Academic literature on the topic 'Grasslands – South Africa'
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Journal articles on the topic "Grasslands – South Africa"
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Burgoyne, B. M., G. J. Bredenkamp, and N. Van Rooyen. "Wetland vegetation in the North-eastern Sandy Highveld, Mpumalanga, South Africa." Bothalia 30, no. 2 (September 25, 2000): 187–200. http://dx.doi.org/10.4102/abc.v30i2.558.
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The wetland vegetation of the high mountain grasslands of Mpumalanga w as sampled by using stratification based on geology and land types. Floristic data were classified by TWINSPAN procedures and refined by using the Braun-Blanquet method. This resulted in the recognition of four major w etland plant communities w hich are subdiv ided into eleven minor plant communities. The major communities include the Phragmites australis Wetland occurring in relatively deep water, the Miscanthus junceus Wetland from moist river banks and wet drainage lines, the Eragrostis biflora-Stihurus allopecuroides Moist Grassland restricted to moist, poorly drained soils w ith a high water table, and Arundinella nepalensis Moist Grasslands on black vertic soils.
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Van den Hoof, Catherine, Michel Verstraete, and Robert Scholes. "Differing Responses to Rainfall Suggest More Than One Functional Type of Grassland in South Africa." Remote Sensing 10, no. 12 (December 18, 2018): 2055. http://dx.doi.org/10.3390/rs10122055.
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Grasslands, which represent around 40% of the terrestrial area, are mostly located in arid and semi-arid zones. Semiarid ecosystems in Africa have been identified as being particularly vulnerable to the impacts of increased human pressure on land, as well as enhanced climate variability. Grasslands are indeed very responsive to variations in precipitation. This study evaluates the sensitivity of the grassland ecosystem to precipitation variability in space and time, by identifying the factors controlling this response, based on monthly precipitation data from Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) and the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) data from the Multi-angle Imaging SpectroRadiometer-High Resolution (MISR-HR) datasets, used as proxy for productivity, at 60 grassland sites in South Africa. Our results show that MISR-HR products adequately capture the spatial and temporal variability in productivity at scales that are relevant to this study, and they are therefore a good tool to study climate change impacts on ecosystem at small spatial scales over large spatial and temporal domains. We show that combining several determinants and accounting for legacies improves our ability to understand patterns, identify areas of vulnerability, and predict the future of grassland productivity. Mean annual precipitation is a good predictor of mean grassland productivity. The grasslands with a mean annual rainfall above about 530 mm have a different functional response to those receiving less than that amount of rain, on average. On the more arid and less fertile soils, large inter-annual variability reduces productivity. Our study suggests that grasslands on the more marginal soils are the most vulnerable to climate change.
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Räsänen, Matti, Mika Aurela, Ville Vakkari, Johan P. Beukes, Juha-Pekka Tuovinen, Pieter G. Van Zyl, Miroslav Josipovic, et al. "Carbon balance of a grazed savanna grassland ecosystem in South Africa." Biogeosciences 14, no. 5 (March 7, 2017): 1039–54. http://dx.doi.org/10.5194/bg-14-1039-2017.
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Abstract. Tropical savannas and grasslands are estimated to contribute significantly to the total primary production of all terrestrial vegetation. Large parts of African savannas and grasslands are used for agriculture and cattle grazing, but the carbon flux data available from these areas are limited. This study explores carbon dioxide fluxes measured with the eddy covariance method for 3 years at a grazed savanna grassland in Welgegund, South Africa. The tree cover around the measurement site, grazed by cattle and sheep, was around 15 %. The night-time respiration was not significantly dependent on either soil moisture or soil temperature on a weekly temporal scale, whereas on an annual timescale higher respiration rates were observed when soil temperatures were higher. The carbon dioxide balances of the years 2010–2011, 2011–2012 and 2012–2013 were −85 ± 16, 67 ± 20 and 139 ± 13 gC m−2 yr−1, respectively. The yearly variation was largely determined by the changes in the early wet season fluxes (September to November) and in the mid-growing season fluxes (December to January). Early rainfall enhanced the respiratory capacity of the ecosystem throughout the year, whereas during the mid-growing season high rainfall resulted in high carbon uptake.
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Zaloumis, Nicholas P., and William J. Bond. "Reforestation or conservation? The attributes of old growth grasslands in South Africa." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1703 (September 19, 2016): 20150310. http://dx.doi.org/10.1098/rstb.2015.0310.
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Deforestation as a result of burning and land conversion in the tropics and subtropics has been widely studied and active restoration of forests has been widely promoted. Besides other benefits, reforestation can sequester carbon thereby reducing CO 2 emissions to the atmosphere. However, before grasslands are targeted for ‘reforestation', it is necessary to distinguish whether they are ancient natural grasslands or secondary vegetation colonizing deforested areas. Here we report the results of a study comparing primary grasslands in South Africa with 4–40 year old secondary grasslands recovering from afforestation with Pinus species. Primary grasslands had significantly higher plant species richness overall, especially of forb species. Ground cover of primary grasslands was more evenly distributed among species than secondary grasslands which tended to mono-dominance. Forbs with underground storage organs (USOs) were common in primary grasslands but conspicuously absent in the recovering systems. Comparison of secondary grasslands of different ages (up to 40 years) showed negligible recovery of the original species composition. Three key features distinguish old growth primary from secondary grasslands: total and forb species numbers, evenness of species contributions to cover and the presence of USOs. Old growth grasslands also differed in their fire response, showing significant post-burn resprouting and fire-stimulated flowering in contrast to secondary grasslands. Though similar contrasting attributes of ancient and secondary grasslands have been reported in South America, more studies are needed to explore their generality in other geographical regions. This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’.
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Gomes, Amândio L., Rasmus Revermann, Francisco M. P. Gonçalves, Fernanda Lages, Marcos P. M. Aidar, Graciela A. Sanguino Mostajo, and Manfred Finckh. "Suffrutex grasslands in south-central Angola: belowground biomass, root structure, soil characteristics and vegetation dynamics of the ‘underground forests of Africa’." Journal of Tropical Ecology 37, no. 3 (May 2021): 136–46. http://dx.doi.org/10.1017/s0266467421000298.
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AbstractDespite its importance for carbon stocks accounting, belowground biomass (BGB) has seldom been measured due to the methodological complexity involved. In this study, we assess woody BGB and related carbon stocks, soil properties and human impact on two common suffrutex grasslands (Brachystegia- and Parinari grasslands) on the Angolan Central Plateau. Data on BGB was measured by direct destructive sampling. Soil samples were analysed for select key parameters. To investigate vegetation dynamics and human impact, we used Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) and fire data retrieved via Google Earth Engine. Mean belowground woody biomass of sandy Parinari grasslands was 17 t/ha and 44 t/ha in ferralitic Brachystegia grasslands of which 50% correspond to carbon stocks. As such, the BGB of Brachystegia grasslands almost equals the amount of aboveground biomass (AGB) of neighbouring miombo woodlands. Almost the entire woody BGB is located in the top 30 cm of the soil. Soils were extremely acid, showing a low nutrient availability. Both grassland types differed strongly in EVI and fire seasonality. The Parinari grasslands burnt almost twice as frequent as Brachystegia grasslands in a 10-year period. Our study emphasizes the high relevance of BGB in suffrutex grasslands for carbon stock accounting.
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DESCHODT, CHRISTIAN M., and ADRIAN L. V. DAVIS. "New southern African species and a revalidation in the dung beetle genus Gyronotus van Lansberge, 1874 (Scarabaeidae: Scarabaeinae) with an updated key." Zootaxa 4624, no. 2 (June 28, 2019): 275–82. http://dx.doi.org/10.11646/zootaxa.4624.2.10.
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Three new species are described in the genus Gyronotus van Lansberge, 1874 (Scarabaeidae: Scarabaeinae), from upland grasslands of South Africa. They are Gyronotus dracomontanus Deschodt & Davis, new species, Gyronotus ovalis Deschodt & Davis, new species and Gyronotus kearneyorum Deschodt & Davis, new species. The South African coastal forest species, Gyronotus marginatus Péringuey, 1888, status revised, is removed from synonymy with Gyronotus pumilus (Boheman, 1857) and revalidated at species level. An updated key to all South African and eSwatini species is provided.
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Zaloumis, N. P., and W. J. Bond. "The fragility of mesic C4 grasslands in South Africa." South African Journal of Botany 86 (May 2013): 167. http://dx.doi.org/10.1016/j.sajb.2013.02.108.
