12 research outputs found

    Biodiversity value of grassland ecological networks in afforested areas, KwaZulu-Natal, South Africa

    Get PDF
    Thesis (MSc)--University of Stellenbosch, 2011.ENGLISH ABSTRACT: The current biodiversity crisis requires creative initiatives for mitigating further biodiversity loss. The use of ecological networks (ENs) is such an initiative. The South African forestry industry recognizes that there is loss of biodiversity at the smaller patch scale, while attempting to mitigate this loss at the landscape scale by implementing largescale ENs. The aim of this study was to determine how representative grassland biodiversity in ENs are of similar habitat in a nature reserves (NR). The study was conducted in the northeast of the KwaZulu-Natal Province, adjacent iSimangaliso Wetland Park, which is a natural World Heritage site. A systematic approach compared a wide range of taxa, namely plants, decomposition macrofungi, vertebrates (birds and large mammals) and faunal manifestations (e.g. molehills, dung and ant nests) between the EN and nature reserve, while controlling for differences in disturbance regime. Species richness was compared using Mann-Whitney U tests, while differences in species composition were determined using Correspondence Analyses, Multi-Dimensional Scaling and Analyses of Similarity. Grassland ENs had significantly less plant species. In addition, there were differences in plant and fungi species composition. Differences were probably caused by (1) degree of isolation i.e. proximity to source habitat patches in the surrounding matrix, and (2) habitat quality. Habitat quality was determined by local disturbance regimes (e.g. grazing and fire) and plantation-induced drought for plants, and size and amount of coarse woody debris for fungi. In addition, significant differences in abundances of mole hills (NR>EN) and small mammal burrows (EN>NR) might have had an effect on succession and regeneration of plant communities. There were differences in plant species composition between grassland EN and that at the adjacent nature reserve. However, differences between EN and NR were small when compared to differences between habitat types at the landscape spatial scale. It is concluded that grassland ENs among forestry plantations contribute to biodiversity conservation in the commercially-productive landscape. This approach to land use planning should be explored for other commercial land uses.AFRIKAANSE OPSOMMING: Die huidige biodiversiteitskrisis vereis kreatiewe strategieĂ« om ‘n verdere verlies in biodiversiteit te bekamp. Ekologiese Netwerke (EN’e) is een voorbeeld van sulke kreatiewe strategieĂ«. Die Suid Afrikaanse bosbou-industrie erken die verlies in biodiversiteit wat kenmerkend in plantasies gevind word. Implementering van grootskaalse EN’e kan egter die verlies aan biodiversiteit, wat in plantasies ondervind word, temper. Die doel van hierdie studie was om vas te stel hoe goed biodiversiteit in grasveld EN’e soortgelyke habitat in ‘n nabygeleĂ« natuurreservaat verteenwoordig. Die studie was uitgevoer in die noordooste van KwaZulu-Natal, langs iSimangaliso Wetland Park wat ‘n wĂȘrelderfenisgebied is. Ons het ‘n stelselmatige benadering gevolg waartydens ‘n wye verskeidenheid taksa, naamlik plante, makro-fungi, vertebrate (groot soogdiere en voĂ«ls) en tekens van diere-aktiwiteit (bv. miersneste, dieremis en molshope), in die EN vergelyk is met die van ‘n natuurreservaat terwyl ons vir verskillende versteuringe gekontrolleer het. Spesiesrykheid is vergelyk met Mann-Whitney U toetse terwyl verskille in spesiessamestelling vasgestel is met Correspondence Analyses, Multi-Dimensional Scaling en Analyses of Similarity. Daar was ‘n statisties beduidende verskil in die hoeveelheid spesies tussen grasveld EN’e en die natuurreservaat. Grasveld EN’e het minder plant spesies gehad. Boonop was daar verskille in die samestelling van plant en fungi gemeenskappe. Verskille was waarskynlik veroorsaak deur (1) isolasie of die hoeveelheid nabygeleĂ« habitatbronne in die omliggende omgewing, en (2) habitat kwaliteit. Habitat kwaliteit word bepaal deur versteuringe (bv. brand en beweiding) en die uitdrogingseffek van plantasies vir plante, en die hoeveelheid en grootte van growwe houtagtige puin vir fungi. Daar was ook beduidende verskille in die hoeveelheid molshope (NR>EN) en klein soogdier gate (EN>NR), wat moontlik ‘n effek kon hĂȘ op suksessie en herstel van plantgemeenskappe. Daar was verskille in plantspesiessamestelling tussen grasveld EN’e en die van die langsliggende natuurreservaat. Hierdie verskille was egter klein wanneer dit vergelyk word met die verskille tussen verskillende soorte habitatte in die landskap. Daarom kom ons tot die gevolgtrekking dat grasveld EN’e tussen bosbouplantasies bydra tot die bewaring van biodiversiteit in kommersiĂ«le landskappe. Hierdie benadering tot grondgebruik behoort verder verken te word vir ander kommersiĂ«le bosbou en boerderypraktyke

