south african national spatial biodiversity assessment 2004 technical...

South African National Spatial Biodiversity Assessment

2004 Technical Report

Volume 4: Marine Component

Prepared by

Dr Amanda T. Lombard1 Ms Taniia Strauss1

Dr Jean Harris2 Dr Kerry Sink3

Dr Colin Attwood4 Dr Larry Hutchings4

1Conservation Systems

2 Ezemvelo KwaZulu-Natal Wildlife 3 Independent Marine Research

4 Marine and Coastal Management

Principal Contributors Dr Rob Anderson (Marine and Coastal Management)

Prof. John Bolton (University of Cape Town) Prof. George Branch (University of Cape Town)

Prof. Richard Cowling (University of Port Elizabeth) Mr Laurent Drapeau (Marine and Coastal Management, IDYLE Project)

Dr Peter Goodman (Ezemvelo KwaZulu-Natal Wildlife) Prof. Charles Griffiths (University of Cape Town)

Mr Bruce Mann (Oceanographic Research Institute) Dr Jane Turpie (University of Cape Town)

DRAFT October 2004

This report forms part of a set of five reports on the South African National Spatial Biodiversity Assessment 2004. The full set is as follows: Summary Report Driver, A., Maze, K., Lombard, A.T., Nel, J., Rouget, M., Turpie, J.K., Cowling, R.M., Desmet, P., Goodman, P., Harris, J., Jonas, Z., Reyers, B., Sink, K. & Strauss, T. 2004. South African National Spatial Biodiversity Assessment 2004: Summary Report. Pretoria: South African National Biodiversity Institute. Technical Reports Volume 1: Terrestrial Component Rouget, M., Reyers, B., Jonas, Z., Desmet, P., Driver, A., Maze, K., Egoh, B. & Cowling, R.M. 2004. South African National Spatial Biodiversity Assessment 2004: Technical Report. Volume 1: Terrestrial Component. Pretoria: South African National Biodiversity Institute. Volume 2: River Component Nel, J., Maree, G., Roux, D., Moolman, J., Kleynhans, N., Silberbauer, M. & Driver, A. 2004. South African National Spatial Biodiversity Assessment 2004: Technical Report. Volume 2: River Component. CSIR Report Number ENV-S-I-2004-063. Stellenbosch: Council for Scientific and Industrial Research. Volume 3: Estuary Component Turpie, J.K. 2004. South African National Spatial Biodiversity Assessment 2004: Technical Report. Volume 3: Estuary Component. Pretoria: South African National Biodiversity Institute. Volume 4: Marine Component Lombard, A.T., Strauss, T., Harris, J., Sink, K., Attwood, C. & Hutchings, L. 2004: South African National Spatial Biodiversity Assessment 2004: Technical Report. Volume 4: Marine Component. Pretoria: South African National Biodiversity Institute. Comments and feedback The reports are currently in draft format. Comments and feedback are welcome, and should be sent to the lead author in each case: Mandy Driver: [email protected] Mathieu Rouget: [email protected] Jeanne Nel: [email protected] Jane Turpie: [email protected] Mandy Lombard: [email protected] Final versions of the reports will be available at www.nbi.ac.za The National Spatial Biodiversity Assessment was commissioned by the Department of Environmental Affairs and Tourism as part of the NBSAP. It was co-funded by the Department of Environmental Affairs and Tourism and the South African National Biodiversity Institute.

South African National Spatial Biodiversity Assessment 2004: Technical Report Vol. 4 Marine Component

DRAFT October 2004 i

Acknowledgements This report was made possible because of the commitment of the South African community to the conservation of our marine living resources. I thank each and every person who attended the expert workshops, who answered the phone many times, and who gave freely of his or her data, expertise and time. I thank my contributors for the many hours they invested in this project, often at times that were very inconvenient for them. I apologise if I have misquoted anyone in this report. An enormous amount of information was made available to this project, and not all of it appears in this report. However, with more time, and further projects (as recommended in this report), these data will hopefully be incorporated into future assessments. Although I attempted to be as consultative as possible during the course of this project, crucial people, or data, or information, may have been overlooked. My apologies also to those people, and I hope this report will stimulate even more networking and integration of our pooled marine expertise and resources. Mandy Lombard, September 2004 Additional contributors (i) Expert workshop participants (many participants also provided data) Name Affiliation Adams, Janine University of Port Elizabeth Allen, John South African National Parks Best, Peter Mammal Research Institute, University of Pretoria

Bornman, Tom South African Biodiversity Institute for Environmental and Coastal Management

Cellier, Louis Oceanographic Research Institute Cliff, Geremy Natal Sharks Board Dudley, Sheldon Natal Sharks Board Forbes, Tikki University of KwaZulu-Natal Hamilton, Rose Ezemvelo KZN Wildlife Hanekom, Nick South African National Parks Jury, Mark University of Zululand

Klages, Norbert South African Biodiversity Institute for Environmental and Coastal Management

Leslie, Rob Marine and Coastal Management Leuci, Rio Council for Marine Geoscience Morty, Ken Ezemvelo KZN Wildlife Moss, Tamsyn Ezemvelo KZN Wildlife Nel, Deon World Wildlife Fund South Africa Nel, Ronel Ezemvelo KZN Wildlife Peddemors, Vic University of KwaZulu-Natal Prochazka, Kim International Ocean Institute Ramsay, Peter Marine GeoSolutions Reaugh, Kathleen Ezemvelo KZN Wildlife Roberts, Mike Marine and Coastal Management Roos, Lesley De Beers


DRAFT October 2004 ii

Name Affiliation Rouget, Mathieu South African National Biodiversity Institute Samaai, Toufiek University of KwaZulu-Natal Schleyer, Micheal Oceanographic Research Institute Schoeman, David University of Port Elizabeth

Scott, Lucy African Coelacanth Ecosystem Programme, South African Institute for Aquatic Biodiversity

Smith, Kyle Orca Foundation Tomalin, Mariana Ezemvelo KZN Wildlife Whitfield, Allen South African Institute for Aquatic Biodiversity (ii) Other participants (provided advice, information, digital data, publications and support) Name Affiliation Anderson, Eric South African Institute for Aquatic Biodiversity Clark, Barry Anchor Environmental Consultants Coetzee, Muller Common Ground Consultants Connell, Allan Council for Scientific and Industrial Research Driver, Mandy Botanical Society Gardner, Len GISCOE Geach, Bev Department of Environmental Affairs and Tourism Goetz, Albrecht Rhodes University Herbert, Dai Natal Museum Job, Nancy South African National Biodiversity Institute Kaehler, Sven Rhodes University Kampfer, Captain A. Hydrographic Office, South African Navy Kerwath, Sven Rhodes University Laing, David Conservation Systems Laing, Rory Conservation Systems Leslie, Kathy Common Ground Consultants Maneveldt, Gavin University of the Western Cape Maze, Kristal South African National Biodiversity Institute McClurg, Tim Council for Scientific and Industrial Research McQuaid, Chris Rhodes University Osborne, Sidney Hydrographic Office, South African Navy Peschak, Tom University of Cape Town Rand, Andrew University of Cape Town Reyers, Belinda Council for Scientific and Industrial Research Savy, Conrad University of Cape Town Scott, Robyn University of Cape Town Stewart, Warrick Biodiversity Conservation Unit, Wildlife and Environment Society

of South Africa Wolf, Trevor Conservation Systems Wood, James Mpenjati Nature Reserve and Trafalgar MPA


DRAFT October 2004 iii

Contents

PageExecutive Summary 1

1. Introduction………………………...………………………………………… 3

2. Planning domain………………………..………………………………………… 6

3. South African oceanography…………………………………………………… 7

4. Habitat classification and scope of project…………………………….…….. 11

5. Inshore bioregions………………………………………………………………... 17

6. Offshore bioregions………………………………………………………………. 18

7. Biozones………..…………………………………………………………………… 21

8. Marine protected areas………………………………………………………….. 23

9. Target achievement analyses………………………………………………….. 32

10. Planning units……………………………………………………………………… 34

11. Species analyses…………………………………………………………………. 37

12. Intertidal analyses………………………………………………………………… 46

13. Subtidal analyses…………………………………………………………………. 61

14. Deep photic complexity………………………………………………………….. 73

15. Protection status of biozones …….……………………….…..……………….. 80

16. Threat status of biozones……………………………………………….………. 82

17. Priority status of biozones………………………………………..………… 93

References…………………………………………………………………… 95

Appendix 1: Bioregions 97

Appendix 2: Threats 110

Appendix 3: Marine species targeted by South African fisheries 139

Appendix 4: Threatened marine species 151

Appendix 5: Threatened marine habitats 152

Appendix 6: Recommended future projects 153

Appendix 7: GIS map projection information 154


DRAFT October 2004 1

Executive summary This report presents a spatial assessment of the conservation status of selected marine biodiversity patterns in South Africa, at a national scale. It addresses a subset of marine species, and broad scale intertidal and subtidal habitats (within South African waters, to the Exclusive Economic Zone - EEZ). The Prince Edward Islands are not addressed. The mobile component of marine biodiversity is also not addressed (i.e. biodiversity processes, and the fish and bird fauna). Estuaries are dealt with in a separate NSBA report (Turpie 2004). This report is therefore not useful for fisheries management and does not provide information on sustainable use. It is, however, useful for improving biodiversity management in the marine environment. In addition to a spatial conservation assessment, we provide lists of the top ten biodiversity crises in South Africa’s marine environment; important biodiversity processes; marine species targeted by South African fisheries; threatened marine species; and priority projects for future research. We also provide two detailed Appendixes discussing the bioregions defined for this report, and threats to marine biodiversity. The take-home messages of this report are that the top ten crises listed in the introduction need to be addressed urgently; improved fisheries management is required; and the spatial gaps in South Africa’s marine protected area estate need to be filled. This report provides suggestions as to where to fill these gaps, but without a complete analysis of the fish fauna, the conclusions presented here must be regarded as preliminary. Our spatial evaluation of existing marine protected areas (MPAs) in South Africa shows that although 23% of the South African coastline falls within MPAs, only 9% of this is fully protected (i.e. occurs in no-take MPAs). In addition, this 23% is not evenly distributed among bioregions, and is thus not representative of South Africa’s coastal marine biodiversity. The entire Namaqua bioregion (on the west coast) has no MPA, whereas the Delagoa bioregion (on the Mozambique border) enjoys over 20% protection in no-take MPAs. Moving offshore, less than 1% of South Africa’s EEZ falls within MPAs, and of this, less than 0.2% is no-take. The proclamation of the proposed Namaqualand MPA would more than double the sea surface area under protection, but would still fall very short of the ≥ 20% target set by international recommendations (WPC 2003). Results of the species analyses show that many species may occur in existing no-take MPAs, but their status within these MPAs is unknown and surveys within reserves are required to confirm both their presence, and their viability. Even if all existing MPAs were proclaimed as no-take, gaps would still exist in the protection of these species. We list seven geographical areas where these gaps can be filled. If the proposed Namaqualand MPA is proclaimed, it may possibly represent all of the species we analysed along the Northern Cape coastline. Owing to the fact that the fish fauna are the most exploited and threatened component of marine species, we stress that an accurate fish distribution database needs to be compiled with urgency, to allow these analyses to be repeated (the fish data we used were range-based and require updating). Analyses of intertidal habitats show that no-take MPAs do not provide adequate protection for these habitats. Declaring all other MPAs no-take would still leave many habitats inadequately protected, such as the sandy beaches of the Agulhas and Natal bioregions, and the entire Namaqua bioregion. We identify 11 areas that need to be added to the MPA



estate to adequately represent intertidal habitats. Fortunately, many of these overlap with the areas identified by the species gap analyses. Results of the offshore analyses show that representative protection of the South African EEZ cannot be achieved with coastal MPAs that extend two or three nautical miles offshore. Even with the proposed Namaqualand MPA, many west coast offshore habitats will remain unprotected. Although our data and analyses must be considered as preliminary, they show that to meet internationally recommended targets of ≥ 20% of the extent of habitats, South Africa will have to consider the proclamation of offshore MPAs very seriously. In order to do this, further sampling of the offshore biota will be required. Calculations of the complexity within 10 or 50km stretches of the deep photic zone (10-30m depth) show that many of the most complex areas fall within existing MPAs. However, a few areas of high complexity do not, and we identify these areas. Owing to data constraints, several habitats were not mapped or analysed in this report, but are considered, by expert opinion, to be the most threatened. These are high profile reefs and pinnacles, soft-bottom trawling grounds, and the areas currently being mined on the west coast (both coastal and subtidal). To conclude the report, we subdivide the marine environment into 34 biozones, which are depth zones (moving from the coast to the abyss), subdivided by bioregions (moving from west to east). We present three sets of statistics for these biozones: a protection status, a threats status, and a priority status. Protection status data show that 23 of the 34 biozones have either zero or poor protection. None of the Namaqua biozones are protected, and no part of the lower slope or the abyss in South Africa’s EEZ is protected. Well-protected biozones include many of the supratidal biozones, and the biozones of the Delagoa bioregion. We note, however, that MPAs do not always ensure adequate protection of their biodiversity, and more effort needs to be put into ensuring compliance within MPAs. The threat status analyses make it clear that extractive marine living resource use is the overriding threat to South African marine biodiversity, and it affects all depth strata and all bioregions. Pollution and mining are the next most serious threats, but mining is restricted to particular biozones, especially on the west coast. Both mining and commercial fishing are responsible for the Critically Endangered status of the west coast biozones. All threats are predicted to increase in the next ten years, especially alien invasive species, and mariculture. Owing to the high number of species (~340) targeted by South African fisheries, more species-level interventions may be required in the marine environment than in the terrestrial environment. Finally, the priority status results show that the west coast biozones not only have the least protection (zero), but also currently experience the greatest threats. Conservation intervention in these biozones is required immediately. A spatially-explicit conservation assessment, as is provided in this report, goes some of the way to identifying what to do, and where, in the marine environment. As data improve, the assessment can be expanded to more species, and more habitats, at finer scales. An additional challenge, however, is to improve our understanding of the moving component of biodiversity, both biotic and abiotic, if we are to conserve marine biodiversity in the long term.