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Sershen, Charmaine C. Drury, Clinton Carbutt, and Syd Ramdhani. "Seed banks of subtropical grassland patches within an urban matrix in South Africa: reflecting the past and foretelling the future." Botany 97, no. 4 (April 2019): 231–44. http://dx.doi.org/10.1139/cjb-2018-0155.
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Urban grasslands often exist as fragmented patches with varying threat levels. These patches are generally inappropriately managed due to limited data on their responses to disturbance and seed bank regenerative potential. This study compared seed banks between non-naturally disturbed and undisturbed patches of South African subtropical grasslands in an urban environment. Standing vegetation was characterised via year-round quadrat and monthly transect sampling. The seed banks were sampled after the two main dispersal periods and assessed for species composition and density. The seed bank species (24) represented a subset (9%) of the standing vegetation, with forbs being the most speciose life form and grasses the most abundant. Disturbance had a moderate impact on seed bank density but significantly affected species composition and ordering. Clustering and ordination analyses separated seed banks based on disturbance history. However, seed banks in disturbed patches maintained the general character of the grassland type. Diagnostic, rare and threatened taxa were absent from seed banks, irrespective of disturbance history. Consequently, restoration will possibly require seed enrichment and species reintroduction rather than exploitation of natural seed banks. Identifying disturbance-sensitive species through seed bank surveys can inform grassland conservation and restoration strategies.
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Matthews, W. S., A. E. Van Wyk, and N. Van Rooyen. "Vegetation of the Sileza Nature Reserve and neighbouring areas, South Africa, and its importance in conserving the woody grasslands of the Maputaland Centre of Endemism." Bothalia 29, no. 1 (September 30, 1999): 151–67. http://dx.doi.org/10.4102/abc.v29i1.586.
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An analysis of the plant communities of the Sileza Nature Reserve and surrounding areas (± 4 124 ha) is presented. The study area falls within the Maputaland Centre o f Endemism, which is part ot the Maputaland-Pondoland Region, a centre of plant diversity rich in endemic plants and animals. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed 12 distinct, mainly grassland plant communities. A hierarchical classification, description and ecological interpretation ot these communities are presented. The level o f the water table, either directly, or indirectly through its role in soil formation, is the deciding factor in defining plant communities on the geologically young sandy substrate. Fire is an essential factor, particularly in maintaining the woody grasslands, a rare vegetation type rich in geoxylic suffrutices. and unique to the Maputaland Centre. A comparison between the endemic complement in the subtropical coastal grasslands of Maputaland and the high-altitude Afromontane grasslands of the Wolkberg Centre of Endemism shows marked differences in grow th form and vegetation type partitioning between the two centres. This can probably be ascribed to the relative youth (Quaternary) of the Maputaland coastal plain and its associated plant communities. Notable for their richness in Maputaland Centre endemic/near-endemic taxa. the conservation of sand forest and woody grasslands should receive high priority. Afforestation with alien trees is the most serious threat to the biodiversity of the Maputaland coastal grasslands, not only because of habitat destruction, but also through its expected negative effect on the hydrology of the region
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Avenant, Nico. "The potential utility of rodents and other small mammals as indicators of ecosystem 'integrity' of South African grasslands." Wildlife Research 38, no. 7 (2011): 626. http://dx.doi.org/10.1071/wr10223.
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Context The expansive grassland biome is one of the most extensively transformed in South Africa, yet no strategy for monitoring its integrity is in place. A grassland health program, incorporating different ecosystem levels, was recently initiated. The suitability of three taxonomic groups as indicators has been tested so far: vegetation (by calculating an ecological index value, El), insects (using the South African grassland scoring system, SAGraSS) and small mammals (this study). All of these methods aim to be rapid and easy to perform. Whereas SAGraSS still needs further refinement, several factors already indicate the importance of including small mammal community parameters in integrity assessments. Aims This contribution reports on more than 12 years of results from various studies on small mammals in the Free State Grasslands, with the aim of exploring the utility of small mammal survey for assessment of ecosystem integrity. Methods The hypothesis was based on the outcomes of several short-term studies conducted in the grassland biome. Combining all previous results, this paper re-evaluates the parameters of trap success, species richness, diversity, evenness and individual species as bio-indicators. Key results By combining data from many sites and years, the effect of seasonal and inter-annual variations in habitat and population parameters was diminished, and a more general picture of small mammal community structure revealed. New insights were gleaned into the status of several indicator species. By providing a summary of small mammal community parameter scores and indices, the study establishes a benchmark for future small mammal assessments and monitoring. To be effective, small mammal surveys in the grassland biome of southern Africa should be carried out in autumn and early winter. Conclusions This study suggests that small mammal species richness and diversity decline with habitat degradation; that the generalist rodent Mastomys coucha dominates community numbers at low ecological integrity; that the number of specialist species increases towards ecological climax; and that specific species act as indicators during the successional process. Implications This study should benefit the monitoring, conservation and management of grassland ecosystems, make environmental impact assessments more effective, and identify new topics for ecological research.
Dissertations / Theses on the topic "Grasslands – South Africa"
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Judd, Rachel Anne. "The coastal grasslands of the Eastern Cape west of the Kei River." Thesis, Rhodes University, 1999. http://hdl.handle.net/10962/d1003772.
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The grasslands of South Africa are the foundation of commercial and subsistence agriculture yet they are being degraded at an alanning rate. The coastal grasslands of the Eastern Cape are no exception and they suffer added pressure of coastal resort development because of their proximity to an attractive coastline. In order to determine the degree of conservation necessary for any area it is essential to know what species occur there in order to determine if protection from habitat destruction is required. Four aims were defined for this studv. The initial aim was a phytogeographical classification of the grasslands in the coastal region west of the Kei River. This was done by vegetation sampling followed by computer based analysis with TWINSPAN. This analysis defined ten grassland associations. five being located in the area west of the Keiskamma River and five occurring east of it. The associations in the eastern half are termed mesic while those in the western balf are xeric. The second aim was to determine the presence of any underlying ecological gradients affecting the distribution of tbe associations. Indirect gradient analysis was carried out where samples are analysed irrespective of environmental factors. Direct gradient analysis was then carried out using scores per sample of various environmental factors. Environmental factors whicb migbt produce such gradients are both naturally-ocurring and man-induced. Natural factors which were recorded in the field include depth of soil at sample site, soil family, aspect and distance from the shore. An important factor is the land / sea interface. Natural factors analysed in the laboratory include soil pH. conductivity. percent organic matter, calcium, magnesium, phosphate and potassium. Man-induced factors are land use history e.g. Ploughing and grazing. Both direct and indirect gradient analysis were carried out with the computer based programme CANOCO. The third aim of the study was to determine the presence of any successional trends between the ten defined associations. This was done using several characteristics of the associations. Alpha and beta diversity were the first factors compared between associations. The percentage contribution of the Cyperaceae, Fabaceae, Asteraceae and Poaceae to each association was assessed and compared. The presence of various life forms of the species occurring in each association was determined together with the cover abundance of different classes of grass species. These results were then combined and analysed in the light of the results from CANOCO analvsis. They show that the mesic Themeda Iriandra - Anthospermum herhoceum, association which occurs closest to the shore and with the least disturbance is a depauperate form of the mesic climax Themeda triandra association. The mesic Hyparrhenia hirta - Dtheteropogon amplectens association may be a secondary grassland on account of phosphate and potassiun poor soils and land-use. The mesic Hyparrhenia hirta - Themedo triandra association is a slightly degraded form of the climax association due to grazing. The severely disturbed Stenotaphrum secundatum - C'entella coriacea association, which is located close to the shore, is a secondary grassland. Analysis of the xeric associations indicates a clearly defined ordination of associations on the basis of land-use. The Cynodon daclylon - Helictolrichon hirtulum and Sporobolis africanus - Setaria sphacelata associations which occur where ploughed lands have been left to lie fallow are secondary in nature. The Themeda triandra - Ehrharta calycina association is thought to be the closest representati ve of a climax xeric association but the presence of E. calycina indicates that some disturbance has occurred. The vegetation is subject to moderate grazing. The Cynodon dactylon - Ehrharla calycina and Diheleropogon filifolius - Ehrharla calycina associations are subject to varying intensities of trampling and grazing and are degraded forms of the Themeda triandra - Ehrharla calycina association. Because of tbe overriding influence of the land-use gradient separation along gradients of the remaining eight factors was limited. The effect of fire and temporal change in the mesic Themeda triandra and Hyparrhenia hirta - Themeeia trianda associations was assessed via long-term studies at Potter's Pass outside East London. The results show a quick response to burning with a return to 100% cover within six months by both associations. During spring the two associations could not be separated by either TWINSPAN or DECORANA. indicating a temporal shift from the Hyparrhenia hirta - Themeda triandra association to the Themeda triandra association. The fourth and final aim was to identify plants requiring protection from habitat destruction and to make recommendations for further conservation areas and management of the coastal grasslands. Through the collection and identification of as many plants as possible a species checklist was prepared and the status of each was determined through reference to the Red Data Book of threatened and endangered species. Kniphofia rooperi is vulnerable in the Cape and Euphorbia hupleuroides is considered rare in kwazulu-Natal. Ten species are endemic to the Cape and / or South Africa. The richness of the vegetation lies in the presence of species representative of the four major floras which converge in the eastern Cape. i.e. The Cape, NamaKarroo, Tongoland-Pondolaod floras and the Kalahari Highveld Regional Transitional Zone. Suggestions are made for the conservation of the grassland associations at various sites within the study area based on the present area conserved. Less than 2% of the coastline in the study area is conserved and it is felt that the area under conservation should be increased. Management suggestions based on the available literature are given for both farmed and conserved areas. There is a great potential for further studies on grassland dmamics within the areas surveyed. In terms of management, the grasslands require careful examination to determine the most effective season in which to burn if at all. As with most agricultural systems in South Africa. grazing strategies will benefit from further research. Any additional research on the dynamics of these grasslands can only be of benefit to the sustained utilisation of this vital resource.
