Ecosystems on the South African west coast provide a number of resources including food, minerals and oil and gas. The west coast therefore supports large commercial fishing and mining industries highlighting the economic importance of this area (Sink et al. 2012).
However, these commercial activities also present a threat to biodiversity. It is therefore
48
imperative to reach a compromise which allows for both the protection of biodiversity and the continuation of commercial activities.
Commercial activities on the west coast include diamond mining, oil and gas exploration and demersal trawl fishing. The effects of diamond mining and demersal trawl fishing have been quantified on the west coast (Savage et al. 2001, Steffani 2007, Atkinson et al. 2011).
However, these impact studies highlighted concerns about the lack of baseline information.
Differences between impacted and control sites could not be assessed in the context of the general variation in biological communities on the continental shelf since this has not yet been investigated (Steffani 2007). In addition a baseline is lacking, since diamond mining and the demersal trawl fishery have been in operation since the early 1900s and the 1920s respectively (Griffiths et al. 2005). The lack of foundational understanding of macrofaunal community or species distributions has made it difficult to properly assess the impacts of various human activities (Steffani 2007, Atkinson et al. 2011).
The spatial extent of each user or threat has been mapped for the entire Exclusive Economic Zone of South Africa based on the best available data (Sink et al. 2012). Activities other than fishing and mining include naval activities, dumping of waste, placement of submarine cables and shipping. These mapped layers will be combined into a single cost layer which quantifies the cost of rezoning a particular area for conservation rather than the current use, commercial or not. This map will be developed in Chapter 8, where it will be incorporated into a systematic conservation plan.
Currently, a very small fraction of the west coast is formally protected in marine protected areas (MPAs) or management zones (Sink et al. 2012). Marine protected areas are limited to Cape Point, the West Coast National Park and Sixteen-mile beach (Fig. 2.8). All these MPAs are coastal, in depths shallower than 30 m, which leaves the entire offshore region of the west coast unprotected (Sink et al. 2012). The South African National Protected Area Expansion Strategy aims to expand the protection to 20 % of each habitat over the next 20 years by proclaiming new MPAs (Government of South Africa 2010) especially in the offshore and the northern part of the west coast where there is no protection at all (Sink et al. 2012).
A previous attempt to proclaim an MPA off the west coast (which was proposed in 2004) was met with great resistance from the fishing and mining industries operating in the area,
49
as well as the Department of Minerals and Energy (Sink 2007). One of the objections raised by industry was that the scientific basis for the nominated area was not clear or robust. It is thus pertinent to conduct foundational research in order to develop a more scientifically robust nomination for a west coast MPA.
Figure 2.8: Marine protected areas on the South African West Coast (Sink et al.
2012). “Other MPAs” refer to management areas where some extraction activities are allowed.
No-take MPAs Other MPAs
50
Systematic conservation planning in the marine environment is improving as better models are developed and tested (Carwardine et al. 2008, Game et al. 2008) and in South Africa as data are constantly added to these plans. The first South African National Marine and Coastal (SANMC) habitat classification system and integrated maps were recently developed (Sink et al. 2012). Thus far, most targets have been based on heuristics due to the limited data available, however it is a national priority to undertake scientific research to support conservation target setting for marine habitats in South Africa (Sink et al. 2012, Harris et al.
in press), for example Harris et al. (in press). In addition, marine unconsolidated sediment habitats were not considered vulnerable, so they were included in biodiversity plans for representation only (Clark and Lombard 2007, Lombard et al. 2007). A national beach classification has recently been developed (Harris et al. 2010), which was verified and tested with biological data (Harris 2012). Harris (2012) revealed that despite the perception of robustness/resilience, South African beaches were under significant threat. Through a data intensive exercise, the standard 20 % biodiversity target was deemed too low to ensure the protection of South Africa’s beaches, and a 27 % target was derived instead.
Harris (2012) then produced the first ecosystem-based conservation plan for South African beaches. This thesis will produce the first systematic conservation plan for the South African west coast subtidal unconsolidated sediments.
