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Water regime requirements and possible climate change effects on Fynbos Biome RestionaceaeAyuk, James January 2018 (has links)
Philosophiae Doctor - PhD / The Cape Floristic Region (CFR) of southern Africa is one of the world’s most unique
biodiversity hotspots. However, this biodiversity continues to be threatened by habitat loss
due to rapid urbanisation, agriculture and alien vegetation encroachment, and now, by future
groundwater extraction and climate change. Previous work had shown that soil moisture is
important in structuring wetland plant communities at fine-scale. What is not fully known,
however, is how the spatial distribution of species at a local scale is related to soil hydrology
and what the response in the future of species distributions will be to perturbations arising
from changes in climate or subsurface moisture in the future. The current research
investigated the water regime of the Restionaceae which is a key family in the Fynbos biome
and the implications of possible changes in soil hydrology caused by climate change in
communities within this region. The Restionaceae were particularly appropriate because
they are shallow rooted perennials with the ability to tolerate a wide range of water regimes
which allows them to successfully co-habit within mixed plant communities as segregated
clusters along fine-scale hydrologic gradients. Vegetation survey counts for the presence of
these species along with measurements of soil water table depth and moisture content data
generated from eight small-scale plots (50 x 50 m) were used to investigate the possible
hydrological niches and to envision the potential impacts of a substantial reduction in rainfall
and an increase in temperature as projected by Global Climate Models (GCMs) on the
structure of Restionaceae communities in seasonal wetlands by 2100. A comparative
analysis of the effects of two extreme Representative Concentration emission Pathways
(RCP2.6 and RCP8.5) on significant hydrological variables to plant water regimes was
carried out. The IPCC AR5 report describes the RCP8.5 emissions scenario as the likely
‘business as usual’ scenario where emissions continue to rise through the 21st century while
the RCP2.6 scenario assumes that emissions peak between 2010 and 2020 and
substantially subside thereafter.
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Assessing the values and impacts of invasive alien plants on the livelihoods of rural land-users on the Agulhas Plain, South AfricaDe la Fontaine, Samantha 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Invasive alien plants (IAPs) are known for their detrimental impacts on biodiversity and ecosystem goods and services. A substantial body of research has contributed to our understanding of their impacts on ecology. In comparison the socio-economic aspects of IAPs, are not well understood. Additionally, valuation practises have usually excluded the positive and the non-monetary impacts (benefits and uses) that IAPs hold for local livelihoods. Holistic valuation has been regarded as imperative for decision-making and managerial frameworks.
A study was conducted in Elim on the southern Cape coast of the Agulhas Plain, South Africa, which aimed to explore the various impacts of IAPs on the livelihoods of rural land-users. Individual qualitative interviews were conducted face to face with landholders (referred to as farmers) (N = 12) and individuals from the economically marginalized community (referred to as marginalized community) (N = 12). The grounded theory approach to data analysis was used and results of the coding method used were displayed by means of superscripts.
Results indicate that farmers were aware of broader uses of IAPs although they themselves did not utilise them as extensively as members of the marginalized communities. Invasive alien and problem plants that held value for both land-users were not perceived as being „invasive‟. Invasive alien plants were believed to have detrimental impacts on biodiversity and ecosystems goods and services which support people‟s livelihoods.
Alien clearing programmes such as Working for Water (WfW) and LandCare have done much to alleviate the socio-economic burden of unemployment in this marginalized community. Aside from the social development aims set out by WfW (i.e. employment of low-income communities, poverty alleviation and skills training), knock-on social development benefits (e.g. feelings of pride, responsibility and awareness as well as conflict management skills) were also realised by individuals from the marginalized community that were previously employed by the programme.
Farmers regarded alien clearing and management as a process that demands excessive time, energy and financial resources. On single occasions it was found that farmers employed methods other than the conventional clearing and management strategies (e.g. livestock that feed on IAPs and giving refuse IAP biomass from clearing and felling to neighbouring poor communities). No clear consensus was reached about regarding alien clearing and management but more support is desired from government. Working for Water relies on private landholders for alien clearing as it is required by law.
This study emphasizes that stronger relationships between government and private landholders as well as more substantial incentives to clear IAPs on private land are prerequisites if required outcomes are to be achieved. Educating society at large about the detrimental impacts of IAPs is fundamental. Additionally, informing landholders on effective alien clearing methods and policies and legislation pertaining to it are key activities for the South African government. Finally, clearing and management programmes need to consider the benefits that local land-users obtain from IAPs when prioritising areas for the management of alien vegetation. / AFRIKAANSE OPSOMMING: Uitheemse indringerplante (UIPe) is bekend vir die nadelige gevolge wat hulle vir biodiversiteit en ekosisteem goedere en dienste inhou. ʼn Aansienlike liggaam van navorsing het bygedra tot ons begrip van die impak daarvan op ekologie. In teendeel, die sosio-ekonomiese aspekte van UIPe word egter nie goed verstaan nie. Daarbenewens, evalueringspraktyke het gewoonlik die positiewe en nie-monetêre impakte (voordele en gebruike) wat UIPe vir plaaslike lewensbestaan hou, uitgesluit. Holistiese evaluering word as noodsaaklik beskou vir besluitneming en bestuursraamwerke.
