Vegetation, soil and grazing relationships in the Middelburg District of the Eastern Cape

Thesis (MSc)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: Arid and semi-arid rangelands of the Nama-Karoo Biome are believed to have changed considerably since the arrival of domestic livestock in the veld. Severe grazing pressure is considered to be one of the prime factors responsible for the perceived degradation of vegetation and concurrent soil degradation. To understand the process of degradation and to make further recommendations for future veld restoration, a large-scale project was undertaken in the Eastern Cape. This project focused on the role that landscape heterogeneity plays in providing refuges for plant species. The key question asked in this project was: What role do these hypothetically less grazed mesas play in the conservation of rangelands in the Nama-Karoo of the Eastern Cape? This study, a component of the larger project, investigated grazing and soil landscape gradients on- and off- the three mesas (Tafelberg, Folminkskop and Buffelskop) in the Middelburg District of the Eastern Cape, South Africa and the possible influences that they might have on the veld. The flats surrounding the mesas were mostly used as grazing camps in contrast to the plateaux of the mesas, which had varied levels of accessibility. In the absence of direct observations, the primary objective of the study was to test the differential dung pellet abundance and impact of animals on different parts of the landscape. As such, dung pellet counts in this study were correlated with surrogates of soil physical properties including bare ground, trampling and litter cover. Variation in dung pellet density was found at the different habitats (flats, slopes and plateaux) of all mesas. The flats to the north-eastern and south-western of Tafelberg mesa were found to be more heavily utilized by livestock and herbivores, while the plateaux and southeastern slopes of Folminkskop and Buffelskop were also utilized by grazers. The Tafelberg mesa was the only study site that was consistent with the hypothesis which stated that grazers would be less concentrated on the plateau compared to the surrounding flats due to its inaccessibility, whilst the high mean dung pellet density on the plateaux of the smaller Folminkskop and Buffelskop mesas due to easier access contradicted the original hypothesis. It appeared that dung pellet density did not clearly turn out to be an indicator of habitat use in this study, but showed where slopes and plateaux were accessible to herbivores, as in the case for the Buffelskop mesa, a higher abundance of dung pellets were found suggesting that higher intensities of habitat use took place. During this study a strong pattern was observed of bare soil patches on the flats surrounding the mesas. There was a decrease in percentage of bare soil along the gradient of the three mesas with a high percentage of bare soil on the plateaux of the mesas. A significant correlation was found between bare soil and dung pellet density. However, the plateaux of Folminkskop and Buffelskop had a high percentage of bare soil compared to the plateau of Tafelberg mesa. Farmers mainly used these smaller mesas as grazing camps for their livestock and herbivores. A positive correlation between bare soil and litter cover of the different habitats was evident in this study. A lower percentage of litter cover at these sites was associated with a high percentage of bare soil. Litter is very important in a healthy vegetation community in terms of nutrient cycling and fertile patches. A detailed assessment of soil chemical and physical properties would reveal, firstly, if vegetation change is better explained by soil or grazing effects and, secondly, if changes in soil have resulted from land use. Differences in macro- and micro-site variations between open-canopy (between shrubs) and closed-canopy (under shrubs) sites for each habitat were determined to differentiate between local scales due to land use and landscape scales due to geomorphology. The results suggested that carbon, phosphorus, calcium, magnesium, copper and manganese levels in soils at landscape scale better explain vegetation changes between habitats. At a local scale (open- and closed-canopy sites) land use was responsible for little changes in soils. Changes in only soil potassium, zinc and boron elements were actually a consequence of local scales due to land use. The soil nutrient content on the slopes appeared to be intermediate between the flats and plateaux of all three mesas. It appeared that dolerite capped Tafelberg and Folminkskop mesas had high silt and clay content, while Buffelskop (sandstone) mesa had a lower silt and clay content. Consequently, the texture and parent material of the soils contributed to the variations in soil nutrient composition between these mesas. High infiltration rate together with low nutrient content on the flats clearly showed that these flats, surrounding the mesas were degraded. The high infiltration rates were caused by high activity by livestock and other indigenous animals on the flats which breaks the surface crusting of bare soil and improve infiltration. It was concluded that high levels of grazing at these sites have also altered the textural and soil properties. Endozoochory dispersal and the deposition of dung pellets in areas of small patch disturbances play an important role in veld regeneration in degraded areas. Dung pellets collected from permanent study sites on the southeastern and northwestern flats and slopes, and all the study sites on the plateau of Tafelberg mesa, was sown in seedling trays, watered and monitored for seedling germination. Species list were then compared to below-ground soil seed bank data and above-ground vegetation data collected by other researchers at the same permanent study sites. Higher seedling percentages were recorded from dung pellets collected on the flats than on the plateau. A total of sixteen species were found to germinate in dung pellets collected on the flats compared to ten species germinating in dung pellets collected on the slopes and two species on the plateau of Tafelberg mesa. The seeds that germinated represent a variety of palatable grasses and shrub species. Aristida sp., Eragrostis bicolor, Eragrostis ch/orome/as and Eragrostis obtusa were palatable grasses recorded for dung pellets collected on the flats. Of the species recorded, Aristida sp., Chenopodium sp. and Pentzia sp. were found in dung pellets but were not recorded in parallel soil seedbank and vegetation studies. Successful restoration of veld conditions requires strict grazing management practices. Germination of seed in dung pellets might be considered to be a valuable means of indicating restoration potential and rangeland conditions for the identification of both degraded and conservation worthy areas. With appropriate land management skills and restoration measures, these challenges can be constructively and creatively faced.AFRIKAANSE OPSOMMING: Daar word geglo dat die ariede en sernl-arlede weivelde van die Nama-Karoo bioom aansienlik verander het sedert die aankoms van mak lewende hawe in die veld. Swaar weidingsdruk word beskou as een van die vernaamste faktore verantwoordelik vir die waarneembare oorbeweiding van plantegroei en die gelyktydige grond agteruitgang (degradasie). Ten einde die proses van degradasie beter te verstaan, en om verdere aanbevelings te kan maak vir toekomstige veld herstel, is huidiglik 'n grootskaalse projek in die Oos-Kaap aan die gang oor die rol wat landskap ongelyksoortigheid speel in die voorsiening van skuiling aan plant spesies. Hierdie studie ondersoek weiding en grondlandskap gradiënte (op en af) van die drie mesas (Tafelberg, Folminkskop en Buffelskop) in die Middelburg streek van die Oos- Kaap, Suid-Afrika en die moontlike invloed wat hierdie gradiënte op die veld het. Die vlaktes was meestal gebruik vir weidingskampe in teenstelling met die kruin van die mesas. Hierdie studie het duidelike patrone vir habitat-gebruik op die vlaktes, hange en kruine van al die mesas aangetoon. Die vraag wat gestel was, was watter rol speel hierdie hipoteties minder beweide mesas in die bewaring van weivelde in die Nama- Karoo van die Oos-Kaap? Hierdie studie toets nie direk vir mis verspreiding as 'n plaasvervanger vir dier verspreiding in die landskap sedert werklike dier getalle nie oorweeg was nie. In die awesigheid van direkte waarneming, die primêre doelwit was om te toets die differensiaal misdigtheid en die impak van diere op verskillende dele van die landskap. Mis getalle in hierdie studie was gekorreleer met plaasvervangers van fisiese eienskappe insluitent onbedekte grond, vertrapping en droë plant material decking. Variasie in misdigtheid was gevind by die verskillende habitate (vlaktes, hange en kruine) van all die mesas. Die vlaktes aan die noord-oostelike en suid-westelike kante van die Tafelberg mesa was meer hewig benut deur lewende hawe en hêrbivore, terwyl die kruine en suid-oostelike hange van Folminkskop en Buffelskop ook gebruik was deur weidende diere. Die Tafelberg mesa was die enigste studie area wat konsekwent was met die hipotese, terwyl die hoë gemiddeld misdigtheid op die kruine van die kleiner Folminkskop en Buffelskop mesas, as gevolg van makliker toegang weerspreek die oorspronklike hipotese. Dit blyk dat misdigtheid duidelik opkom as 'n nie aanwyser habitat-gebruik in hierdie studie, maar wys well waar hange en kruine toeganklik was vir herbivore, soos in die geval van Buffelskop mesa, oorvloed van mis was gevind wat voorstel dat hoer intensiteit van habitat-gebruik voorgekom het. 