In this thesis, the South African west coast is used as a case study for the development of habitat classifications, setting of habitat-specific targets and production of an ecosystem-based systematic conservation plan for marine unconsolidated sediments. Since the physical processes on the west coast are similar to that of other Eastern Boundary Upwelling Regions, the results of this study will be applicable elsewhere.
References
Andrews, W. R. H. and L. Hutchings. 1980. Upwelling in the Southern Benguela Current. Progress in Oceanography 9:1-81.
Atkinson, L. J., J. G. Field, and L. Hutchings. 2011. Effects of demersal trawling along the west coast of southern Africa: multivariate analysis of benthic assemblages. Marine Ecology Progress Series 430:241- 255.
Bailey, G. W. 1991. Organic carbon flux and development of oxygen deficiency on the modern Benguela
continental shelf of 22°S: spatial and temporal variability. Pages 171-183 in R. V. Tysen and T. H. Pearson, editors. Modern and Ancient Continental Shelf Anoxia. Geological Society.
Bailey, G. W. and P. Chapman. 1985. The nutrient status of the St Helena Bay region in February 1979. Pages 125-145 in L. V. Shannon, editor. South African Ocean Colour and Upwelling Experiment. Sea Fisheries Research Institute, Cape Town.
Bally, R. 1987. The ecology of sandy beaches of the Benguela ecosystem. South African Journal of Marine Science 5:759-770.
51
Birch, G. F. and J. Rogers. 1973. Nature of the seafloor between Luderitz and Port Elizabeth. South African Shipping News and Fishing Industry Review 28:56-65.
Birch, G. F., J. Rogers, J. M. Bremner, and G. J. Moir. 1976. Sedimentation controls on the continental marginof southern Africa. Pages Fiche 20a, C21-D12 in Proceedings of the 1st Interdisciplinary Conference of Marine and Freshwater Research South Africa.
Branch, G. M. and G. C.L. 1988. The Benguela Ecosystem. Part V. The coastal zone. Oceanography and Marine Biology: an Annual Review 26.
Brown, A. C. and A. McLachlan. 1990. Ecology of Sandy Shores. Elsevier, Amsterdam.
Brown, A. C., A. McLachlan, G. I. H. Kerley, and R. A. Lubke. 2000. Functional Ecosystems: sandy beaches and dunes. National Research Foundation Report.
Carwardine, J., K. A. Wilson, M. Watts, A. Etter, C. J. Klein, and H. P. Possingham. 2008. Avoiding costly
conservation mistakes: the importance of defining actions and costs in spatial priority setting. Plos One 3:e2586.
Chapman, P. and L. V. Shannon. 1985. The Benguela ecosystem part II. Chemistry and related processes.
Oceanography and Marine Biology: an Annual Review 23:183-251.
Christie, N. D. 1975. Relationship between sediment texture, species richness and volume of sediment sampled by a grab. Marine Biology 30:89-96.
Christie, N. D. 1976a. The efficiency and effectiveness of a diver-operated suction sampler on a homogeneous macrofauna. Estuarine and Coastal Marine Science 4:687-693.
Christie, N. D. 1976b. A numerical analysis of the distribution of a shallow sublittoral sand macrofauna along a transect at Lamberts Bay, South Africa. Transactions of the Royal Society of South Africa 42:149-172.
Clark, B. M. and A. T. Lombard. 2007. A marine conservation plan for the Agulhas Bioregion: options and opportunities for enhancing the existing MPA network.
Crawford, R. J. M., L. V. Shannon, and D. E. Pollock. 1987. The Benguela Ecosystem. Part IV. The major fish and invertebrate resources. Oceanography and Marine Biology: an Annual Review 25:353-505.
De Decker, R. H. 1970. Notes on an oxygen-depleted subsurface current off the west coast of South Africa. Division of Sea Fisheries.
Demarcq, H., R. Barlow, and L. Hutchings. 2007. Application of a chlorophyll index derived from satelllite data to investigate the variability of phytoplankton in the Benguela ecosystem. African Journal of Marine Science 29:271-282.
