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The effects of goat browsing on ecosystem patterns and processes in succulent thicket, South AfricaLechmere-Oertel, Richard Geoffrey January 2003 (has links)
Transformation in the arid succulent thicket of the Eastern Cape of South Africa in response to unsustainable livestock production has been widespread, with less than 10 percent remaining intact. Transformation in succulent thicket has resulted in large areas of dense thicket (comprising a two-phase mosaic of perennial-vegetated patches separated by animal paths and bare patches) being replaced with a ‘pseudo-savanna’ of remnant canopy trees with a structurally simple field layer of ephemeral and short- lived perennial grasses and forbs. There is an extensive literature describing the transformation of succulent thicket, with many speculative statements about the underlying mechanisms of transformation. The central focus of this study was to improve our mechanistic understanding of transformation in succulent thicket using field experiments. Hopefully these results will set another foundation upon which future management of succulent thicket can be improved and large-scale restoration initiated. This study comprises four themes that are linked to the concept of landscape function. The central premise of landscape function is that functional landscapes have mechanisms that capture and retain scarce resources. Conversely, as landscapes become increasingly dysfunctional, so these mechanisms become disrupted. In succulent thicket, dysfunctio n appears to be linked to the reduced ability to harvest water, cycle carbon and a loss of organic carbon. In this thesis I examined some of the key processes that influence water and organic carbon fluxes: perennial vegetation cover, soil fertility, litter fall and decomposition, and runoff and soil erosion. The experimental design that was used for all this work was a factorial ANOVA based on replicated fenceline contrasts that reflect differences in long-term management history. The main objectives of this thesis were to: quantify the patterns of transformation in an arid form of succulent thicket, including changes in the biomass, cover and structure of the dominant vegetation guilds; test the stability of the transformed succulent thicket ecosystem to show whether it is a new stable state or an intermediate stage in a trajectory towards a highly desertified state where only the ephemeral grasses and forbs persist; describe and compare soil fertility across transformation contrasts, concentrating on changes in the spatial patterns of soil resources and the ability of the soil to harvest precipitation; to compare litter fall and decomposition of leaf material from the dominant plants in intact and transformed succulent thicket; to quantify and compare run-off and erosion from run-off plots in intact and transformed succulent thicket. Transformation and stability I quantified the changes in plant diversity, physiognomy and biomass that occur across transformation contrasts. Thicket transformation results in a significant loss of plant diversity and functional types. There is also a significant reduction in the biomass (c. 80 t.ha-1) and structural complexity of the vegetation, both vertically and horizontally. These results were interpreted in terms of their implications for ecosystem functioning and stability. To test the stability of the transformed succulent thicket I used aerial photographs and ground-truthing to track the survivorship of canopy trees over 60 years in pseudo-savanna landscapes. I also measured seedling establishment in different habitats. I show that the pseudo-savanna is not a stable state owing to ongoing adult mortality and no recruitment of canopy trees. Soil fertility and water status I hypothesised that the above-ground changes in ve getation would be accompanied by similar trends in the pattern and levels of soil nutrient resources and the ability of the landscape to harvest precipitation. I compared soil fertility (organic carbon, available nitrogen and phosphorus), texture, matric potential, and surface micro-topography in the two main micro- habitats on either side of the replicated fenceline contrasts. The results show that intact spekboom thicket has a distinct spatial pattern of soil fertility where nutrients and organic carbon are concentrated under the patches of perennial shrubs, compared to under canopy trees and open spaces. Transformation results in a significant homogenisation out of this pattern and an overall reduction in the fertility of the landscape. The proportion of the landscape surface that would promote infiltration of water decreases from 60 – 0.6 percent. Soil moisture retention (matric potential) also decreases with transformation. I interpreted these patterns in terms of the ability of the landscape to harvest and release water after rainfall events. Litter fall and decomposition Surface litter and soil organic matter are critical components to wooded ecosystems; contributing to several ecosystem functions. The rates of litter fall and decomposition are ratelimiting steps in nutrient cycling and incorporation of organic matter into the soil. The ecological mechanisms behind the collapse of succulent thicket in the face of domestic herbivory are not fully understood, but are believed to include the breakdown of several ecosystem processes, including litter fall and decomposition. I quantified the changes in litter fall and litter decomposition of four of the dominant perennial woody plants (Euclea undulata, Pappea capensis, Portulacaria afra and Rhus longispina) across the replicated fenceline. Litter fall was measured over 14 months using mesh traps. Decomposition was measured over 15 months using a combination of litterbags and unprotected leaf packs. I also quantified soil microclimate during the experimental period; hypothesising that transformation would lead to soil conditions less amenable for biotic activity. Litter fall in succulent thicket was very high for a semi-arid system, comparing more to temperate forests. The leaf-succulent P. afra contributed the largest single component of the total litter