ʼn Studie was uitgevoer in Elim op die Suid-Kaapse kus van die Agulhas-vlakte, Suid-Afrika. Die doel was om die verskillende aspekte van UIP impakte op die lewensbestaan van landelike grondgebruikers aan te spreek. Individuele kwalitatiewe onderhoude is van aangesig tot aangesig gevoer met grondeienaars (na wie verwys word as boere) (N = 12) en individue van die ekonomies gemarginaliseerde gemeenskap (na wie verwys word as gemarginaliseerde gemeenskap) (N = 12). Die gegronde teorie metode tot data analise was gebruik en die resultate van die kodering metode is vertoon deur middel van boskrifte.
Resultate dui daarop dat boere bewus was van ʼn wyer reeks van gebruike van UIPe alhoewel hulle dit nie so ekstensief benut het soos die lede van die gemarginaliseerde gemeenskappe nie. Uitheemse en probleem plante wat waarde gehou het vir beide landgebruikers,was nie soseer beskou as „indringers‟ nie. Daar was geglo dat UIPe nadelige impakte het op biodiversiteit en ekosisteme goedere en dienste wat mense se lewensbestaan ondersteun.
Programme soos Werk vir Water (WvW) en LandCare wat fokus op die uitroeiing van UIPe, het baie gedoen om die sosio-ekonomiese laste as ʼn gevolg van werkloosheid in hierdie gemarginaliseerde gemeenskap te verlig. Benewens die sosiale ontwikkelings doelwitte uiteengesit deur WvW (o.a. indiensneming van lae-inkomste gemeenskappe, armoedeverligting en vaardigheidsopleiding), is daar ook domino-voordele (bv. gevoelens van trots, verantwoordelikheid en bewustheid sowel as konflik bestuursvaardighede) aangaande sosiale ontwikkeling ervaar deur individue van die gemarginaliseerde gemeenskap wat voorheen in diens van die program was. Boere beskou die uitroeiing en bestuur van UIPe as ʼn proses wat oormatige tyd, energie en finansiële hulpbronne vereis. Op enkele geleenthede was dit gevind dat boere gebruik maak van metodes anders as die konvensionele skoonmaak-en bestuurs strategieë (bv. vee wat voed op UIPe en biomassa wat na afloop van skoonmaak aan die naburige arm gemeenskappe gegee word). Geen duidelike konsensus is bereik met betrekking tot die uitroeiing en bestuur van UIP nie, maar meer ondersteuning van die regering word verlang. Werk vir Water maak staat op private grondeienaars vir die uitroeiing van UIPe.
Hierdie studie beklemtoon dat sterker verhoudings tussen die regering en private grondeienaars sowel as meer aansienlike aansporings om UIPe op private grond skoon te maak ʼn voorvereiste is as verwagte uitkomste bereik wil word. Opvoeding van die breër gemeenskap oor die nadelige impakte van UIPe is fundamenteel. Om grondeienaars in te lig oor effektiewe UIP verwyderingsmetodes asook beleide en wetgewing met betrekking daartoe, is belangrikste aktiwiteite vir die Suid-Afrikaanse regering. Ten slotte, skoonmaak- en bestuursprogramme moet oorweging skenk aan die voordele wat plaaslike landgebruikers put uit UIPe wanneer daar geprioritiseer word vir gebiede vir die bestuur van indringerplante.
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Determining the hydrological benefits of clearing invasive alien vegetation on the Agulhas Plain, South AfricaNowell, Megan Sarah 03 1900 (has links)
Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Invasive alien plants (IAPs) reduce streamflow and threaten the biodiversity of South Africa’s Cape Floristic
Region. Up-to-date information on invasive vegetation is required for land management agencies to
formulate policies and make appropriate resource management decisions. Invasion maps are typically not
updated often enough because of the time and expenses required to do so. As a result, invasion maps for
South Africa are limited to coarse resolution data or isolated small scale studies. Invasive alien plants
change the landscape by destabilizing catchments and thereby increasing soil erosion, altering fire regimes
and hydrology, as well as changing the physical and chemical composition of the soil. Information on IAPs is
needed at a landscape scale. Remote sensing is a powerful tool that can be used to characterise landscapes
in a biologically meaningful manner. The Normalised Difference Vegetation Index (NDVI) was used to create
an up-to-date invasion map of the Agulhas Plain, lying at the heart of the species rich Cape Floristic Region.
This information was combined with actual evapotranspiration data from the Surface Energy Balance
Algorithm for Land (SEBAL) study done by Water Watch and the Council for Scientific and Industrial
Research. The results showed that invasive vegetation uses more water than natural fynbos vegetation and
that the greatest amount of water would be made available by clearing the invaded deep sands on the
Agulhas Plain. These deep sand areas conflict with the priority areas of the Working for Water programme.
