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Spatial patterns of vegetation and soil fertility along a grazing gradient in a desert steppe in Inner Mongolia, ChinaLin, Yang Unknown Date
No description available.
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The effect of cattle grazing in riparian areas on winter biodiversity and ecologyFranz, Simone, University of Lethbridge. Faculty of Arts and Science January 2009 (has links)
Livestock grazing in riparian habitats alters the vegetation structure, which has a detrimental effect on wildlife. This study examined the effect of cattle grazing in riparian habitats on winter bird biodiversity, small mammal biodiversity, and microclimate. Study sites were ungrazed, moderately grazed, and heavily grazed riparian habitats along the Oldman River, Alberta during winter 2005 and 2006. Bird species richness, individual abundance, and diversity indices were higher in ungrazed habitats than in grazed habitats. Deer mouse population sizes were not different except during spring 2006, when populations were larger in ungrazed sites. Microclimate data were collected in riparian sites and upland sites in winter 2006. Temperatures were higher and wind speeds were slower in riparian sites than in upland sites. Wind speeds were faster in heavily grazed riparian sites than in lightly grazed sites. Faster winds in heavily grazed sites may account for the decreased winter biodiversity in these habitats. / x, 118 leaves ; 29 cm
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The influence of environment and livestock grazing on the mountain vegetation of Lesotho.09 December 2013 (has links)
The mountains of Lesotho form the catchments for the Lesotho Highlands Water
Project (LHWP), which is presently under construction, and their condition will
determine the longevity of the LHWP. The mountain rangelands also support an
extensive livestock system. However, there is concern that grazing is negatively
affecting the mountain vegetation to the detriment of both livestock production and
catchment function. Therefore, the impact of environment and grazing on the
vegetation was investigated to aid the development of management policy for the
conservation of the grazing, floristic and water resources of the mountains.
Vegetation surveys were conducted in the mountains in the east (Study Area 1: 2 625
- 3 350 m a.s.l.) and in the west (Study Area 2: 2 240 - 3 125 m a.s.l.). Indirect
gradient analysis (IGA) and classification were used to investigate the influence of
environment on vegetation pattern. Results of the IGA indicated that variation in
species composition in the mountains is related primarily to topographic variation, in
particular elevation and aspect. Five vegetation communities were identified in Study
Area 1 and seven in Study Area 2. These communities occurred consistently in
specific topographic positions in the landscape and were arranged along a
temperate/subtropical grass species continuum which was associated with a gradient
in elevation and aspect. In Study Area 1, the elevation boundary between the high-lying temperate grasslands and the lower subtropical grasslands corresponded with
the generally recognised boundary between the Alpine and Subalpine vegetation belts (viz. c. 2 950 m a.s.l. on northerly aspects and c. 2 750 m a.s.l. on southerly aspects). This boundary was lower in Study Area 2 (viz. c. 2 800 m a.s.l. on northerly aspects and c. 2 300 m a.s.l. on southerly aspects). Vegetation-insolation relationships were investigated in Study Area 1 using a model for
simulating solar radiation, temperature and potential evaporation patterns on sloping terrain (RADSLOPE). The spatial distribution of the identified vegetation communities
and the ratio of temperate (C₃) and subtropical (C₄) grasses in the sward were related to solar irradiance patterns, as influenced by topography. Results suggest that exposure, which increases with altitude, is probably also an important determinant of vegetation pattern in the mountains. The influence of grazing on the vegetation was studied by examining changes in species composition and cover that were associated with gradients in grazing intensity that exist around cattleposts in the mountains. There was little evidence of a shift in species composition and cover under grazing in the Alpine Belt but there was an identifiable grazing gradient in the Subalpine belt. There, short dense grasslands,
dominated by palatable species, degrade to a dwarf karroid shrubland with sparse
cover under prolonged, intense grazing. The optimum position along the grazing
gradient of the more abundant species was identified. It was proposed that the
relative positions, or scores, of these species along the grazing gradient can be used
in a weighted scoring procedure to provide an index for monitoring the response of the
mountain vegetation to grazing. However, the species’ scores still require verification.
The need for monitoring temporal changes in vegetation composition and cover in
order to assess the possible effects of the LHWP and other development initiatives
was noted. Such monitoring should be undertaken in conjunction with an overall
programme to assess the dynamics of the socio-economy in the mountains.
Therefore, interdisciplinary monitoring programmes are required to achieve this.
These programmes should be focused in a few key study locations rather than spread over a wide area. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg.