production at a landscape scale. The effect of transformation on litter fall was species specific. Deep-rooted or drought-adapted species showed no change in litter yield with transformation; shallow-rooted species showed a significant decrease. There were few significant differences in decomposition rates across the transformation gradient and between litter types. Portulacaria afra litter had the steepest rate of mass loss, and was most affected by transformation. The more recalcitrant (high C:N ratio) leaves of P. capensis remained largely unaffected by transformation. These results indicate the critical role of the perennial vegetation in incorporating organic carbon into the soil. Transformation of succulent thicket leads to a disruption of the flow of carbon into the soil, reinforcing the cycle of transformation through reduced fertility. Rehabilitation of this ecosystem will require the active establishment of species, such as P. afra, that will restart the flow of carbon into the soil. Run-off & Erosion The landscape function model predicts that functional semi-arid shrublands efficiently conserve limiting resources such as water and water-bourn sediments (soil and organic matter). As these rangelands become transformed through unsustainable livestock production, so their ability to conserve resources decreases. The primary determinant of landscape function and conservation of resources appears to be the proportional cover of perennial vegetation. I hypothesised that the switch from a two-phase mosaic dominated by perennial succulent and woody shrubs to a single phase system dominated by an ephemeral field layer would be accompanied by disruption of the mechanisms that conserve resources. Specifically, I tested the hypothesis that transformation of succulent thicket increases runoff volume, sediment concentration of runoff, soil erosion and loss of organic matter at a patch scale (c. 100 m2). Runoff and water-borne sediment were measured from runoff plots established across replicated fenceline contrasts. Data were collected from eight extreme weather events over two years. There were no significant differences between runoff and erosion across the transformation contrast, as each extreme weather event was unique in terms of its runoff response. The transformed runoff plots alone also gave inconsistent results, largely due to differences in the cover of ephemeral forbs and weakly perennial grasses. Runoff and erosion were not predictable from the data across the transformation gradient due to complex interactions between the nature of the above-ground vegetation, soil micro-topography and land use history. The results highlighted the need for longer-term catchment experiments to generate a predictive understanding of the effect of transformation on runoff and erosion in succulent thicket.
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Opportunity and connectivity : selecting land managers for involvement in a conservation corridor linking two protected areas in the Langkloof Valley, South AfricaMcClure, Alice January 2011 (has links)
The Eden To Addo Corridor Initiative aims to connect formally protected areas in a conservation corridor from the coastal area of the Eden District near Plettenberg Bay, Western Cape, South Africa to the Addo National Elephant Park, Eastern Cape, South Africa. The corridor will incorporate government and privately owned land, and will be an attempt to maintain ecological processes at a range of spatial and temporal scales. The Langkloof Valley lies between the Baviaanskloof World Heritage Area and the Tstitsikamma National Park; two formally protected areas that will be incorporated into the Eden To Addo Corridor. Spatial prioritization analyses allow conservation planners to select areas that should be targeted for conservation action based on a range of criteria. Historically, ecological criteria have been included mostly alone in spatial prioritization. Recently, the idea of ‘conservation opportunity’ has emerged in the field of conservation planning; the notion suggests that a range of different types of data should be included in processes to spatially prioritise for conservation. By including those data defined as ‘human’ and ‘social’ data into prioritising activities, the feasibility of conservation plans can be accounted for, but historically conservation planners have failed to do so. I conducted a literature review that demonstrated that although the importance of human and social data are acknowledged in the conservation planning literature, these data that define opportunity are rarely actually included in spatial prioritisation analyses. I then carried out a social assessment that allowed me to define the social and human context of our study area and, specifically, what stewardship instruments land managers in the Langkloof would be prepared to engage. We found that land managers were generally willing to engage, but lacked the financial capacity to adopt conservation methods. Using a subset of the social and human data that were collected in the social assessment, I trialled a new Decision Support Software to fuse those data with ecological data in a novel attempt to identify priority areas for conservation action based on ecological integrity and feasibility. We also scheduled (ranked) land managers to approach for conservation action with a focus on local champions and clusters of land managers displaying strong conservation characteristics. Two corridors were identified; a major corridor in the western region of the valley and a secondary corridor closer to the middle. The members of the Initiative have been briefed on the outcomes, which provided them an opportunity to provide feedback; it is hoped that the framework of this study can be used for planning future connections. The Eden To Addo Corridor Initiative sent out a stewardship extension officer in February 2011 to approach those land managers areas that were identified. This planning exercise is a good demonstration of how, by collaborating effectively, academic conservation planners can contribute to supporting decision making by organizations that are implementing conservation action.
