of others, continued advocacy for extreme forms of rotational grazing management is unfounded. [ABSTRACT FROM AUTHOR]

Although the savanna biome of South Africa is a major resource for rangeland management, little is known about how differences in rangeland management systems affect soil properties in such biomes. Near to Kuruman, commercial farms have practiced rotational grazing for decades. In communal areas of former homeland Bophuthatswana, similar strategies were used prior to 1994. Nowadays, a continuous grazing system is common. We hypothesized that these changes in management affected soil properties. To test this, we sampled soils at communal and commercial land along a gradient with increasing distance to water points. The results revealed that communal systems with continuous grazing showed enlarged spatial gradients. The soils were depleted in most nutrients close to the water relative to those of commercial systems. In contrast, as the distance to the water increased, the nutrient stocks of these communal systems were higher. Changes in soil nutrient stocks were related to a zone of increased bush encroachment (up to 25%). Specific analyses (phosphorus fractions, particulate organic carbon, δ 13 C) confirmed that the soils of the communal grazing systems benefited from the shift of grass-dominated to bush-dominated system with woody Acacia vegetation, while the rangeland degraded in the sense that it lost palatable grass species. [ABSTRACT FROM AUTHOR]

Questions Plant communities fulfil key functions in the ecosystem, which can be characterized by their plant functional traits. In functional ecology, plant communities are considered to hold a set of trait attributes reflecting a specific plant strategy adapted to persist in the environment to which they are exposed. In semi-arid grasslands of the Republic of South Africa, we addressed the following questions: how are community-aggregated plant functional traits ( CPFT) shaped by grazing gradients; which plant strategies are associated with the response of CPFTs; and are environmental factors, such as soil properties and grazing management, interrelated with the functional response of vegetation to grazing gradients? Location Semi-arid grasslands close to Thaba Nchu, Free State ( Republic of South Africa). Methods Piosphere transects from a water point into the field were established to portray grazing gradients on two communal grazing areas with continuous grazing and two commercial farms with rotational grazing. Along each transect, six plots (5 × 5 m) were evenly distributed. The trait-transect sampling was applied to record 12 CPFT related to light capture and forage quality. A redundancy analysis was performed to derive relationship between CPFTs, grazing gradients and environmental conditions. Results Grazing intensity decreased along piosphere transects, from the water point into the field. Most CPFTs responded to this decreasing gradient of grazing intensity and so allowed derivation of trait syndromes that clearly reflect plant strategies of ruderal and competitive vegetation. Close to water points, plants had higher nitrogen concentrations, fewer cell wall components and higher specific leaf area, hence light capture might be faster and more efficient per leaf area and leaf mass. Plant communities exposed to intensive grazing were well adapted to defoliation, trampling and nutrient accumulation through fast growth rates and a quick return strategy. Conclusions In the sacrifice zone around water points, there is an ecological niche for vegetation communities exhibiting a strategy of fast growth, which is well adapted to intense and frequent grazing and is also associated with forage of high nutritional quality. [ABSTRACT FROM AUTHOR]

Abstract: The grassland biome of South Africa is a major resource for livestock farming; yet the soils of these rangelands are stressed differently by various management systems. The aim of this study was to investigate how basic soil properties respond to different management systems. For this purpose we sampled rangeland management systems under communal (continuous grazing), commercial (rotational grazing) and land reform (mixture of grazing systems) farming. Within each of these systems a grazing gradient was identified with decreasing grazing pressure with increasing distance to the water points. Results showed that communal farms with continuous grazing were generally depleted in the respective nutrient stocks. The depletion increased with rising grazing pressure. Along that line there was a breakdown of macroaggregates with losses of the C and N stored therein. However, the commercial farms also exhibited a decline of macroaggregates and their associated C content nearby the water points. Aggregate fractionation is a sensitive indicator for detecting the beginning of soil degradation in this biome; yet, degradation was less pronounced under the rotational grazing of the commercial farms than under communal property right conditions. Hence, soil analyses confirm that fences and appropriate grazing periods are needed to manage these rangelands sustainably. [Copyright &y& Elsevier]

A study on grasshopper assemblage response to seasonal grazing, rotational grazing, continuous resting and continuous grazing was undertaken in the eastern Karoo, South Africa. Rotationally-grazed sites supported the highest number and abundance of grasshopper species while continuously-grazed sites had the lowest. Spring-grazed and winter-grazed sites were the most similar, with continuously-rested sites being the next similar to these. Rotationally-grazed sites showed the least similarity to the other sites. There were clear groupings of sites and grasshopper species, with most species associated with rotationally-grazed sites. Continuously-grazed sites had a different grasshopper assemblage. The assemblages followed definite gradients of measured environmental variables. Rotationally-grazed sites occurred along gradients of increasing bare ground, while continuously-grazed and summer-grazed sites occurred along increasing gradients of shrub cover and soil temperature. Spring-grazed, autumn-grazed, winter-grazed and rotationally-grazed sites were characterized by high vegetation density. Grasshopper dominance differed between sites. Summer-grazed sites had high dominance of Pycnodictya flavipes (40%), winter-grazed sites of Pseudogmothela sp. (32%) The significance of variable grazing management systems for maintaining floral and grasshopper diversity is discussed. Rotational grazing in this arid system is most suited to maintaining plant and insect diversity. [Copyright &y& Elsevier]

• Assessment of woody encroachment in different tenure based rangeland management systems. • Communal areas exhibited higher bush encroachment after management change. • Woody encroachment went along with an improvement of soil properties, especially SOM. • Management change was an important driver for bush encroachment. Woody encroachment is increasingly threatening savanna ecosystems, but it remains unclear how this is driven by different land tenures and management systems. In South Africa, communal land is mainly managed under continuous grazing, while commercial land is under rotational grazing. We hypothesize that woody encroachment has increased since the end of the Apartheid era in 1994, when rotational grazing systems in communal land switched to continuous grazing. To test this hypothesis, we sampled six subsites in each of three replicates of the two tenure systems in the savannah biome, South Africa, and monitored the degree of woody encroachment and effects on soil using remotely-sensed normalized difference vegetation index (NDVI), dendro-ecology, and grid-based soil analyses. The results confirmed that there has been a positive greening trend over the past 25 years in communal areas due to an increase in woody cover, particularly for tree in the 50–150 cm height class. These trees corresponded to Senegalia tree ages between 10 and 25 years. Greater woody cover in communal areas was accompanied by height-dependent elevated nutrient and organic matter concentrations that increased in the topsoils by a factor of up to 1.5, relative to the freehold systems. Isotopic analyses identified debris of C 3 bushes and trees as main carbon input into the soil of communal areas, where the δ13C value of −20.1‰ was significantly lower than it was at private farms (−19.2‰). Isotopic values also indicated that this carbon input took place beyond the edges of the bush canopy. We conclude that the tenure-based management system in the communal areas has promoted woody encroachment, with the associated changes in soil properties homogenizing the savanna system. [ABSTRACT FROM AUTHOR]