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Wakeling, Julia. "Limitations of savanna trees in the highveld grasslands of South Africa." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/9019.
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Includes bibliographical references (leaves 85-91).Many grassland areas throughout the world may support a woody biomass if fire is suppressed. It is puzzling that fire-tolerant savanna trees do not grow in these grasslands. The Highveld grasslands of South Africa are one such grassland. Hypotheses including fire, human intervention, grass competition and various attributes of soil have been proposed to explain the tree-less nature of the Highveld grasslands, but they have mostly been discounted. In this study it was hypothesised that cool temperatures or low nutrient availability would result in slow growth of saplings in grassland areas that would subsequently not be able to escape frequent fires. Alternatively, frost may exclude trees from grasslands. A seedling transplant experiment of savanna tree species of the Acacia genus, into grassland and savanna areas arranged across an altitudinal gradient, was used to compare growth in these varying climates over one growing season, and the influence of frost on seedlings in the following winter. Soils were collected from grassland and savanna regions to establish if nutrients varied between these areas, and seedling growth was measured in a pot experiment including these different soils. To minimise the effect of other variables, seedlings were watered and grass was excluded. Higher altitude grassland areas were cooler, and the grassland soils that were collected were nutrient-poor, relative to the savanna equivalents, with the exception of one nutrient-poor low altitude soil. Growth was well correlated to both temperature and nutrient availability, and in general there was slower growth in grassland climates and grassland soils compared to in savannas. These seedling growth rates were extrapolated to the growth rates of saplings in natural environments and the time it would take saplings to reach a height above flame height was calculated. This showed that although there were significant differences between growth rates in grassland and savanna soils, the magnitude of these differences was not large enough to prevent saplings from growing into adults in grassland soils. Differences in growth due to temperature variations, however, were large enough to suggest that saplings in grassland climates would grow too slowly to ever reach escape height between frequent fires. Frost caused damage to seedlings and decreased seedling survival at the highest elevation sites, but trees were absent well below the altitudinal limit of frost damage. There has been much discussion about the tree-less nature of the Highveld grasslands, but very little experimental work to back it. Neither temperature nor fire alone can explain the lack of trees. This study provides empirical evidence that slow growth due to low temperatures in combination with frequent fire could exclude savanna trees from the grasslands. The effect of grass competition still needs investigation. The incorporation of fire is useful as it is a fundamental part of C4 ecosystems; this, on top of a base of variable growth due to changes in resource availability. The barely recognised savanna tree-line deserves attention, as savannas continue to invade grasslands in a warming world.
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Crous, Casparus Johannes. "The mesofilter concept and biodiversity conservation in Afro-montane grasslands." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79892.
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Thesis (PhD)--Stellenbosch University, 2013.ENGLISH ABSTRACT: Conservation planners use many traditional biodiversity conservation tools to help alleviate the global biodiversity crisis. However, ongoing biodiversity loss has stimulated the development of new and improved methods for conserving biodiversity. One such new conservation tool is the mesofilter approach. Mesofilters are biotic or abiotic ecosystem elements which are critical to the well-being of many species, and therefore could help to explain spatial heterogeneity in species across a landscape. It is also complementary to more traditionally used concepts such as coarse- and fine-filter conservation concepts. Applying the mesofilter approach in protected area, conservancy, or land-sparing design and management, could optimise biodiversity conservation in a rapidly developing world. For example, the timber industry has been pro-active in its approach to lessen biodiversity loss, by optimising design and management of the plantation matrix through ecological networks. Here, I explore the use of mesofilters within highly threatened remnant Afro-montane grasslands in KwaZulu-Natal, South Africa, to optimise biodiversity conservation planning for such landscapes. As per anecdotal evidence, I used rockiness in the landscape as a possible driver of species richness and species assemblage variability at the meso-scale, using a multi-taxon and multi-trophic approach. In this montane landscape, I also examined the effect of elevation on spatial heterogeneity of taxa. I further examined the functional responses of taxa to rockiness in the landscape. Rockiness in the landscape significantly influenced the species richness and assemblage structure of three key grassland taxa: flora, butterflies, and grasshoppers. I showed that for plants, this response was due to growth forms such as geophytes and perennial grasses that were more closely associated with rockiness, and therefore the main contributors to observed differences in the dispersion patterns of flora. Grasshoppers were not necessarily responding to higher rock exposure per se, but rather towards the environmental conditions created by rockiness within the landscape, such as lower vegetation density. For butterflies, certain behavioural traits, such as resting, territorial behaviour and/or mate-locating behaviour, were more typical in areas of higher rock exposure. This suggested that rocks are a definite habitat resource to certain butterflies. Overall, this finding where an abiotic surrogate is representative of key taxa in an ecosystem is interesting, as cross-taxon surrogacy has been shown to be stronger than surrogates based on environmental data. Furthermore, taxa responded functionally to rockiness in the landscape. This thesis therefore supports the idea that environmental surrogates are indeed useful for biodiversity conservation planning. Furthermore, ecosystems can potentially have many attributes or features that would be of conservation interest, and delineating a set of mesofilters is a useful way of expressing particular attributes to be used in wildlife conservation evaluation. The concept of the mesofilter as a practical biodiversity conservation tool is therefore validated here. I also argue the importance of habitat heterogeneity for biodiversity conservation planning in this montane grassland landscape. The potential for optimising the design of landscape configurations such as ecological networks, through information obtained from the mesofilter, is emphasised. We can safely add another tool in the biodiversity conservation toolbox of this Afro-montane grassland ecosystem.