'n Duidelike patroon is waargeneem tydens hierdie studie van onbedekte grond areas op die vlaktes rondom mesas. Daar was 'n afname in persentasie onbedekte grond langs die gradiënt van die drie mesas. Die kruine van Folminkskop en Buffelskop toon hoër persentasies onbedekte grond in vergelyking met die kruin van die Tafelberg mesa. Daar is 'n betekenisvolle korrelasie tussen onbedekte grond en misdigtheid gevind. Boere gebruik hierdie kleiner mesas hoofsaaklik as weidingskampe vir hulle lewende hawe en hêrbivore. In hierdie studie is daar 'n positiewe korrelasie gevind tussen onbedekte grond en droë plant material decking van die verskillende habitatte. Droë plantmateriaal bedekking speel 'n baie belangrik rol in 'n gesonde plant gemeenskap in terme van voedingsirkulering en vrugbare kolle. 'n Breedvoerige skatting van grond chemise en fisiese eienskappe wou openbaar eerstens of plantegroei verandering beter verklaar word deur grond of weiding effekte en tweedens, of verandering in grond veroorsaak was deur land-gebruik. Verskille in makro- en mikroterrein-wisseling tussen oop-blaredak (tussenplantruimtes) en toeblaredak (onderplantdekking) terreine vir elke habitat was bepaal om te onderskei tussen lokaal effek as gevolg van land-gebruik en landskap effek as gevolg van geomorfologie. Die resultate stel voor dat koolstof, fosfor, kalsium, magnesium, koper en mangaan vlakke in die grond by landskap effek beter plantegroei verandering tussen habitate verduidelik. By 'n lokaal effek (oop-en toe-blaredak terreine) land-gebruik was verantwoordelik vir min veranderinge in grond. Verandering in grond kalium, sink en baron elemente was werklik 'n gevolg van lokaal effek as gevolg van land-gebruik. Die nutrient inhoud van grond op die hange blyk intermediêr te wees tussen die van die vlaktes en kruine van al drie mesas. Hierdie studie toon ook dat die geologie en topografie van hierdie mesas die grond tekstuur en nutrient samestelling op en af van die mesas beinvloed. Dit wil voorkom asof die dolerite bedekte Tafelberg en Folminkskop mesas, hoë slik en klei materiaal bevat, terwyl Buffelskop (sandsteen) mesa 'n laer slik en klei inhoud het. Gevolglik, tekstueel en ouer materiaal grond dra by tot die variasie in grond nutrient samestelling tussen hierdie mesas. Hoë infiltrasie tempo tesame met lae voedingstof van die vlaktes dui daarop dat die vlaktes rondom die mesas oorbewei was. Hierdie hoë infiltrasie tempo word veroorsaak deur hoë dierlike aktiwieteite op die vlaktes deur lewende hawe en ander inheemse diere wat die oppervlakke van onbedekte grond versteur en infiltrasie verbeter. Die gevolgtrekking word gemaak dat die hoë weidingsvlakke van hierdie terreine ook die tekstuur en ander grond eienskappe verander het. Endozoochoreeuse verspreiding en die mis-afsetting in gebiede van klein areaversteurings, speel 'n belangrike rol in veld herlewing in oorbeweide gebiede. Mis versamel by permanente studie terreine op die SO en NW vlaktes en hange, as ook al die studie terreine op die kruin van die Tafelberg mesa, is gesaai in saailing bakke, besproei en gekontroleer vir saailing ontkieming. 'n Lys van spesies is vergelyk met onder-grondse saadbank gegewens en bo-grondse plantegroei gegewens wat deur ander navorsers by dieselfde studie terreine versamel was. Hoër saailing persentasies is gevind vir mis wat op die vlaktes versamel is as op die kruine. 'n Totaal van sestien geidentifiseerde spesies het uit die mis op die vlaktes ontkiem in vergelyking met die tien spesies wat ontkiem het uit die mis van die hange en twee spesies iut die mis van die kruin van Tafelberg mesa. Die ontkiemde saad verteenwoordig 'n verskeidenheid van vreetbare gras en struik spesies. Aristide sp., Eragrostis bicolor, Eragrostis chloromelas en Eragrostis obtusa is vreetbare grasse wat gevind was in die mis versamelop die vlaktes. Die spesies opname wys dat Aristida sp., Chenopodium sp. en Pentzia sp. Gevind was in die mis, maar nie in die parallelle grond saadbank en plantegroei studies nie. Die suksesvolle herstel van veldtoestande vereis "n streng weidingsbestuur toepassing. Die ontkieming van saad in mis kan beskou word as "n bekostigbare manier om veld herstel potentiaal te bepaal, asook weiveld toestande vir die indentifiseering van beide degradasie en bewaring van waardevolle areas. Met gepaste veldbestuur vaardighede en herstel maatreels, kan hierdie uitdagings konstruktief en kreatief aangespreek word