Dingle, R. V. and G. Nelson. 1993. Sea-bottom temperature, salinity and dissolved oxygen on the continental margin off south-western Africa. South African Journal of Marine Science 13:33-49.
Field, J. G. 1971. A numerical analysis of changes in the soft-bottom fauna along a transect across False Bay, South Africa. Journal of Experimental Marine Biology and Ecology 7:215-253.
Game, E. T., M. E. Watts, S. Wooldridge, and H. P. Possingham. 2008. Planning for persistence in marine reserves: A question of catastrophic importance. Ecological Applications 18:670-680.
Gibbons, M. J.-. 1999. The taxonomic richness of South Africa’s marine fauna: a crisis at hand. South African Journal of Science 95:8-12.
Gordon, A. L., R. F. Weiss, J. Smethie, W.M., and M. J. Warner. 1992. Thermocline and intermediate water
communication between the South Atlantic and Indian Oceans. Journal of Geophysical Research 97:7223-7240.
Government of South Africa. 2010. South African National Protected Area Expansion Strategy: priorities for expanding the protected area network for ecological sustainability and climate change adaptation.
Government of South Africa, Pretoria.
Griffiths, C. L. 2005. Coastal marine biodiversity in East Africa. Indian Journal of Marine Sciences 34:35-41.
Griffiths, C. L., T. B. Robinson, L. L. Lange, and A. Mead. 2010. Marine Biodiversity in South Africa: an evaluation of current states of knowledge. Plos One 5:1-13.
Griffiths, C. L., L. van Sittert, P. B. Best, A. C. Brown, B. M. Clark, P. A. Cook, R. J. M. Crawford, J. H. M. David, B. R.
Davies, M. H. Griffiths, K. Hutchings, A. Jerardino, N. Kruger, S. Lamberth, R. W. Leslie, R. Mellville-Smith, R. Tarr, and C. D. Van der Lingen. 2005. Impacts of human activities on marine animal life in the Benguela:
a historical overview. Oceanography and Marine Biology an Annual Review 42:303-392.
Harris, L., R. Nel, and E. Campbell. 2010. Report to SANBI for the Marine Component of the National Biodiversity Assessment 2011: National Beach Classification and Mapping. Nelson Mandela Metropolitan University.
52
Harris, L., R. Nel, S. Holness, K. Sink, and D. Schoeman. in press. Setting conservation targets for sandy beach ecosystems. Estuarine, Coastal and Shelf Science.
Harris, L. R. 2012. An ecosystem-based spatial conservation plan for the South African sandy beaches. Nelson Mandela Metropolitan University, Port Elizabeth.
Holden, C. J. 1987. Observations of low-frequency currents and continental shelf wavesalong the west coast of South Africa. South African Journal of Marine Science 5:197-208.
Jarre, A., L. Hutchings, M. Crichton, K. Wieland, T. Lamont, L. K. Blamey, C. Illert, and E. Hill. in prep. Oxygen-depleted bottom waters along the west coast of South Africa, 1950-2011.
Kruger, N., G. M. Branch, C. L. Griffiths, and J. G. Field. 2005. Changes in the epibenthos of Saldanha Bay, South Africa, between the 1960s and 2001: an analysis based on dredge samples. African Journal of Marine Science 27:471-477.
Lange, L. 2012. Use of demersal bycatch data to determine the distribution of soft-bottom assemblages off the West and South Coasts of South Africa. Uiversity of Cape Town, Cape Town.
Leslie, R. W., R. L. Tinley, and J. Rogers. 2000. Functional Ecosystems: soft subtidal substrates. National Research Foundation Report.
Lombard, A. T., B. Reyers, L. Y. Schonegevel, J. Coopers, L. B. Smith-Adao, D. C. Nel, P. W. Froneman, I. J. Ansorge, M. N. Bester, C. A. Tosh, T. Strauss, T. Akkers, O. Gon, R. W. Leslie, and S. L. Chown. 2007. Conserving pattern and process in the Southern Ocean: Designing a marine protected area for the Prince Edward Islands. Antarctic Science 19:39-54.