1. Introduction This report is a spatial assessment of the conservation status of selected marine biodiversity patterns in South Africa’s marine environment. The scale is national, and the results can be interpreted at a national scale only. It is not intended to provide fine-scale spatial solutions, and it does not cover all marine biodiversity patterns, nor does it address biodiversity processes. The biodiversity patterns addressed include the intertidal (both species and habitats) and the subtidal (abiotic sediments). Notable exceptions are fish, birds, reefs, and the water column. Owing to data availability and time constraints, the study was confined to that component of marine biodiversity that can currently be mapped at a national scale, and is not mobile. We acknowledge that one of the most threatened components of marine biodiversity is the fish fauna, and that a separate assessment of fish conservation status is required when appropriate data have been collated in a usable format. This report is therefore not useful for fisheries management and does not provide information on sustainable use. It is, however, useful for improving biodiversity management in the marine environment. In order to ensure that all of the impacts faced by marine biodiversity are at least listed in this report, if not dealt with spatially, we provide a list of the top ten most pressing non-spatial conservation concerns in South Africa’s marine environment (Table 1.1). Also, although we do not deal with biodiversity processes spatially, we provide a general list of the important processes in the South African marine environment (Table 1.2). Many of these processes have been mapped, at various scales, in South African waters (e.g. Hutchings et al. 2002), and the integration of this information into future conservation assessments is crucial. Threats to marine biodiversity have also been addressed at a national, rather than regional, scale. We provide a summary of the spatial distribution of these threats, and an Appendix that deals with them in qualitative detail. The report is concluded with a selection of other appendices which deal with non-spatial issues: a list of species targeted by South African fisheries; a list of threatened marine species; a list of threatened marine habitats; and a list of recommendations for future research. We gratefully acknowledge the inputs of the marine community in South Africa in making this report possible, and for providing us with much published material to work with (e.g. Huntley 1989; Attwood et al. 1997; Durham and Pauw 2000). We hope that the results produced and data collated in this report will be of use to future conservation assessments.



Table 1.1. The top ten biodiversity crises in South Africa’s marine environment. They require immediate intervention and crisis management. They are supplementary to the results of the biodiversity assessment provided in this report. 1. Fishing pressures and effort (both harvesting and processing) must be reduced, for

example, by reducing the number of boats, and the number of processing factories. 2. Access points to the coast must be limited, and possibly reduced (sea access from

e.g. launch sites, slipways and storm water pipes, and shore access from e.g. parking areas and paths). These are also areas where alien species are likely to arrive.

3. The future arrivals of invasive alien species must be prevented. They arrive in harbours via ballast water (this is currently being addressed by the Globallast Programme, Dr L. Jackson), but there are other species that arrive on the outside of ships, and there are also deliberate introductions. There have, however, been surprisingly few invasive aliens. Of these, the blue mussel (Mytilus galloprovincialis) cannot be eradicated but the European shore crab (Carcinus maenas) can, and needs to be.

4. Abalone poaching must be stopped. Abalone require a CITES listing. There should also be strict control on the mariculture of abalone (foreign species are already being brought in to the county, dead). Local abalone populations have been severely reduced and are therefore susceptible to alien invasion by the foreign species. Specific abalone reserves are needed, with strict control.

5. Mining on the west coast (diamonds, oil and gas) needs to be countered with good research on the effects of this mining, and the setting aside of representative habitats, in which no mining is permitted. These representative areas are also required for benchmarks and research (as reference sites). We need a better understanding of the impacts of mining on biodiversity and marine habitats. The shallow/on-shore mining operations cause the greatest environmental problems. There are also many almost sub-economic small mining operations. There is repeated mining of the same site and no recovery period is allowed (the recovery period is about 3-8 years). The Namaqualand MPA needs to be proclaimed with urgency.

6. Research into an ecosystem approach to fisheries (EAF) must be expanded. Fisheries need to address (i) bycatch side effects, (ii) indirect habitat modification/destruction and (iii) indirect effects to other components of the ecosystem e.g. top predators. In addition, the fishing practices of the fishing industry need to be improved (to achieve biodiversity best practice).

7. Areas for offshore MPAs (shelf and deep water) need to be identified. A systematic deep benthic survey is required. The most heavily impacted areas are trawlable soft sediments between 200-700 m.

8. A complete investigation into the impacts of pollution is required (e.g. sewerage and storm water, especially in False Bay). Mass migration of people into coastal areas is placing many coastal municipalities under pressure and their waste management requires careful monitoring and regulation.

9. Mariculture industries can pose an enormous threat to biodiversity and they need very strict regulation. Mariculture results in both ecosystem impacts and genetic pollution.

10. Coastal developments and their associated impacts need to be very strictly controlled. These developments pose a major threat to many components of the marine environment, owing to their cumulative effects, which are often not taken into account by impact assessments. These effects include organic pollution of run off and sewerage, transformation of the supratidal environment, alteration of dune movement, increased access to the coast and sea, and the negative impacts on estuaries.



Table 1.2. Important biodiversity processes in the South African marine environment. Understanding these processes will help us to understand, and therefore conserve, the mobile component of marine biodiversity. Important biotic processes

• Aggregation areas (e.g. for spawning, or feeding) • Feeding grounds • Migration routes • Nursery grounds • Spawning sites

Important abiotic processes (these pertain to water mass characteristics: the water mass moves, and the characteristics of the benthos below are inherited from the water column above it)

• Depth variation (this includes shelf width) • Large marine ecosystems/bioregions and interfaces between them • Low oxygen water • Major currents • Productivity (and nutrient flux to the photic zone) • Turbidity (this is linked to riverine input and productivity) • Upwelling areas (these are linked to productivity) • Water temperature • Wave action (at a finer scale)



2. Planning domain The planning domain for this study covers the South African coastline (from the Orange River mouth in the west to Ponta do Ouro in the east), and that part of the Atlantic and Indian Oceans that fall within South Africa’s Exclusive Economic Zone (EEZ) (Figure 2.1). The EEZ is defined as “an area, not exceeding 200 nautical miles from the baselines from which the breadth of the territorial sea is measured, subject to a specific legal regime established in the United Nations Convention on the Law of the Sea under which the coastal state has certain rights and jurisdiction” (IHO Dictionary, S-32, 5th Edition). Although the Prince Edward Islands are South African, they were not included in this study, because a separate programme is being developed for their conservation. Digital data for the South African coastline were obtained from 1:50 000 maps (South African Surveyor General). Based on these data, the total length of the South African coastline is approximately 3650km - note that this is an underestimation of the real coastal length because of the scale of the data: 1:10 000 data would give a longer length of coastline. However, this underestimation is offset to some extent by the fact that the 1:50 000 data include symbology for rocky coastlines. Digital data for the EEZ were obtained from the South African Navy Hydrographic Office. The total surface area of sea that falls within the EEZ is 1 071 883 km2.

Figure 2.1. The planning domain of the marine component of the National Spatial Biodiversity Assessment. The South African coastline length is approximately 3650km and the area within South Africa’s EEZ is 1 071 883 km2.

South Africa

Namibia

Mozambique

Botswana

MadagascarZimbabwe

Lesotho

Swaziland

South Africa (Prince Edward Islands)

EEZ



3. South African oceanography L. Hutchings South Africa is unique in having sharply contrasting currents on opposite coasts. The cold, productive Benguela Current occurs on the west coast and comprises a general equatorward flow of cool water in the South Atlantic gyre, with dynamic wind-driven upwelling close inshore at certain active upwelling sites. This helps create the low-rainfall Namib Desert, which extends northwards through Namibia and southern Angola. The water is characterised by high nutrient supply to the upper layers, dense plankton blooms, which reduce light levels and rich fisheries based on a few, dominant species such as anchovies, sardines, horse mackerel and hake. Much organic-rich matter sinks onto the relatively wide continental shelf, where decay processes reduce the dissolved oxygen content of the bottom waters to extremely low levels on the mid- and inner shelf. Occasional harmful algal blooms develop which independently, or in combination with low-oxygen water, result in mass mortalities of rock lobster, fish and invertebrates. River input is via the Orange, Olifants and Berg Rivers, but flow is intermittent and generally weak, except for occasional flood events such as in 1988, when millions of tons of fresh water and silt were transported onto the entire shelf region. The warm western boundary Agulhas Current flows strongly southward along the east coast, bringing nutrient-poor tropical water from the equatorial region of the western Indian Ocean. The waters are typically blue and clear, with low nutrient levels but very diverse biota from the rich Indo-Pacific region. Coral reefs, mangroves and high river input from numerous sources along the east coast characterise the shelf waters. Along the narrow shelf on the east coast, the Agulhas Current runs close to the shelf break, except off the Tugela Banks in the Natal Bight, where the shelf is a little wider. The coastline and adjoining interior has much higher rainfall than on the west coast as heat and moisture are transferred from the ocean to the atmosphere. South of the continent, the swift Agulhas Current moves offshore along the edge of the Agulhas Bank, a broad triangular section of the shelf extending nearly 100 nautical miles south of the coastline. Most of the Agulhas Current then bends back (retroflects) eastwards into the western Indian Ocean and heads towards Australia. Occasionally huge rings of warm water break off and slowly spin off into the South Atlantic, carrying heat, salt and some pelagic plants and animals characteristic of the Agulhas Current far into the South Atlantic Ocean. This movement of surface waters from the Indian Ocean to the Atlantic is an important component of the global circulation of water which replaces water sinking in the Greenland Sea and circulating throughout the world’s oceans, maintaining high oxygen levels in the deepest depths of the ocean. On the south coast, upwelling of nutrient-rich sub-photic water occurs along the shelf break and at promontories along the southern coastline, creating an intensive, dynamic mixing region on the broad Agulhas Bank of the south coast, intermediate in terms of temperature and productivity between the Benguela and Agulhas regimes. The south coast is an extremely important area for pelagic fish spawning, as eggs and larvae are swept westwards and northwards onto the west coast shelf, which the young fish utilise as a productive nursery area before returning to spawn on the Agulhas Bank. There are many endemic species on both the west and south coasts, while many east coast species are extensions from the diverse western Indian Ocean assemblages.



The entire South African coastline is generally subject to strong wave action, where swell heights in excess of five meters occur frequently. The prevailing swell direction is from the south west, and peak roughness occurs on the south-western Cape coastline, diminishing northwards and eastwards. The large semi-lunate bays and the minor rocky headlines and promontories provide isolated areas of relative calm along a generally exposed shoreline, providing contrasts on a bay scale within the different biogeographic regions. The strong oceanographic variability and in particular the contrasts in temperature, productivity and dissolved oxygen are reflected in the division of the marine biodiversity into three broad biogeographic regions, the cool temperate west coast, the warm temperate south coast and the subtropical east coast. There are complex interactions between the oceans and the atmosphere on a regional scale, combined with the effects of latitude, topography and soil types, which affect the rainfall patterns in South Africa. It is therefore not surprising that South Africa displays such high levels of both terrestrial and marine biodiversity within such a small area. The oceanic characteristics described in the text are illustrated in Figures 3.1 and 3.2. Figure 3.1 shows the temperature regimes of the two major currents (the Benguela and the Agulhas), and Figure 3.2 shows sea surface temperature and chlorophyll a values for January 2003 and 2004.



a

cd

e

f

f

f

b

South Africa

Figure 3.1. Satellite image of sea surface temperatures (thermal infrared radiance) off the South African south and west coasts. On the image red shows warm temperatures and blue cool temperature water. The features discussed in the text are: (a) The Agulhas Current. (b) Retroflection of the Agulhas Current into the south Indian Ocean. (c) Upwelling on the coastal margin driven by the Agulhas Current. (d) The mid-shelf ridge of cool water on the Agulhas Bank. (e) Wind driven upwelling on the west coast. (f) Major upwelling nodes.