    Humans Share More Preferences for Floral Phenotypes With Pollinators Than With Pests.

    Get PDF
    Studies on the selection of floral traits usually consider pollinators and sometimes herbivores. However, humans also exert selection on floral traits of ornamental plants. We compared the preferences of bumblebees (Bombus terrestris), thrips (Frankliniella occidentalis), and humans for flowers of snapdragon. From a cross of two species, Antirrhinum majus and Antirrhinum linkianum, we selected four Recombinant Inbred Lines (RILs). We characterised scent emission from whole flowers and stamens, pollen content and viability, trichome density, floral shape, size and colour of floral parts. We tested the preferences of bumblebees, thrips, and humans for whole flowers, floral scent bouquets, stamen scent, and individual scent compounds. Humans and bumblebees showed preferences for parental species, whereas thrips preferred RILs. Colour and floral scent, in combination with other floral traits, seem relevant phenotypes for all organisms. Remarkably, visual traits override scent cues for bumblebees, although, scent is an important trait when bumblebees cannot see the flowers, and methyl benzoate was identified as a key attractant for them. The evolutionary trajectory of flowers is the result of multiple floral traits interacting with different organisms with different habits and modes of interaction

    The diversity and evolution of pollination systems in large plant clades: Apocynaceae as a case study

    Get PDF
    Background and Aims Large clades of angiosperms are often characterized by diverse interactions with pollinators, but how these pollination systems are structured phylogenetically and biogeographically is still uncertain for most families. Apocynaceae is a clade of >5300 species with a worldwide distribution. A database representing >10 % of species in the family was used to explore the diversity of pollinators and evolutionary shifts in pollination systems across major clades and regions. Methods The database was compiled from published and unpublished reports. Plants were categorized into broad pollination systems and then subdivided to include bimodal systems. These were mapped against the five major divisions of the family, and against the smaller clades. Finally, pollination systems were mapped onto a phylogenetic reconstruction that included those species for which sequence data are available, and transition rates between pollination systems were calculated. Key Results Most Apocynaceae are insect pollinated with few records of bird pollination. Almost three-quarters of species are pollinated by a single higher taxon (e.g. flies or moths); 7 % have bimodal pollination systems, whilst the remaining approx. 20 % are insect generalists. The less phenotypically specialized flowers of the Rauvolfioids are pollinated by a more restricted set of pollinators than are more complex flowers within the Apocynoids + Periplocoideae + Secamonoideae + Asclepiadoideae (APSA) clade. Certain combinations of bimodal pollination systems are more common than others. Some pollination systems are missing from particular regions, whilst others are over-represented. Conclusions Within Apocynaceae, interactions with pollinators are highly structured both phylogenetically and biogeographically. Variation in transition rates between pollination systems suggest constraints on their evolution, whereas regional differences point to environmental effects such as filtering of certain pollinators from habitats. This is the most extensive analysis of its type so far attempted and gives important insights into the diversity and evolution of pollination systems in large clades