Social and Economic Activity of the Elder Generation in Tomsk Region

Social and economic activity of the Russian elder generation has a contradictory nature. On the one hand, Russian pensioners often continue working beyond the existing comparatively low retirement age, on the other hand, in terms of involvement in volunteering, political activities, and even in care for children and grandchildren they lag significantly behind the average European level. Explaining it only by the lack of time does not seem plausible, since in many European countries, the employment rates, involvement in unpaid work and caring for other family members are all higher than in Russia. In our study we attempt to identify reasons for lower social and economic activity of older adults in Russia as compared with European countries. We use data of Tomsk regional survey (2015, N=400) for accessing older adults' social activity. Data analysis on Tomsk region suggests that employment (as an activity) and education (as a prerequisite) contribute to higher involvement in social interactions in later life

Being HIV positive and staying on antiretroviral therapy in Africa: A qualitative systematic review and theoretical model

Abstract : Background Adherence to antiretroviral therapy (ART) and long-term uninterrupted engagement in HIV care is difficult for HIV-positive people, and randomized trials of specific techniques to promote adherence often show small or negligible effects. Understanding what influences decision- making in HIV-positive people in Africa may help researchers and policy makers in the development of broader, more effective interventions and policies..

Competition among Sellers in Securities Auctions

We study simultaneous security-bid second-price auctions with competition among sellers for potential bidders. The sellers compete by designing ordered sets of securities that the bidders can offer as payment for the assets. Upon observing auction designs, potential bidders decide which auctions to enter. We characterize all symmetric equilibria and show that there always exist equilibria in which auctions are in standard securities or their combinations. In large markets the unique equilibrium is auctions in pure cash. We extend the model for competition in reserve prices and show that binding reserve prices never constitute equilibrium as long as equilibrium security designs are not call options. (JEL D44, D82, G10)

Testing for saturation in qualitative evidence syntheses: An update of HIV adherence in Africa

Background A systematic review of randomised trials may be conclusive signalling no further research is needed; or identify gaps requiring further research that may then be included in review updates. In qualitative evidence synthesis (QES), the rationale, triggers, and methods for updating are less clear cut. We updated a QES on adherence to anti-retroviral treatment to examine if thematic saturation renders additional research redundant. Methods We adopted the original review search strategy and eligibility criteria to identify studies in the subsequent three years. We assessed studies for conceptual detail, categorised as ‘rich’ or ‘sparse’, coding the rich studies. We sought new codes, and appraised whether findings confirmed, extended, enriched, or refuted existing themes. Finally, we examined if the analysis impacted on the original conceptual model. Results After screening 3895 articles, 301 studies met the inclusion criteria. Rich findings from Africa were available in 82 studies; 146 studies were sparse, contained no additional information on specific populations, and did not contribute to the analysis. New studies enriched our understanding on the relationship between external and internal factors influencing adherence, confirming, extending and enriching the existing themes. Despite careful evaluation of the new literature, we did not identify any new themes, and found no studies that refuted our theory. Conclusions Updating an existing QES using the original question confirmed and sometimes enriched evidence within themes but made little or no substantive difference to the theory and overall findings of the original review. We propose this illustrates thematic saturation. We propose a thoughtful approach before embarking on a QES update, and our work underlines the importance of QES priority areas where further primary research may help, and areas where further studies may be redundant