Figure courtesy Sue Lane and Robin Carter



(a) (b) (c) (d)

Figure 3.2. Sea surface temperature (a and c) and near-surface chlorophyll a (b and d) images showing the high biomass, cool upwelled water on the west coast, the intermediate water on the south coast, and the tropical low chlorophyll a water on the east coast (except for the Natal Bight / Tugela Banks, b*).

27 January 2003

4 January 2004

*



4. Habitat classification and scope of project The marine environment was classified hierarchically for this study, in order to give clarity to the terminology used (Figure 4.1). We attempted to follow existing published classification structures and terminology where possible, and consulted many sources, for example Connor et al. (1995) and Zacharias and Howes (1998), as well as a local project being conducted by J. Harris (Biodiversity mapping and conservation planning for marine & coastal ecosystems of the east coast of South Africa). In all cases, we attempted to base our subdivisions on biological, rather than abiotic, differences. However, in cases where biological data were very limited (such as the abyssal zone), we had to use abiotic patterns as surrogates for biological patterns. We are aware that this relationship still needs to be tested (for example, see Stevens and Connolly 2004). Below we provide a brief summary of the rationale behind our classification. Bioregions Subdivisions are based on large-scale biological variability and biogeography, plus large scale habitat differences related to different current systems with different temperatures and productivity. We defined both inshore and offshore bioregions, both of which are described in following chapters. Tidal Zones Subdivisions are based on a large-scale dessication gradient. The supratidal zone is influenced by oceanic processes (such as sand movement and spray) but is not submerged; the tidal zone is sometimes submerged (and extends from mean spring high to mean spring low); and the subtidal zone is always submerged. Topographic zones Subdivisions are based on large-scale topographic variation e.g. rivers in the supratidal zone, estuaries in the tidal zone, and then the continental shelf, slope, and abyss in the subtidal zone. Depth strata Depth strata are subdivisions of the topographic zones according to depth. Figure 4.2 illustrates the depth strata defined for this study. The variables responsible for biological variation along depth strata include many factors such as wave action and light attenuation, but these vary at different depths depending on geographical location. For example, light attenuates at a much deeper level on the east coast than on the west coast, owing to the less productive and thus less turbid waters on the east coast. Wave action also attenuates at different depths, depending on the bottom topography, wave amplitude and wind regime. We attempted to define generic cut offs for depth strata, based on broad biological similarities along the South African coastline. The shallow photic, from mean spring low to roughly 10m depth, is the area with constant light and turbulence. At about 10m depth, there is a split with the seaweeds (and herbivory) dominating from 0-10m, and filter feeders replacing them below 10m. For example, herbivorous abalone occur in beds mostly from 0-15m. There is also a shift in seaweed genera - Ecklonia dominates the shallows and is replaced by Laminaria below 10m (on the west coast). In addition, plunge-diving birds most frequently dive to 12-15m. The first 10m is also sometimes referred to as the surf zone, and is impacted both by wave action, and by exploitation, for example the lobster trade and shore angling.



The 30m division between the deep photic and sub photic strata was based mainly on the attenuation of light and loss of wave-generated water movement, but as previously mentioned, this depth varies according to geographical location. Biological support for this depth is that there is very little macroalgae below 30m, and diving birds dive most frequently to 30m (e.g. penguins). In addition, the sardine runs occurs to this depth, and coral reefs occur up to about 25/30 m (although non-reef corals do occur below this depth in deeper subtidal habitats). The shelf break is the division between the sub photic part of the continental shelf, and the continental slope. Owing to the vastly different depths at which this break occurs, we refer to it simply as the shelf break, and do not attempt to place an actual depth value to it. It varies from about 400m in the Namaqua bioregion, to 200m in the Agulhas bioregion, 100m off Natal, and is as shallow as 50m in the Delagoa bioregion. It is most correctly defined by slope angle. The upper slope and lower slope meet between 1600-1800m, where there is maximum species diversity in all animal groups studied so far, with a mixing of the two zones’ biotas. The upper and lower slopes are also referred to as the upper and lower bathyal zones, respectively. From 1800-3500m, diversity decreases, and the distinct fauna harboured by this area is currently not fished, although new fishing techniques are penetrating as far as 1600m. The abyss is defined as the area below 3500m, and abyssal species generally do not occur above 2500m. Biologically, we assume more homogeneity around the South African coast at this depth, and consequently have defined fewer bioregions offshore than inshore. Substratum types Substratum types refer to the level of consolidation of the substratum, which can be unconsolidated (e.g. beaches, dunes, muddy sediments), or consolidated (e.g. rocky ledges or reefs), or mixed (e.g. mixed shore with rock and sand). Each of the depth strata can be divided into the substratum types shown in Figure 4.1. Ecosystems We divided ecosystems within each substratum type into plains, peaks and valleys. Examples for each of these are listed from 1 to 5 in the Ecosystems row in Figure 4.1. These numbers also refer the depth strata (as shown in the Depth Strata row in Figure 4.1). Habitats Our habitats are subdivisions of ecosystems, and occur at relatively broad scales. Different variables are used for the subdivisions. For example, we divided rocky shores according to wave exposure, and we divided subtidal sediments according to grain size. Biotopes Biotopes represent fine-scale biodiversity pattern (at the community level) and were not dealt with in this national-scale analysis.



Species We used the distribution data of three groups of species in our analyses: seaweeds, intertidal invertebrates, and fish. These data sets are described in detail in Chapter 11. Within Figure 4.1, the solid-coloured squares indicate features that were not dealt with in this study, either because of a lack of suitable data, or because of time constraints. Table 4.1 lists the habitats and species that were addressed, and the analyses that were conducted, in this report. A n/a in the Table indicates that habitats or species data are not currently available at a national scale.



Figure 4.1. The hierarchical marine habitat classification defined for this study.

SPECIES (examples) Seaweeds Invertebrates Fish Birds Marine mammals

BIOREGIONS (inshore)

AgulhasNamaqua South-western Cape Natal Delagoa

Prince Edward Islands

BIOTOPES (examples) e.g. zooanthid/barnacle community

TIDAL ZONES Supratidal SubtidalTidal

SUBSTRATUM TYPES Unconsolidated ConsolidatedMixed

HABITATS(examples)

DEPTH STRATA

Intertidal (has zones)

Sub photic

Deep photic

Upper slope

Lower slope

Coastal fringe (has zones)

AbyssShallow photic

1 2 3 4 5

ECOSYSTEMSPeaks1. Coastal cliff2. Intertidal cliff3. Reef4. Slope reef5. Seamount

Valleys1. River2. Estuary3. n/a4. Canyon5. Trench

Plains1. Rocky coast2. Rocky shore3. Rocky ledge4. Rocky slope5. Abyssal rock

Plains1. Back beach2. Beach3. Subtidal plain4. Sediment slope5. Abyssal plain

Peaks1. Dune2. n/a3. Subtidal dune4. Submerged delta5. Abyssal delta

Plains1. Mixed back beach2. Mixed shore3. Scattered reef4. Mixed slope5. Mixed abyssal plain

TOPOGRAPHIC ZONES

Shelf Slope AbyssRiverine Terrestrial/Marine interface

Estuarine Marine

e.g. sponge/hard coral community

BIOREGIONS (offshore)

Atlantic Indo-Pacific South-west Indian West Indian

DEPTH STRATUM: Intertidal (2)

HABITATS: sheltered, semi-exposed, exposed, very exposed

SUBSTRATUM TYPE: Consolidated

ECOSYTEM: Plains - Rocky shore

DEPTH STRATUM: Sub photic (3)

HABITAT: East Coast dunes

SUBSTRATUM TYPE: Unconsolidated

ECOSYTEM: Peaks – Subtidal dune

DEPTH STRATUM: Deep photic (3)

HABITATS: kelp reef, coral reef

SUBSTRATUM TYPE: Consolidated

ECOSYTEM: Peaks – Reef



Figure 4.2. The subdivision of the subtidal environment into depth strata.

EstuarineMarine

Intertidal

Upper Slope Lower

Slope

-1800m

Abyssal

Shelf break -3500m

AbyssShelf Slope

Shallow photic Deep

photic

Sub photic

-10m -30m

Tidal Subtidal

Mean Spring High

Mean Spring

Low

Depth strata

Topo-graphic zones

Tidal zones



Table 4.1. Habitats and species addressed, and analyses conducted, in this report (see Figure 4.1 for habitat classification). Tidal zone Topographic

zone Depth

stratum Habitat Species Analyses

Supratidal Terrestrial/ Marine

interface

Coastal fringe n/a n/a Threats (per bioregion)

Tidal Marine Intertidal Seaweeds1, Invertebrates2

and Fish3

Gap analyses (bioregions combined) Target achievement analyses (bioregions combined)

Intertidal Rocky shores4 Mixed shores4

Sandy beaches Pebble beaches Boulder beaches

Gap analyses (per bioregion) Target achievement analyses (per bioregion) Threats (per bioregion)

Subtidal Shelf, slope and abyss combined

All depth strata

combined

Benthic sediments5

Untrawlable gound6

Canyons Seamounts

Gap analyses (bioregions combined) Target achievement analyses (bioregions combined)

Subtidal Shelf Shallow photic n/a n/a Threats (per bioregion) Deep photic Bottom complexity Identification of 50 and 10km stretches of bottom

complexity Threats (per bioregion)

Sub photic n/a n/a Threats (per bioregion) Slope Upper slope n/a n/a Threats (per bioregion) Lower slope n/a n/a Threats (per bioregion) Abyss Abyss n/a n/a Threats (per bioregion)

1Bolton and Stegenga (2002); Bolton et al. (2004) 2Emanuel et al. (1992); Awad et al. (2002) 3Turpie et al. (1999) (this was the only fish dataset used in this study, see species chapter for more discussion) 4Subdivided according to wave exposure 5Subdivided according to Dingle et al. (1987) and grain size 6Agulhas Banks only



5. Inshore bioregions Appendix 1 provides a detailed discussion of the bioregion breaks around South Africa, and the rational behind the divisions recognised for this study. We defined five inshore bioregions (Figure 5.1): the Namaqua bioregion extends from just north of the upwelling cell at Lüderitz to Cape Columbine; the South-western Cape bioregion extends from here to Cape Point; the Agulhas bioregion extends to the Mbashe River; the Natal bioregion extends to Cape Vidal; and the Delagoa bioregion extends from here into Mozambique (we have not defined its northern limit owing to lack of fine-scale data). Although we treat each bioregion as equally distinct in this study, we recognize that our bioregion breaks are not all equal. For example, the Cape Point break is far more distinct than the Cape Columbine break. However, for the national-scale analyses we conduct here, it is safer to split areas and to target representative components of their biota for protection, than to assume that they are homogeneous (the precautionary principle). The extent to which these inshore bioregions penetrate offshore is discussed in the next chapter.

Figure 5.1. The five inshore bioregions defined for this study.

#

#

#

#

Cape Vidal

Cape Point

Sylvia Hill

Mbashe River

(NamibBioregion)

NamaquaBioregion

Agulhas Bioregion

Natal Bioregion

DelagoaBioregion

30 m

150 m

South-western Cape Bioregion

Cape Columbine



6. Offshore bioregions As one moves offshore within the South African EEZ, from the intertidal to the abyssal zones, it can be assumed that the marine biota become more homogeneous. One of the key determinants of biotic composition is water temperature, and there is more homogeneity in water temperature around the South African coastline at greater depths than there is in the shallows. For this reason, we defined fewer bioregions offshore than inshore. Figures 6.1, 6.2 and 6.3 demonstrate how we did this. First, all of the inshore bioregions were assumed to extend to the edge of the continental shelf (where the sub photic and upper slope meet, Figures 6.1 and 6.2). We used a straight line, perpendicular to the shoreline, to separate these bioregions, except in the case of the Cape Point break, where the continental shelf is the widest. The Cape Point break line drops due south from the Point to the 30m isobath, and then follows the 150m isobath until it reaches 21o E (Figure 6.2). This angled line is more consistent with the mixing zone of the Benguela and Agulhas currents, and their associated fish communities. It groups the eastern Agulhas shelf as part of the Agulhas bioregion, and the western area as part of the South-western Cape bioregion. The extension of the Cape Point break to the abyss (and the EEZ boundary) forms the Atlantic offshore bioregion in the west. This represents the upper and lower slopes and the abyssal regions of both the Namaqua and South-western Cape inshore bioregions (Figure 6.3). On the east coast, we recognised another subdivision at Cape Vidal. This divides the eastern continental slope into a West Indian offshore bioregion (the slopes to the south) and the South-west Indian offshore bioregion (the slopes to the north). The rationale for this was the differences in biota found in slope canyons to the north and south of Cape Vidal (K. Sink, pers. comm.). This Cape Vidal line, however, did not subdivide the abyss of the east coast, because there is no abyss in this area. Figures 6.1 and 6.2 show that the 3500m isobath (which defines the abyss) does not extend as far north as Cape Vidal. Consequently, the abyss to the east of the Cape Point bioregional break is referred to as the Indo-Pacific offshore bioregion, in keeping with the Indo-Pacific affinities of the abyssal fauna. The result of these subdivisions is four offshore bioregions, as shown in Figure 6.3.