    Disturbance factors related to conservation of biodiversity in large-scale ecological networks

    Get PDF
    Thesis (PhD)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Globally, habitat transformation causes biodiversity loss, with the transformed matrix often affecting the disturbance regime in remnant natural patches. In South Africa, significant parts of the Indian Ocean coastal belt and grassland biomes have been transformed into commercial forestry plantations of alien trees, which are detrimental to local biodiversity. Consequently, large scale ecological networks (ENs) of remnant natural vegetation, maintained areas (e.g. firebreaks) and special landscape features (e.g. rocky outcrops and wetlands) have been implemented among forestry compartments to offset the negative effect of this land use on biodiversity. Different grassland areas, which constitute a major portion of ENs, were managed in different ways, as governed by their primary purpose (e.g. fire protection or conservation). The overall aim of this study was to determine how grassland floral and grasshopper herbivore communities responded to different disturbances (mowing, burning and grazing), and how we can adjust management of the major disturbances to effectively conserve these major components of biodiversity in ENs. Sampling was carried out in the commercial forestry ENs in the lower-elevation Zululand area and adjacent reserve area iSimangaliso Wetland Park, as well as in the forestry ENs in the higher-lying Midlands and adjacent iMpendle Nature Reserve. Both the reserves or protected areas (PAs) acted as reference sites, while other sites were chosen to represent the predominant disturbances in ENs at each locality: mowing, annual vs. longer-rotation burning, time since last fire, and domestic cattle grazing. In the Zululand subtropical grassland (chapter 2), I explored the effect of frequent mowing on firebreaks, and the effect of patch size and isolation on plant communities in non-firebreak natural areas of the EN. Frequent mowing resulted in plant species loss and a shift in species composition of firebreaks. Furthermore, small, isolated patches in the EN far away from the PA border had lower plant species richness and greater species turnover than wide, interconnected corridors near the PA border, which, in turn, was similar to reference sites in the PA. As plant species were lost from frequently-mown firebreaks and small, isolated patches in the EN, I recommend that this management practice should be confined to demarcated areas (e.g. forestry compartment edges and firebreaks) and that creation of wide, interconnected corridors should be prioritized when designing ENs. In higher elevation Afromontane grassland (chapter 3), I investigated the effect of annual burning on plant communities in firebreaks by comparing them to less frequently burned grassland in the EN and PA, respectively. Grazing by domestic cattle was taken as an embedded factor for firebreak and less frequently burned sites in the EN. There were three firebreak types: annually-burned with heavy cattle grazing (plantation firebreaks), annually-burned with light cattle grazing (peripheral firebreaks), and annual burning without cattle grazing (PA firebreaks). Burned reference grassland in the EN and PA hosted plant communities that were similar in species richness, composition and turnover. This was also the case for lightly-grazed peripheral EN firebreaks and PA firebreaks. However, species composition and turnover of plantation EN firebreaks with heavy cattle grazing differed from that in the other two firebreak types. Although not significant (P12 months prior to sampling), ungrazed grassland in the PA. Burning and grazing both caused a change in plant species composition that went hand in hand with an increase in plant species richness and turnover. However, burning (burned vs. unburned) only affected plant communities in ungrazed grassland in the PA. Similarly, the presence of large mammalian grazers (EN vs. PA) only affected plant communities in unburned grassland. Unburned plant communities grazed by domestic cattle in the EN were similar to those in the PA grazed by indigenous black wildebeest, indicating that cattle grazing simulates, at least to some degree, the effect of indigenous ungulate grazing. Nevertheless, heavily-grazed grassland had less plant species than moderately-grazed grassland in the EN. I recommend that burning and grazing should continue in grassland ENs, as these natural disturbances are necessary to maintain diverse and dynamic ecosystems. Nevertheless, managers should instigate cattle grazing with caution, as high intensity grazing can be detrimental to conservation efforts. In Chapter 