This IAP eradication programme targets sparsely invaded upland areas for long-term sustainability. The
recommendation of this study is to clear invaded wetland and riparian areas as these zones yield the
greatest hydrological benefit per hectare and meet the priorities of Working for Water. Overall, 36 million
cubic meters of water would be made available by clearing the Agulhas Plain. It can be concluded that there
is a significant hydrological benefit to clearing invasive alien vegetation on the Agulhas Plain. / AFRIKAANSE OPSOMMING: Indringerplante (IP) verminder stroomvloei en bedreig die biodiversiteit van Suid-Afrika se Kaapse
Floristiese Streek. Die nuutste inligting oor uitheemse plantegroei is nodig vir
grondbestuuragentskappe om beleide te formuleer vir die neem van toepaslike hulpbronbestuur
besluite. As gevolg van die tyd en uitgawes wat nodig is om indringingskaarte op te dateer, word
dit gewoonlik nie dikwels genoeg gedoen nie. Dus is indringingskaarte vir Suid-Afrika beperk tot
growwe resolusie data of geïsoleerde kleinskaal studies. Indringerplante verander die landskap
deur opvangsgebiede te destabiliseer en sodoende te lei tot gronderosie, verandering van
vuurregimes en hidrologie, sowel as die verandering in die fisiese en chemiese samestelling van
die grond. Inligting oor IP is nodig op 'n landskapskaal. Afstandswaarneming is 'n kragtige tegniek
wat gebruik kan word om landskappe op 'n biologies betekenisvolle manier te karakteriseer. Die
Normalised Difference plantegroei-indeks (NDVI) is gebruik om 'n opgedateerde indringingskaart
van die Agulhas-vlakte, wat in die hart van die spesiesryke Kaapse Floristiese Streek lê, te skep.
Hierdie inligting is gekombineer met die werklike evapotranspirasie data vanaf die Surface Energy
Balance Algorithm for Land (SEBAL) studie gedoen deur Water Watch en die Raad vir
Wetenskaplike en Nywerheidnavorsing. Die resultate het getoon dat uitheemse plantegroei meer
water gebruik as natuurlike fynbosplantegroei en dat die grootste hoeveelheid van hierdie water
beskikbaar gestel sal word deur IP op diepsand op die Agulhas-vlakte skoonte maak. Hierdie
diepsand areas is in konflik met die prioriteitsgebiede van die Werk vir Water-program. Hierdie IP
uitroeiingsprogram fokus op yl ingedringde berggebiede vir langtermyn volhoubaarheid. Die
aanbeveling van hierdie studie is om duidelik ingedringde vleilande en oewergebiede skoon te
maak, siende dat hierdie sones die hoogste opbrengs en die grootste hidrologiese voordeel per
hektaar bied, en voldoen aan die prioriteite van Werk vir Water. In totaal sou 36 miljoen kubieke
meter water beskikbaar gestel word deur die skoonmaak van die Agulhas-vlakte. Dus kan dit
afgelei word dat die verwydering van hidrologiese indringerplante op die Agulhas-vlakte 'n
beduidende voordeel sal inhou.
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Effect of invasion and clearing of alien riparian vegetation on benthic macroinvertebrate and adult odonata assemblages in Soutpansberg riversMagoba, Rembuluwani Norman Nicholas 12 1900 (has links)
Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2005. / Benthic macroinvertebrates (sampled using South African Scoring System, SASS5) and adult male Odonata (sampled with close-focus binoculars) were recorded on two streams and a river of Soutpansberg, with the aim of determining the effect of invasion and removal of alien riparian vegetation on their assemblages. A secondary aim was to establish the importance of dragonflies as indicators of degree of disturbance in rivers. Forty two aquatic macroinvertebrate families and 33 adult Odonata species were recorded at a total of 71 sampling units. Three distinct riparian vegetation types were selected (natural, alien and cleared). Cleared vegetation refers to clearing of invasive alien trees, allowing regrowth of natural vegetation. Natural and cleared vegetation supported more benthic macroinvertebrate families compared to alien vegetation. Certain families that were lost to alien vegetation were recorded from natural vegetation. The highest SASS5 score was recorded from natural vegetation, followed by cleared vegetation, and the lowest was from alien vegetation. The highest number of adult Odonata was recorded at cleared vegetation, with alien and natural vegetation supporting the least number of Odonata species. Vegetation type, stream flow and microhabitats were statistically identified as the most influential variables for benthic macroinvertebrate assemblages. For adult Odonata assemblages, vegetation type, shade and temperature were the most important environmental variables. Species assemblages of adult Odonata can be used as indicators of environmental condition of rivers. The clearing of alien riparian vegetation clearly benefits the indigenous benthic macroinvertebrates as conditions are restored to their natural state. It also benefits dragonfly species richness, but if natural succession proceeds to a shaded tree canopy, the effect becomes similar to that of habitat shaded by alien vegetation. The impact of alien vegetation is to reduce sun-loving invertebrate species, especially dragonflies, with lesser impact on shade-loving species.
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