Figure 6.1. Offshore bathymetry of the South African EEZ. The continental shelf break is shown in red, and the 1800m and 3500m isobaths are shown in brown and blue respectively.

Continental shelf break

- 3500 m

EEZ

South Africa

- 1800 m

MOZAMBIQUE RIDGE

AGULHAS PLATEAU

TRANSKEI BASIN

NATAL VALLEY

CAPE BASIN

AGULHAS BASIN

AGULHAS RIDGE

MOZAMBIQUE BASIN



Figure 6.2. Depth strata within the EEZ. The shallow and deep photic zones are narrow bands along the coastline, with the sub photic forming most of the continental shelf. Inshore and offshore bioregion breaks are shown as black lines (see Figure 6.3 for bioregion names).

Figure 6.3. The five inshore and four offshore bioregions in the South African EEZ.

AtlanticOffshoreBioregion Indo-Pacific

OffshoreBioregion

South-westIndian OffshoreBioregion

NamaquaBioregion

West IndianOffshoreBioregion

NatalBioregion

DelagoaBioregion

South-western CapeBioregion

AgulhasBioregion

Depth StrataShallow PhoticDeep PhoticSub Photic

Upper SlopeLower Slope

Abyss



7. Biozones Biozones are simply the depth strata divided by the inshore and offshore bioregions (Figure 7.1). They are the units used for the protection status, threat status, and priority status analyses, reported in Chapters 15-17. There are 34 in total. Owing to the narrow area of the intertidal, shallow and deep photic depth strata, Figure 7.1 shows them as exaggerated strips on the inside of the actual coastline. The supratidal bioregion is also shown here, because it was used for status analyses in Chapters 15-17. Bioregion breaks for the supratidal zone were based on Tinley (1985), and occur, from west to east, at the Olifants River mouth, Cape Agulhas, Cape St Francis, the Kei River mouth, and the Mtamvuna River mouth.

South Africa National Spatial Biodiversity Assessment 2004: Technical Report Vol. 4 Marine Component


Map shows true area of Biozonep

Sub Photic

Upper SlopeLower Slope

Abyss

SupratidalIntertidal

Shallow PhoticDeep Photic

Map shows symbolic area of Biozone

Indo-PacificAbyss

AtlanticAbyss

AgulhasSubPhotic

AtlanticLowerSlope

NamaquaSubPhotic

SouthwestIndianUpperSlope

AgulhasDeepPhotic

WestIndianUpperSlope

AgulhasShallowPhotic

WestIndianLowerSlope

NatalDeepPhotic

South-westernCapeSubPhotic

NatalShallowPhotic

SouthwestIndianLowerSlope

NamaquaShallowPhotic West

CoastSupratidal

South-westCoastSupratidal

DelagoaDeepPhotic

TranskeiCoastSupratidal

AtlanticUpperSlope

AgulhasIntertidal

NamaquaDeepPhotic Natal

Intertidal

SouthCoastSupratidal

NamaquaIntertidal

NatalSubPhotic

Kwazulu-NatalCoastSupratidal

South-eastCoastSupratidal

South-westernCapeDeepPhotic

DelagoaShallowPhotic

DelagoaIntertidal

South-westernCapeShallowPhotic

South-westernCapeIntertidal

DelagoaSubPhotic

-west

-west

Figure 7.1. The 34 marine biozones used in this study. Biozones are created by subdividing the depth strata with the bioregions.



8. Marine protected areas (MPAs) Figures 8.2 to 8.8 show the current MPA estate in South Africa. Protected areas shown here are only those that are listed in the Government Gazette (Marine Living Resources Act) as MPAs. Areas referred to in the Gazette as “Closed areas” are not shown, and were not used in the current project, with the exception of the three closed areas near East London. These three areas are more likely to achieve MPA status in the near future than any of the other closed areas (C. Attwood, pers. comm.). However, some of the other closed areas, e.g. those closed to trawling, may be very important to maintain, or even to expand, given the adverse effects on biodiversity from trawling in adjacent areas. Figures 8.2 and 8.3 also show the position of the proposed Namaqualand MPA. For the analyses in this report, marine protected areas were divided into four categories, and are henceforth referred to as category 1-4 MPAs. Category 1: no-take MPAs (MPAs in which no marine living resource extraction is

permitted) Category 2: other MPAs (MPAs in which some extraction is permitted, e.g. fishing from

the shore) Category 3: closed areas (the three closed areas near East London) Category 4: proposed MPA (the proposed Namaqualand MPA) Digital data for the MPAs were obtained from the Government Gazette (Marine Living Resources Act). Each MPA was plotted in a Geographic Information System (GIS) using the coordinates from the Gazette. Statistics of the MPAs are provided in Table 8.1 (km of coastline in MPAs) and Table 8.2 (areas of EEZ in MPAs). Table 8.1. Protection status of South Africa’s coastline in MPAs (category 1-4). Numbers are lengths of untransformed* coastline. Data are provided per bioregion. The same data are expressed as percentages in Figure 8.1. Length of coastline (km)

Bioregion Category 1

MPAs Category 2

MPAs Category 3

MPAs Category 4

MPA Not in MPAs

Total length

Namaqua 0 0 0 55 629 684 SW Cape 51 163 0 0 207 420 Agulhas 197 78 52 0 1379 1706 Natal 43 100 0 0 550 693 Delagoa 43 110 0 0 0 153 Total 334 451 52 55 2764 3656 *Irreversibly transformed areas (e.g. harbours) were excluded Table 8.2. Areas (and percentages) of the South African EEZ in MPAs (category 1-4).

Area in km2

Category 1

MPAs Category 2

MPAs Category 3

MPAs Category 4

MPA Not in MPAs Total area

All bioregions

1761 (0.16)

2501 (0.23)

261 (0.02)

9980 (0.93)

1057380 (98.65)

1071883 (100)



0

20

40

60

80

100

Namaqua South-westernCape

Agulhas Natal Delagoa Total

Bioregion

%C

oast

line

in M

PAs

Category 4Category 3Category 2Category 1

Figure 8.1. The percent of the untransformed South African coastline in Category1-4 MPAs. Data are presented for each of the five bioregions, and then summarised for the whole country (column Total).

The data in the above two Tables and Figure make two striking points. First, although 23% of the South African coastline falls within category 1-3 MPAs, only 9% of this is no-take. In addition, this 23% is not evenly distributed among bioregions, and is thus not representative of South Africa’s coastal marine biodiversity. The entire Namaqua bioregion has no MPA, whereas the Delagoa bioregion enjoys over 20% protection in no-take MPAs. The second striking point is that only 0.41% of South Africa’s EEZ falls within MPAs, and of this, only 0.16% is no-take. The addition of the proposed Namaqualand MPA to the MPA estate would more than double the sea surface area under protection.



MPAsCategory 1 (no-take MPAs)Category 2 (other MPAs)Category 3 (three closed areas)Category 4 (proposed Namaqualand MPA)

Inshore Bioregion Breaks

Figure 8.2. South Africa’s marine protected area estate. Only MPAs listed in the Government Gazette are shown (with the exception of three closed areas off East London, and the proposed Namaqualand MPA).




Inshore Bioregion Break

Proposed Namaqualand MPA

Figure 8.3. The proposed Namaqualand MPA within the Namaqua bioregion. There are no proclaimed MPAs in this bioregion yet.



Figure 8.4. MPAs within the South-western Cape bioregion.

Cape Peninsula National Park MPA

Cape of Good HopeRestricted Zone

Sixteen MileBeach MPA <

Langebaan Lagoon MPA

Marcus Island MPAMalgas

Island MPA

Jutten Island MPA

Zone CSixteen MileBeach MPA



KarbonkelbergRestricted Zone

<<



Goukamma MPA

De Hoop MPA

Helderberg MPA

Betty's Bay MPACape PeninsulaNational Park MPA

St James Restricted Zone

Boulders Restricted Zone

Castle Rock Restricted Zone

Paulsberg Restricted Zone



Figure 8.5. MPAs on the western side of the Agulhas bioregion.





Robberg MPA

Tsitsikamma MPASardinia Bay MPA

Bird Island MPA

Dwesa-Cwebe MPA

Nyara River mouth to Great Kei River mouth

Nahoon Point to Gonubie Point

Christmas Rock to Gxulu River mouth

Figure 8.6. MPAs on the eastern side of the Agulhas bioregion. The three closed areas are also shown.



Figure 8.7. MPAs within the Natal bioregion.

AliwalShoalMPA

Trafalgar MPA<

Pondoland MPA

Hluleka MPA

Dwesa-Cwebe MPA



Produce RestrictedZone

Crown AreaRestricted

Zone

ControlledZone

<

<

InshoreRestricted

Zones

InshoreControlled

Zones

OffshoreControlledZone

OffshoreControlledZone

OffshoreRestrictedZone

OffshoreRestrictedZone



MaputalandMPA

St LuciaMPA

RestrictedArea

SanctuaryArea

RestrictedArea

RestrictedArea

RestrictedArea

SanctuaryArea

SanctuaryArea

RestrictedArea



Figure 8.8. MPAs within the Delagoa bioregion.



9. Target achievement analyses Conservation targets, which are the cornerstones of the systematic approach to conservation planning (Margules and Pressey 2000), are defined here as minimum aerial requirements of habitats, or occurrences of species, for protection in MPAs. These habitats and species are referred to as biodiversity features and are mapped as km of coastline, km2 of subtidal habitats, or as the presence-only of species in stretches of coastline. During 2003, the World Parks Congress recommended that the minimum targets for the protection of marine biodiversity features should be 20-30% of each habitat (WPC 2003). Target achievement analyses were conducted with C-Plan software (Pressey 1999; Ferrier et al. 2000; Anon. 2001). The analyses require three datasets (see Table 9.1): (i) a spatial map of the distribution of the biodiversity feature, (ii) a spatial map of planning units that overlays the biodiversity feature map, and (iii) quantitative targets for the biodiversity features. The spatial extent of each biodiversity feature is then calculated in each planning unit. Irreplaceability analyses The analyses then produce two products: the first product is an irreplaceability map, which measures the contribution that each planning unit makes to the achievement of the targets set for each biodiversity feature. Planning units that contain the total extent of a particular feature, will definitely be required for selection if targets for that feature are to be met (in a subset of all planning units). These planning units are referred to as “irreplaceable”, and have the maximum value possible (irreplaceability = 1). Alternatively, planning units that contribute nothing to targets have an irreplaceability = 0 (e.g. a planning unit that contains only transformed habitat such as a harbour). All other planning units have irreplaceability values between 0 and 1. Minimum sets The second product is a minimum set, which is one option for a subset of all planning units that would meet all the specified targets for all biodiversity features. There is usually more than one subset of planning units that would do the job equally well (i.e. using the same number of planning units). C-Plan attempts to select the minimum number of planning units to meet all targets.



C-Plan runs Target achievement analyses (both irreplaceability and minimum sets) were conducted on the three datasets listed in Table 9.1. For each of the three data sets, various C-Plan analyses were run with the following options: Run 1 Category 1 (no-take) MPAs were selected up front as being mandatory for

target achievement analyses. In other words, the biodiversity features they contain are considered adequately protected. Category 2, 3 and 4 MPAs are not considered adequately protected, and are not mandatory (but are available) for selection.

Run 2 Category 1, 2 and 3 MPAs were selected up front as being mandatory - this is a “what if the category 2 and 3 MPAs were made no-take?” scenario.

Run 3 Category 1, 2, 3 and 4 MPAs were selected up front as being mandatory - this adds the proposed Namaqualand MPA to the “what if” scenario.

Table 9.1. The three datasets used for target achievement analyses. These are described in more detail in their relevant chapters.