Phenothiazines as a solution for multidrug resistant tuberculosis: From the origin to present

Historically, multiplicity of actions in synthetic compounds is a rule rather than exception. The science of non-antibiotics evolved in this background. From the antimalarial and antitrypanosomial dye methylene blue, chemically similar compounds, the phenothiazines, were developed. The phenothiazines were first recognised for their antipsychotic properties, but soon after their antimicrobial functions came to be known and then such compounds were designated as non-antibiotics. The emergence of highly drug-resistant bacteria had initiated an urgent need to search for novel affordable compounds. Several phenothiazines awakened the interest among scientists to determine their antimycobacterial activity. Chlorpromazine, trifluoperazine, methdilazine and thioridazine were found to have distinct antitubercular action. Thioridazine took the lead as researchers repeatedly claimed its potentiality. Although thioridazine is known for its central nervous system and cardiotoxic side-effects, extensive and repeated in vitro and in vivo studies by several research groups revealed that a very small dose of thioridazine is required to kill tubercle bacilli inside macrophages in the lungs, where the bacteria try to remain and multiply silently. Such a small dose is devoid of its adverse side-effects. Recent studies have shown that the (–) thioridazine is a more active antimicrobial agent and devoid of the toxic side effects normally encountered. This review describes the possibilities of bringing down thioridazine and its (–) form to be combined with other antitubercular drugs to treat infections by drug-resistant strains of Mycobacterium tuberculosis and try to eradicate this deadly disease. [Int Microbiol 2015; 18(1):1-12]Keywords: Mycobacterium tuberculosis · phenotiazines · thioridazine · tuberculosi

Phenothiazines as a solution for multidrug resistant tuberculosis:From the origin to present

Historically, multiplicity of actions in synthetic compounds is a rule rather than exception. The science of non-antibiotics evolved in this background. From the antimalarial and antitrypanosomial dye methylene blue, chemically similar compounds, the phenothiazines, were developed. The phenothiazines were first recognised for their antipsychotic properties, but soon after their antimicrobial functions came to be known and then such compounds were designated as non-antibiotics. The emergence of highly drug-resistant bacteria had initiated an urgent need to search for novel affordable compounds. Several phenothiazines awakened the interest among scientists to determine their antimycobacterial activity. Chlorpromazine, trifluoperazine, methdilazine and thioridazine were found to have distinct antitubercular action. Thioridazine took the lead as researchers repeatedly claimed its potentiality. Although thioridazine is known for its central nervous system and cardiotoxic side-effects, extensive and repeated in vitro and in vivo studies by several research groups revealed that a very small dose of thioridazine is required to kill tubercle bacilli inside macrophages in the lungs, where the bacteria try to remain and multiply silently. Such a small dose is devoid of its adverse side-effects. Recent studies have shown that the (–) thioridazine is a more active antimicrobial agent and devoid of the toxic side effects normally encountered. This review describes the possibilities of bringing down thioridazine and its (–) form to be combined with other antitubercular drugs to treat infections by drug-resistant strains of Mycobacterium tuberculosis and try to eradicate this deadly disease. [Int Microbiol 2015; 18(1):1-12]Keywords: Mycobacterium tuberculosis · phenotiazines · thioridazine · tuberculosi

Anspruch und Wirklichkeit: Kann das Pariser Klimaabkommen funktionieren?

