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Economic consequences of ecological change: restoration options for the Mfolozi floodplain and implications for Lake St. Lucia, South AfricaCollings, Sandy Lyn January 2010 (has links)
Lake St Lucia in northern KwaZulu-Natal, South Africa, experiences severe ecological stress during dry periods largely as a result of diminishing freshwater supplies and conditions of hypersalinity. Possible intervention involves diverting the Mfolozi River to the St Lucia Lake system. However, due to high sediment loading, water from the Mfolozi river requires considerable filtration before a link can be established. A suggested option considered in this study is to restore the existing sugarcane farmlands on the Mfolozi Floodplain (~20 800 ha) to previous wetland conditions to reinstate a sediment removal function amongst other benefits. Proposed restoration will have a direct impact on the industries currently supported by the iSimangaliso Wetland Park and the Mfolozi Floodplain (tourism, sugar, conservation). to understand a measure of such impacts, ecosystem services for both Lake St Lucia and the Mfolozi Floodplain were analysed (flood alleviation, water provision, water purification, sediment regulation, tourism, fisheries, vegetation for harvest, existence, cultural and research). Annual economic values for each ecosystem service were determined by means of valuation methods that included benefit transfer and replacement cost. Results showed a current annual minimum value of the Mfolozi Floodplain and Lake St Lucia as greater than R21 million and R1.1 billion respectively. Partial restoration of the floodplain (~6 000 ha) is expected to increase the sum of all ecosystem services values by approximately 26% for the Mfolozi Floodplain and by 23% for the St Lucia System. Full restoration (~20 800 ha) increases the total ecosystem services value by 88% and 50% for the Mfolozi Floodplain and St Lucia System respectively. Results showed that economic values for existence, fisheries, tourism and water provision increase by the greatest percentage for the St Lucia System under both restoration scenarios. Partial and full restoration of the floodplain will result in the greatest increases in economic value for the services existence, tourism, fisheries and the harvesting of vegetation on the Mfolozi Floodplain.
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Montane Wetlands of the South African Great Escarpment : plant communities and environmental driversJanks, Matthew Richard January 2015 (has links)
Wetlands provide a number of valuable functions to both the surrounding environment and society. The anaerobic conditions created by flooding in wetlands provide a habitat that supports unique assemblages of plant life. High altitude wetlands are amongst the most species-rich in South Africa. They house a number of rare species and play a vital role in the supply of water to lower lying areas. These are some of the reasons that mountain wetlands are of high conservation value. A phytosociological study was undertaken on the high altitude wetlands of the Great Escarpment with the aim of classifying the plant communities and identifying the environmental drivers of plant community patterns within these ecosystems. Data collection was focused in the Eastern Cape and was supplemented with data from existing studies to gain a more complete understanding of the wetlands of the Great Escarpment of South Africa. Using the Braun-Blanquet approach, Hierarchical Cluster Analysis and Indicator Species Analysis; five broad wetland groups were identified, comprised of 33 individual plant communities and 81 indicator species. Multivariate analysis, including Canonical Correspondence Analysis revealed that the effects of altitude, such as temperature and rainfall, are the most significant large-scale drivers of vegetation patterns. Smaller scale drivers include wetness and soil nutrients including nitrogen, phosphorus, electrical conductivity, sodium, and organic content. The identification of indicator species served to reveal potentially important wetland species across different areas of the Great Escarpment. The effects of altitude on plant community patterns highlights the susceptibility of the high altitude specific communities to upward temperature zone shifts resulting from global warming. Other threats include livestock trampling, water extraction, and land use change for agricultural purposes. The relative absence of alien species in these wetlands gives an indication of their pristine condition and therefore their importance as a reference from which they may be monitored. A large proportion of the wetlands studied here occur outside protected areas, and given the rate of wetland loss in South Africa, it is important that continued effective land management is practiced to ensure that these ecosystems are conserved in the future .