Dataset Planning units Targets 1 Species 50km stretches of coastline 1 occurrence of each species 2 Intertidal habitats 50km stretches of coastline 20% of total length, per

intertidal bioregion 3 Offshore habitats 20' x 20' grid cells (the

commercial reference grid used by MCM*)

20, 30 or 50% of total area

*Marine and Coastal Management



50 Km strips

10. Planning units Species Species data existed as presence-only in either 50km, or 100km, stretches of coastline (these are described in detail in their relevant chapters). The three datasets used in this study (seaweeds, intertidal invertebrates, and fish) were all developed with different measurements, and consequently their coastal stretches did not overlap neatly with one another. We thus generated an independent (and more accurate) set of 50km stretches along the South African coastline, using 1:50 000 digital data. A total of 66 planning units at 50km, and one at 30 km, were generated for the ~3330 km South African coastline (after removing harbour lines and rocky shore symbology). A digital polygon was created around each 50km stretch of coastline simply for display purposes (Figure 10.1).

Figure 10.1. Planning units for the species target achievement analyses. Each planning unit represents a linear 50km stretch of coastline (except the one on the Mozambique border which is only 30km).



Category 1Category 2Category 3Category 4

Intertidal habitats The same planning units used for the species analyses were used for the intertidal habitats, except that they were bisected by the MPAs. This means that each MPA along the coast was a separate planning unit. This was possible with the intertidal data because they were spatially explicit (they were mapped along the actual coastline). It was not possible to do this with the species data because they were not spatially explicit within any particular 50km stretch (species are referred to as present within a particular stretch, but we don’t know exactly where in that particular stretch). We kept the distance at 50km, for two reasons: (i) to be consistent with the species analyses, and (ii) 50km is a sensible distance for MPA management. Figure 10.2 shows the 130 planning units that were generated for the intertidal analyses.

Figure 10.2. Planning units for the intertidal habitat target achievement analyses. Planning units are 50km stretches of coastline bisected by MPAs in categories 1-4.



Category 1Category 2Category 3Category 4Seamount

Subtidal habitats The 20 x 20 minute commercial reference grid cells used by Marine and Coastal Management were used as offshore planning units for the subtidal marine environment. The grid cells have a mean area of 1143 km2. The grid cells were bisected by existing MPAs, resulting in a total of 1179 planning units (Figure 10.3).

Figure 10.3. Planning units for the subtidal habitat target achievement analyses. Planning units are 20 x 20 minute commercial reference grid cells bisected by MPAs in categories 1-4. Grid cells occupied by seamounts are shown in red.



11. Species analyses Data Three data sets were made available for these analyses (Table 11.1): (i) The seaweed distribution data supplied by J. Bolton (Bolton and Stegenga 2002;

Bolton et al. 2004). This dataset is a presence matrix of 803 species, in 59 x 50km coastal strips around South Africa.

(ii) The intertidal invertebrate data supplied by C. Griffiths (Emanuel et al. 1992; Awad et al. 2002). This dataset is a presence matrix of 2524 species, in 27.5 x 100km coastal strips around South Africa.

(iii) The fish data supplied by J. Turpie (Turpie et al. 1999). This dataset is a presence matrix of 1239 species, in 52 x 50km coastal strips around South Africa.

Owing to the different way in which each of the data sets measured 50 or 100km coastal strips, each of the data sets was converted to match the 50km strips generated for this study. The following rule was used: if one of the 50 or 100km species strips incorporated more than one third of one of our 50km strips (i.e. >16.667 km), then the species complement of that strip was assigned to our strip. For the seaweed data, if any species was assigned to only one of our strips, that species was deleted from the analysis (undersampling was assumed, J. Bolton, pers. comm.). All the data were then combined into one final data set. Targets Each species received a target of one (i.e. we require each species to occur at least once in any MPA). Gap analysis A gap analysis reports the current protection status of biodiversity features. For the species analyses, we determined which species currently occur in MPAs (i.e. already reach their targets in existing MPAs). To do this, we used the original data sets (not the data converted to our strips), and identified which of the original strips fell within MPAs. The species in these strips were then labelled as being present in MPAs (Table 11.1). We acknowledge two problems: (i) owing to the lack of point data, we are assuming that a species is present along the entire length of the strip to which it is assigned, and (ii) presence in an MPA does not necessarily equate to adequate conservation, in that the species may not be part of a viable population. This is especially true of the fish data set, which was based on species ranges, rather than on data point collection. Although Table 11.1 shows that 98% of the fish species in the data set were assigned to coastal strips that fall within MPAs, this in no way equates to adequate conservation for any of the fish species. Table 11.1 does show that within the seaweeds and intertidal invertebrates, about 90% of species may well occur in existing protected areas. Owing to the problems explained above, species lists from MPAs are required to test this assumption.



Table 11.1. Occurrence of species within existing MPAs. Columns are mutually exclusive (if a species is found in a column to the left, it is not repeated in a column to the right). Number (and %) of species present in:

Species group Category 1

MPAs Category 2 and 3 MPAs

Category 4 MPA

No MPAs Total number of species

Seaweeds 704 (88%) 72 4 23 803 Invertebrates 2346 (93%) 148 3 27 2524 Fish 1217 (98%) 8 0 14 1239 Target achievement analyses As explained in the target achievement analyses chapter, we ran three sets of analyses (C-Plan options, Runs 1 to 3), based on different MPA starting scenarios (Table 11.2). These analyses were repeated without the fish data, to allow us to compare how the range-based fish data affected our results. Analyses were run only on those species that do not occur in the mandatory planning units assigned for that run (i.e. only on currently “unreserved” species). Table 11.2. The number of species to target in each of the three target achievement analyses (Runs 1-3). Each run was repeated (b) without the fish data. Analyses were run only on the combined data sets.

Mandatory planning units: Category 1 MPAs Category 1,2&3 MPAs Category 1,2,3&4 MPAs

Data set Run 1(a) Run 1(b) Run 2(a) Run 2(b) Run 3(a) Run 3(b) Seaweeds 99 99 27 27 23 23

Invertebrates 178 178 30 30 27 27 Fish 22 0 14 0 14 0

Combined data 299 277

71 57

64 50

Results of the irreplaceability analyses for each run are shown in Figures 11.1, 11.2 and 11.3. These show the contribution that each planning unit makes to the achievement of targets for each run as shown in Table 11.2. Figures 11.4, 11.5 and 11.6 show the results of the minimum set analyses, and also indicate which of the minimum set planning units are flexible (i.e. where there is a choice amongst planning units). Conclusions 1. The pairs of figures on each page show that removing the fish data does not greatly alter the results, except that there is reduced irreplaceability (and thus increased flexibility) in the Natal and Delagoa regions (where fish diversity is highest). 2. Adding the category 2 and 3 MPAs as mandatory (i.e. assuming that they become no-take), vastly improves protection status along the east coast (in the vicinity of Eastern Cape Province border with KwaZulu-Natal). Figure 11.5 shows that far fewer planning units are required for the minimum set if the category 2 and 3 MPAs in that area become no-take.



3. Adding the proposed Namaqualand MPA to mandatory planning units (i.e. assuming it is proclaimed as no-take) vastly improves protection status along the west coast. In fact, the proposed Namaqualand MPA is representative of all the species we analysed along the Northern Cape Province coastline. Figure 11.6 shows that no further planning units within the Northern Cape are required for minimum set if Namaqualand is proclaimed. 4. Even if all the category 2, 3 and 4 MPAs are proclaimed as no-take (Figure 11.6), there are still a number of areas that require protection (if the objective is to represent all the species in our combined dataset in an MPA). These areas are: (i) the coastal strip between Cape Columbine and the Northern Cape border (ii) the coastal strip between Pringle Bay and Cape Agulhas (iii) the coastline in the vicinity of Mossel Bay (iv) the coastline in the vicinity of Cape St Francis (v) Algoa Bay (immediately north of Port Elizabeth) (vi) The coastline immediately north of Port Alfred (vii) The coastline between Durban and the St Lucia Estuary Note that these results are based on species data only. The data sets are incomplete, both geographically and taxonomically (although the seaweed and invertebrate data sets are the result of many years of collection and can be considered very good data sets). With more complete data, and with a proper assessment of those species that are adequately protected in existing MPAs, the results obtained here might well be different. These results must therefore be considered as a preliminary assessment only.



Site Irreplaceability1 (Totally Irreplaceable)>0.8 - <1>0.6 - 0.8>0.4 - 0.6>0.2 - 0.4 >0 - 0.2IRREPL = 0

Category 1 MPAs


Category 1 MPAs

Figure 11.1. Run 1(a): Irreplaceability analyses for seaweeds, intertidal invertebrates, and fish, in 50km strips around South Africa. Category 1 MPAs are mandatory.

Figure 11.1. Run 1(b): Irreplaceability analyses for seaweeds and intertidal invertebrates, in 50km strips around South Africa. Category 1 MPAs are mandatory.




MPAsCategory 1Category 2Category 3



Figure 11.2. Run 2(a): Irreplaceability analyses for seaweeds, intertidal invertebrates, and fish, in 50km strips around South Africa. Category 1, 2 and 3 MPAs are mandatory.

Figure 11.2. Run 2(b): Irreplaceability analyses for seaweeds and intertidal invertebrates, in 50km strips around South Africa. Category 1, 2 and 3 MPAs are mandatory.




MPAsCategory 1Category 2Category 3Category 4



Figure 11.3. Run 3(a): Irreplaceability analyses for seaweeds, intertidal invertebrates, and fish, in 50km strips around South Africa. Category 1, 2, 3 and 4 MPAs are mandatory.

Figure 11.3. Run 3(b): Irreplaceability analyses for seaweeds and intertidal invertebrates, in 50km strips around South Africa. Category 1, 2, 3 and 4 MPAs are mandatory.



Not flexible2 of these 51 of these 3 (a)1 of these 3 (b)1 of these 50Co

Category 1 MPAs

Not flexible2 of these 51 of these 2 (a)1 of these 2 (b)1 of these 2 (c)1 of these 3 (a)1 of these 3 (b)1 of these 50Co

Category 1 MPAs

Figure 11.4. Run 1(a): Minimum set analyses for seaweeds, intertidal invertebrates, and fish, in 50km strips around South Africa. Category 1 MPAs are mandatory.

Figure 11.4. Run 1(b): Minimum set analyses for seaweeds and intertidal invertebrates, in 50km strips around South Africa. Category 1 MPAs are mandatory.



Not flexible1 of these 2 (a)1 of these 2 (b)1 of these 3 (a)1 of these 3 (b)1 of these 3 (c)1 of these 50Co


Not flexible

0Co

1 of these 2 (a)1 of these 2 (b)1 of these 3 (a)1 of these 3 (b)1 of these 5 (a)1 of these 5 (b)


Figure 11.5. Run 2(a): Minimum set analyses for seaweeds, intertidal invertebrates, and fish, in 50km strips around South Africa. Category 1, 2 and 3 MPAs are mandatory.

Figure 11.5. Run 2(b): Minimum set analyses for seaweeds and intertidal invertebrates, in 50km strips around South Africa. Category 1, 2 and 3 MPAs are mandatory.



Not flexible1 of these 2 (a)1 of these 2 (b)1 of these 3 (a)1 of these 3 (b)1 of these 50Co


Not flexible1 of these 2 (a)1 of these 2 (b)1 of these 3 (a)1 of these 3 (b)1 of these 50Co


Figure 11.6. Run 3(a): Minimum set analyses for seaweeds, intertidal invertebrates, and fish, in 50km strips around South Africa. Category 1, 2, 3 and 4 MPAs are mandatory.

Figure 11.6. Run 3(b): Minimum set analyses for seaweeds and intertidal invertebrates, in 50km strips around South Africa. Category 1, 2, 3 and 4 MPAs are mandatory.



12. Intertidal analyses Data Intertidal habitats and their degree of wave exposure were mapped along the South African coastline using seven sources of spatial data: (i) Scanned 1:50 000 topocadastral maps from the Surveyor General. These provide a

distinction among rock, sand and estuarine habitats. (ii) The Coastal Sensitivity Atlas (CSA) of Southern Africa (Jackson and Lipschitz 1984).

This classifies coastal substrata into fine-grained sandy beaches, coarse-grained sandy beaches, pebble/shingle beaches, exposed rocky headlands, wavecut rocky platforms, and estuarine environments.

(iii) A wave exposure index, developed by consultation with R. Anderson and R. Cowling. They coded the CSA to provide four levels of exposure: very exposed, exposed, sometimes exposed and sheltered. The shapes of bays and direction of prevailing winds and swell were the primary determinants for decision-making.

(iv) Habitat types and wave exposure were independently mapped onto 1:150 000 marine charts (Hydrographic Office, SA Navy) by G. Branch (Namibian border to Port Shepstone) and K. Sink (Port Shepstone to Mozambique border). They mapped both substratum type, and exposure in the same four categories developed for the CSA. Consultation among all these experts ensured consistency of coding in all cases.

