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Journal articles on the topic 'Landforms - South Africa'
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SEPPÄLÄ, MATTI. "Evolution of landforms in South Africa." Boreas 9, no. 4 (January 16, 2008): 320. http://dx.doi.org/10.1111/j.1502-3885.1980.tb00712.x.
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Boelhouwers, Jan C. "Periglacial landforms at Giant'S Castle, Natal Drakensberg, South Africa." Permafrost and Periglacial Processes 5, no. 3 (August 1994): 129–36. http://dx.doi.org/10.1002/ppp.3430050302.
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Heyns, Andries M., Warren du Plessis, Kevin M. Curtin, Michael Kosch, and Gavin Hough. "Analysis and Exploitation of Landforms for Improved Optimisation of Camera-Based Wildfire Detection Systems." Fire Technology 57, no. 5 (April 10, 2021): 2269–303. http://dx.doi.org/10.1007/s10694-021-01120-2.
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AbstractTower-mounted camera-based wildfire detection systems provide an effective means of early forest fire detection. Historically, tower sites have been identified by foresters and locals with intimate knowledge of the terrain and without the aid of computational optimisation tools. When moving into vast new territories and without the aid of local knowledge, this process becomes cumbersome and daunting. In such instances, the optimisation of final site layouts may be streamlined if a suitable strategy is employed to limit the candidate sites to landforms which offer superior system visibility. A framework for the exploitation of landforms for these purposes is proposed. The landform classifications at 165 existing tower sites from wildfire detection systems in South Africa, Canada and the USA are analysed using the geomorphon technique, and it is noted that towers are located at or near certain landform types. A metaheuristic and integer linear programming approach is then employed to search for optimal tower sites in a large area currently monitored by the ForestWatch wildfire detection system, and these sites are then classified according to landforms. The results support the observations made for the existing towers in terms of noteworthy landforms, and the optimisation process is repeated by limiting the candidate sites to selected landforms. This leads to solutions with improved system coverage, achieved within reduced computation times. The presented framework may be replicated for use in similar applications, such as site-selection for military equipment, cellular transmitters, and weather radar.
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Obalum, S. E., J. C. Nwite, J. Oppong, C. A. Igwe, and T. Wakatsuki. "Variations in selected soil physical properties with landforms and slope within an inland valley ecosystem in Ashanti region of Ghana." Soil and Water Research 6, No. 2 (May 30, 2011): 73–82. http://dx.doi.org/10.17221/17/2010-swr.
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One peculiar feature of the inland valleys abundant in West Africa is their site-specific hydrology, underlain mainly by the prevailing landforms and topography. Development and management of these land resources under the increasingly popular sawah (a system of bunded, puddled and levelled rice field with facilities for irrigation and drainage) technology is a promising opportunity for enhancing rice (Oryza sativa L.) production in the region. Information on the variations in selected soil physical properties as influenced by the prevailing landforms may serve as a useful guide in site selection. This is of practical importance since majority of the inland valleys are potentially unsuitable for sawah development and most farmers in the region are of low technical level. Three landforms (river levee, elevated area and depressed area) were identified within a sawah field located in an inland valley at Ahafo Ano South District of Ghana. Each of these landforms was topsoil-sampled along on identified gradient (top, mid and bottom slope positions). Parameters determined included particle size distribution, bulk density, total porosity and field moisture content. The soil is predominantly clayey. There were no variations in the particle size distribution among the slope positions in the river levee. Overall, the river levee had lower silt content than the elevated and the depressed landforms. The bulk density, total porosity, and gravimetric moisture content indicated relative improvements only in the depressed area in the order, bottom > mid > top slope. Irrespective of slope position, the three landforms differed in these parameters in the order, depressed > river levee > elevated. The sand fraction impacted negatively on the silt fraction and bulk density of the soil, both of which controlled the soil moisture status. Despite the fairly low silt content of the soil, the silt fraction strongly influenced the gravimetric moisture content (R<sup>2</sup> = 0.80). So too did the soil bulk density on the gravimetric moisture content (R<sup>2</sup> = 0.90). It is concluded that: (1) since the landforms more prominently influenced the measured parameters than the slope positions, the former should take pre-eminence over the latter in soil suitability judgment; (2) with respect to moisture retention, variations in silt fraction and bulk density of this and other clayey inland-valley soils should be used as guide in site selection for sawah development.