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Grasshopper bioindicators of effective large-scale ecological networksBazelet, Corinna Sarah 03 1900 (has links)
Thesis (PhD)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Land use change is leading to rapid biodiversity loss in terrestrial ecosystems worldwide. Ecological
networks (ENs) are systems of remnant natural habitat which remain intact in a transformed matrix,
and have been suggested as a means to mitigate the effects of habitat loss and transformation and the
resulting loss of biodiversity. Conceptually, ENs are similar to habitat corridors but are larger in scale
and more heterogeneous in their design and management. Like corridors, the efficacy of ENs for
biodiversity conservation has been called into question and requires empirical investigation. South
Africa boasts a unique system of extensive ENs associated with exotic timber plantations, mostly
within the highly endangered grassland biome and Indian Ocean Coastal Belt in KwaZulu-Natal
Province, South Africa. In these regions, grasshoppers respond sensitively to management practices
such as grazing, mowing and burning, justifying their a priori selection as an ecological indicator. In
this study, I utilize grasshopper assemblages to determine the efficacy of ENs for biodiversity
conservation and suggest guidelines for EN optimization. Specifically, I assess grasshopper
assemblage sensitivity and robustness to habitat quality within ENs, congruence of grasshoppers with
butterflies, and I identify indicator species which can be utilized by managers for EN assessment in
future. I also perform a case study of isolated fragment utilization by a highly mobile generalist
species, the bird locust, Ornithacris cyanea (Stoll, 1813) (Acrididae: Cyrtacanthacridinae).
Grasshopper assemblages were sampled within ENs in two geographic regions (Zululand and
the KwaZulu-Natal Midlands) and in two years (2007 and 2008) during the peak season of
grasshopper abundance, late summer (February-April). Local-scale environmental variables relating
to management practices and landscape-scale environmental variables relating to design of the ENs
were quantified. Management practices explained, on average, two-thirds of the variability in
grasshopper assemblages that could be explained, while design variables explained one-third. Grass
height and the time since the last fire event were most consistently influential, while area, context,
isolation, proportion of bare ground and proportion of forbs at a site, proved influential in some
analyses but not others. This response was robust over time and among geographic regions.
Grasshopper species richness and abundance were highly congruent with that of butterflies and did
not differ among isolated fragments, connected corridors and reference sites, although they did differ
among geographic regions.
Not all grasshopper species responded similarly to ENs. There was a strong phylogenetic
signal in species response to environmental variables, with the distribution of highly mobile families
varying more among years. Linear, heavily disturbed power line servitudes had higher grasshopper
abundance, and generalist species consistent with early successional assemblages. Reference sites
had more graminivorous species and those with intermediate mobility. Three species of grasshopper were identified with IndVal and validated on an independently collected dataset as indicators of high
habitat quality. A case study of the bird locust showed that populations of this highly mobile species
were effectively isolated and undergoing anthrovicariance even at short distances.