(v) Ecosystems (on 1:10 000 orthophotos) defined by the Town and Regional Planning Commission Report (Cooper 1995). These were used for the area from the Namibian border to Port Shepstone.

(vi) A data set developed by J. Harris, containing information about occurrence of different intertidal habitats at 100m resolution from Cabo Santa Maria (Mozambique) to Port St Johns.

(vii) Satellite imagery: orthorectified Landsat Thematic Mapper Mosaics (30 meter resolution) of southern Africa.

J. Harris integrated these seven sources into a single data set of habitat and wave exposure categories for the South African coastline. An explicit rule-based decision tree was developed to solve inconsistencies amongst data sets. The exercise produced twelve categories of intertidal habitats (Table 12.1). Beaches were not subdivided owing to a lack of consistent information, but we recommend that a national spatial classification of beaches is completed as a separate project. Rocky and mixed shores were divided into either four, or three, exposure categories, depending on bioregion. On the west and south coasts (Namaqua, South-western Cape and Agulhas Bioregions), four exposure categories were coded (very exposed, exposed, sometimes exposed, and sheltered). On the east coast (Natal and Delagoa bioregions), only three categories were coded (very exposed, exposed, and sheltered), owing to the more exposed coastline and the difficulty in distinguishing exposed, from sometimes exposed. Exposure categories are defined as follows: > 15 N.m-2 (very exposed); 10-15 N.m-2 (exposed); 5-10 N.m-2 (semi exposed); and 0-5 N.m-2 (sheltered). Although estuaries were coded in this dataset and are part of the analyses that follow, a separate exercise on estuaries was undertaken for the NBSAP report and is reported separately (Turpie 2004). Figure 12.1 shows the final classification of intertidal habitats on the South African coastline. There are twelve types of habitats, and four types of transformation.



boulderspebbles

sand

estuary

breakwatercanalharbourpieruncoded

rocky shore (very exposed)rocky shore (exposed)rocky shore (sometimes exposed)rocky shore (sheltered)

mixed shore (very exposed)mixed shore (exposed)mixed shore (sometimes exposed)mixed shore (sheltered)

Figure 12.1. Intertidal habitats on the South African coastline. The inset shows a scanned 1:50 000 topocadastral map in the background.



Figure 12.2 (a to e) plots the percentage length of each habitat in each bioregion. Only extant areas were used for these calculations (i.e. breakwaters, canals, harbours and piers were excluded). Not all of the intertidal habitats occur in each bioregion. Consequently, these habitats have been left off the X-axes in each graph (except for the Agulhas bioregion, which contains all habitats). Coding for the X-axes is as follows: Table 12.1. The twelve categories of intertidal habitats mapped and analysed in this report. X-axis Intertidal habitat BOULDERS Boulders PEBBLES Pebbles RS (V EXP) Rocky Shores (very exposed) RS (EXP) Rocky Shores (exposed) RS (S EXP) Rocky Shores (sometimes exposed) RS (SHL) Rocky Shores (sheltered) MS (V EXP) Mixed Shores (very exposed) MS (EXP) Mixed Shores (exposed) MS (S EXP) Mixed Shores (sometimes exposed) MS (SHL) Mixed Shores (sheltered) SAND Sand ESTUARIES Estuaries Exposed rocky shores and sandy beaches dominate all of the bioregions, except for the Delagoa bioregion, where sandy beaches dominate. This emphasises the need for a national sandy beach classification exercise. (a) Namaqua bioregion

Intertidal Habitat

Figure 12.2 (a). Percentage contribution of each intertidal habitat to each bioregion. Data are provided for the Namaqua (inshore) bioregion.

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BOULDERS PEBBLES RS (V EXP) RS (EXP) RS (S EXP) RS (SHL) MS (EXP) MS (SHL) SAND ESTUARIES

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on(b) South-western Cape bioregion (c) Agulhas bioregion

Intertidal Habitat

Figure 12.2 (b and c). Percentage contribution of each intertidal habitat to each bioregion. Data are provided for the South-western Cape and Agulhas (inshore) bioregions.



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Intertidal Habitat

Figure 12.2 (d and e). Percentage contribution of each intertidal habitat to each bioregion. Data are provided for the Natal and Delagoa (inshore) bioregions.



Targets Owing to the climatic, oceanographic, geological and geomorhphological differences among the five bioregions, we set a target of 20% of the length of each intertidal habitat in each of the bioregions. We hope that this will capture diversity among similar habitats in different parts of the country. This is especially important in the case of sandy beaches, where we have no subdivisions into beach or exposure type. Gap analysis Table 12.2 shows which intertidal habitats, per bioregion, meet their targets of 20% in existing MPAs. The first scenario (a) is within Category 1 MPAs only, and the second scenario (b) is with the Category 2 and 3 MPAs added to the protected area estate. Table 12.2. Intertidal habitats that meet their targets in existing MPAs. Scenario (a): Category 1 MPAs only Bioregion Intertidal habitat Namaqua SW Cape Agulhas Natal Delagoa Boulders n/a Pebbles *n/a YES n/a Rocky Shores (very exposed) YES Rocky Shores (exposed) YES Rocky Shores (sometimes exposed) n/a n/a Rocky Shores (sheltered) n/a n/a Mixed Shores (very exposed) n/a n/a n/a n/a Mixed Shores (exposed) Mixed Shores (sometimes exposed) n/a n/a n/a n/a Mixed Shores (sheltered) n/a n/a Sand YES Estuaries YES Number of habitats to reach target /total number of habitats 0/10 1/9 1/12 0/7 3/5 Scenario (b): Category 1, 2 and 3 MPAs Bioregion Intertidal habitat Namaqua SW Cape Agulhas Natal Delagoa Boulders n/a Pebbles **(YES) n/a YES YES n/a Rocky Shores (very exposed) YES YES YES Rocky Shores (exposed) YES YES YES YES Rocky Shores (sometimes exposed) YES YES n/a n/a Rocky Shores (sheltered) n/a n/a Mixed Shores (very exposed) n/a n/a n/a n/a Mixed Shores (exposed) YES YES YES Mixed Shores (sometimes exposed) n/a n/a YES n/a n/a Mixed Shores (sheltered) n/a n/a Sand YES YES Estuaries YES YES YES YES Number of habitats to reach target /total number of habitats (1)/10 6/9 5/12 5/7 5/5 *Habitat does not occur in bioregion **Adding the proposed Namaqualand MPA brings only one other Namaqua bioregion habitat up to target (Pebbles).



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BOULDERS PEBBLES RS (V EXP) RS (EXP) RS (S EXP) RS (SHL) MS (EXP) MS (SHL) SAND ESTUARIES

% L

engt

h

%in Category 1 MPAs %in Category 2 & 3 MPAs

These data are illustrated in Figures 12.3 (a to e). Coding of the X-axes is the same as for the previous set of graphs. The 20% target line has been placed on each graph. It is obvious that category 1 MPAs do not provide adequate protection for intertidal habitats. Outside of the Delagoa bioregion, only two habitats reach their targets in these MPAs (pebbles in the Agulhas bioregion, and estuaries in the South-western Cape bioregion). Making all the existing category 2 and 3 MPAs no-take would bring 16 more habitats up to target in the different bioregions. This still leaves many habitats inadequately protected, such as the sandy beaches of the Agulhas and Natal bioregions, and the entire Namaqua bioregion. Four habitats do not reach their targets in any bioregions: boulders, sheltered rocky shores, very exposed mixed shores, and sheltered mixed shores. (a) Namaqua bioregion

Intertidal Habitat

Figure 12.3 (a). Percentages of intertidal habitats in MPAs. Data are provided for the Namaqua (inshore) bioregion.



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(b) South-western Cape bioregion (c) Agulhas bioregion

Intertidal Habitat

Figure 12.3 (b and c). Percentages of intertidal habitats in MPAs. Data are provided for the South-western Cape and Agulhas (inshore) bioregions.



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(d) Natal bioregion (e) Delagoa bioregion

Intertidal Habitat

Figure 12.3 (d and e). Percentages of intertidal habitats in MPAs. Data are provided for the Natal and Delagoa (inshore) bioregions.



Target achievement analyses As explained in the target achievement analyses chapter, we ran three sets of analyses (C-Plan options, Runs 1 to 3), based on different MPA starting scenarios. The analyses were run per bioregion, meaning that a habitat (e.g. an exposed rocky shore) in a particular bioregion had to meet its target of 20% of its length, in MPAs, in that bioregion. Results of the irreplaceability analyses for each run are show in Figures 12.4, 12.5 and 12.6. These show the contribution that each planning unit makes to the achievement of targets for each run. Figures 12.7, 12.8 and 12.9 show the results of the minimum set analyses, and also indicate which of the minimum set planning units are flexible (i.e. where there is a choice amongst planning units to meet targets). Conclusions 1. Adding the category 2 and 3 MPAs as mandatory (i.e. assuming that they become no-take), increases the flexibility on the east and south coasts (i.e. provides more choices of areas to meet outstanding targets). However, a number of extra areas (in addition to existing category 1, 2 and 3 MPAs) are still required for protection, all around the country, if all intertidal habitat targets are to be met. 2. Adding the proposed Namaqualand MPA to mandatory planning units (i.e. assuming it is proclaimed as no-take) increases flexibility on the west coast, but there is still an area that is not flexible (i.e. has no alternatives), just north of Port Nolloth. This area contains the only boulder beaches in the bioregion, and their targets can thus be met here only. 3. Even if all the category 2, 3 and 4 MPAs are proclaimed as no-take (Figure 12.9), there are still a number of areas that require protection (if the objective is to represent all intertidal habitats in an MPA). These areas are: (i) the boulder beach area just north of Port Nolloth, as previously discussed (ii) another section of the Namaqua bioregion coast – owing to the flexibility here, an

area that overlaps with the species results (Figure 11.6) could be chosen, such as the southern orange planning unit in Figure 12.9, in the vicinity of Doringbaai.

(iii) at the southern end of the Namaqua bioregion, the area just north of Cape Columbine (this overlaps with species results)

(iv) in the South-western Cape bioregion, the area just north of Langebaan Lagoon, and south of the Sixteen Mile Beach MPA

(v) on the western side of the Agulhas bioregion, the False Bay eastern coastline (vi) the coastal strip between Pringle Bay and Cape Agulhas (this area overlaps with the

species results) (vii) the coastline in the vicinity of Mossel Bay (again, this overlaps with the species

results) (viii) the area directly to the east of the Tsitsikamma MPA (ix) Algoa Bay (immediately north of Port Elizabeth) – this is the same area required by

the species analyses (x) another portion of the southern KwaZulu-Natal coastline – owing to flexibility in this

region, the species results can determine which area is chosen. (xi) The area just south of the Saint Lucia estuary – this overlaps again with species

requirements.



Note that these results would need to be ground-truthed (recommended areas would need to be surveyed) before any boundaries are decided upon for additional protected areas.




Initial Reserve

Inshore Bioregion BreaksProposed MPA (Namaqua)

Category 1 MPAs


Initial Reserve

1 (Totally Irreplaceable)>0.8 - <1>0.6 - 0.8>0.4 - 0.6>0.2 - 0.4 >0 - 0.2IRREPL = 0

Mandatory ReserveSite Irreplaceability

Category 1, 2 and 3 MPAs

Figure 12.4. Run 1: Irreplaceability analyses for intertidal habitats, in 50km strips around South Africa, per bioregion. Category 1 MPAs are mandatory.

Figure 12.5. Run 2: Irreplaceability analyses for intertidal habitats, in 50km strips around South Africa, per bioregion. Category 1, 2 and 3 MPAs are mandatory.



Inshore Bioregion BreaksProposed MPA (Namaqua)Initial Reserve

1 (Totally Irreplaceable)>0.8 - <1>0.6 - 0.8>0.4 - 0.6>0.2 - 0.4 >0 - 0.2IRREPL = 0

Mandatory ReserveSite Irreplaceability

Category 1, 2, 3 and 4 MPAs

Figure 12.6. Run 3: Irreplaceability analyses for intertidal habitats, in 50km strips around South Africa, per bioregion. Category 1, 2, 3 and 4 MPAs are mandatory.




Initial ReserveNot flexible

1 of these 2 (a)1 of these 2 (b)1 of these 2 (c)3 of these 5

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Inshore Bioregion BreaksProposed MPA (Namaqua)Initial ReserveMandatory ReserveNot flexible1 of these 2 (a)1 of these 2 (b)1 of these 2 (c)1 of these 41 of these 10

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Figure 12.7. Run 1: Minimum set analyses for intertidal habitats, in 50km strips around South Africa, per bioregion. Category 1 MPAs are mandatory.