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Evans, Mary, Bridget Fleming, and Gillian Drennan. "Can the augmented reality sandbox help learners overcome difficulties with 3-D visualisation?" Terrae Didatica 14, no. 4 (November 30, 2018): 389–94. http://dx.doi.org/10.20396/td.v14i4.8654110.
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Research has shown that students have difficulties in understanding topographic maps and landforms associated with contour patterns and therefore have problems in reading and interpreting topographic maps and relating these 2-dimensional representa-tions to a real 3-dimensional environment. However, maps are a fundamental tool for understanding geographical concepts and solving geographical problems. Current research indicates that this is not uniquely a South African problem and various at-tempts have been made to address this problem such as the use of videos, models and fieldtrips – each with their own limita-tions and difficulties. Nevertheless, the ability to visualize in 3-dimensions from a 2-dimensional representation is an essential skill in understanding and interpreting topographical maps. To address the problem of 3-D visualisation, an augmented reality sandbox (AR-Sandbox) was introduced to a Geography classroom, to Grade 11 students at a Secondary school in Johannes-burg, South Africa. The aim of this study is to determine the effectiveness of using the AR-Sandbox to enhance the learning of – and improve the learner's performance – in mapwork, and thereby address the problems experienced with 3-D visualisation. The results of the pre-test and post-intervention test are presented and show that the AR-Sandbox is an effective tool for en-hancing an understanding of landscapes rather an improving performance in the construction of cross-sectional profiles.
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Çöltekin, A., V. Rautenbach, S. Coetzee, and T. Mokwena. "LANDFORM PERCEPTION ACCURACY IN SHADED RELIEF MAPS: A REPLICATION STUDY CONFIRMS THAT NNW LIGHTING IS BETTER THAN NW AGAINST THE RELIEF INVERSION EFFECT." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4 (September 19, 2018): 101–6. http://dx.doi.org/10.5194/isprs-archives-xlii-4-101-2018.
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<p><strong>Abstract.</strong> Relief inversion effect is a perceptual phenomenon that leads to an inverted perception of convex and concave shapes. This perceptual inversion occurs in scenes where the shading/shadows act as the main depth cue. In visuospatial displays, such as shaded relief maps, the positioning of the shadows in the northern slopes, thus when light source placed broadly in south, mislead the cognitive system based on the ‘light from above prior’ assumption (Mamassian and Goutcher 2001). Thus, assuming the light must come from above, our mind creates an illusion, and we perceive the landforms incorrectly. To judge the 3D spatial relationships in terrain representations correctly, the relief inversion effect must be avoided. Cartographic convention against this effect is to place the light source at northwest (NW), whereas a recent study demonstrated that north-north-west (NNW), or even north yields more precise results (Biland and Çöltekin, 2016). Since this finding goes against decades of convention, to establish its validity further, we attempted replicating the results with a different sample in South Africa. In this paper, we present our findings, which broadly confirm that the NNW (or also N) is better than NW against the relief inversion effect.</p>
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Pánek, Tomáš. "Recent progress in landslide dating." Progress in Physical Geography: Earth and Environment 39, no. 2 (October 7, 2014): 168–98. http://dx.doi.org/10.1177/0309133314550671.