These results indicated that heterogeneous ENs supported diverse grasshopper assemblages,
although movement among isolated fragments may have been limited. A grasshopper bioindication
method for South Africa’s ENs is suggested and has great potential for assessment of a crucial and
sensitive trophic layer within the ENs. This method should be field-tested and revised over time as
grasshopper relative abundances and species compositions may change. Increased heterogeneity,
simulation of multiple successional stages, and increased connectivity are expected to positively
impact biodiversity, particularly of insect primary herbivores. Globally, ENs, if managed and
designed appropriately, have potential to enhance biodiversity, particularly of smaller resident
organisms which can utilize the ENs for movement and live within them. / AFRIKAANSE OPSOMMING: Veranderinge in grondgebruik lei tot ‘n vinnige verlies van biodiversiteit in terrestriële
ekosysteme wêreldwyd. Ekologiese netwerke (ENs) is sisteme van oorblywende natuurlike
habitat wat ongeskonde bly in getransformeerde matrikse, en is voorgestel as ‘n manier om
die verlies aan biodiversiteit as gevolg van habitatverlies en transformasie te verminder.
Konseptueel, is ENs soortgelyk aan habitat korridors, maar is groter in omvang en meer
heterogeen in hulle ontwerp en bestuur. Soos korridors, is die effektiwiteit van ENs om
biodiversiteit te bewaar bevraagteken, en vereis dit empiriese ondersoek. Suid-Afrika spog
met ‘n unieke stelsel van uitgebreide ENs wat geassossieer is met uitheemse plantasies,
meestal in die hoogs bedreigde grasveld bioom en Indiese Oseaan kusstrook in KwaZulu-
Natal Provinsie, Suid Afrika. In hierdie streek reageer sprinkane sensitief op
bestuurspraktyke soos beweiding, sny en brand. In hierdie studie het ek sprinkaan
gemeenskappe gebruik om die effektiwiteit van ENs vir bewaring van biodiversiteit te bepaal
en om riglyne te stel vir EN optimering. Spesifiek het ek sprinkaan gemeenskap sensitiwiteit
en robustness tot habitat kwaliteit bepaal, oreenstemming tussen sprinkane en skoenlappers
getoets, en het ek indikator species geïdentifiseer wat in die toekoms deur bestuurders
gebruik kan word vir EN assessering. Ek het ook ‘n gevallestudie gedoen van geïsoleerde
fragment benutting deur ‘n hoogs mobiele, algemene spesie, Ornithacris cyanea (Stoll, 1813)
(Acrididae: Cyrtacanthacridinae).
Sprinkaan gemeenskappe was versamel in twee geografiese gebiede (Zululand en die
KwaZulu-Natal Midlands) en in twee jare (2007 en 2008) gedurende die seisoen van hoogste
sprinkaan aktiwiteit, laat somer (Februarie – April). Plaaslike-skaal omgewingsveranderlikes
met betrekking tot bestuurspraktyke en landskap-skaal omgewingsveranderlikes met
betrekking tot die ontwerp van ENs is gekwantifiseer. Bestuurspraktyke verduidelik,
gemiddeld, twee derdes van die variasie in die sprinkaan gemeenskappe, terwyl
ontwerpveranderlikes een derde verduidelik. Grashoogte en tyd sedert die laaste brand was
konsekwent invloedryk, terwyl area, konteks, isolasie, hoeveelheid kaal grond en hoeveelheid
kruidagtige plantegroei invloedryk was in sekere analyses, maar in ander nie. Hierdie reaksie
was konstant oor tyd en tussen geografiese gebiede. Sprinkaan spesies rykheid en
hoeveelheid was hoogs kongruent met die van skoenlappers, en het nie verskil tussen
geïsoleerde fragmente, verbinde korridors en verwysingsareas nie, maar hulle het verskil tussen geografiese streke. Nie alle sprinkaan spesies het soortgelyk gereageer tot ENs nie.
Daar was ‘n sterk filogenetiese sein in spesies reaksies op die omgewingsveranderlikes, met
meer variasie tussen jare in die verspeiding van hoogs mobiele families. Liniêre, hoogs
versteurde kraglyn dienspaaie het hoer sprinkaan hoeveelhede gehad en algemene spesies wat
geassosieer is met gemeenskappe in vroeë stadiums van suksessie. Verwysingsareas het meer
graminivorous spesies gehad en spesies met intermediêre mobiliteit. Drie sprinkaan spesies is
geïdentifiseer met IndVal en bevestig met ‘n onafhanklik versamelde dataset as indikators
van hoë kwaliteit habitat. ‘n Gevallestudie op O. cyanea het aangedui dat populasies van
hierdie hoogs mobiele spesie geïsoleerd is en dat hulle anthrovicariance ondergaan, selfs op
kort afstande.