Figure 12.8. Run 2: Minimum set analyses for intertidal habitats, in 50km strips around South Africa, per bioregion. Category 1, 2 and 3 MPAs are mandatory.




Initial ReserveMandatory ReserveNot flexible

1 of these 21 of these 41 of these 61 of these 10

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Figure 12.9. Run 3: Minimum set analyses for intertidal habitats, in 50km strips around South Africa, per bioregion. Category 1, 2, 3 and 4 MPAs are mandatory.



13. Subtidal analyses Data Habitats in the subtidal marine environment were mapped by using abiotic data as surrogates for biodiversity pattern. Five sources of spatial data were used: (i) The deep-sea sedimentary environment map of Dingle et al. (1987) (provided by L.

Drapeau, MCM, and updated in this report). (ii) Texture of surficial sediments of the continental margin (Marine Geoscience, Series

3, Department of Mineral and Energy Affairs, 1986). (iii) Submarine canyons from P. Ramsay (Marine GeoSolutions) (iv) Untrawlable grounds on the Agulhas Bank (R. Leslie, MCM). These were treated as

a separate habitat, because it is assumed that they differ in complexity from surrounding areas (they are untrawlable because of hard outcrops).

(v) Seamounts (marine chart SAN 4, Hydrographic Office, SA Navy) Figures 13.1, 13.2 and 13.3 show the extent of all five data sets. Targets Figure 13.4 shows the targets that were set for each offshore habitat. All habitats received a target of 20% of their total area, with a few exceptions: authigenic sediments, terrigenous muds and untrawlable grounds on the Agulhas Bank received a target of 30% (assumed higher biodiversity), while canyons were targeted at 50% of their area within each bioregion (the inshore bioregion breaks only, were used). Note that not all of the habitat categories in the Dingle et al. (1987) map were targeted (Figure 13.2), because their ability to act as biological pattern surrogates was questionable (P. Ramsay and A. Connell, pers. comm.). Gap analysis Figure 13.4 also shows that owing to the lack of offshore MPAs, no offshore habitats reach their targets in existing MPAs. The addition of the proposed Namaqualand MPA improves the protection status of many of the habitats, but many more offshore areas require protection if offshore targets are to be met. Table 8.2 in the MPA chapter shows that only 0.16% of the South African EEZ falls within category 1 MPAs.



SHELF SOURCE AREASterrigenous mudsWest Coast carbonate sands & mudsEast Coast dunesrelict shelly sandsauthigenic sediments (>5% content)Pre-Mesozoic basementPre-Mesozoic basement - outcrop

ALLOCHTHONOUS ENV&FEEDERSturbidites, channel-fill, LAYER C sedimentschute depositcanyon & feeder valleysrise lobes LAYER B sedimentsslumps & slides LAYER B sedimentsprobable allochthonous masses, LAYER B sedimentsglide planes & scarsfissured & unstable zones

STEADY-STATE ACCRETION & EROSIONsediment drift, LAYER B sedimentsridge and plateau billows & other LAYER A sedimenbasin fill, LAYER B sedimentsterrigenous construction: submarine fanscour core zoneferro-manganese deposits

OTHERSseamount, uncertain compositionundefined areasLand

Figure 13.1. Deep-sea sedimentary environments in the South African EEZ, after Dingle et al. (1987). Canyons have been augmented with data from P. Ramsay.



Targets20%30%50%

EEZ

Figure 13.2. Components of the deep-sea sedimentary environments (Dingle et al. 1987) and additional canyon data from P. Ramsay, for which targets were set.



çç

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seamount

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ChildsBank

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% Banksç Seamounts

Untrawlable GroundSouth African EEZ

Mudsandy Mudmuddy Sand and gravelly MudSandsandy GravelGravel

Texture

Figure 13.3. Texture of surficial sediments of the continental margin (Marine Geoscience 1986). Seamounts, large banks, and untrawlable grounds on the Agulhas Bank, are also shown.



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nous

mud

s

Untraw

lable

goun

d (Agu

lhas B

ank)

(Nam

aqua

biore

gion)

(SW

C biore

gion)

(Agu

lhas b

ioreg

ion)

(Nata

l bior

egion

)

(Dela

goa b

ioreg

ion)

Offshore habitat

% o

f tot

al a

rea

Category 4 MPA

Category 2 and 3 MPAs and Seamounts

Category 1 MPAs

Targets = 20%

Targets = 30%

Targets = 50%

CANYONS

Figure 13.4. The extent of offshore habitats in MPAs. Target achievement analyses As explained in the target achievement analyses chapter, we ran three sets of analyses (C-Plan options, Runs 1 to 3), based on different MPA starting scenarios. However, for the subtidal analyses we added planning units with seamounts or large banks to the category 2 and 3 MPAs for the second and third runs. The rationale for this is that there is an international initiative that is seeking to give all seamounts protection status (D. Nel, pers. comm.). In the figures that follow, we refer to the seamounts and banks collectively as seamounts. The irreplaceability analyses are shown in Figures 13.5, 13.6 and 13.7. This is the contribution that each planning unit makes to the achievement of targets for offshore habitats. Figures 13.8, 13.9 and 13.10 show the results of the minimum set analyses. Flexibility results are not shown here, owing to the high number of planning units in the minimum set.



Conclusions Off the west coast of South Africa, the irreplaceability and minimum set results are driven by the presence of terrigenous muds and authigenic sediments, both of which have a target of 30%. Off the southern coast and on the Agulhas bank, the authigenic sediments, mud banks south of Cape Agulhas, and the untrawlable grounds drive the results. Off the east coast, the presence of submarine canyons is the major driver. The results show that representative protection of the South African EEZ cannot be achieved simply along the coastline, with MPAs that do not extend very far offshore. Even with the proposed Namaqualand MPA, many west coast offshore habitats will not meet their targets. Although our data and analyses must be considered as preliminary, they show that to meet internationally recommended targets of ≥ 20% of the extent of habitats, South Africa will have to consider the proclamation of offshore MPAs very seriously. In order to do this, further sampling of the biota of the offshore habitats will be required.



Category 1 MPAs


Shelf break Figure 13.5. Run 1: Irreplaceability analyses for subtidal habitats, in 20' x 20' grid cells within the South African EEZ. Category 1 MPAs are mandatory.



Category 1 MPAsCategory 2 & 3 MPAs and SeamountsSite Irreplaceability

IRREPL = 0 >0 - 0.2>0.2 - 0.4>0.4 - 0.6>0.6 - 0.8>0.8 - <11 (Totally Irreplaceable)

Shelf break Figure 13.6. Run 2: Irreplaceability analyses for subtidal habitats, in 20' x 20' grid cells within the South African EEZ. Category 1, 2 and 3 MPAs, and grid cells with seamounts, are mandatory.



Figure 13.7. Run 3: Irreplaceability analyses for subtidal habitats, in 20' x 20' grid cells within the South African EEZ. Category 1, 2, 3 and 4 MPAs, and grid cells with seamounts, are mandatory.

Category 1 MPAsCategory 2 & 3 & 4 MPAs and SeamountsSite Irreplaceability1 (Totally Irreplaceable)>0.8 - <1>0.6 - 0.8>0.4 - 0.6>0.2 - 0.4 >0 - 0.2IRREPL = 0

Shelf break



Category 1 MPAsMinimum setIRREPL = 0

Shelf break Figure 13.8. Run 1: Minimum set analyses for subtidal habitats, in 20' x 20' grid cells within the South African EEZ. Category 1 MPAs are mandatory.



Category 1 MPAsCategory 2 & 3 MPAs and SeamountsMinimum setIRREPL = 0

Shelf break

Figure 13.9. Run 2: Minimum set analyses for subtidal habitats, in 20' x 20' grid cells within the South African EEZ. Category 1, 2 and 3 MPAs, and grid cells with seamounts, are mandatory.



Category 1 MPAsCategory 2 & 3 & 4 MPAs and SeamountsMinimum setIRREPL = 0

Shelf break Figure 13.10. Run 3: Minimum set analyses for subtidal habitats, in 20' x 20' grid cells within the South African EEZ. Category 1, 2, 3 and 4 MPAs, and grid cells with seamounts, are mandatory.



14. Deep photic complexity Reefs are one of the most threatened habitats within the subtidal environment, but there are currently no spatial data readily available regarding their type, distribution, density, etc., in South African waters. We attempted to generate broad scale data on reef positions and densities, by means of an expert questionnaire, but it proved too difficult to control for consistency in this exercise. We then turned to the 1:150 000 SAN charts (Hydrographic Office, SA Navy) and obtained all the depth contour and sounding data that were digitally available from the Hydrographic Office. We augmented the sounding data with the GEODAS data set (Boulder-IHO Data Center, Colorado). Our objective was to look for reefs (both shallow and deep), but the data were not of a high enough resolution, so we attempted to look for areas of bottom complexity (assuming these to be areas of higher biodiversity, but not necessarily of higher biomass). We measured bottom complexity by taking the 50km coastal strips we had generated for the species and intertidal analyses, offshore, to a depth of 30m. This generated 67 polygons around the South African coast. We then cut these polygons with the 15m isobath, thus generating 67 polygons, around the coast, that covered the 15 to 30m subtidal zone (the majority of the deep photic depth stratum, see Figure 4.2). We then summed the lengths of the 15, 20 and 30m isobaths in each polygon, and generated a complexity index for each polygon. Consequently, areas with a lot of contour variation (long, winding contours) in this relatively narrow depth band would have a high index, and area of little variation (short, straight contours parallel to the coast) would have a low index. The reason that we attempted this for only the deep photic area was because we needed digital depth contour data with a relatively small depth interval (e.g. 10, rather than 50 or 100m metre intervals) to make the exercise meaningful. The only data readily available at a national scale that satisfied this criterion were the 15, 20, 30m isobaths. Using data with bigger contour intervals would miss too much information in between the contours, rendering our assumptions regarding bottom complexity meaningless. After seeing the results of this exercise for the 50km coastal strips, we decided to repeat the exercise using 10km strips, because the bottom complexity offshore was often restricted to small areas, and we felt that the 50km analyses might miss too much of this variation. The 10km analysis generated 333 deep photic polygons around the country. Results of both sets of analyses are shown in Figures 14.1 to 14.12. We chose to display the areas with the highest index in each of the bioregions. In three of the bioregions (Namaqua, Agulhas and Delagoa), the highest 10km index was for an area that fell within the highest 50km index. Of the 50km strips with the highest indexes per bioregion, two of these strips fall in existing MPAs (Table Mountain National Park MPA and the St Lucia MPAs), and one is partly protected by Bird Island MPA. Of the 10km strips with the highest indexes per bioregion, most of these strips fall in existing MPAs (Table Mountain National Park MPA, Bird Island MPA, Aliwal Shoal MPA and the St Lucia MPAs). The area just north of Port Nolloth was again identified as important by the 10 and 50 km analyses, supporting the results of the intertidal habitat analyses.



Profile Index for 50 km StripsVery LowLowMediumHighVery High


Complexity index for 50km strips

Figure 14.1. Deep photic complexity in 50km strips around the South African coastline.

Figure 14.2. The 50km strip with the highest deep photic complexity index in the Namaqua bioregion.

#Y

#Y

<

Orange

Holgat

ALEXANDER BAY

PORT NOLLOTH

Depth Strata (m)

0 to 15

15 to 2020 to 30

0 to 5015 to 30

Deep Photic



Figure 14.3. The 50km strip with the highest deep photic complexity index in the South-western Cape bioregion. The entire deep photic stratum of this strip falls within the Table Mountain National Park MPA.

Figure 14.4. The 50km strip with the highest deep photic complexity index in the Agulhas bioregion. The deep photic stratum is partly protected by the Bird Island MPA.

CAPE TOWNDepth Strata (m)

0 to 15

15 to 2020 to 30

0 to 5015 to 30

MPAs

Deep Photic

<Cape of Good Hope Restricted Zone

Table Mountain National Park MPABioregion Break

PORTELIZABETH

Sundays

Bird Island MPA

Depth Strata (m)

0 to 150 to 5015 to 30

15 to 2020 to 30

MPAs

Deep Photic

<



Figure 14.5. The 50km strip with the highest deep photic complexity index in the Natal bioregion.

Figure 14.6. The 50km strip with the highest deep photic complexity index in the Delagoa bioregion. The entire deep photic stratum of this strip falls within the St Lucia MPAs.

#Y

#YRICHARDS BAY

St. LUCIA ESTUARY

Depth Strata (m)

0 to 15

15 to 2020 to 30

0 to 5015 to 30

Deep Photic

<

St Lucia Restricted Area

St Lucia Sanctuary Area


Greater St Lucia Wetland Park

Depth Strata (m)

0 to 15

15 to 2020 to 30

0 to 5015 to 30

MPAs

Deep Photic

<



Very LowLowMediumHighVery High


Profile Index for 10 km StripsComplexity index for 10 km strips

Figure 14.7. Deep photic complexity in 10km strips around the South African coastline.