AFRIKAANSE OPSOMMING: Bewaringbeplanners gebruik tans baie tradisionele biodiversiteit-bewarings metodes om die huidige biodiversiteits krisis te help verlig. Tog, die huidige voortdurende verliese in biodiversiteit wêreldwyd, vra na nuwer en verbeterde metodes van biodiversiteit-bewaring. Een so ‘n nuwe bewaring metode, is die mesofilter. Mesofilters is biotiese of abiotiese ekosisteem elemente wat kritiek is tot die welstand van spesies, en daarom veral waardevol is om variasie in spesies verspreiding in ‘n landskap te help verduidelik. Daarby is die mesofilter konsep ook komplementêr tot meer tradisioneel gebruike bewaringskonsepte, soos fyn-filter en breë-filter konsepte. Deur die mesofilter benadering toe te pas in die ontwerp en bestuur van beskermde areas, bewaareas, of land-spaar initiatiewe, kan ons biodiversiteitbewaring in ‘n vining ontwikkelende wêreld optimaliseer. Byvoorbeeld, die bosbou industrie is pro-aktief in hul benadering om biodiversiteit verliese te verminder, deur optimalisering van die ontwerp en bestuur van ekologiese netwerke in die plantasiematriks. In hierdie tesis, ondersoek ek die gebruik van mesofilters in hoogs bedreigde oorblyfels Afrikaberg grasvelde in KwaZulu-Natal, Suid-Afrika, om die bewaringsbeplanning van dié gebiede te optimaliseer. Vanaf anekdotiese bewyse, het ek spesifiek gebruik gemaak van klipperigheid in die landskap as ‘n moontlike drywer van spesies-rykheid en spesies-samestelling variasie by ‘n meso-skaal, deur ‘n multi-takson en multi-trofiese benadering. In hierdie berglandskap, het ek ook die effek van hoogte bo seevlak op ruimtelike verspreiding van taksa bestudeer. Verder het ek ook gekyk na die funksionele reaksie van taksa tot klipperigheid in die landskap. Klipperigheid in die landskap het ‘n beduidende invloed gehad op spesies-rykheid en spesiessamestelling van drie sleutel grasveld taksa: plante, skoenlappers, en springkane. Ek wys dat vir plante, hierdie reaksie as gevolg was van spesifieke plantgroeivorme, soos bolplante en meerjarige grasse, se noue verband met klipperigheid, en daarom, dat hierdie groepe die hoof bydraers is tot gesiene variasie in plantspesies verspreiding in die landskap. Vir springkane, was hierdie reaksie nie noodwendig omdat hulle die klippe self gebruik het nie, maar meer as gevolg van die omgewingskondisies geskep deur verhoogde klipperigheid in die landskap, soos laer plantegroei digtheid. Vir skoenlappers, was hierdie reaksie tot klippe as gevolg van sekere gedragskaraktereienskappe, soos rus op klippe, gebied beskerming en/of paarmaat soektog, wat tipies meer gesien was in klipperige omgewings. Dit dui daarop dat klippe ‘n definitiewe habitat hulpbron is vir sekere skoenlappers. Oor die algemeen is hierdie bevinding, waar abiotiese surrogate verteenwoordig is van drie sleutel taksa in ‘n ekosisteem, baie interessant, siende dat tussen-takson surrogate soms gesien word as sterker as surrogate gebaseer op omgewingsdata. Verder, taksa het funksioneel gereageer teenoor die klippe in die landskap. Hierdie tesis ondersteun dus die idee dat omgewingssurrogate wel nuttig is vir biodiversiteit-bewaring beplanning. Ekosisteme mag vele potensiele elemente van bewarings belang bevat, maar om sulke elemente as ‘n stel mesofilters te klassifiseer, is ‘n nuttige manier om spesifieke elemente te gebruik in natuurbewarings evaluasie initiatiewe. Gevolglik word die konsep van die mesofilter as ‘n praktiese biodiversiteit-bewaring gereedskapstuk hier bevestig. Ek beredeneer ook die belangrikheid van habitat heterogeniteit vir biodiversiteit-bewaring van hierdie berggrasveld landskap. Die potensiaal vir optimalisering van ontwerp en bestuur van landskap konfigurasies, soos ekologiese netwerke, word beklemtoon. Ons kan met veiligheid nog ‘n gereedskapstuk plaas in die biodiversiteitbewarings gereedskapkis van hierdie Afrikaberg grasveld ekosisteem.
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Hoare, David Barry. "Patterns and determinants of species richness in mesic temparate grasslands of South Africa." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/1275.
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The aim of this study is to gain a predictive understanding of the patterns and determinants of plant biodiversity in temperate, mesic grasslands of South Africa with a primary focus on the geographical area of the Eastern Cape. From a review of the literature on hypotheses explaining diversity (Chapter 2) it was possible to formulate a number of hypotheses that could be tested to explain species richness patterns in Eastern Cape grasslands. This thesis is organised so that each main chapter deals with a specific body of theory concerning the explanation of diversity patterns. A detailed description of the study area is provided (Chapter 3), including environmental variation and a description of major vegetation patterns. A summary is provided of grassland plant community patterns, as determined by phytosociological studies in the study area. A multivariate analysis of environmental variables was undertaken to determine which variables contributed the most towards explaining environmental variation in the study area and to determine whether any variables co-vary, a possible problem for any multivariate analysis in later chapters. Altitude produced one of the strongest gradients in the study area. There were a number of variables that were correlated with altitude, most notably temperature. Rainfall co-varied partially with altitude, but there was also a strong rainfall gradient perpendicular to the altitude gradient. A description of species richness, diversity and evenness patterns at the plot scale within different grassland plant communities of the Eastern Cape is provided in Chapter 4. To determine whether the environment acts differently on different growth forms, the contribution to species richness by different major growth forms is analysed. Furthermore, since the majority of literature attempts to explain diversity in terms of environmental factors, it was necessary to analyse the relationship between species richness and various environmental variables. The results indicate that there is high variation in species richness both within and among grassland communities. Forbs make the most significant contribution to overall species richness per 100 m2, followed by grasses. Variance in richness of all species together is not significantly related to environmental variables in mesic grasslands, but is significantly related to environmental variables in semi-arid grasslands. The result of greatest interest from this chapter is the fact that richness amongst different life-forms in the same place is explained by different environmental factors, indicating that the environmental factors that affect coexistence of species have a different effect on different life-forms. A classification of all the species of the dataset into plant functional types using a multivariate approach based on functional traits was conducted (Chapter 5). The grass species were classified into 16 functional types and the forbs into 14 functional types. The functional type classification provided the opportunity for undertaking analyses to develop an understanding of 8 the contribution by niche differentiation towards promoting species richness (Chapter 6). The results provide evidence of niche differentiation in the grasslands of the study area and also that niche differentiation promotes species richness in the grasslands of the study area. It was found that higher rainfall grasslands are less structured by niche differentiation than semi-arid grasslands. A regional / historical analysis is undertaken (Chapter 7) to investigate the relationship between the regional species pool and local richness, and the relationship between local richness and phytochorological diversity. Regional richness appears to have little effect in promoting local richness in grassland plant communities of the study area except at sites where there is high local richness. This provides an indication that regional richness only promotes local richness in the absence of local limiting factors. Phytochorological diversity promotes local richness, but mostly through diversity amongst species with narrow distribution ranges. Some theories ascertain that seasonal uncertainty may provide opportunities to species that would otherwise be outcompeted and thereby promote local richness. The degree to which seasonal uncertainty and seasonality promote local richness in the Eastern Cape grasslands was therefore investigated (Chapter 8). A weak relationship exists between these variables and local species richness in grassland communities of the study area, indicating that they do not promote niche differentiation to a significant degree in the study area. It is clear that in the grasslands of the Eastern Cape, environmental limiting factors are more important in semi-arid grasslands and species interactions are more important in mesic grasslands for structuring plant communities (Chapter 9, Discussion). Regional processes do not appear to be important in structuring local communities, but the analysis undertaken in this study shows that they may be significant when factors operating at the other two levels are overcome (species interactions and environmental limiting factors.
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Helm, Chantal Vinisia. "Ecological separation of the black and blue wildebeest on Ezemvelo Nature Reserve in the highland grasslands of South Africa." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-10022007-104926.
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Raitt, Gwendolyn R. "Themeda Triandra Renosterveld in the Heidelberg District." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/20939.
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Thesis (MSc)--University of Stellenbosch, 2005.ENGLISH ABSTRACT: This study investigated the composition of Themeda triandra Renosterveld in part of the Grootvadersbosch Conservancy and the effects of selected environmental and management variables to provide guidelines for promoting the presence of Themeda triandra in the veld. The Zürich-Montpellier phytosociological method was used to determine the composition of the Renosterveld communities. The point quadrat method was used to determine the cover of Themeda triandra at three grass dominated sites and compare cover from one site with past cover measurements at the specific site. Ordination was used to examine the effects of the environmental and management variables on the plant communities. Two community groups, five communities and five subcommunities were identified and described. The Themeda triandra – Stoebe phyllostachys Grassland Community Group consists of two communities of which one has two subcommunities. The Themeda triandra – Elytropappus rhinocerotis Shrubland Community Group consists of three communities of which one has three subcommunities. The vegetation units described in this study have not been described previously in the literature. One community belongs to Silcrete Fynbos while another subcommunity is transitional between Renosterveld and thicket and gallery forest. The rest of the plant communities fit the definition for Renosterveld (the local Renosterveld type is Eastern Rûens Shale Renosterveld). Cover of Themeda triandra did not differ significantly either between sites or between years. The comparison of Themeda triandra cover between years was done at a site that had been burnt between the last two sampling times yet the cover was not significantly different. This indicates that fire and other management practices did not have a negative impact on Themeda triandra at the site. Unconstrained ordination of the dataset in which cover/abundance values were included, grouped the relevés by moisture and disturbance but the presence/absence dataset indicates that the two community groups have a slight transitional overlap. Constrained ordination of both datasets with a) soil variables and b) management variables, both showed a tendency to separate the relevés into community groups, that did not happen with topographic and vegetation variables. Ordination did not separate the community groups into their subdivisions. The soil variables (both nutrients and texture) influence the vegetation structure and the community distribution. Under the existing grazing management regime, fire at three to five year intervals promoted the dominance of Themeda triandra by affecting the structure of the plant communities, the abundance of species other than Themeda triandra, and influencing which plant community is present. The use of fire as a management tool was regulated by the importance of the natural veld pastures to the farmers. The natural veld pastures are not suitable for dairy cattle in milk. Thus dairy farmers are less likely to burn the natural veld (no planned burns only chance fires) than those who farm with mutton or beef (planned burns on a three to five year interval).