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Recent progress of dating techniques has greatly improved the age determination of various types of landslides. Since the turn of the 21st century, the number of dated landslides throughout the world has increased several fold and the introduction of modern dating methods (e.g. cosmic ray exposure dating) has enabled the dating of new landslide features and elements. Based on the analysis of >950 dated landslides (of which 734 have been dated since the year 2000), it is clear that the predominant traditional strategies have continued to rely on the radiocarbon method; however, there is a remarkable trend of using cosmic ray exposure techniques for dating both the accumulation (e.g. landslide boulders) and the depletion (e.g. landslide scarps) parts of landslides. Furthermore, an increasing number of slope failures is determined by a multi-dating approach, which enables the verification of particular dating methods. Although coherent regional landslide chronologies are still relatively scarce in comparison with extensive databases of fluvial, glacial and/or eolian landforms, they offer important insights into temporal landslide distribution, long-term landslide behavior and their relationships with paleoenvironmental changes. The most extensive data sets exist for the mountain areas of North America (Pacific Coast Ranges), South America (Andes), Europe (Alps, Scottish Highlands, Norway, Carpathians and Apennines), the Himalaya-Tibet orogeny and the Southern Alps of New Zealand. Dated landslides in the plate interiors are lacking, especially in South America, Africa and Australia. Despite the fact that some dating results are well correlated with major regional and continental-scale changes in the seismic activity, moisture abundance, glacier regimes and vegetation patterns, some of these results contradict previously established straightforward hypotheses. This indicates the rather complex chronological behavior of landslides, reflecting both intrinsic (e.g. gradual stress relaxation within a rock mass) and external factors, including high-magnitude earthquakes or heavy rainfalls.
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Cullum, Carola, Gary Brierley, George LW Perry, and Ed TF Witkowski. "Landscape archetypes for ecological classification and mapping." Progress in Physical Geography: Earth and Environment 41, no. 1 (October 24, 2016): 95–123. http://dx.doi.org/10.1177/0309133316671103.
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We propose the use of archetypes as a way of moving between conceptual framings, empirical observations and the dichotomous classification rules upon which maps are based. An archetype is a conceptualisation of an entire category or class of objects. Archetypes can be framed as abstract exemplars of classes, conceptual models linking form and process and/or tacit mental models similar to those used by field scientists to identify and describe landforms, soils and/or units of vegetation. Archetypes can be existing taxonomic or landscape units or may involve new combinations of landscape attributes developed for a specific purpose. As landscapes themselves defy precise categorisation, archetypes, as considered here, are deliberately vague, and are described in general terms rather than in terms of the details that characterise a particular instance of a class. An example outlining the use of archetypes for landscape classification and mapping is demonstrated for granitic catenas in Kruger National Park, South Africa. Some 81% of the study area can be described in terms of archetypal catenal elements. However, spatial clustering of two classes that did not correspond to the archetypes prompted development of new archetypes. We show how the archetypes encoded in the map can be used to frame further knowledge in an ongoing, iterative and adaptive process. Building on this, we reflect on the value of vagueness in conservation science and management, highlighting how archetypes that are used to interpret and map landscapes may be better employed in the future.
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Green, Paul F., Karna Lidmar-Bergström, Peter Japsen, Johan M. Bonow, and James A. Chalmers. "Stratigraphic landscape analysis, thermochronology and the episodic development of elevated, passive continental margins." Geological Survey of Denmark and Greenland (GEUS) Bulletin 30 (December 30, 2013): 1–150. http://dx.doi.org/10.34194/geusb.v30.4673.