5, I examined the effect of annual burning, cattle grazing (presence vs. absence) and time since last fire on grasshopper assemblages in Afromontane grassland. In general, grasshoppers benefitted from disturbance, and were remarkably resilient to different disturbance regimes. Grasshopper species richness and their abundance were both greatest in annually-burned firebreaks with light cattle grazing, and lowest in moribund grassland in the PA which had not been burned for several years. Yet, time since last fire only affected grasshopper communities in the absence of large grazers (in the PA). None of the individual disturbances had an effect on the grasshopper assemblage. Rather, these insects responded to the combined effect of annual burning with cattle grazing. Sites were similar in grasshopper species richness, composition and abundance whenever either annual burning or cattle were absent, which suggests that these two disturbances drive changes in the grasshopper assemblage in these grasslands. Although grasshoppers benefited from annual burning with light cattle grazing, I would not recommend this disturbance regime outside firebreaks. Rather, management of other grassland areas in the EN should adapt longer fire-return intervals with a rotational cattle grazing system, so that undisturbed habitat is provided for other sensitive taxa. In conclusion, grassland plants and grasshoppers benefited from some form of disturbance, but were lost from small, isolated patches in the EN, as well as from areas with high disturbance frequency and intensity. Simulation of natural disturbances (moderate levels of fire and grazing) in wide, interconnected corridors is necessary for maintaining diverse and dynamic grassland ecosystem in ENs among commercial forestry plantations.AFRIKAANSE OPSOMMING: Omskepping van natuurlike habitat na lande of plantasies veroorsaak biodiversiteitsverlies wĂȘreldwyd. Boonop het sulke veranderinge dikwels 'n effek op die versteurings binne-in oorblywende kolle natuurlike plantegroei wat verreikende gevolge kan hĂȘ. Groot gedeeltes van die Suid-Afrikaanse grasveldbioom is omskep in bosbou plantasies wat bestaan uit uitheemse bome wat 'n baie groot nadelige effek op plaaslike biodiversiteit het. Daarom is grootskaalse ekologiese netwerke (EN’e), wat bestaan uit oorblywende kolle natuurlike plantegroei, brandbane en spesiale habitattipes in die landskap (bv. rotsriwwe en vleilande), tussen bosbouplantasies geĂŻmplimenteer met die doel om die negatiewe effek van plantasies op plaaslike biodiversiteit te verlig. Bestuur van grasvelde, wat 'n groot gedeel van EN’e uitmaak, wissel dikwels en hang af van hulle primĂȘre doel (bv. beskerming van plantasies teen wegholveldbrande of natuurbewaring). Die doel van hierdie projek was om vas te stel hoe plant- en springkaangemeenskappe in grasvelde reageer op verskillende versteurings (grassny, brand en beweiding), en die optimale bestuur van die versteurings om die biodiversiteit in grasvelde beter te bewaar. Steekproewe is geneem in EN’e tussen bosbouplantasies in die laagliggende Zululand en langsliggende wĂȘrelderfenisgebied, iSimangaliso Wetland Park, asook in die hoĂ«rliggende Midlands en langsliggende iMpendle Natuurreservaat (NR). NR’e het as verwysing gedien waarteen die effek van grassny, frekwensie van brande, tydsverloop vanaf die laaste brand, en beweiding deur beeste, wat tipiese versteuringe in EN’e is, gemeet is. In hoofstuk 2 het ek vasgestel wat die effek van grassnyfrekwensie op plantgemeenskappe in brandbane is, en hoe plantgemeenskappe in subtropiese grasveld in die res van die EN reageer op die grootte en strukturele isolasie van oorblywende kolle natuurlike plantegroei. 'n HoĂ« grassnyfrekwensie het 'n verandering in die spesiesamestelling van plantgemeenskappe in brandbane veroorsaak wat gepaard gegaan het met spesiesverlies. Terselfdertyd was daar minder plant spesies in klein, geĂŻsoleerde kolle natuurlike plantegroei as wat daar in wyer, aaneenskakelende gange nader aan die natuurreservaatgrens was. Laasgenoemde het plantgemeenskappe bevat wat baie soortgelyk aan die in die natuurreservaat was. Daarom stel ek voor dat die skep van wye, aaneengeskakelde natuurlike habitat prioriteit moet geniet wanneer nuwe EN’e ontwerp word, en dat gras slegs gereeld gesny moet word in spesifieke, afgebakende areas (bv. brandbane). Die rede hiervoor is dat hierdie bestuurspraktyk nie bevorderlik was vir die bewaring van plantdiversiteit in EN’e nie. In hoofstuk 3 het ek gekyk hoe die plantgemeenskappe in brandbane daarop reageer om elke jaar gebrand te word deur hulle te vergelyk met Afrikaberg grasveld in die EN en NR wat minder gereeld gebrand word. Beweiding deur beeste is gesien as 'n integrale deel van