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Spatial patterning and demography in Strandveld succulent Karoo : implications for biodiversity managementCheney, Chad (Chad Crispian) 12 1900 (has links)
Thesis (MSc) -- University of Stellenbosch, 2004. / ENGLISH ABSTRACT: This thesis focuses on the effects of vegetation resting on biodiversity and community
dynamics at Rocherpan Nature Reserve (320 36'S, 180 18'E) in the semi-arid coastal strip of
the Succulent Karoo known as Strandveld. As a whole, the Succulent Karoo has an
extraordinary high level of phyto diversity with high levels of endemism. This is particularly
true for succulent shrubs belonging to the groups Mesembryanthemaceae, Crassulaceae and
Asteraceae.
The thesis begins with an investigation into effects that vegetation resting has on plant
diversity. The aim was to determine if resting affected biodiversity levels and if so, which
plant groups are affected and why. Through a numerical approach, it was determined that
with resting overall species richness remained the same. However, different plant life forms
responded to resting differently. With increased resting, abundance of succulent shrubs
decreased, while richness of annuals increased.
The second aspect under investigation was to determine how resting the vegetation affected
community dynamics. The aim was to understand how vegetation structure and interspecific
associations changed with resting and to apply these findings to known community models.
Through an autocorrelation approach, it was found that horizontal patterning of long-lived
woody species, that formed distinctive vegetation clumps, did not change with resting, while
differences were found in woody matrix species and succulent species. These changes in
structure were investigated further through a study on the demography of specific species.
Demography of woody species associated with vegetation clumps did not change with
vegetation resting, while significant changes were observed for woody matrix species and
succulent species. In longer rested vegetation, woody matrix species showed a greater range in
size class distribution (i.e. had both very large and smaller plants) with the tendency towards
larger plant sizes. Succulents on the other hand, had a smaller range in size class distribution
with a tendency towards larger plants. For all species investigated there were low seedlings
counts. It was concluded that succulent shrub populations were 'mature' and continued resting
could result in local extinction of some species due to the lack of regeneration. The overall
lack of seedlings was attributed to a saturated establishment environment. Implications for
conservation management were discussed. / AFRIKAANSE OPSOMMING: Hierdie tesis fokus op die gevolge van plantegroeirus op biodiversiteit en
gemeenskapsdinamika by die Roeherpan Natuurreservaat (320 36'S, 180 18"0) in die halfdor
kusstrook van die Sukkulente Karoo, bekend as die Sandveld. In die geheel gesien het die
Sukkulente Karoo 'n buitengewone hoë vlak plantdiversiteit met hoë vlakke endemie. Dit is
veral waar vir sukkulente struike wat tot die groepe Mesembryanthemaceae, Crassulaceae en
Asteraceae behoort.
Hierdie tesis ondersoek eerstens die gevolge wat plantegroeirus op plantdiversiteit het. Die
doel was om te bepaal of rus die biodiversiteitsvlakke beïnvloed het en indien wel, watter
plantgroepe en waarom. Deur middel van 'n numeriese benadering is bepaal dat die algehele
diversiteit, numeries gesproke, met plantegroeirus dieselfde gebly het. Verskillende
plantlewensvorme het egter verskillend gereageer. Met toenemende rus het die diversiteit van
sukkulente struike afgeneem, terwyl die diversiteit van jaarplante verhoog het.
Die tweede aspek wat ondersoek is, was om te bepaal hoe die plantegroeirus die dinamika van
die omgewingsgemeenskap beïnvloed het. Die doel was om te verstaan hoe die struktuur van
die plantegroei en die interspesifieke assosiasies verander het met rus en om dan hierdie
bevindinge toe te pas op bekende gemeenskapsmodelle. Deur middel van 'n outokorrelasiebenadering
is gevind dat die horisontale patrone van meerjarige houtagtige spesies wat in
duidelik-uitkenbare plantegroeigroeperings voorkom, nie met rus verander het nie.
Veranderinge is egter wel in die houtagtige matriksspesies en die sukkulente spesies
waargeneem. Hierdie veranderinge in struktuur is verder ondersoek deur 'n studie te maak van
die demografie van spesifieke spesies. Daar is gevind dat die demografie van houtagtige
spesies geassosieer met plantegroeigroeperings nie met plantegroeirus verander het nie, maar
beduidende veranderinge is waargeneem in die geval van houtagtige matriksspesies en
sukkulente spesies. By plantegroei wat langer gerus het, het die houtagtige matriksspesies 'n
wyer verspreiding in klasgroottes vertoon (d.i. daar was baie groot plante én kleiner plante)
met 'n gemiddelde afname in plantgrootte. Sukkulente, aan die ander kant, het 'n kleiner
verspreiding in klasgroottes vertoon met 'n neiging tot groter plante. Vir al die spesies wat
ondersoek is, was daar lae saailingtellings. As gevolg van die "volwassenheid" van die
populasies van sukkulente struike, sou voortdurende rus, weens die gebrek aan regenerasie, kon lei tot die plaaslike uitwissing van sommige spesies. Die algemene gebrek aan saailinge is
toegeskryf aan die versadigde vestigingsomgewing. Die implikasies VIr
natuurbewaringsbestuur word bespreek.