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The continental margin of West Greenland is similar in many respects to other elevated, passive continental margins (EPCMs) around the world. These margins are characterised by extensive regions of low relief at elevations of 1–2 kilometres above sea level sloping gently inland, with a much steeper, oceanward decline, often termed a 'Great Escarpment', terminating at a coastal plain. Recent studies, based on integration of geological, geomorphological and thermochronological evidence, have shown that the high topography of West Greenland was formed by differential uplift and dissection of an Oligo-Miocene peneplain since the late Miocene, many millions of years after continental break-up between Greenland and North America. In contrast, many studies of other EPCMs have proposed a different style of development in which the high plateaux and the steep, oceanward decline are regarded as a direct result of rifting and continental separation. Some studies assume that the elevated regions have remained high since break-up, with the high topography continuously renewed by isostasy. Others identify the elevated plains as remnants of pre-rift landscapes. Key to understanding the development of the West Greenland margin is a new approach to the study of landforms, stratigraphic landscape analysis, in which the low-relief, high-elevation plateaux at EPCMs are interpreted as uplifted peneplains: low-relief surfaces of large extent, cutting across bedrock of different age and resistance, and originally graded to sea level. Identification of different generations of peneplain (re-exposed and epigene) from regional mapping, combined with geological constraints and thermochronology, allows definition of the evolution leading to the formation of the modern-day topography. This approach is founded particularly on results from the South Swedish Dome, which document former sea levels as base levels for the formation of peneplains. These results support the view that peneplains grade towards base level, and that in the absence of other options (e.g. widespread resistant lithologies), the most likely base level is sea level. This is particularly so at continental margins due to their proximity to the adjacent ocean. Studies in which EPCMs are interpreted as related to rifting or break-up commonly favour histories involving continuous denudation of margins following rifting, and interpretation of thermochronology data in terms of monotonic cooling histories. However, in several regions, including southern Africa, south-east Australia and eastern Brazil, geological constraints demonstrate that such scenarios are inappropriate, and an episodic development involving post-breakup subsidence and burial followed later by uplift and denudation is more realistic. Such development is also indicated by the presence in sedimentary basins adjacent to many EPCMs of major erosional unconformities within the post-breakup sedimentary section which correlate with onshore denudation episodes. The nature of the processes responsible is not yet understood, but it seems likely that plate-scale forces are required in order to explain the regional extent of the effects involved. New geodynamic models are required to explain the episodic development of EPCMs, accommodating post-breakup subsidence and burial as well as subsequent uplift and denudation, long after break-up which created the characteristic, modern-day EPCM landscapes.
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Jha, V. C., and S. Kapat. "Rill and gully erosion risk of lateritic terrain in South-Western Birbhum District, West Bengal, India." Sociedade & Natureza 21, no. 2 (August 2009): 141–58. http://dx.doi.org/10.1590/s1982-45132009000200010.
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It is a known fact that no part of the earth surface is free from threat.It applies to Birbhum District, West Bengal, Indian Lateritic Terrain also. The existing terrain is characterized by mainly climatogenetic processes. Though the impact of climate change is vital in the shaping of the lesser topographies in the study-area. The study-area is characterized by micro landforms e. g. rills, gullies, water falls, terraces, gorges type features and limestone topographic type features. The denudational processes are very significant in the area in general but the differential erosion is evident in particular. It resembles the topographies with the African and the Brazillian Highlands. This paper interprets the rill and gully erosion risk in the lateritic terrain and their consequences in regional sustainable development and environmental management
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Gaki - Papanastassiou, K., E. Karymbalis, H. Maroukian, and K. Tsanakas. "GEOMORPHIC EVOLUTION OF WESTERN (PALIKI) KEPHALONIA ISLAND (GREECE) DURING THE QUATERNARY." Bulletin of the Geological Society of Greece 43, no. 1 (January 19, 2017): 418. http://dx.doi.org/10.12681/bgsg.11193.
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Kephalonia Island is located in the Ionian Sea (western Greece). The active subduction zone of the African lithosphere submerging beneath the Eurasian plate is placed just west of the island. The evolution of the island is depended mostly on the geodynamic processes derived from this vigorous margin. The geomorphic evolution of the western part of the island (Paliki peninsula) during the Quaternary was studied, by carrying out detailed field geomorphological mapping focusing on both coastal and fluvial landforms, utilizing aerial photos and satellite image interpretation with the use of GIS technology. The coastal morphology of Paliki includes beachrocks, aeolianites, notches and small fan deltas which were all studied and mapped in detail. The drainage systems of the peninsula comprise an older one on carbonate formations in the northwest and a younger Quaternary one in the south and southeast. Eight marine terraces found primarily on the Pliocene marine formations range in elevation from 2 m to 440 m are tilted to the south. In the Late Pleistocene some of the main drainage networks flowed towards the newly-formed gulf of Argostoli to the east.