Hierdie resultate dui aan dat heterogene ENs diverse sprinkaan gemeenskappe
ondersteun, hoewel beweging tussen geïsoleerde fragmente dalk beperk is. Verhoogde
heterogeneïteit, simulasie van verskeie suksessiewe fases en meer konnektiwiteit sal moontlik
‘n positiewe invloed op biodiversiteit hê, aangesien sprinkane verteenwoordigend was van
insek primêre herbivore. Wêreldwyd, as ENs op ‘n gepaste manier bestuur en ontwerp word,
het dit die potensiaal om biodiversiteit te bevorder. Dit is veral belangrik vir kleiner, plaaslike
organisms wat ENs kan benut vir beweging en as leefhabitat. ‘n Sprinkaan bioindikasie
metode vir Suid-Afrika se ENs is voorgestel en het groot potensiaal vir die assessering van ‘n
belangrike en sensitiewe trofiese laag binne die ENs. Hierdie metode moet in die praktyk
getoets word en hersien word oor tyd om veranderinge in sprinkaan relatiewe hoeveelhede en
spesies komposisies in ag te neem.
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The mesofilter concept and biodiversity conservation in Afro-montane grasslandsCrous, Casparus Johannes 03 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Conservation planners use many traditional biodiversity conservation tools to help alleviate
the global biodiversity crisis. However, ongoing biodiversity loss has stimulated the
development of new and improved methods for conserving biodiversity. One such new
conservation tool is the mesofilter approach. Mesofilters are biotic or abiotic ecosystem
elements which are critical to the well-being of many species, and therefore could help to
explain spatial heterogeneity in species across a landscape. It is also complementary to more
traditionally used concepts such as coarse- and fine-filter conservation concepts. Applying the
mesofilter approach in protected area, conservancy, or land-sparing design and management,
could optimise biodiversity conservation in a rapidly developing world. For example, the
timber industry has been pro-active in its approach to lessen biodiversity loss, by optimising
design and management of the plantation matrix through ecological networks. Here, I explore
the use of mesofilters within highly threatened remnant Afro-montane grasslands in
KwaZulu-Natal, South Africa, to optimise biodiversity conservation planning for such
landscapes. As per anecdotal evidence, I used rockiness in the landscape as a possible driver
of species richness and species assemblage variability at the meso-scale, using a multi-taxon
and multi-trophic approach. In this montane landscape, I also examined the effect of elevation
on spatial heterogeneity of taxa. I further examined the functional responses of taxa to
rockiness in the landscape. Rockiness in the landscape significantly influenced the species
richness and assemblage structure of three key grassland taxa: flora, butterflies, and
grasshoppers. I showed that for plants, this response was due to growth forms such as
geophytes and perennial grasses that were more closely associated with rockiness, and
therefore the main contributors to observed differences in the dispersion patterns of flora.
Grasshoppers were not necessarily responding to higher rock exposure per se, but rather
towards the environmental conditions created by rockiness within the landscape, such as
lower vegetation density. For butterflies, certain behavioural traits, such as resting, territorial
behaviour and/or mate-locating behaviour, were more typical in areas of higher rock
exposure. This suggested that rocks are a definite habitat resource to certain butterflies.
Overall, this finding where an abiotic surrogate is representative of key taxa in an ecosystem
is interesting, as cross-taxon surrogacy has been shown to be stronger than surrogates based
on environmental data. Furthermore, taxa responded functionally to rockiness in the
landscape. This thesis therefore supports the idea that environmental surrogates are indeed
useful for biodiversity conservation planning. Furthermore, ecosystems can potentially have many attributes or features that would be of conservation interest, and delineating a set of
mesofilters is a useful way of expressing particular attributes to be used in wildlife
conservation evaluation. The concept of the mesofilter as a practical biodiversity conservation
tool is therefore validated here. I also argue the importance of habitat heterogeneity for
biodiversity conservation planning in this montane grassland landscape. The potential for
optimising the design of landscape configurations such as ecological networks, through
information obtained from the mesofilter, is emphasised. We can safely add another tool in
the biodiversity conservation toolbox of this Afro-montane grassland ecosystem. / AFRIKAANSE OPSOMMING: Bewaringbeplanners gebruik tans baie tradisionele biodiversiteit-bewarings metodes om die
huidige biodiversiteits krisis te help verlig. Tog, die huidige voortdurende verliese in
biodiversiteit wêreldwyd, vra na nuwer en verbeterde metodes van biodiversiteit-bewaring.
