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Aspects of the ecology of sandy beaches along Durban's urbanised coastline.Govender, Natasha. January 2009 (has links)
Urban sandy beaches are the primary focus of numerous pressures. Among these are
the disruption of sand budgets because of an increasing demand for coastal
infrastructure, pollution from landward sources, and recreation and the associated
stressors such as trampling and off-road vehicles. More recently, climate change and
the manifestations thereof, such as sea-level rise and increased storminess have added
to the suite of threats to sandy beach ecosystems. Despite being important natural and
economic resources these urban systems have not received adequate research
attention and, consequently, the management of sandy beaches has been based on
ecologically unsustainably principles.
The aims of this study were to provide baseline biodiversity information of
urban beaches along the Durban coastline, South Africa, as a step toward the
application of improved ecological management procedures for metropolitan beach
ecosystems. Macro- and meiofaunal communities of 15 representative beaches along
the Durban coastline were quantitatively surveyed using standard sandy beach
sampling protocols.
This study showed that Durban’s beaches, despite being highly urbanised,
harbour rich and abundant faunal communities. This is contrary to previous findings
that reported a paucity of life on Durban beaches. A total of 23 macrofauna taxa were
identified, with the dissipative Battery Beach having highest diversity with 13
macrofaunal species. La Lucia, a reflective beach, had the highest macrofaunal
abundance and was the second most diverse beach, thus departing from global trends
that report a poor macrofaunal community of reflective beaches. Twenty higher-level
meiofauna taxa were recorded in this study and it was found that meiofauna
abundance showed a significant and positive relationship with beach width. Because
of the coarse taxonomic resolution, meiofauna diversity may likely be much greater
than that recorded in this study.
The conventional view that sandy beaches are resilient to exploitation was
questioned when it was found that meiofauna assemblages were significantly and
negatively impacted by stormwater outlets on two of the sampled beaches, possibly
through freshwater intrusion or erosional effects. This raises questions regarding the
functioning of beach ecosystems, and the services they provide, when faced with
anthropogenic stressors that impact faunal communities.
This snapshot survey of aspects of the ecology of Durban’s sandy beaches has
provided much needed baseline data for this coastline. These data will be used in
conjunction with other available data toward the development of a fine scale
systematic conservation plan for Durban to enable the prioritisation of conservation
and management efforts. The use of these data will also facilitate the development of
guidelines for the integrated ecological management of urban sandy beach
ecosystems. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2009.
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A comparative study of the plant ecology of three estuaries : Mgeni, Mhlanga and Mdloti.Raiman, Feisal. 21 October 2013 (has links)
The vegetation of the Mgeni Estuary, Mhlanga Estuary and Mdloti Estuary
was analysed according to the Braun-Blanquet phytosociological method
using quadrats of 4m2 and 25m2 in area placed subjectively and the
Point-Centred Quarter method with points chosen whilst traversing. A
classification of plant communities is given. These are described
floristically and related to habitat variables. Indicator species of
the climatic climax of coast forest occur within the study area. The
absence of coast forest is ascribed to low altitude, tidal inundation
and the consequent effect of salinity, basal inundation resulting in a
high water-table and the influence of man. The floodplain of the Mgeni
Estuary is dominated by mangrove vegetation comprising mainly Bruguiera
gymnorrhiza and Avicennia marina whereas vegetation established on
Athlone Island is dominated by mesophytic thicket comprising mainly
Schinus terebinthifolius, Lantana camara, Chromolaena odorata and
Cardiospermum grandiflorum. The floodplain of the Mhlanga Estuary is
dominated by Phragmites australis. The shores of the Mdloti Estuary are
dominated by Barringtonia racemosa, Phragmites australis and Echinochloa
pyramidalis. Major differences in vegetation patterns of the three
systems are related primarily to the differences in the open nature of
the river mouths. This is controlled mainly by river flow and longshore
drift. Differences in vegetation patterns within an estuary are
dependent on differences in tolerances to salinity, basal inundation and
shade, together with variations in altitude and edaphic factors and
competition between species. Generally soils of Mgeni Estuary had higher
contents of small sized fractions, bulk densities, reserve acidities, organic matter, salts and exchangeable bases and lower pH than soils at
Mhlanga Estuary and Mdloti Estuary. Differences exist between mangrove
and non-mangrove soils at Mgeni Estuary and differences between the non-
mangrove soils at the three study sites. Major differences in soil characteristics are as a result of differences in tidal inundation,
geogenetic parameters and biotic factors. Information on topography,
hydrology, geology, climatic factors, biotic factors and historical
background of the area is given. A check-list of vascular plants is included. The work is illustrated by 44 figures. / Thesis (M.Sc.)-University of Durban-Westville, 1986.
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