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Guimarães, Thaís Oliveira, Mariano Gorki, and Artur A. Sá. "Inventário e avaliação qualitativa como subsídio à geoconservação e ao geoturismo: Litoral Sul do Estado de Pernambuco (Nordeste-Brasil) (Inventory and qualitative evaluation for geoconservation and geoturism: Southern Coast of the estate of ...)." Revista Brasileira de Geografia Física 10, no. 4 (May 17, 2017): 1218. http://dx.doi.org/10.26848/rbgf.v10.4.p1218-1238.
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A configuração geológica do Litoral Sul de Pernambuco, bem como suas formas de relevo, decorre em grande parte do magmatismo ocorrido no Cretáceo, lhe conferindo uma paisagem bastante distinta das demais áreas do litoral do Estado. A diversidade geológica e suas principais ocorrências estão diretamente relacionadas com a última etapa de fragmentação do antigo continente Gondwana que resultou na formação dos continentes Africano e Sul-americano. Na região afloram rochas da Bacia Sedimentar de Pernambuco, rochas ígneas vulcânicas e plutônicas associadas ao magmatismo do Cretáceo e rochas neoproterzóicas do embasamento cristalino. O trabalho compreende um estudo de caso, onde foram selecionados 13 geossítios, através da metodologia de abordagem qualitativa, tendo como objetivo inicial a descrição, classificação e valoração deste patrimônio geológico, resultando em um inventário do patrimônio geológico dessa região. Trata-se de uma pesquisa classificada como exploratória e explicativa, onde os resultados foram obtidos através de trabalho de campo e pesquisa bibliográfica interdisciplinar, relativa tanto aos elementos das Geociências como das Ciências Sociais, bem como análise qualitativa dos sítios. Diante dos resultados obtidos constatou-se a grande relevância dessa área não só do ponto de vista geológico, mas a todos os valores naturais e socioculturais a ela agregados. Esta conclusão abre precedentes para uma segunda etapa de pesquisas, que compreenderá a elaboração de um diagnóstico mais completo acerca da relevância e vulnerabilidade destes sítios para que sejam futuramente estruturadas estratégias de geoconservação e desenvolvimento local, utilizando como principais ferramentas a popularização das Geociências e o fortalecimento do geoturismo na região. A B S T R A C TThe geological setting of the southern coast of Pernambuco, as well as its landforms, stems largely from the Cretaceous felsic which provides a very different landscape from the remaining areas of Pernambuco’s coast. Geological diversity and its main occurrences are directly related to the last fragmentation step of the ancient continent Gondwana, which resulted the formation of the African and South American continents. In the region arise sedimentary rocks from the local Sedimentary Basin, volcanic and plutonic igneous rocks associated with Cretaceous felsic, and neoproterozoic rocks from the crystalline. This work comprises a case study, where 13 geosites were selected through a qualitative approach, with the initial goal of description, classification and valuation of their geological patrimony, resulting in an inventory of the geological heritage of the region. It comprises an exploratory and explanatory research, where the results were obtained through fieldwork and interdisciplinary bibliographical research on both Earth and Social Sciences. Eventually, it was noticed the importance of the area, not only from the geological point of view, but also from the natural and social-cultural perspective. The findings opened a second stage of research, which shall include the preparation of a full diagnosis about the importance and vulnerability of these sites to be structured in the future using geoconservation and local development strategies as a main tool for the popularization of Geosciences and strengthening of Geotourism in the region.Keywords: qualitative analyses, geoconservation, geoheritage, Pernambuco, popularization of geosciences, coastal zone.
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"Landscapes and landforms of South Africa." Choice Reviews Online 53, no. 06 (January 20, 2016): 53–2643. http://dx.doi.org/10.5860/choice.194027.
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Grab, Stefan W., Andrew S. Goudie, Heather A. Viles, and Nicola Webb. "Sandstone geomorphology of the Golden Gate Highlands National Park, South Africa, in a global context." Koedoe 53, no. 1 (March 2, 2011). http://dx.doi.org/10.4102/koedoe.v53i1.985.