Een so ‘n nuwe bewaring metode, is die mesofilter. Mesofilters is biotiese of abiotiese
ekosisteem elemente wat kritiek is tot die welstand van spesies, en daarom veral waardevol is
om variasie in spesies verspreiding in ‘n landskap te help verduidelik. Daarby is die
mesofilter konsep ook komplementêr tot meer tradisioneel gebruike bewaringskonsepte, soos
fyn-filter en breë-filter konsepte. Deur die mesofilter benadering toe te pas in die ontwerp en
bestuur van beskermde areas, bewaareas, of land-spaar initiatiewe, kan ons biodiversiteitbewaring
in ‘n vining ontwikkelende wêreld optimaliseer. Byvoorbeeld, die bosbou industrie
is pro-aktief in hul benadering om biodiversiteit verliese te verminder, deur optimalisering
van die ontwerp en bestuur van ekologiese netwerke in die plantasiematriks. In hierdie tesis,
ondersoek ek die gebruik van mesofilters in hoogs bedreigde oorblyfels Afrikaberg grasvelde
in KwaZulu-Natal, Suid-Afrika, om die bewaringsbeplanning van dié gebiede te optimaliseer.
Vanaf anekdotiese bewyse, het ek spesifiek gebruik gemaak van klipperigheid in die landskap
as ‘n moontlike drywer van spesies-rykheid en spesies-samestelling variasie by ‘n meso-skaal,
deur ‘n multi-takson en multi-trofiese benadering. In hierdie berglandskap, het ek ook die
effek van hoogte bo seevlak op ruimtelike verspreiding van taksa bestudeer. Verder het ek
ook gekyk na die funksionele reaksie van taksa tot klipperigheid in die landskap.
Klipperigheid in die landskap het ‘n beduidende invloed gehad op spesies-rykheid en spesiessamestelling
van drie sleutel grasveld taksa: plante, skoenlappers, en springkane. Ek wys dat
vir plante, hierdie reaksie as gevolg was van spesifieke plantgroeivorme, soos bolplante en
meerjarige grasse, se noue verband met klipperigheid, en daarom, dat hierdie groepe die hoof
bydraers is tot gesiene variasie in plantspesies verspreiding in die landskap. Vir springkane,
was hierdie reaksie nie noodwendig omdat hulle die klippe self gebruik het nie, maar meer as
gevolg van die omgewingskondisies geskep deur verhoogde klipperigheid in die landskap,
soos laer plantegroei digtheid. Vir skoenlappers, was hierdie reaksie tot klippe as gevolg van
sekere gedragskaraktereienskappe, soos rus op klippe, gebied beskerming en/of paarmaat
soektog, wat tipies meer gesien was in klipperige omgewings. Dit dui daarop dat klippe ‘n
definitiewe habitat hulpbron is vir sekere skoenlappers. Oor die algemeen is hierdie
bevinding, waar abiotiese surrogate verteenwoordig is van drie sleutel taksa in ‘n ekosisteem,
baie interessant, siende dat tussen-takson surrogate soms gesien word as sterker as surrogate gebaseer op omgewingsdata. Verder, taksa het funksioneel gereageer teenoor die klippe in die
landskap. Hierdie tesis ondersteun dus die idee dat omgewingssurrogate wel nuttig is vir
biodiversiteit-bewaring beplanning. Ekosisteme mag vele potensiele elemente van bewarings
belang bevat, maar om sulke elemente as ‘n stel mesofilters te klassifiseer, is ‘n nuttige
manier om spesifieke elemente te gebruik in natuurbewarings evaluasie initiatiewe. Gevolglik
word die konsep van die mesofilter as ‘n praktiese biodiversiteit-bewaring gereedskapstuk
hier bevestig. Ek beredeneer ook die belangrikheid van habitat heterogeniteit vir
biodiversiteit-bewaring van hierdie berggrasveld landskap. Die potensiaal vir optimalisering
van ontwerp en bestuur van landskap konfigurasies, soos ekologiese netwerke, word
beklemtoon. Ons kan met veiligheid nog ‘n gereedskapstuk plaas in die biodiversiteitbewarings
gereedskapkis van hierdie Afrikaberg grasveld ekosisteem.