AFRIKAANSE OPSOMMING: Die studie het die samestelling van Themeda triandra Renosterveld in ’n deel van die Grootvadersbosch-Bewaria en die uitwerking van geselekteerde omgewings- en bestuursveranderlikes ondersoek om riglyne vir die bevordering van Themeda triandra in die veld daar te stel. Die Zürich-Montpellier fitososiologiese metode is gebruik om die samestelling van die Renosterveldgemeenskappe te bepaal. Die puntkwadraat-metode is gebruik om ’n skatting van die dekking van Themeda triandra by drie gras-gedomineerde persele te bepaal en om ’n vergelyking te maak tussen die huidige en vorige dekking van ’n enkele perseel. Ordinasie is gebruik om die invloed van omgewings- en bestuursveranderlikes op die plantgemeenskappe te bepaal. Twee gemeenskapsgroepe, vyf gemeenskappe en vyf subgemeenskappe is geïdentifiseer en gedefinieer. Die Themeda triandra – Stoebe phyllostachys Grasland-gemeenskapsgroep bestaan uit twee gemeenskappe waarvan een in twee subgemeenskappe onderverdeel is. Die Themeda triandra – Elytropappus rhinocerotis Struik-gemeenskapsgroep bestaan uit drie gemeenskappe waarvan een in drie subgemeenskappe onderverdeel is. Die plantegroei-eenhede wat in die studie beskryf is, is nie voorheen in die literatuur beskryf nie. Een gemeenskap behoort aan Silkreet-fynbos en ’n ander subgemeenskap is ’n oorgangsfase tussen Renosterveld en struikbosveld of woud, terwyl die res van die plantgemeenskappe binne die definisie van Renosterveld val (die plaaslike Renosterveld tipe staan bekend as Oostelike Rûens Skalierenosterveld). Die bedekking van Themeda triandra het nie betekenisvol gevarieer tussen óf die verskillende lokaliteite óf die verskillende jare nie. Die vergelyking van Themeda triandra-bedekking oor tyd is onderneem in ’n gebied wat tussen opnames gebrand is. Die bedekking het nie betekenisvol verskil nie. Dit dui aan dat vuur en ander bestuurspraktyke nie ’n negatiewe invloed op Themeda triandra in hierdie gebied het nie. Onbeperkte ordinasie van die datastel met die vergelyking van bedekking/volopheidwaardes, groepeer die relevés volgens vogtigheid en versteuring, terwyl die datastel ten opsigte van teenwoordigheid/ afwesigheid aandui dat die twee gemeenskapsgroepe ’n effense oorgangs-oorvleueling het. Beperkte ordinasie van beide datastelle met a) grondveranderlikes en b) bestuursveranderlikes, toon albei ’n neiging om die gemeenskapsgroepe te skei, wat nie gebeur het met die topografiese- en plantegroeiveranderlikes nie. Ordinasie het nie die gemeenskapsgroepe onderverdeel in gemeenskappe of subgemeenskappe nie. Die grondveranderlikes (beide voedingstowwe en tekstuur) beïnvloed die struktuur en die verspreiding van die plantegroei. Met die bestaande weidingsbestuur bevorder brande met ’n interval van tussen drie tot vyf jaar die oorheersing van Themeda triandra deur die struktuur van die teenwoordige plantgemeenskap te beïnvloed, deur die getal van die verskillende plantsoorte te beïnvloed en selfs deur die plantgemeenskap se voorkoms te beïnvloed. Die waarde wat die boer aan die natuurlike veld as weiveld heg bepaal die mate waartoe hulle veldbrand gebruik as ’n deel van bestuur. Die natuurlike veld is nie geskik vir melkkoeie wat in die melkproduksiestadium is nie. Die melkboere is dus minder geneig om die natuurlike veld te brand (geen beplande brande nie net kans brande) as die boere wat met vleisbeeste of skape boer (beplande brande elke drie tot vyf jaar).
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Mongwe, Hlamalani Godfrey. "The status of soil organic carbon under indigenous forests, grasslands, wetlands and pine plantations in Woodbush, Limpopo Province, South Africa." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16392.
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Thesis (MScAgric)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: Storing soil organic carbon (SOC) is a possible way of reducing atmospheric CO2 and potentially mitigating the effects of global warming. This study looks at soil carbon stocks, the sampling methodology and modelling of soil organic carbon in indigenous forests, wetlands, grasslands and pine plantations in Woodbush in the North-Eastern escarpment of Limpopo Province, South Africa. Dominant Pine species planted in Woodbush are Pinus patula, Pinus elliotti and Pinus taeda. Woodbush plantation was selected as study area because it provided easy access to all the ecosystems that were to be studied. All ecosystems in Woodbush are located in such a way that it was easy to compare them, as they existed under similar environmental and climatic conditions. The climatic conditions of Woodbush promote accumulation of SOC due to relatively higher precipitation and cooler temperatures than most parts of Limpopo Province. Five transects were made: two in indigenous forests and three in plantations. Only the surface (0-7 cm) layer was sampled with a distance of 20 m between sampling points. Transects were not made in grasslands and wetlands because of the patchy occurrence of these ecosystems. In addition to transects, eight 1ha plots, two in each ecosystem, were sampled. Surface (0- 7 cm depth) samples were collected on a grid of 20 x 20 m in each sampling plot. Two soil profile pits were sampled in each sampling plot, with samples being taken at 5, 10, 15, 20 30, 40, 50 60, 75 and 100 cm depth. The average carbon stocks per hectare of land to a soil depth of 100 cm were as follows: 71 t.ha-1 in wetlands, 28 t.ha-1 in grasslands, 64 t.ha-1in indigenous forests, and 46 t.ha-1 in pine plantations. Although wetlands sequestered large amounts of SOC per hectare, their relative contribution to carbon sequestration was low because of the relatively small area (87.2 ha) they occupy in the study area (and in South Africa). Prediction models for vertical distribution of SOC were developed using STATISTICA 6.0 for each ecosystem in order to estimate the carbon stocks to a depth of 100 cm based on SOC content and soil bulk density of the surface samples. These models were developed from observed values in soil profiles for each ecosystem. SOC content and carbon stocks were analyzed using GIS (ARCVIEW). The GIS analysis was aimed at assessing the effect of topography, elevation, soil type, and vegetation on accumulation and distribution of SOC stocks. Most shallow Inanda soils were distributed at elevations between 1545 m and 1777 m, and on a gentle slope in the Northern aspect of the mountain. Deep Inanda soils were found mostly in the lower elevation range of 967 m and 1545 m on moderate slopes. Deep and shallow Inanda soils were found on the southern aspect. Deep Kranskop soils are evenly distributed and mostly found at an elevation range of between 1080 and 1430 m on gentle slopes, while at an elevation range of between 1430 and 1780 m, they were found on moderate slopes. Deep soils had higher SOC stocks than shallow soils and soils in the southern aspects had higher SOC stocks than in the northern aspects.