die EN. Ek het onderskei tussen plantasiebrandbane met swaar beweiding, randbrandbane met ligte beweiding en brandbane in die NR sonder beweiding. Die plantspesiesamestelling van brandbane, met ligte of geen beweiding nie, het verskil van grasvelde wat minder gereeld gebrand word. Tog is die hoeveelheid plantspesies nie geraak nie. Alhoewel die plantgemeenskappe in ligbeweide brandbane soos die in onbeweide brandbane in die NR was, het die plantspesiesamestelling van beide verskille getoon wanneer hulle vergelyk is met plantasiebrandbane wat swaarder deur beeste bewei is. Plantspesierykheid in plantasiebrandbane was boonop heelwat laer as wat in NR grasvelde gevind is, en daar was heelwat meer kaal grond in plantasiebrandbane as in enige van die ander areas. Oor die algemeen het plantspesiesrykheid van brandbane nie daaronder gely om elke jaar gebrand te word nie, maar kwesbare plantgemeenskappe in brandbane het wel daaronder gely om swaar bewei te word. Daarom stel ek voor dat jaarlikse brande tot brandbane beperk word en dat beeste se toegang tot brandbane streng beheer word. In die hoofstuk 4 ondersoek ek die effek van beweiding deur beeste (teenwoordigheid teenoor afwesigheid, sowel as beweidingsintensiteit) op die plantspesiesrykheid en samestelling van gebrande en ongebrande Afrikaberg grasvelde wat minder gereeld gebrand word. Die minste plant spesies is aangeteken in ongebrande, onbeweide grasveld in die NR. Brande en beweiding het albei 'n effek op plantspesiesamestelling gehad wat gepaard gegaan het met 'n toename in plantspesiesrykheid. Plantgemeenskappe in grasvelde wat onlangs (<12 maande voor die steekproef geneem is) gebrand is, het slegs van die in ongebrande grasvelde verskil wanneer nie een van die twee areas bewei is nie. Op 'n soortgelyke trant het die teenwoordigheid van beeste (EN teenoor NR) slegs n effek gehad in ongebrande grasvelde. Ongebrande plantgemeenskappe in die EN wat deur beeste bewei is, was baie soos die in die NR wat deur swartwildebeeste bewei is. Dit dui daarop dat beeste die effek van inheemse wildsoorte tot 'n mate naboots. Des nieteenstaande die bogenoemde, het swaar-beweide grasvelde minder plantspesies gehad as grasvelde wat slegs matig bewei is. Ek stel voor dat brande en beweiding deel moet vorm van die bestuur van grasvelde in EN’e, want hierdie natuurlike versteuringe dra by tot 'n diverse, dinamiese grasveldekosisteem. Tog moet bestuurders versigtig wees wanneer hulle die plaaslike gemeenskap se beeste in EN’e toelaat, want swaar beweiding kan bewaringsinisiatiewe in die wiele ry. In hoofstuk 5 het ek die klem na springkane verskuif, en die effek van jaarlikse brande, beweiding deur beeste (teenwoordigheid teenoor afwesigheid) en tydsverloop sedert laaste brand op hierdie sensitiewe insekte in Afrikaberg grasvelde ondersoek. Alhoewel springkaangemeenskappe baat gevind het by versteuringe, het hulle nie beduidend gereageer op enige van die indiwiduele versteuringe nie. Die digste sprinkaan bevolking met die hoogste spesies diversiteit is aangeteken in brandbane in die EN wat liggies deur beeste bewei is. Darenteen is die laagste bevolking en spesies diversiteit aangeteken in grasvelde in die NR wat groot hoeveelhede dooie plantmateriaal bevat wat aandui dat hierdie grasvelde nie onlangs gebrand het nie. Springkaangemeenskappe in gebrande grasvelde het slegs van ongebrande grasvelde verskil wanneer nie een van die twee bewei is nie. Die sleutelkombinasie van versteuringe wat die rykheid en samestelling van springkaangemeenskape bepaal het, was 'n hoĂ« brandfrekwensie (soos in brandbane) en beweiding deur beeste. Wanneer een van hierdie versteuringe afwesig was, was springkaangemeenskappe tussen verskillende areas dieselfde. Alhoewel springkaangemeenskappe daarby baat gevind het wanneer brandbane elke jaar gebrand en deur beeste bewei is, kan ek nie hierdie bestuurspraktyk vir die res van die EN aanbeveel nie. Grasvelde in die res van die EN behoort eerder minder gereeld (elke 2-4 jaar) gebrand en met 'n rotasiestelsel bewei word. Sodoende sal brandbane voorsien in die behoeftes van springkane, en die res van die EN in die behoeftes van sensitiewe taksa wat onversteurde habitat benodig om te floreer. My slotsom is dat versteuringe nodig is om die volle diversiteit van plante en springkane en die dinamika binne-in grasvelde te bewaar. Tog verdwyn daar plantspesies uit areas met 'n hoĂ« versteuringsintensiteit of frekwensie en klein, geĂŻsoleerde kolle natuurlike plantegroei in die EN. Daarom beveel ek aan dat natuurlike versteuringe (brande en beweiding) matig toegepas moet word in wye, aaneengeskakelde gange in die EN. Hierdie benadering tot natuurbewaring kan biodiversiteit tussen bosbouplantasies beveilig teen verdere verlies

