Aspects of the ecology of sandy beaches along Durban's urbanised coastline.
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Date
2009
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Abstract
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.
Description
Thesis (M.Sc.)-University of KwaZulu-Natal, 2009.
Keywords
Coastal ecology--KwaZulu-Natal--Durban., Beaches--KwaZulu-Natal--Durban., Theses--Environmental biology.