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An assessment of vegetation condition of small, ephemeral wetlands ecosystem in a conserved and non-conserved area of the Nelson Mandela Bay MetropoleDlamini, Mandla E January 2015 (has links)
Wetlands in South Africa are increasingly coming under threat from agriculture and urban development and rapidly disappearing, especially small, ephemeral wetlands. In response to the many threats to wetlands, South Africa has seen an increased interest in wetland research, which has introduced many methods to help standardize the approach to research, management and conservation of wetlands. Remote sensing can be a powerful tool to monitor changes in wetland vegetation and degradation leading to losses in wetlands. However, research into wetland ecosystems has focused on large systems (> 8 ha). Small wetlands (< 2 ha), by contrast, are often overlooked and unprotected due to the lack of detailed inventories at a scale that is appropriate for their inclusion. The main aim of this study was to determine if remote sensing (RS) and Geographical Information System (GIS) techniques could detect changes in small, ephemeral wetlands within areas under different management regimes in the Nelson Mandela Bay Metropole (NMBM) at different time intervals. Further, to explore the potential of hyperspectral remote sensing for the discrimination between plant species and to see if differences could be detected in the same species within two areas different management regimes. Four SPOT satellite images taken within a 6-year period (2006-2012) were analysed to detect land cover land changes. Supervised classification to classify land cover classes and post-classification change detection was used. Proportions of dense vegetation were higher in the conservation area and bare surface was higher outside that conservation area in the metropolitan open space area. Statistical tests were performed to compare the spectral responses of the four individual wetland sites using Normalized Difference Vegetation Index (NDVI) and red edge position (REP) .REP results for conserved sites showed significant differences (P < 0.05), as opposed to non-conserved ones. By implication, wetland vegetation that is in less degraded condition can be spectrally discriminated, than the one that is most degraded. Field spectroscopy and multi-temporal imagery can be useful in studying small wetlands.
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Economics of wetland cultivation in Zimbabwe: case study of Mashonaland East ProvinceTaruvinga, Amon January 2009 (has links)
Wetlands are stocks of natural resources limited in supply, in the middle of unlimited human wants with multiple uses to society, presenting an economic problem in as far as their rational and sustainable use is concerned. To that end, conflicting recommendations have been forwarded regarding wetland cultivation as a possible land use across the globe and from within the same regions. On one extreme, wetland cultivation has been linked to degradation of wetlands with pure wetland conservation as the prescribed viable and sustainable land use option to society. Closer to reality, partial wetland conversion to crop land has been found compatible with wetland bio-diversity; implying that partial wetland cultivation is the prescribed wetland use option viable and sustainable to societies, a dictum mainly claimed by rural communities. With that conflicting background and based on the “Safe Minimum Standard” approach, a ban on wetland cultivation was maintained in several early environmental policies in Zimbabwe as a basis for legislative protection of wetlands, a position that is still legally binding in current statutes. Contrary to that, rural communities have responded by invading wetlands as a coping strategy in pursuit of the claimed values of wetland cultivation, further conflicting with standing policies. This scenario has managed to “lock” and is currently locking the claimed 1,28 million hectares of wetlands in Zimbabwe in a “legal-operational impasse”, at a cost to the entire nation since no meaningful investment is possible in wetlands when there is a legal conflict.
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Relationship of vegetation to salinity and sodicity in wetland meadows of the Chilcotin region of British ColumbiaMayall, Alison Christina January 1985 (has links)
This study investigates the relationships between vegetation and salinity and sodicity in wetland meadows in the Chilcotin region of British Columbia.
Eleven vegetation communities and one group of releves with no vegetation
were identified using cluster analysis. An exchangeable sodium per cent of 15 and an electrical conductivity of 4 mmhos/cm were found to be appropriate boundaries for distinguishing between saline and sodic tolerant and intolerant vegetation communities. Some salt tolerant species and communities occurred in fresh conditions; however, intolerant species and communities were rarely found in saline or sodic conditions. Most meadows have soils that are low in salts, but 20 per cent had a high electrical conductivity and 18 per cent had a high exchangeable sodium per cent. / Land and Food Systems, Faculty of / Graduate
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Pre and post field trip activities for the Big Morongo Canyon Preserve: An oasis in the desertRichert, Kira Elizabeth 01 January 2002 (has links)
This teaching unit consists of pre and post field trip activities for the Big Morongo Canyon Preserve in Morongo Valley, California. The lessons provide background information to teachers and provide classroom activities on the desert and wetland environments. The lessons can be easily adapted for kindergarten through sixth grades.