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The Golden Gate Highlands National Park (GGHNP) is well known for its impressive sandstone formations. While previous geoscience research in the park has focused on geology, palaeontology, slope forms and the prominent lichen weathering, remarkably little has been written on the diversity and possible origins of sandstone phenomena in the region. The objectives of this study were (1) to present a geomorphological map of prominent and interesting landforms for particular portions of the park and (2) to document the variety of macro- and microscale sandstone formations observed. During field work, we undertook global positioning system measurements to map landforms and, in addition, measured the dimensions of several landform types. A Schmidt hammer was used to conduct rock hardness tests at a variety of localities and lithologies for comparative purposes. We indentified and mapped 27 macro- and microscale sandstone landforms, of which 17 are described in detail. It is demonstrated that for the most part, the landforms are a likely product of surface lithological reactions to a regional climate characterised by pronounced multitemporal temperature and moisture shifts, recently and in the past. However, many of the geomorphological processes producing landforms are controlled by microclimates set up by factors such as macro- and microtopography. Conservation implications: The GGHNP is best known for its geological, geomorphological and palaeontological heritage. This paper highlights the diversity of sandstone geomorphological phenomena, many of them rare and ‘unique’ to the region. Not only are these landforms of aesthetic interest to tourists, but they also provide microhabitats for biota. Thus, conservation of biota requires associated conservation of geo-environments where they are established.
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Knight, J., and S. W. Grab. "Stratigraphy of late Quaternary mountain slope landforms and deposits in southern Africa and their significance for the dynamics of mountain sediment systems." South African Journal of Geology, July 28, 2021. http://dx.doi.org/10.25131/sajg.124.0037.
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Abstract Mountains are areas of high potential sediment yield due to their steep slopes and generally cool, wet climates. Mountain sediments are moved by gravity-driven and often cryogenically-influenced processes, and captured within valleys or footslopes in the form of screes, alluvial/colluvial fans and terraces, or on hillslopes in the form of solifluction sheets, debris lobes/ridges and openwork block deposits. This study critically examines the geomorphic, sedimentary, stratigraphic and dating evidence from cryogenically-influenced late Quaternary slope deposits found along the highest sectors of the Great Escarpment in the Eastern Cape Province (South Africa) and Maloti–Drakensberg range (Lesotho, and KwaZulu-Natal Province, South Africa). This evidence is set in the context of mountain weathering and erosion/transportation processes during the late Quaternary, and the dynamics of such sedimentary systems. Despite many general reports and observations, there is little detailed and quantitative evidence for late Quaternary slope processes, products and stratigraphy in southern Africa. This study integrates the existing morphological, sedimentary and dating evidence to examine mountain slope evolution in southern Africa based on the conceptual framework of sediment cascades. Application of this framework can help explain the spatial and temporal differences in sediment supply and dynamics observed in different sectors of the Great Escarpment during the late Quaternary.
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Fitchett, Jennifer M., Stefan W. Grab, Marion K. Bamford, and Anson W. Mackay. "A multi-disciplinary review of late Quaternary palaeoclimates and environments for Lesotho." South African Journal of Science Volume 112, Number 7/8 (July 27, 2016). http://dx.doi.org/10.17159/sajs.2016/20160045.
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Abstract Lesotho provides a unique context for palaeoclimatic research. The small country is entirely landlocked by South Africa, yet has considerable variation in topography, climate, and associated vegetation over an approximate east–west transect. The region has been of archaeological interest for over a century, and hosts many Early to Late Stone Age sites with occupation preceding 80 000 years before present. The eastern Lesotho highlands are of interest to periglacial and glacial geomorphologists because of their well-preserved relict landforms and contentious evidence for permafrost and niche glaciation during the late Quaternary. However, continuous proxy records for palaeoenvironmental reconstructions for Lesotho are scarce and hampered by a range of methodological shortfalls. These challenges include uncertain ages, poor sampling resolution, and proxies extracted from archaeological excavations for which there may be bias in selection. Inferences on palaeoclimates are thus based predominantly on archaeological and palaeogeomorphological evidence for discrete periods during the late Quaternary. This review paper presents a more detailed multidisciplinary synthesis of late Quaternary conditions in Lesotho. We simultaneously considered the varying data that contribute to the under-studied palaeoenvironmental record for southern Africa. The collective palaeoenvironmental data for eastern Lesotho were shown to be relatively contradictory, with considerable variations in contemporaneous palaeoclimatic conditions within the study area. We argue that although methodological challenges may contribute to this variation, the marked changes in topography result in contrasting late Quaternary palaeoenvironments. Such environments are characterised by similar contrasting microclimates and niche ecologies as are witnessed in the contemporary landscape. These spatial variations within a relatively small landlocked country are of importance in understanding broader southern African palaeoenvironmental change.