AFRIKAANSE OPSOMMING: Die berging van grond organiese koolstof is ‘n moontlike manier om atmosferiese koolsuurgas (CO2) te verminder en dus om die invloed van globale verwarming te versag. In hierdie studie was die grond-koolstof voorraad bestudeer, asook die metodologie van die monsterneming en modellering van organiese grond-koolstof van inheemse woude, vleie, grasvelde en denneplantasies. Die studie was uitgevoer op Woodbush plantasie gele op die Noord-Oosterlike platorand van die Limpopo Provinsie, Suid-Afrika. Die algemeenste dennespesies in Woodbush is Pinus patula, Pinus elliotti en Pinus taeda. Die Woodbush plantasie was gekies as studiegebied omdat dit oor al die ekosisteme wat bestudeer moet word, beskik. Die ekosisteme in Woodbush is naby mekaar en dus maklik vergelykbaar want die omgewings- en klimaatstoestande is eenders. Die klimaatstoestande van Woodbush bevorder die akkumulasie van grond organiese koolstof omdat die reënval hoër en die temperature laer is as in die meeste ander dele van die Limpopo Provinsie. Vyf dwarssnitte was gemaak, twee in inheemse woude en drie in plantasies. Monsters was net uit die grondoppervlak laag geneem (7 cm) met 20 m tussen monsterpunte. Dwarssnitte was nie in grasvelde en vleie gemaak nie want hierdie sisteme is te gelokaliseerd. Monsters was ook geneem in agt 1 ha persele, twee in elke ekosisteem. Oppervlakmonsters (tot ‘n diepte van 7 cm) is op ‘n ruitnet van 20 x 20 m uit elke perseel versamel. Monsters was verder ook geneem uit twee profielgate per perseel, op dieptes 5, 10, 15, 20, 30, 40, 50, 60, 75 en 100 cm. Die gemiddelde koolstof voorraad per hektaar, op ‘n gronddiepte van 100 cm, was as volg: 71 t.ha –1 in vleie, 28 t.ha-1 in grasvelde, 64 t.ha-1 in inheemse woude en 46 t.ha-1 in denneplantasies. Alhoewel vleie groot hoeveelhede grond organiese koolstof akkumuleer, is hulle bydrae tot koolstof akkumulasie laag want hulle beslaan ‘n klein oppervlak binne die studiegebied (87.2 ha) asook klein oppervlaktes binne Suid-Afrika. Voorspellingsmodelle vir die vertikale verspreiding van grondkoolstof was met die gebruik van STATISTICA 6.0 ontwikkel ten einde te skat wat die koolstofvoorrraad op ‘n diepte van 100 cm was. Die skattings was gebaseer op organiese grondkoolstofinhoud en die gronddigtheid van oppervlakmonsters. Hierdie modelle was ontwikkel vanaf die waargenome waardes van grondprofiele vir elke ekosisteem. Die organiese koolstofinhoud van die grond en die koolstofvoorraad is ontleed met behulp van GIS (ARCVIEW). Die GIS ontleding was daarop gemik om die effek van topografie, hoogte bo seespiëel, grondtipe en plantegroei, op die akkumulasie en verspreiding van organiese grondkoolstof, te beraam. Die meeste vlak Inanda grondvorms kom voor tussen 1545 m en 1777 m bo seespiëel, asook op effens steil hellings op die Noordelike berghang. Die diep Inanda grondvorms is geleë op laer hoogtes bo seespiëel, gewoonlik tussen 967 en 1545 m, op effens steil hellings. Beide diep en vlak Inanda gronde word gevind op die suidelike berghang. Diep Kranskop gronde is eweredig versprei en word gewoonlik tussen 1080 en 1430 m bo seespiëel, op effens steil hellings, gevind. Dit kom ook voor op matig steil hellings, tussen 1430 en 1780 m bo seespiëel. Daar is meer organiese koolstof in diep grond as in vlak grond en meer in gronde teen die suidelike hang as op die noordelike hang.
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Gwate, Onalenna. "Modelling plant water use of the grassland and thicket biomes in the eastern cape, South Africa: towards an improved understanding of the impact of invasive alien plants on soil chemistry, biomass production and evapotranspiration." Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/54800.
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It is imperative to understand the strong coupling between the carbon capture process and water use to sustainably manage rangelands. Woody encroachment is undermining rangelands grass production. Evapotranspiration (ET) highlights the links between ecosystem carbon capture process and water use. It forms the biggest flux of the hydrological cycle after precipitation yet it is not well understood. The Grassland and the Albany Thicket (AT) biomes in the Eastern Cape, South Africa, provide an interesting space to study the dynamics in rangelands biomass production and the associated water use. Therefore, the main purpose of this study was to contribute towards management of rangelands by understanding the dynamics in rangeland grass production and water use. To achieve this aim, the impact of Acacia mearnsii, an invasive alien plant, on soil chemical properties and rangelands grass production was investigated. This was achieved by analysing the biophysical attributes of A. mearnsii as they related to grass production. Secondly, selected soil variables that could be used as a prognosis for landscape recovery or deterioration were evaluated. In addition, aboveground grass biomass was measured in areas cleared of A. mearnsii and regression equations were prepared to help model aboveground grass biomass in areas cleared of A. mearnsi. The thesis also explored dynamics in water vapour and energy fluxes in these two biomes using an eddy covariance system. Consequently, water vapour and energy fluxes were evaluated in order to understand landscape water use and energy partitioning in the landscape. The study also tested the application of Penman-Monteith equation based algorithms for estimating ET with micrometeorological techniques used for validation. Pursuant to this, the Penman- Monteith-Leuning (PML) and Penman-Monteith-Palmer (PMP) equations were applied. In addition, some effort was devoted to improving the estimates of ET from the PMP by incorporating a direct soil evaporation component. Finally, the influence of local changes in catchment characteristics on ET was explored through the application of a variant of the Budyko framework and investigating dynamics in the evaporative index as well as applying tests for trends and shifts on ET and rainfall data to detect changes in mean quaternary catchment rainfall and ET. Results revealed that A. mearnsii affected soil chemical properties and impaired grass production in rangelands. Hence, thinning of canopies provided an optimal solution for enhanced landscape water use to sequestrate carbon, provide shade, grazing, and also wood fuel. It was also shown that across sites, ET was water limited since differences between reference ET and actual ET were large. ET was largely sensitive to vapour pressure deficit and surface conductance than to net radiation, indicating that the canopies were strongly coupled with the boundary layer. Rangeland ET was successfully simulated and evaporation from the soil was the dominant flux, hence there is scope for reducing the so-called ‘unproductive’ water use. Further, it was shown that the PML was better able to simulate ET compared to the PMP model as revealed by different model evaluation metrics such as the root mean square error, absolute mean square error and the root mean square observations standard deviation ratio. The incorporation of a soil evaporation component in the PMP model improved estimates of ET as revealed by the root mean square error. The results also indicated that both the catchment parameter (w) and the evaporative index were important in highlighting the impacts of land cover change on ET. It was also shown that, despite changes in the local environment such as catchment characteristics, global forces also affected ET at a local scale. Overall, the study demonstrated that combining remote sensing and ground based observations was important to better understand rangeland grass production and water use dynamics.
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Zaloumis, Nicholas Paul. "South African grassland ecology and its restoration." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/6629.
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The aim of this study is to investigate how human related disturbances affect mesic grasslands. I identified what was lost from the system after a disturbance and what biological constraints ecologists and managers will face when approaching their restoration. I then investigated biological limitations to grassland restoration by attempting species reintroduction into secondary grasslands and exploring the interaction between grasses and forbs.
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Swanepoel, Barbara Anna. "The vegetation ecology of Ezemvelo Nature Reserve, Bronkhorstspruit, South Africa." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-09142007-143511.
Full textBooks on the topic "Grasslands – South Africa"
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Wyk, Braam Van. Field guide to the wild flowers of the highveld: Also useful in adjacent grassland and bushveld. 2nd ed. Cape Town: Struik, 1997.
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Landmann, Tobias. A case study for Skukuza: Estimating biophysical properties of fires using EOS-MODIS satellite data : a field and remote sensing study to quantify burnt area and fire effects in South African semi-arid savannas. Aachen: Shaker, 2004.
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Malan, Sasa, and Braam Van Wyk. Field Guide to the Wild Flowers of the Highveld: Also Useful in Adjacent Grassland and Bushveld (Photographic Field Guides). 3rd ed. New Holland Publishers,, 1998.
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Holmes, Jonathan, and Philipp Hoelzmann. The Late Pleistocene-Holocene African Humid Period as Evident in Lakes. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.531.
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From the end of the last glacial stage until the mid-Holocene, large areas of arid and semi-arid North Africa were much wetter than present, during the interval that is known as the African Humid Period (AHP). During this time, large areas were characterized by a marked increase in precipitation, an expansion of lakes, river systems, and wetlands, and the spread of grassland, shrub land, and woodland vegetation into areas that are currently much drier. Simulations with climate models indicate that the AHP was the result of orbitally forced increase in northern hemisphere summer insolation, which caused the intensification and northward expansion of the boreal summer monsoon. However, feedbacks from ocean circulation, land-surface cover, and greenhouse gases were probably also important.Lake basins and their sediment archives have provided important information about climate during the AHP, including the overall increases in precipitation and in rates, trajectories, and spatial variations in change at the beginning and the end of the interval. The general pattern is one of apparently synchronous onset of the AHP at the start of the Bølling-Allerød interstadial around 14,700 years ago, although wet conditions were interrupted by aridity during the Younger Dryas stadial. Wetter conditions returned at the start of the Holocene around 11,700 years ago covering much of North Africa and extended into parts of the southern hemisphere, including southeastern Equatorial Africa. During this time, the expansion of lakes and of grassland or shrub land vegetation over the area that is now the Sahara desert, was especially marked. Increasing aridity through the mid-Holocene, associated with a reduction in northern hemisphere summer insolation, brought about the end of the AHP by around 5000–4000 years before present. The degree to which this end was abrupt or gradual and geographically synchronous or time transgressive, remains open to debate. Taken as a whole, the lake sediment records do not support rapid and synchronous declines in precipitation and vegetation across the whole of North Africa, as some model experiments and other palaeoclimate archives have suggested. Lake sediments from basins that desiccated during the mid-Holocene may have been deflated, thus providing a misleading picture of rapid change. Moreover, different proxies of climate or environment may respond in contrasting ways to the same changes in climate. Despite this, there is evidence of rapid (within a few hundred years) termination to the AHP in some regions, with clear signs of a time-transgressive response both north to south and east to west, pointing to complex controls over the mid-Holocene drying of North Africa.