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The effects of timber harvest and herbivory on understory vegetation and composition of beef cattle diets on forested rangelandsWalburger, Kenric 28 October 2005 (has links)
Graduation date: 2006 / Best scan available. Ink on original is smeared.
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Assessing waterhole design and determining the impact of artificial waterholes in Balule nature reserve, South AfricaSmith, Eilidh 01 1900 (has links)
Herbivores have a significant influence on their environment. Factors that influence herbivore distribution in a landscape are important for conservation. Artificial water provision is one such factor, with water sources being focal points of herbivore activity. Variation between herbivore utilisation of different waterhole types and habitat integrity surrounding the different waterholes is assessed in this study. Correlations are drawn between herbivore utilisation and habitat integrity to quantify the impact that artificial waterholes have on the landscape. A scoring system is devised to investigate the various factors affecting vegetation around artificial waterholes. Results show that there are significant variations between herbivore utilisation for different artificial waterhole types, as well as significant variation in habitat integrity surrounding the different waterhole types. Distance between waterholes and drainage lines, and utilisation by specific herbivore species have a significant impact on habitat integrity - specifically affecting veld condition and disturbance observed on woody plant species. A habitat score that was created by combining data from both the herbaceous and woody layers is not affected by waterhole type, distance from waterholes, or the different herbivore species utilising the different waterhole types. Earth dams have the greatest impact on surrounding vegetation and are the most utilised waterhole type. Closures of earth dams are not recommended due to their importance to herbivores. Less utilised waterhole types are also important, mitigating the impact of herbivore damage to vegetation at earth dams. / Environmental Sciences / M. Sc. (Nature Conservation)
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Using nutritional quality of forage and faeces for predicting sustainable livestock and game stocking rates at Pniel Estates in Northern Cape, South AfricaMbatha, Khanyisile R. 03 1900 (has links)
Thesis (PhD)--University of Stellenbosch, 2010. / The aim of the study was to assess the importance of spatial and temporal variation in diet quality and abundance for determining sustainable stocking rates on commercial, communal and game ranches in a semi-arid savanna, with the ultimate goal of avoiding land degradation in the long term, to provide sustainable livelihoods in rangelands and to make policy that will help in managing the available natural resources in the rangelands. Thus, firstly the effects of grazing, fire, nitrogen and water availability on nutritional quality of grass in semi-arid savanna was assessed. Secondly, spatial and temporal variation in plant quantity and quality among management (commercial, communal and game) types and habitat types (open savanna, rocky, shrubby and pans) and stocking rates in different management types were determined. Thirdly, the quality and quantity of variation inside and outside herbivore exclosures among commercial, communal and game management and habitat types in the semi arid savanna were estimated. Fourthly, faecal profiling was used to assess the effects of different management types on diet quality in semi-arid savanna. Lastly, policy based on the results of the present study was formulated.
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Renosterveld restoration : the role of competition, herbivory and other disturbancesMidoko-Iponga, Donald 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: West Coast Renosterveld is one of the most threatened vegetation types in South
Africa. Less than 5% of the original extent of this vegetation type remains, of which
80% is on private land. In addition to fragmentation, much of the vegetation has been
ploughed for crop production and then abandoned and invaded by alien plants.
Restoration of transformed areas may improve the conservation status of this
vegetation type. Indigenous species do not return to abandoned agricultural fields for
decades even if these are adjacent to natural areas since their return is limited either
by seed dispersal or seedling establishment. The aim of this study was to examine
the recovery of indigenous vegetation on abandoned fields.
Renosterveld, as we know it today, is an asteraceous shrubland, dominated mainly
by renosterbos (Eytropappus rhinocerotis), but might have been a grassland or a
grassland-shrubland mosaic. Historical records indicate that species of large game
were common in the Western Cape when the early settlers arrived, but most of these
have since disappeared. It is thus impossible to reconstruct exactly the ecological
processes and functioning of Renosterveld.