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Masubelele, Mmoto L., Michael T. Hoffman, William Bond, and Peter Burdett. "Vegetation change (1988–2010) in Camdeboo National Park (South Africa), using fixed-point photo monitoring: The role of herbivory and climate." Koedoe 55, no. 1 (February 20, 2013). http://dx.doi.org/10.4102/koedoe.v55i1.1127.
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Fixed-point photo monitoring supplemented by animal census data and climate monitoring potential has never been explored as a long-term monitoring tool for studying vegetation change in the arid and semi-arid national parks of South Africa. The long-term (1988–2010), fixed-point monitoring dataset developed for the Camdeboo National Park, therefore, provides an important opportunity to do this. Using a quantitative estimate of the change in vegetation and growth form cover in 1152 fixed-point photographs, as well as series of step-point vegetation surveys at each photo monitoring site, this study documented the extent of vegetation change in the park in response to key climate drivers, such as rainfall, as well as land use drivers such as herbivory by indigenous ungulates. We demonstrated the varied response of vegetation cover within three main growth forms (grasses, dwarf shrubs [< 1 m] and tall shrubs [> 1 m]) in three different vegetation units and landforms (slopes, plains, rivers) within the Camdeboo National Park since 1988. Sites within Albany Thicket and Dwarf Shrublands showed the least change in vegetation cover, whilst Azonal vegetation and Grassy Dwarf Shrublands were more dynamic. Abiotic factors such as drought and flooding, total annual rainfall and rainfall seasonality appeared to have the greatest influence on growth form cover as assessed from the fixed-point photographs. Herbivory appeared not to have had a noticeable impact on the vegetation of the Camdeboo National Park as far as could be determined from the rather coarse approach used in this analysis and herbivore densities remained relatively low over the study duration.Conservation implications: We provided an historical assessment of the pattern of vegetation and climatic trends that can help evaluate many of South African National Parks’ biodiversity monitoring programmes, especially relating to habitat change. It will help arid parks in assessing the trajectories of vegetation in response to herbivory, climate and management interventions.
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Wang, Jian-Sheng, Yi-Fei Lu, Yue-Liang Xu, Shui-Hu Jin, and Xiao-Feng Jin. "Impatiens wuyiensis (Balsaminaceae), a new species from Fujian of Southeast China, based on morphological and molecular evidences." Botanical Studies 61, no. 1 (November 2, 2020). http://dx.doi.org/10.1186/s40529-020-00306-1.
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Abstract Background Southeast Asia, together with tropical Africa, Madagascar, South India and Sri Lanka, and the eastern Himalayas, are the five primary hotspots of species diversity of Impatiens (Balsaminaceae). China is also rich in Impatiens species, especially in the limestone karsts or ‘Danxia’ landforms. With zygomorphic flowers and diverse corolla morphology and color, the species in Impatiens are well-known for their ornamental use, but they are also notorious in taxonomy. During the preparation of revision of Impatiens in Zhejiang and adjacent regions, an unknown species was collected from Mt. Wuyi in Fujian Province, Southeast China. Results Phylogenetic analyses based on nuclear ITS, chloroplast atpB-rbcL and trnL-F sequences, together with micromorphology of pollen grains and seed coats, strongly supported the close relationship of the new species with Impatiens platysepala Y.L.Chen and I. chloroxantha Y.L.Chen. In turn, both molecular data and morphological characters also were sufficient to distinguish the new species from the other two counterparts. Conclusions Our detailed morphological observations and molecular phylogenetic analyses support the recognition of Impatiens wuyiensis as a species new to science.