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Exploring the Utility of High Resolution Imagery for Determining Wetland SignaturesDeLury, Judith Ann 03 July 2012 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Wetland habitats are characterized by periodic inundation and saturation by water creating anaerobic conditions that generate hydric soils and support hydrophytic vegetation. Wetland habitats provide important ecological functions including breeding grounds for fish, other wildlife, water purification, reduction in flooding, species diversity, recreation, food production, aesthetic value, and transformation of nutrients (Tiner, 1999). The multiple benefits of wetlands make them an important resource to monitor.
A literature review suggests a combination of geospatial variables and methods should be tested for appropriateness in wetland delineation within local settings. Advancements in geospatial data technology and ease of accessing new, higher resolution geospatial data make study at local levels easier and more feasible (Barrette et al, 2000).
The purpose of the current study is to evaluate new sources of geospatial data as potential variables to improve wetland identification and delineation. High resolution multispectral digital imagery, topographic data, and soils information are used to derive and evaluate independent variables. Regression analysis was used to analyze the data.
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Nutrient addition and the use of stable isotope techniques in wetlands of the Interlake Region of Manitoba, CanadaWeeber, Russell C. January 1994 (has links)
No description available.
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The interaction between vegetation and near-surface water in a wetland system, Stellenbosch, South AfricaKareko, John K.(John Kariuki) 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Understanding the responses of individual plant communities to variations in
near-surface water levels and to water quality is a step towards determining the critical or
important factors applicable to a Rapid Wetland Assessment System.
This thesis describes and discusses factors associated with wetland plant
communities, with an attempt to predict changes in a wetland system. This study was
initiated with a primary aim of establishing the relationship between plant communities
and the variation in near-surface water levels in areas occupied by various plant
communities in the Middelvlei wetland system at Stellenbosch. A second aim was to
assess whether water quality had an influence on the plant communities.
Seven plant communities are identified and described from this particular wetland
system using standard Braun-Blanquet techniques (Typha capensis Reedswamp; Cyperus
textilis Sedgeland; Pennisetum macrourum Grassland; Juncus effusus Sedgeland;
Cyperus longus Sedgeland; Cliffortia strobilifera Shrubland and Populus canescens
Forest). The Typha capensis Reedswamp community is found in the wettest parts of the
wetlands, with a fluctuation in water table from 0.10 m above surface during the wet
season to 0.43 m below surface during the dry season. The Populus canescens Forest is
actively invading the wetland replacing the wetland species by modifying the wetland
hydrological condition. Water samples from 35 wells, collected on a monthly basis over
11 months, are used to assess sodium, magnesium, potassium, calcium, nitrate and
phosphate, pH, redoxs potencial and dissolved oxygen levels in each community, over
four seasons.
Both multivariate analysis (ANOVA) and regression tree analysis (CART) are
applied to evaluate differences between communities or groups of plant communities on a
seasonal basis. Direct gradient analysis (CCA) is used to determine the relationship
between plant communities and environmental variable gradients.
A wide variation in water quality condition between plant communities is present.
The Typha capensis Reedswamp community is associated with low nutrient levels
(phosphates and nitrates) in all seasons. The Cyperus textilis Sedgeland is associated with low levels of nitrates and high phosphate levels. The Juncus effusus Sedgeland displays
the highest phosphate concentration, occurring in summer, while low nitrate levels occur
in this community during all the seasons.
Dissolved oxygen in the near-surface water in this wetland is at very low
concentrations, and has no significant difference between communities. It plays no major
role in determining the occurrence and distribution of the plant communities.
Most of the water chemical constituents measured in this study are the result of
multiple complex relationships, with constituent variations occurring differently between
communities. A remarkable seasonal distinction in the chemical constituents in different
communities is present.