Lombard, A. T., T. Strauss, J. Harris, K. Sink, C. Attwood, and L. Hutchings. 2004. National Spatial Biodiversity Assessment 2004 Technical Report. Volume 4: Marine Component. South African National Biodiversity Institute, Pretoria.
McArdle, S. B. and A. McLachlan. 1991. Dynamic of swash zone and effluent line on sandy beaches. Marine Ecology Progress Series 76:91-99.
McLachlan, A., E. Jaramillo, T. E. Donn, and F. Wessels. 1993. Sandy beach macrofauna communities and their control by the physical environment: a geographical comparison. Journal of Coastal Research 15:27-38.
McLachlan, A., T. Wooldridge, and A. H. Dye. 1981. The ecology of sandy beaches in southern Africa. South African Journal of Marine Science 16:219-231.
Monteiro, P. M. S., G. Nelson, A. K. van der Plas, E. Mabille, G. W. Bailey, and E. Klingelhoeffer. 2005. Internal tide-shelf topography interactions as a forcing factor governing the large-scale distribution and burial fluxes of particulate organic matter (POM) in the Benguela upwelling system. Continental Shelf Research 25.
Monteiro, P. M. S. and A. K. van der Plas. 2006. Low oxygen water (LOW) variability in the Benguela system: key processes and forcing scales releveant to forecasting. Pages 71-90 in V. Shannon, G. Hempel, P.
Malanotte-Rizzoli, C. Moloney, and J. Woods, editors. Benguela: Predicting a Large Marine Ecosystem.
Elsevier B.V./Ltd.
Nelson, G. 1985. Notes on the physical oceanography of the Cape Peninsula upwelling system. Pages 63-95 in L. V.
Shannon, editor. South African Ocean Colour and Upwelling Experiment. Sea Fisheries Research Institute, Cape Town.
Nelson, G. and A. Polito. 1987. Information on currents in the Cape Peninsula area, South Africa. South African Journal of Marine Science 5:287-304.
Penney, A. J., A. Pulfrich, J. Rogers, N. Steffani, and V. Mabille. 2007. Data Gathering and Gap Analysis for Assessment of Cumulative Effects of Marine Diamond Mining Activities on the BCLME Region.
Rogers, J. and J. M. Bremner. 1991. The Benguela Ecosystem. Part VII. Marine-geological aspects. Oceanography and Marine Biology: an Annual Review 29:1-85.
Rogers, J. and A. J. Rau. 2006. Surficial sediments of the wave-dominated Orange River Delta and the adjacent continental margin off south-western Africa. African Journal of Marine Science 28:511-524.
Savage, C., J. G. Field, and R. M. Warwick. 2001. Comparative meta-analysis of the impact of offshore marine mining on macrobenthic communities versus organic pollution studies. Marine Ecology Progress Series 221:265-275.
Shannon, L. V. 1985. The Benguela ecosystem: Part i. Evolution of the Benguela physical features and processes.
Oceanography and Marine Biology: an Annual Review 23:105-182.
Sink, K. 2007. Report on Constraints and Opportunities for the Proclamation of Offshore Marine Protected Areas in South Africa. WWF-SANBI-DEAT, Cape Town.
53
Sink, K., S. Holness, L. Harris, P. Majiedt, L. Atkinson, T. Robinson, S. Kirkman, L. Hutchings, R. Leslie, S. Lamberth, S.
Kerwath, S. von der Heyden, A. Lombard, C. Attwood, G. Branch, T. Fairweather, S. Taljaard, S. Weerts, P.
Cowley, A. Awad, B. Halpern, H. Grantham, and T. Wolf. 2012. National Biodiversity Assessment 2011:
Technical Report. Volume 4: Marine and Coastal Component. South African National Biodiversity Institute, Pretoria.
Steffani, N. 2007. Biological baseline survey of the benthic macrofaunal communities in the Atlantic 1 Mining Area and the inshore area off Pomona for the Marine Dredging Project. De Beers Marine Namibia.
Veitch, J. 2009. Equilibrium dynamics of the Benguela system: a numerical modelling approach University of Cape Town, Cape Town.