The first part of the study was designed to examine the effects of grass competition,
grazing by indigenous large herbivores, and interaction of these two factors on the
establishment, growth and survival of transplanted Renosterveld seedlings on an
abandoned agricultural field. Experimental transplanting of indigenous shrubs into an
old field showed that most of the plants investigated competed for resources with
lawn grasses on the field, and competition affected the seedlings throughout the
experiment. Mortality was higher, and growth was reduced for seedlings exposed to
grass competition. With the exception of wild olive (Olea europaea spp.africana),
herbivory alone had no significant impact on the target species. Herbivory was at a
low intensity (20 ha/large animal unit); higher grazing pressures might have given
different results. No interaction between competition and herbivory was found for the
species investigated; competition and grazing therefore seem to influence the
seedlings independently. The second part of this study was conducted to examine the effects of different
management strategies, viz: brush cutting, burning and herbicide application on plant
species recruitment and community composition and to ascertain their applicability
by farmers for large scale restoration of Renosterveld. My comparison of the different
strategies for controlling annual alien grasses indicated that these did not differ
significantly in their effects on species richness. Burning reduced shrub cover and
increased overall species richness and diversity. Burning also reduced grass
biomass, and increased recruitment of indigenous seedlings. The use of herbicide
resolved the problem of grass biomass invasion and increased shrub species
richness. The herbicide application did not appear to have long-term negative effects
on the soil quality. Brush cutting did not remove grass biomass on the old field.
Experimental re-seeding with an indigenous grass and shrub species into treated
plots resulted in low recruitment.
My conclusion is that grass can reduce recruitment and growth of many indigenous
shrub species. My recommendation for the restoration of old fields in West Coast
Renosterveld is to apply herbicide to remove grass competition, and then, after the
herbicide has degraded, to oversow the field with seeds of indigenous shrub and
grass species of early successional stages to increase overall species diversity. / AFRIKAANSE OPSOMMING: Weskus Renosterveld is een van die mees bedreigde plantegroei soorte in Suid
Afrika. Minder as 5% van die oorspronklike omvang van hierdie plantegroei tipe is
oor, en dit hoofsaaklik (80%) op privaatlande. Saam met fragmentasie, is baie
Renosterveld areas ook omgeploeg vir boerdery en dan net so gelos, met die gevolg
dat uitheemse plante hierdie areas ingedring het. Restorasie of herstelling van sulke
bewerkte lande kan dalk die bewaringsstatus van hierdie plantegroei tipe verbeter.
Natuurlike vestiging van Renosterveld spesies op sulke ou bewerkte lande gebeur
nie, selfs al is daar Renosterveld direk langs so ‘n ou veld. Die hervestiging van
inheemse spesies is dus tot saadverspreiding or saailingbevestiging beperk. Die
doel van hierdie studie is om die stadige terugkoms van inheemse plantegroei na
verlate bewerkte velde te verduidelik.
Renosterveld is ‘n struikveld waarin die renosterbos (Eytropappus rhinocerotis)
domineer, maar kan ook ‘n grasveld of ‘n grasveld-struikland mengsel wees. Groot
herbivore was algemeen in die Wes Kaap toe die eerste settelaars gearriveer het,
maar intussen het omtrent al die groot wild spesies verdwyn. Dit is dus ontmoontlik
om die ekologiese prosesse en funksionering van Renosterveld presies so te herstel.
Die eerste deel van hierdie studie bestudeer die effek van graskompetisie, weiding
deur inheemse groot herbivore, en die interaksie tussen hierdie twee faktore op die
vestiging, groei en oorlewing van oorgeplante Renosterveld saailinge in ‘n verlate ou
veld. Die eksperimentele oorplanting van inheemse struike in ‘n ou land het gewys
dat die meeste van hierdie plante kompeteer vir hulpbronne met kweekgras wat op
die ou veld groei. Kompetisie het die saailinge deur die hele eksperiment
geaffekteer. ‘n Hoër mortaliteit en verminderede groei in saailinge wat aan gras
kompetisie blootgestel was, is waargeneem. Met die uitsondering van Olea
europaea spp. africana, het herbivorie alleen geen betekenisvolle impak op plant
spesies gehad nie. Weidingsdruk was laag (20 ha/groot vee eenheid); ‘n groter
weidingsdruk sou miskien ‘n ander uitkoms gehad het. Geen interaksie tussen
kompetisie en herbivorie is waargeneem in die bestudeerde plantspesies nie. Dit wil dus voorkom of kompetisie en weiding die saailinge onafhanklik van mekaar
beïnvloed.