    A Journey into the Life of a Mission-Ethnographer

    No full text
    <p>The film attempts to give the viewer a better understanding of the man behind these textual sources described in <em>Ethnography from the Mission Field, The Hoffmann Collection of Cultural Knowledge</em>, 978 90 04 29763 0, Brill 2015: Missionary Carl Hoffmann. This film traces a timeline through his life. He is placed in the centre of the narrative by reviewing different facets of his life and experiences in order to link them with the texts and the visuals he produced. The dialectics between a Lutheran missionary and an ‘incidental’ ethnographer constitute the central motif in the quest to understand the discursive context in which the texts annotated in this book had been compiled and particularly the man that was instrumental in the making of this collection of cultural knowledge. The film envisages to put the readers/viewers in a position where they can ‘imagine’ missionary Hoffmann’s life – a human story embedded in a South African interior where different cultural and political systems prevailed – “a story of changing interests and shifting alliances”.</p

    LIP Woordfeeskoerant 2010

    No full text
    The LIP Woordfeeskoerant is an independent Woordfees festival newspaper produced by the BPhil (Journalism) class of that specific year in the Department of Journalism, Stellenbosch University.The LIP Woordfeeskoerant is an independent Woordfees festival newspaper produced by the BPhil (Journalism) class of that specific year in the Department of Journalism, Stellenbosch University
    corecore