Ist das Klimaabkommen, das auf der Weltklimakonferenz in Paris im Dezember 2015 beschlossen wurde, ein wichtiger Schritt für den weltweiten Klimaschutz? Joachim Weimann, Universität Magdeburg, sieht zwar in der Tatsache, dass es überhaupt ein Abkommen gibt und dass sich Länder verpflichten, Klimaschutz zu betreiben, einen gewissen Fortschritt. Ein erfolgreicher Klimaschutz kann aber seiner Ansicht nach nur gelingen, wenn eine internationale Klimapolitik betrieben wird. In Paris wurde das genaue Gegenteil festgeschrieben, nämlich eine nationale Politik, bei der jedes einzelne Land seine eigenen Reduktionsziele definiere und selbstständig umsetze. Für Rüdiger Pethig, Universität Siegen, stellt das Pariser Abkommen trotz vielen Schwachstellen einen Meilenstein gegenüber dem davor Erreichten dar. Es sei zwar keineswegs die Lösung des Klimaproblems, aber habe die Hoffnung auf eine zukünftige Lösung ein wenig erhöht. Barbara Hendricks, Bundesministerin für Umwelt, Naturschutz, Bau und Reaktorsicherheit, sieht in dem Paris-Abkommen die Chance, den Klimawandel in den Griff zu bekommen, denn mit dem Pariser Abkommen sei das Fundament für erfolgreichen internationalen Klimaschutz gelegt worden. Zentraler Bezugspunkt für die nationalen Planungen bleibe die europäische Klimaschutzpolitik. Für Ottmar Edenhofer, Potsdam-Institut für Klimafolgenforschung, Christian Flachsland und Ulrike Kornek, MCC, Berlin, ist das Abkommen noch kein klimapolitischer Durchbruch. Jetzt komme es darauf an, die Diskussion über koordinierte CO2-Mindestpreise und konditionale Klimafinanzierung so voranzutreiben, dass die Chancen internationaler Kooperation steigen. Zentral ist für Thomas Puls und Thilo Schae­fer, Institut der deutschen Wirtschaft Köln e.V., dass die großen CO2-Emittenten eine koordinierte Klimapolitik verfolgen und dass sich die Verweigerung von Klimaschutz nicht mehr ökonomisch rechnet. Das gehe am besten, wenn »die Schwergewichte« ein Preissystem für CO2 vereinbarten. Sven Schulze,

Jointly mapping hydraulic conductivity and porosity by assimilating concentration data via ensemble Kalman filter

[EN] Real-time data from on-line sensors offer the possibility to update environmental simulation models in real-time. Information from on-line sensors concerning contaminant concentrations in groundwater allow for the real-time characterization and control of a contaminant plume. In this paper it is proposed to use the CPU-efficient Ensemble Kalman Filter (EnKF) method, a data assimilation algorithm, for jointly updating the flow and transport parameters (hydraulic conductivity and porosity) and state variables (piezometric head and concentration) of a groundwater flow and contaminant transport problem. A synthetic experiment is used to demonstrate the capability of the EnKF to estimate hydraulic conductivity and porosity by assimilating dynamic head and multiple concentration data in a transient flow and transport model. In this work the worth of hydraulic conductivity, porosity, piezometric head, and concentration data is analyzed in the context of aquifer characterization and prediction uncertainty reduction. The results indicate that the characterization of the hydraulic conductivity and porosity fields is continuously improved as more data are assimilated. Also, groundwater flow and mass transport predictions are improved as more and different types of data are assimilated. The beneficial impact of accounting for multiple concentration data is patent. © 2012 Elsevier B.V.The authors gratefully acknowledge the financial support by ENRESA (Project 0079000029) and the Spanish Ministry of Science and Innovation (Project CGL2011-23295). Extra travel Grants awarded to the first and second author by the Ministry of Education (Spain) are also acknowledged. Dr. Jichun Wu and an anonymous reviewer are grateful acknowledged for their comments which helped improving the final version of the manuscript.Li, L.; Zhou, H.; Gómez-Hernández, JJ.; Hendricks-Franssen, HJ. (2012). Jointly mapping hydraulic conductivity and porosity by assimilating concentration data via ensemble Kalman filter. Journal of Hydrology. 428:152-169. https://doi.org/10.1016/j.jhydrol.2012.01.037S15216942