Die tweede deel van hierdie studie was onderneem om die effek van verskillende
behandelings (kontrole, sny, brand en herbisied toediening) op plantspesie vestiging
en samestelling te bestudeer asook om bestuurmetodes te toets was deur boere op
groot skaal gebruik kan word om Renosterveld te herstel. In ‘n vergelyking van
verskillende bestuur metodes (kontrole, besnoeiing, brand en herbisied) om
eenjarige uitheemse gras te beheer, is gewys dat die behandlings nie betekenisvol
van mekaar verskil in hulle effek op spesierykheid nie. Vuur het struikbedekking
verminder en totale spesies rykheid en diversitiet verhoog. Die gebruik van ‘n
herbisied het die probleem van grasindringing opgelos en het ook
struikspesiesrykheid verhoog. Die herbisied het nie lang termyn negatiewe effekte op
grond kwaliteit gehad nie. Sny het nie gras biomassa verlaag op die ou land nie.
Eksperimentele plant van inheemse grasse en struike in die behandelde areas, het
lae vestiging tot gevolg gehad.
My algemene afleiding is dus dat gras die hervestinging en groei van baie inheemse
struikspesies verminder. Ek stel voor dat herbisied gebruik moet word om gras
kompetisie te verminder. Nadat herbisied residue in die grond afgebreek is, moet
die ou land met inheemse struik en grasspesies, wat in vroeë suksessie stadiums is,
beplant word om sodoende totale spesiediversiteit te verhoog en uiteindelik ou
bewerkte lande in Weskus Renosterveld te herstel.
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Vegetation patterns and dynamics of Renosterveld at Agter-Groeneberg Conservancy, Western Cape, South AfricaWalton, Benjamin Alan 03 1900 (has links)
Thesis (MSc (Conservation Ecology and Entomology)--University of Stellenbosch, 2006. / Swartland Shale Renosterveld is restricted to fertile fine-grained soils in the winter rainfall region of
the Western Cape. Between 91% and 97% of this vegetation type is transformed, mostly due to
agriculture. Remaining fragments have an irreplaceable conservation value due to a high richness of
endemic geophytes. Information on renosterveld vegetation composition and response to
disturbance is sparse. Research occurred at three sites near Wellington: Voëlvlei Provincial Nature
Reserve (CapeNature), Elandsberg Private Nature Reserve (Elandsberg Farms (Pty.) Ltd.), and
Krantzkop munitions factory (Armscor/Somchem) forming a contiguous fragment in the Agter-
Groeneberg Conservancy. The primary research aim was to identify or ascertain patterns of plant
succession in Swartland Shale Renosterveld and associated different-aged old fields (previously
ploughed), with the interaction of grazing. The key research questions are: (1) What are the plant
communities of unploughed renosterveld and different-aged old fields which originated in habitats
of ploughed renosterveld? (2) What are the most characteristic features of the floristic and
ecological relationship between the described plant communities in terms of ecological factors
operating within the studied system? (3) Does total species and life-form group richness differ
between natural vegetation and old fields? (4) Is life-form richness influenced by ploughing and
grazing or the interaction between these disturbances? (5) Is life-form cover-abundance influenced
by ploughing and grazing or the interaction between these disturbances? (6) Does alien plant
species richness differ amongst seres, and with different levels of grazing intensity? A comparison
of life-form richness and cover-abundance of old field vegetation was made with adjacent natural
unploughed “controls”. The effects of ploughing on community structure, with the inclusion of
grazing was established. These life-form richness comparisons also occur across a gradient of
increasing large mammalian herbivore grazing intensity. Sampling was conducted in winter and
spring using nested 1000m2 relevés.
A hierarchical classification, description and floristic interpretation of renosterveld and old field
vegetation were made using TWINSPAN, SYN-TAX 2000 and CANOCO. The samples were
classified with TWINSPAN and two communities were described at the association level, namely:
Ursinia anthemoides–Cynodon dactylon Grassland Community (with two variants) and the
Pterygodio catholici–Elytropappetum rhinocerotis Shrubland Community (with two subassociations),
respectively. The vegetation data were further hierachically classified using SYNTAX
2000 which revealed similar clustering of sample objects to that resulting from classification and ordination. Following ordination of sample objects with CANOCO, select groups of species
were used to depict their response curves in relation to seral development.
Briefly it was found that the effects of grazing vs. non-grazing was more pronounced on old fields
than in unploughed vegetation. Overall total species and life-form richness was reduced by
ploughing with old fields requiring a recovery period of 30 years to resemble unploughed
vegetation.
Keywords: Swartland Shale Renosterveld, phytosociology, vegetation patterns, life-forms,
succession, disturbance, ploughing, grazing, old fields.
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