Despite the complex nature of the relationships between plant communities and
environmental factors, the low species diversity levels through the tendency for single
species dominance and the strong association of these communities with particular
environmental variables, the combination of these factors all add value to the use of
wetland vegetation as a good tool to indicate wetland condition. An effort to understand
wetland plant communities in relation to determining environmental factors would
promote the use of plant communities as user-friendly tools for wetland monitoring and
assessment. / AFRIKAANSE OPSOMMING: Om die reaksies van plantgemeenskappe teenoor variasies in naby-oppervlakte
watervlakke te verstaan, is die eerste krities-belangrike faktor die ontwikkeling van ‘n
sisteem om vleilande vinnig te assesseer. Hierdie studie se basiese mikpunt is om
verwantskappe te soek tussen plantgemeenskappe in die Middelvlei Vleilandsisteem en
wisseling in naby-oppervlak watervlakke. ‘n Sekondêre doel is om te bepaal of daar
enige korrelasie is tussen waterkwaliteit en die plantgemeenskappe teenwoordig in die
vleiland.
Sewe plantgemeenskappe is in hierdie vleilandsisteem geïdentifiseer en beskryf
deur gebruik te maak van standaard Braun-Blanquet tegnieke, naamlik die Typha
capensis Rietmoeras; Cyperus textilis Biesieveld; Pennisetum macrourum Grasveld;
Juncus effusus Biesieveld; Cyperus longus Biesieveld; Cliffortia strobilifera Struikveld
en ‘n Populus canescens Woud. Die Typha capensis Rietmoeras kom in die natste dele
van die vleilande voor, met vrywater wisselling vanaf 0.10 m bo grondoppervlakte,
tydens die nat-seisoen, tot 0.43 m onder grondoppervlakte tydens die droë seisoen. Die
Populus canescens Woud het die grootste wisseling in watervlak vanaf die
grondoppervlakte tot ten minste ‘n diepte van 1.0 m gehad. Dit blyk dat die Populus
canescens Woud besig is om die vleigemeenskappe aktief binne te dring deur die vleiland
uit te droog.
Water is maandeliks, oor 11 maande, uit 35 geperforeerde plastiek pype,
sogenaamde ‘putte’ onttrek, om natrium, magnesium, kalium, kalsium, nitrate en fosfate,
pH, redokspotensiaal en opgeloste suurstof vlakke se seisoenale wisseling te bepaal.
Beide veelvuldige analise (ANOVA) en regressie-analises (CART) is bereken om enige
betekenisvolle verskille tussen plantgemeenskappe te bepaal. Direkte Gradiëntanalise
(CCA) is gebruik om die verwantskap tussen plantgemeenskappe en gradiënte van
omgewingsveranderlikes te bepaal.
Groot variasies in waterkwaliteit tussen plantgemeenskappe is waargeneem. Die
Typha capensis Rietmoeras-gemeenskap is geassosieer met lae voedingstofvlakke (veral
van fosfate en nitrate) in alle seisoene. Die Cyperus textilis Biesieveld-gemeenskap is geassosieer met lae nitraat- en hoë fosfaatvlakke. Die Juncus effusus Biesieveldgemeenskap
vertoon die hoogste fosfaatvlakke, tydens die die somermaande, terwyl die
nitraatvlakke deur al die seisoene ook laag bly.
Opgeloste suurstof in die naby-oppervlakte water in die vleilandsisteem het
deurgaans ‘n lae konsentrasie vertoon met geen betekenisvolle verskille tussen
gemeenskappe nie. Dit speel dus geen belangrike rol in die voorkoms of verspreiding
van die plantgemeenskappe nie
Die meeste van hierdie faktore, gemeet om die waterkwaliteit te bepaal, het
veelvoudige, komplekse verhoudingsverskille, gebaseer veral op konsentrasieverskille,
tussen die gemeenskappe.
Ten spyte van die komplekse verwantskap tussen die plantgemeenskappe en
omgewingsfaktore, is die spesierykheid laag en kom die neiging tot eensoortigedominansie
algemeen in die vleiland-plantgemeenskappe voor. Die sterk assosiasie
tussen die plantgemeenskappe en bepaalde omgewingsveranderlikes voeg aansienlike
waarde daaraan toe om vleilandplantegroei te gebruik as indikator van vleilandtoestand.
‘n Poging om die verwantskappe tussen vleiland-plantgemeenskappe en
omgewingsveranderlikes algemeen te bepaal, sal die gebruikersvriendelike nut van
vleiland-plantgemeenskappe vir vleilandmonitering en assessering duidelik uitwys.
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LONG-TERM MONITORING OF RIPARIAN/WETLAND AREAS.Noon, Kevin Francis. January 1982 (has links)
No description available.
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