Book chapters on the topic "Grasslands – South Africa"
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Mössmer, M., G. F. Smith, H. E. K. Hartmann, and C. M. Smit. "New collections of Mesembryanthema in South African grasslands." In The Biodiversity of African Plants, 92–97. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0285-5_14.
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Peters, Debra P. C., and Robert P. Gibbens. "Plant Communities in the Jornada Basin: The Dynamic Landscape." In Structure and Function of a Chihuahuan Desert Ecosystem. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195117769.003.0014.
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Plant communities of the Jornada Basin are characteristic of the northern Chihuahuan Desert both in structure and dynamics. Although a number of plant communities can be differentiated, five major vegetation types are often distinguished that differ in plant species cover and composition, as well as other factors, such as animal populations, soil properties, and elevation. These five types are black grama (Bouteloua eriopoda) grasslands, playa grasslands, tarbush (Flourensia cernua) shrublands, creosotebush (Larrea tridentata) shrublands, and mesquite (Prosopis grandulosa) shrublands. Similar to many other parts of the Chihuahuan Desert, these plant communities have experienced major shifts in vegetation composition over the past 50–150 years (York and Dick-Peddie 1969). The most dramatic changes in vegetation and associated ecosystem processes have occurred as a result of a shift in life form due to woody plant encroachment into perennial grasslands (Grover and Musick 1990; Bahre and Shelton 1993). This encroachment of shrubs has occurred in many arid and semiarid regions of the world, including the Western United States, northern Mexico, southern Africa, South America, New Zealand, and Australia (McPherson 1997; Scholes and Archer 1997). A number of drivers have been implicated in these grass–shrub dynamics, including various combinations of livestock grazing, small animal activity, drought, changes in fire regime, and changes in climate (Humphrey 1958; Archer 1989; Allred 1996; Reynolds et al. 1997; Van Auken 2000). The causes of shrub invasion are quite variable and often poorly understood, although the consequences consistently lead to the process of desertification (Schlesinger et al. 1990). This chapter describes the characteristics of each vegetation type and the documented changes in each type at the Jornada Basin. We then discuss the key drivers influencing these dynamics. Vegetation in the Chihuahuan Desert region has been classified as desert-grassland transition (Shreve 1917), desert savanna (Shantz and Zon 1924), desert plains grasslands (Clements 1920), desert shrub grassland (Darrow 1944), and shrubsteppe (Kuchler 1964). Desert grassland is often used as a general descriptive name for the area (McClaran 1995), although landscapes at the Jornada and throughout the northern Chihuahuan Desert often consist of a mosaic of desert grasslands, Chihuahuan Desert shrublands, and plains-mesa sand scrub (Dick-Peddie 1993).
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Southgate, Emily W. B. Russell. "Fire: Mimicking Nature." In People and the Land through Time, 63–82. Yale University Press, 2019. http://dx.doi.org/10.12987/yale/9780300225808.003.0005.
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This chapter opens with a discussion naturally ignited fires and fire adaptations, which have evolved over millions of years. It then considers the role people have played over time in manipulating fire regimes, both locally and on a broad scale. Examples from diverse biomes such as the savannas and grasslands of South Africa and Madagascar, the forests of northern Europe and the grasslands and forests of North America provide evidence of the interactions between climate and human-set ignitions. The studies of the systems include analysis of a diverse range of evidence, including sediments, documents, and field evidence, analyzed using models that focus on patterns and processes of fire regimes under differing climates and human activities. The importance of perceptions of the role of fire is also discussed in terms of using fire for management, with examples of changes in attitude in North America from the 19th to the 21st centuries, which have led from seeing all fires as bad to valuing fire as a management tool. Analysis of the historical importance of human-set and natural fires has been critical to arriving at current management decisions.
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Roberts, Patrick. "Into the Woods Early Homo sapiens and Tropical Forest Colonization." In Tropical Forests in Prehistory, History, and Modernity. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198818496.003.0008.
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Popular philosophical associations of tropical forests, and forests in general, with an inherent ancestral state, away from the stresses, pollution, and technosphere of modern life, are nicely summarized by Murakami’s quote above (2002). Given the probable origins of the hominin clade in tropical forests, this quote is also apt from an evolutionary standpoint. Yet, somewhat surprisingly, tropical forests have frequently been considered impenetrable barriers to the global migration of Homo sapiens (Gamble, 1993; Finlayson, 2014). As was the case with the focus on ‘savannastan’ in facilitating the Early Pleistocene expansion of Homo erectus discussed in Chapter 3 (Dennell and Roebroeks, 2005), the movement of H. sapiens into tropical regions such as South Asia, Southeast Asia, and Australia has tended to be linked to Late Pleistocene periods when forests contracted and grasslands expanded (Bird et al., 2005; Boivin et al., 2013). Alternative narratives have focused on the importance of coastal adaptations as providing a rich source of protein and driving cultural and technological complexity, as well as mobility, in human populations during the Middle and Late Pleistocene (Mellars, 2006; Marean, 2016). The evidence of early art and symbolism at coastal cave sites such as Blombos in South Africa (Henshilwood et al., 2002, 2011; Vanhaeren et al., 2013) and Taforalt in North Africa (Bouzouggar et al., 2007) is often used to emphasize the role of marine habitats in the earliest cultural emergence of our species. Indeed, for the last decade, the pursuit of rich marine resources (Mellars, 2005, 2006) has been a popular explanation for the supposed rapidity of the ‘southern dispersal route’, whereby humans left Africa 60 ka, based on genetic information (e.g., Macaulay et al., 2005), to reach the Pleistocene landmass that connected Australia and New Guinea (Sahul) by c. 65 ka (Clarkson et al., 2017). In both of these cases, the coast or expanses of grassland have been seen as homogeneous corridors, facilitating rapid expansion without novel adaptation.
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Bond, William J. "Vertebrate herbivory and open ecosystems." In Open Ecosystems, 121–40. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198812456.003.0008.
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Can herbivores account for the widespread occurrence of open ecosystems? Some suggest that Pleistocene megafauna did so, and large mammal herbivory is still important in some regions today. Exclosure studies have been widely used to test herbivore impacts on trees, but global patterns of the ‘brown world’ are not readily seen from satellites. Areas of mammal consumer dominance occur in cool temperate/boreal regions (e.g. Tibetan montane grasslands) and savannas in Africa, but not in those in Australia or South America. Herbivores vary in their impact on openness of vegetation because of differences in body size, feeding mode, predator avoidance behaviour while plants also differ in their defences and accessibility. Unlike fire, proxies are lacking for how extinct herbivores, even giant sauropods, impacted vegetation. Very few studies deal explicitly with how vertebrate herbivores help create and maintain open ecosystems where climates are suitable for forests, and there is an urgent need to find out more.
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Mitchell, Peter. "Introducing Horse Nations." In Horse Nations. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780198703839.003.0006.
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Hidden by rocks near a waterhole in Australia’s desert interior an Aboriginal woman and her children catch their first sight of the shockingly large animal of which they have previously only heard: the newcomer’s kangaroo. Thousands of kilometres to the west and high in southern Africa’s mountains a shaman completes the painting of an animal that does not exist, horned at the front, bushy tail at the rear, a composite of two species, one long familiar, the other new. Across the Atlantic Ocean on the grasslands of Patagonia the burial of an Aónik’enk leader is in its final stages, four of his favourite possessions killed above the grave to ensure his swift passage to the afterlife. To the north in what Americans of European descent call New Mexico, Diné warriors chant the sacred songs that ensure their pursuers will not catch them and that they will return safely home. And on the wintry plains of what is not yet Alberta, Siksikáwa hunters charge into one of the last bison herds they will harvest before the snows bring this year’s hunting to an end. Two things unite these very different scenes. First, though we cannot be sure, the historical, ethnographic, and archaeological sources on which they are based allow for them all happening on precisely the same day, sometime in the 1860s. Second, all concern people’s relationship with one and the same animal—pindi nanto, karkan, kawoi, ∤íí’, ponokáómita·wa—the animal that English speakers know as ‘horse’. And that simple fact provides the basis for this book. For, before 1492, horses were confined to the Old World—Europe, Asia, and Africa north of the tropical rainforests and a line reaching east through South Sudan, Ethiopia, and Somalia to the sea. They were wholly unknown in Australasia, the Americas, or southern Africa. As a result, the relationships implied by the vignettes I have just sketched, as well as those involving Indigenous populations in Colombia, Venezuela, Brazil, Paraguay, Uruguay, Chile, Mexico, South Africa, and New Zealand, evolved quickly. And they were still evolving when these societies were finally overwhelmed by European colonization.