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Masubelele, Mmoto L., Michael T. Hoffman, William Bond, and Peter Burdett. "Online appendix 1:Vegetation change (1988–2010) in Camdeboo National Park (South Africa), using fixed-point photo monitoring: The role of herbivory and climate." Koedoe 55, no. 1 (October 18, 2013). http://dx.doi.org/10.4102/koedoe.v55i1.1127-1.
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Fixed-point photo monitoring supplemented by animal census data and climate monitoring potential has never been explored as a long-term monitoring tool for studying vegetation change in the arid and semi-arid national parks of South Africa. The long-term (1988–2010), fixed-point monitoring dataset developed for the Camdeboo National Park, therefore, provides an important opportunity to do this. Using a quantitative estimate of the change in vegetation and growth form cover in 1152 fixed-point photographs, as well as series of step-point vegetation surveys at each photo monitoring site, this study documented the extent of vegetation change in the park in response to key climate drivers, such as rainfall, as well as land use drivers such as herbivory by indigenous ungulates. We demonstrated the varied response of vegetation cover within three main growth forms (grasses, dwarf shrubs [< 1 m] and tall shrubs [> 1 m]) in three different vegetation units and landforms (slopes, plains, rivers) within the Camdeboo National Park since 1988. Sites within Albany Thicket and Dwarf Shrublands showed the least change in vegetation cover, whilst Azonal vegetation and Grassy Dwarf Shrublands were more dynamic. Abiotic factors such as drought and flooding, total annual rainfall and rainfall seasonality appeared to have the greatest influence on growth form cover as assessed from the fixed-point photographs. Herbivory appeared not to have had a noticeable impact on the vegetation of the Camdeboo National Park as far as could be determined from the rather coarse approach used in this analysis and herbivore densities remained relatively low over the study duration.Conservation implications: We provided an historical assessment of the pattern of vegetation and climatic trends that can help evaluate many of South African National Parks’ biodiversity monitoring programmes, especially relating to habitat change. It will help arid parks in assessing the trajectories of vegetation in response to herbivory, climate and management interventions.
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Triest, Ludwig, and Tom Van der Stocken. "Coastal Landform Constrains Dispersal in Mangroves." Frontiers in Marine Science 8 (June 28, 2021). http://dx.doi.org/10.3389/fmars.2021.617855.
Full textAbstract:
Mangrove forests are dynamic ecosystems found along low-lying coastal plains along tropical, subtropical, and some warm-temperate coasts, predominantly on tidal flats fringing deltas, estuaries, bays, and oceanic atolls. These landforms present varied hydrodynamic and geomorphological settings for mangroves to persist and could influence the extent of within-site propagule transport and subsequent local regeneration. In this study, we examined how different landform characteristics may influence local genetic diversity, kinship, and neighborhood structure of mangrove populations. To do so, we considered independent populations of Avicennia marina, one of the most abundant and widespread mangrove species, located in estuarine and coastal bay environments spread across the Western Indian Ocean region. A transect approach was considered to estimate kinship-based fine-scale spatial genetic structure using 15 polymorphic microsatellite markers in 475 adult A. marina trees from 14 populations. Elevated kinship values and significant fine-scale structure up to 30, 60, or 90 m distances were detected in sheltered systems void of river discharge, suggesting a setting suitable for very local propagule retention and establishment within a neighborhood. Slopes of a linear regression over restricted distance within 150 m were significantly declining in each sheltered transect. Contrastingly, such a spatial structure has not been detected for A. marina transects bordering rivers in the estuarine systems considered, or alongside partially sheltered creeks, suggesting that recruitment here is governed by unrelated carried-away mixed-origin propagules. South African populations showed strong inbreeding levels. In general, we have shown that A. marina populations can locally experience different modes of propagule movement, explained from their position in different coastal landforms. Thus, the resilience of mangroves through natural regeneration is achieved by different responses in coastal landforms characterized by different hydrodynamic conditions, which can be important information for their management and protection within the variety of coastal environments.