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The role of anthropogenic disturbance in the creation of a socio-ecological landscapeFox, Helen Elizabeth January 2005 (has links)
The aim of this thesis is to examine the role of anthropogenic disturbance in the creation of a socio-ecological landscape. Three key questions were answered: what impact has past anthropogenic disturbance had on present vegetative characteristics; what value did this disturbed landscape have to local people; how did the local peoples' worldviews and eco-cosmologies influence how they perceived, valued and managed their landscape? Research was based in a rural, predominantly amaXhosa village in the Kat River valley, Eastern Cape, South Africa. Four major landscape components characterised the environment, namely dense forests, former grazing lands, abandoned fields and old settlements. A combination of qualitative and quantitative methods were adopted, consisting of a vegetation and soil survey and social science methods including semistructured interviews, focus groups, transect walks and participant observation. The key finding was that anthropogenic disturbance is necessary to enhance the potential of the area to support human habitation. However, anthropogenic disturbance can have positive or negative effects for both local people and the environment. An intermediate level of disturbance is a key factor leading to a resilient socio-ecological system. Various anthropogenic disturbances have had significant affects on vegetation characteristics in terms of species richness, and a change in vegetation composition and species heights. Of the three anthropogenic landscapes examined, former grazing lands were the least intensively disturbed. They were also more species rich and structurally diverse than areas that were under agricultural production or used as a settlement. Dense forests, although the least desirable landscape to local people were, together with sacred pools, sources of ecosystem renewal and played a critical role during times of disturbance. Anthropogenic disturbance has added value to local people's livelihoods; this disturbance has resulted in a patchy landscape that supplies a wide variety of resources to local people. Local people are dependent on their environment for their basic needs; this has encouraged sustainable management practices. The local AmaXhosa still retain many elements of their traditional worldview, which has many characteristics of Animism. The environment is an integral component of their belief system and certain sites and species have significant cultural value and are protected.
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The mutual embodiment of landscape and livelihoods: an environmental history of NqabaraDe Klerk, Henning January 2007 (has links)
This thesis presents a history of the landscape of Nqabara, an administrative area in a rural and coastal area of the Eastern Cape Province, South Africa. In the process of investigating landscape history, the inquiry engages with a range of data sources from diverging discursive contexts, including data from ethnographic fieldwork, from the consultation of archival documents and historical reports as well as from comparative historic and ethnographic research, necessitating a critical consideration of the epistemological contexts of data production and the dialogue between researcher and data. Furthermore, in its aim to move beyond historical description towards explanation, the study interrogates the dualist ontological conceptualisations of nature and culture, society and ecology, object and meaning upon which are built three dominant conceptual frameworks concerned with human-environment relationships: social-ecological systems theory, transdisciplinary landscape studies and political ecology. Drawing primarily upon the works of James Gibson, Anthony Giddens and Tim Ingold, an ontological foundation is developed to guide the enquiry and move towards an alternative understanding of the relationship of people’s livelihoods with respect to the landscape in which it is lived, which I call here the praxisembodiment perspective. This ontology takes the situated patterns of action of a situated agent-in-its-environment as its point of departure and proceeds to develop a framework explaining how relations among the patterns of action of different agents-in-their-environment, emerge in structures that simultaneously enable and constrain future action. The foundation is thereby provided for a monist understanding of how landscape and social structure emerge simultaneously from the complex intersection of patterns of actions and interactions of agents in their environment. This framework calls for an understanding of time, space and scale, not as independent variables influencing process and action, but as emergent properties arising from the patterns of actions of situated agents. Finally the alternative ontology is applied to the history of landscape and livelihoods of people of Nqabara. It is concluded that an appropriate understanding and explanation of the critical transformations in the landscape as well as in social institutions, should be sought through analysis of the complex ways in which patterns of action of multiple spatial and temporal rhythms and between multiple agents in an environment, intersect and resonate.
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