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Ward, David. "The Effects of Grazing on Plant Biodiversity in Arid Ecosystems." In Biodiversity in Drylands. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195139853.003.0021.
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Conventional wisdom views heavy grazing as the major cause of desertification in semiarid and arid areas of Africa, Asia, and Australia (see, e.g., Acocks 1953, Jarman and Bosch 1973, Sinclair and Fryxell 1985, Middleton and Thomas 1997). Nowhere is the effect of heavy grazing more apparent than in the Sahel of Africa (Sinclair and Fryxell 1985). This land denudation has resulted in a negative feedback loop via decreased soil nutrient status and increased soil albedo (due to lower vegetation cover), causing increased evaporation and decreased precipitation, which in turn reduces the stocking capacity of the land, further exacerbating the negative effects of grazing (Schlesinger et al. 1990). A less dramatic result of overgrazing is a long-term decline in agricultural productivity. For example, the arid Karoo region of South Africa has experienced no climatic change over the last two centuries, yet there has been a 50% decline in stocking rates in seven of eight magisterial districts from 1911 to 1981 (Dean and McDonald 1994). These authors ascribe this decline to heavy grazing that reduced palatable plant populations and hence the carrying capacity of the vegetation in the long term. These examples of the negative effects of grazing in arid ecosystems lie in stark contrast with a large number of African studies that compared the effects of commercial (privately owned) and communal (subsistence, no private ownership) ranching on vegetation and soils (e.g., Archer et al. 1989, Tapson 1993, Scoones 1995, Ward et al. 1999a,b, reviewed by Behnke and Abel 1996). In spite of 5–10-fold higher stocking rates on communal ranches, few studies have shown differences in effects on biodiversity, plant species composition and soil quality between these ranching types (Archer et al. 1989, Tapson 1993, Scoones 1995, Ward et al. 1999a,b—fig. 14.1). Similarly, studies of grazing in Mediterranean semiarid grasslands (reviewed by Seligman 1996) and Middle Eastern arid rangelands (Ward et al. 1999b) show that the effects of grazing on biodiversity are relatively small. A consensus has developed in recent years that arid grazing ecosystems are nonequilibrial, event-driven systems (see, e.g., O’Connor 1985, Venter et al. 1989, Milchunas et al. 1989, Parsons et al. 1997).
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Peters, Debra P. C., and William H. Schlesinger. "Future Directions in Jornada Research: Applying an Interactive Landscape Model to Solve Problems." In Structure and Function of a Chihuahuan Desert Ecosystem. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195117769.003.0022.
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The long history of research at the Jornada Basin (through the Agricultural Research Service [ARS] since 1912, New Mexico State University in the late 1920s, and joined by the Long-Term Ecological Research [LTER] program in 1981) has provided a wealth of information on the dynamics of arid and semiarid ecosystems. However, gaps in our knowledge still remain. One of the most perplexing issues is the variation in ecosystem dynamics across landscapes. In this concluding chapter to this volume, we propose a new conceptual model of arid and semiarid landscapes that focuses explicitly on the processes and properties that generate spatial variation in ecosystem dynamics. We also describe how our framework leads to future research directions. Many studies have documented variable rates and patterns of shrub invasion at the Jornada as well as at other semiarid and arid regions of the world, including the Western United States, northern Mexico, southern Africa, South America, New Zealand, Australia, and China (York and Dick-Peddie 1969; Grover and Musick 1990; McPherson 1997; Scholes and Archer 1997; see also chapter 10). In some cases, shrub invasion occurred very rapidly: At the Jornada, areas dominated by perennial grasses decreased from 25% to < 7% from 1915 to 1998 with most of this conversion occurring prior to 1950 (Gibbens et al. 2005; Yao et al. 2002a). In other cases, shrub invasion occurred slowly, and sites were very resistant to invasion; for example, perennial grasses still dominate on 12 out of 57 research quadrats originally established in black grama (Bouteloua eropoda) grasslands in the early twentieth century (Yao et al. 2002b). Soil texture, grazing history, and precipitation patterns are insufficient to account for this variation in grass persistence through time (Yao et al. 2002a). It is equally perplexing that although many attempts to remediate these shrublands back to perennial grasses have led to failure, some methods worked well, albeit with long (> 50 year) time lags (Rango et al. 2002; see also chapter 14). Although variations in vegetation dynamics and shrub invasion are the most well known, other lesser known aspects of arid and semiarid systems have been found to be quite variable as well.
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Pelser, André, Nola Redelinghuys, and Anna-Lee Kernan. "Protected Areas and Ecosystem Services — Integrating Grassland Conservation with Human Well-Being in South Africa." In Biodiversity in Ecosystems - Linking Structure and Function. InTech, 2015. http://dx.doi.org/10.5772/59015.
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Schlesinger, William H., and Sandy L. Tartowski. "Nutrient Cycling within an Arid Ecosystem." In Structure and Function of a Chihuahuan Desert Ecosystem. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195117769.003.0010.
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Low quantities of soil nitrogen limit plant growth in the Chihuahuan Desert (Ettershank et al. 1978; Fisher et al. 1988; Lajtha and Whitford 1989; Mun and Whitford 1989) and in other deserts of the world (Wallace et al. 1980; Breman and de Wit 1983; Sharifi et al. 1988; Link et al. 1995). Indeed, although deserts are often regarded as water-limited systems, colimitation by water and N may be the more general rule (Hooper and Johnson 1999; Austin and Sala 2002). In a broad survey of desert ecosystems, Hooper and Johnson (1999) found evidence for colimitation by water and N even at the lowest levels of rainfall. In arid ecosystems, water is delivered in discrete events separated by drier periods, which restrict biological activity and uncouple plant uptake of nutrients from decomposition. Local variations in net primary production in arid and semiarid ecosystems are largely determined by processes that control the redistribution of water and soil nutrients across the landscape (Noy-Meir 1985; Schlesinger and Jones 1984; Wainwright et al. 2002; see also chapter 11). In this chapter we focus on the N cycle in different plant communities of the Jornada Basin with the recognition that after water, N is the most likely resource to determine the plant productivity of this ecosystem. Where arid environments are dominated by shrubby vegetation, the distribution of soil properties is markedly patchy with strong accumulations of plant nutrients under shrubs and relatively infertile soils in the intershrub spaces (Noy-Meir 1985). These islands of fertility are particularly well described in the Chihuahuan Desert and other areas of the American Southwest. Local accumulations of nutrients under vegetation are also documented for desert habitats on other continents, including Europe (Gallardo et al. 2000), Africa (Gerakis and Tsangarakis 1970; Belsky et al. 1989; Wezel et al. 2000), Australia (Tongway and Ludwig 1994; Facelli and Brock 2000), and South America (Rostagno et al. 1991; Mazzarino et al. 1991, 1998; Gutierrez et al. 1993). In the Jornada Basin, Schlesinger et al. (1996) used geostatistics to compare the scale of soil heterogeneity in arid habitats dominated by shrubs and in adjacent areas of arid grassland.
Conference papers on the topic "Grasslands – South Africa"
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Adepoju, Kayode, and Samuel Adelabu. "Assessment of Fuel and Wind Drivers of Fire Risk in Protected Mountainous Grassland of South Africa." In IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2019. http://dx.doi.org/10.1109/igarss.2019.8900100.
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Furniss, D., I. Weiersbye, D. Tongway, R. Stark, N. Margalit, H. Nel, E. Grond, and E. T. Witkowski. "Deriving indices of landscape function from spectral reflectance of grassland and savanna on gold mines in South Africa." In 2009 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2009. http://dx.doi.org/10.1109/igarss.2009.5417965.
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Ndyamboti, K., J. du Toit, J. Baade, A. Kaiser, M. Urban, C. Schmullius, C. Thiel, and C. Berger. "A Multi-Scale Remote Sensing Approach to Understanding Vegetation Dynamics in the Nama Karoo-Grassland Ecotone of South Africa." In IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2020. http://dx.doi.org/10.1109/igarss39084.2020.9323460.
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