Figure 14.8. The 10km strip with the highest deep photic complexity index in the Namaqua bioregion. This strip falls within the 50km strip with the highest index (see Figure 14.2).

Holgat

Depth Strata (m)

0 to 15

15 to 2020 to 30

0 to 5015 to 30

Deep Photic

<



Depth Strata (m)

0 to 15

15 to 2020 to 30

0 to 5015 to 30

Deep Photic

MPAs

CAPE TOWN

Cape of Good Hope Restricted Zone

Table Mountain National Park MPA

<

<

Bird Island MPA

Depth Strata (m)

0 to 15

15 to 2020 to 30

0 to 5015 to 30

Deep Photic

MPAs

<

Figure 14.9. The two 10km strips with the highest deep photic complexity indexes in the South-western Cape bioregion. The second strip falls within the 50km strip with the highest index (see Figure 14.3), within the Table Mountain National Park MPA.

Figure 14.10. The 10km strip with the highest deep photic complexity index in the Agulhas bioregion. The strip falls within the 50km strip with the highest index (see Figure 14.4), and the deep photic stratum is partly protected by the Bird Island MPA.



Mkomazi

Mzinto

Depth Strata (m)

0 to 15

15 to 2020 to 30

0 to 5015 to 30

Deep Photic

MPAs

Aliwal Shoal MPA

<

Depth Strata (m)

0 to 15

15 to 2020 to 30

0 to 5015 to 30

Deep Photic

MPAs

Greater St Lucia Wetland Park


St Lucia Sanctuary Area

<

Figure 14.11. The 10km strip with the highest deep photic complexity index in the Natal bioregion. This strip does not fall within the 50km strip with the highest index (see Figure 14.5), but it does fall within the Aliwal Shoal MPA.

Figure 14.12. The 10km strip with the highest deep photic complexity index in the Delagoa bioregion. The strip falls within the 50km strip with the highest index (see Figure 14.6), and the entire deep photic stratum of this strip falls within the St Lucia MPAs.



0

20

40

60

80

100

Namaq

ua S

hallo

w Photic

South-

wester

n Cap

e Sha

llow P

hotic

Agulha

s Sha

llow P

hotic

Natal S

hallo

w Pho

tic

Delago

a Sha

llow P

hotic

Namaq

ua D

eep P

hotic

South-

wester

n Cap

e Dee

p Pho

tic

Agulha

s Dee

p Pho

tic

Natal D

eep P

hotic

Delago

a Dee

p Pho

tic

Namaq

ua Sub

Pho

tic

South-

wester

n Cap

e Sub

Photic

Agulha

s Sub

Pho

tic

Natal S

ub Pho

tic

Delago

a Sub

Photic

Atlanti

c Upp

er Slop

e

South-

west In

dian U

pper

Slope

Wes

t India

n Upp

er Slop

e

Atlanti

c Low

er Slop

e

South-

west In

dian L

ower

Slope

Wes

t India

n Low

er Slop

e

Atlanti

c Aby

ss

Indo-P

acific

Aby

ss

Subtidal biozone

% A

rea

in M

PAs

Category4Category 2 and 3Category 1

0 00 0 0

Target = 20%

15. Protection status of biozones For this chapter, please refer to Figure 7.1, which shows the biozones referred to here. The protection status of the South African coastline (the intertidal biozones) is far better than its protection offshore. While 23% of the coastline falls within category 1-3 MPAs (Table 8.1, Figure 8.1), there are no offshore MPAs. Consequently, if one considers the subtidal biozones only, less than 1% (0.41) of South Africa’s EEZ falls within category 1-3 MPAs, and of this only 0.16% falls within category 1 MPAs (Table 8.2). The proposed Namaqualand MPA is more than double in sea surface area than all the existing MPAs combined, but adding it to the marine protected area estate would bring the total percent of the EEZ protected up to only 1.34%, well below the 20% recommendations of the World Parks Congress, 2003. Figure 15.1 shows the percentage of all subtidal biozones in category 1-4 MPAs. These data are mapped in Figure 15.2, which shows the protection status of these biozones, as well as the supratidal and intertidal biozones, divided into five categories (according to Table 15.1). For these calculations, we set targets for protection at 20% of the area of each biozone. Only areas in category 1 MPAs were considered as protected (i.e. contributing to targets).

Figure 15.1. The area of subtidal biozones in MPAs (categories 1 to 4). Data are presented in depth strata from shallowest (left) to deepest (right), and within these, columns are ordered according to bioregions.



Figure 15.2. The protection status of all 34 biozones in the South African EEZ. Categories are described in Table 15.1. All targets are set to 20% of length (supratidal and intertidal biozones) or 20% of area (subtidal biozones). Only category 1 marine and terrestrial protected areas are considered as contributing to targets.

Table 15.1. Categories of protection status as used in Figure 15.2. All targets are 20% of length (supratidal and intertidal biozones) or 20% of area (subtidal biozones).

Protection status Description Well protected ≥100% of target in an MPA Moderately protected 50 to <100% of target in an MPA Poorly protected 5 to 50% of target in an MPA Hardly protected 1 to 5% of target in an MPA Zero protection Nothing in an MPA

Conclusions The data presented here show that two of the six supratidal biozones (West Coast Supratidal and Transkei Coast Supratidal) do not reach their targets of 20% in category 1 MPAs. Within the marine biozones (see Figure 8.1 for intertidal data), only the Delagoa intertidal, shallow, deep and sub photic biozones reach their targets of 20% in category 1 MPAs. The South-western Cape and Natal intertidal biozones, as well as the South-western Cape shallow and deep photic biozones would reach their targets if the category 2 MPAs in those areas were proclaimed as category 1. None of the Namaqua biozones are protected, and no part of the lower slope or the abyss in South Africa’s EEZ is protected. The remaining biozones are all poorly, or hardly, protected. We note, however, that MPAs do not always ensure adequate protection of their biodiversity, and more effort needs to be put into ensuring compliance within MPAs, especially category 1 MPAs.

Biozone Protection StatusWell protectedModerately protectedPoorly protectedHardly protectedZero protection

Intertidal

Deep photic

Shallow photic

Sub photic

Supratidal



16. Threat status of biozones For this chapter, please refer to Figure 7.1, which shows the biozones referred to here. Nine threats (Table 16.1) affecting marine biodiversity in South African waters were rated on a scale of zero to 10 in the 34 biozones. Ratings were applied to current conditions, and to future scenarios (a ten year future) (Figures 16.1 and 16.2). Data were generated at two expert workshops. Having some experts present at both ensured consistency among ratings from the two workshops. What are the greatest threats to marine biodiversity? Table 16.1 and Figure 16.3 show the summed ratings for each of the biozones, for both current and future scenarios. According to the ratings, EMLRU is by far the greatest current threat to South African marine biodiversity. It was rated as exactly double the value of the next greatest threat, pollution (Table 16.1). Mining, coastal development, climate change, catchment issues and non-extractive recreational activities follow in magnitude, with alien invasive species and mariculture having the least impact. This pattern is the same in the future, except that NERA is rated higher than catchment issues. Table 16.1. The summed expert ratings for each of the nine threats, across all biozones.

Threat Current total

rating Future total

rating 1. Extractive marine living resource use (EMLRU) 158 179 2. Pollution 79 100 3. Mining 55 73 4. Coastal development 49 73 5. Climate change 41 72 6. Catchment issues 39 43 7. Non-extractive recreational activities (NERA) 38 48 8. Alien invasive species 22 40 9. Mariculture 18 32 Figure 16.4 shows the current threat status of the 34 biozones. The total ratings, for all threats per biozone, were divided into four categories of threat status, based on natural breaks in the data. The four most threatened biozones (critically endangered) are those on the west coast: the West Coast Supratidal; the Namaqua Intertidal; the Namaqua Shallow Photic; and the Namaqua Deep Photic. Mining activities along this coastline are responsible for this (Figure 16.1). The future scenario is not shown here, because the map stays exactly the same, with one exception: the South-western Cape Intertidal biozone moves from the Endangered category to the Critically Endangered category, owing to an increase in most threats, but mainly EMLRU and coastal development. Future categories were also based on natural breaks in the data.



Figure 16.1. CURRENT SCENARIO: expert ratings (from 0-10) for each of the nine current threats, per biozone.

012345

678910

Extractive MarineLiving Resource Use

Pollution Mining

CoastalDevelopment

ClimateChange

CatchmentIssues

Non-Extractive

RecreationalActivities

AlienInvasiveSpecies

Mariculture



Figure 16.2. FUTURE SCENARIO: expert ratings (from 0-10) for each of the nine future threats, per biozone.

012345

678910

Extractive MarineLiving Resource Use

Pollution Mining

CoastalDevelopment

ClimateChange

CatchmentIssues

Non-Extractive

RecreationalActivities

AlienInvasiveSpecies

Mariculture



Figure 16.3. Summed expert ratings for each threat, across all biozones, for both current and future scenarios.

Figure 16.4. Summed expert ratings for all nine threats, per biozone, divided into four categories of threat status.

0

30

60

90

120

150

180

ExtractiveMLR use

Pollution Mining Coastaldevelopment

Climatechange

Catchmentissues

NErecreational

activities

Alien invasivespecies

Mariculture

Threat

Sum

med

ratin

gs a

cros

s al

l bio

zone

sCurrent threats

Future threats

Biozone Threat StatusCritically endangeredEndangeredVulnerableLeast threatenedIntertidal

Deep photic

Shallow photic

Sub photic

Supratidal



Biozones with a threat rating of ten (the maximum) Within individual biozones, the only current threat to be rated as a 10 (the maximum) was mining (Table 16.2 and Figure 16.1). This mining activity occurs in the West Coast supratidal bioregion and the Namaqua bioregion. In the future, the mining threats continue, but EMLRU also rates a ten in three biozones:

• Agulhas deep photic • Agulhas sub photic • Natal sub photic

Biozones with a threat rating of nine Current threats that received a rating of nine include coastal development in the South-west Coast Supratidal bioregion, and all others result from EMLRU. This affects all marine depth strata, except for the lower slopes and abyss. The biozones with nines for EMLRU are:

• South-western Cape Sub Photic • Agulhas Shallow Photic • Agulhas Deep Photic • Agulhas Sub Photic • Natal Deep Photic • Natal Sub Photic

Future threats to rate a nine include continued coastal development in the South-west Coast Supratidal bioregion, and EMLRU in these biozones:

• Namaqua Sub Photic • Atlantic Upper Slope • South-western Cape Shallow Photic • South-western Cape Deep Photic • South-western Cape Sub Photic • Agulhas Shallow Photic (the number of fishing industries is increasing) • Natal Intertidal • Natal Shallow Photic • Natal Deep Photic



Table 16.2. The two greatest threats in each of the biozones (these are grouped into bioregions moving from west to east). Expert ratings are shown in parentheses. Data are the same for both current and future threats, except where threats are listed in bold (these show where future data differ from current data). Biozone name Greatest threat Second greatest threat West Coast Supratidal Mining (10) Non-extractive recreational activities (5) Namaqua Intertidal Mining (10) Alien invasive species (6) Namaqua Shallow Photic Mining (10) EMLRU (6) Namaqua Deep Photic Mining (10) EMLRU (6) Namaqua Sub Photic EMLRU (8) Mining (5) Atlantic Upper Slope EMLRU (8) Mining (4) Atlantic Lower Slope Pollution (1) + Climate change (1) + Catchment issues (1) [EMLRU] (ties) [Climate change] Atlantic Abyss Pollution (1) + Climate change (1) + Catchment issues (1) [Climate change] (ties) South-west Coast Supratidal Coastal development (9) NERA (7) South-western Cape Intertidal EMLRU (6) + Alien invasive species (6) [EMLRU] Pollution (5) [Alien invasive species] South-western Cape Shallow Photic EMLRU (8) Pollution (5) South-western Cape Deep Photic EMLRU (8) (ties) [Pollution] South-western Cape Sub Photic EMLRU (9) Pollution (2) South Coast Supratidal Coastal development (6) Pollution (4) South-east Coast Supratidal Coastal development (6) Pollution (4) Agulhas Intertidal EMLRU (6) (ties) Agulhas Shallow Photic EMLRU (9) Pollution (3) [(ties)] Agulhas Deep Photic EMLRU (9) (ties) Agulhas Sub Photic EMLRU (9) (ties) South-west Indian Upper Slope EMLRU (5) (ties) [Climate change] South-west Indian Lower Slope Pollution (1) + Climate change (1) [Climate change] (ties) Indo-Pacific Abyss Catchment issues (2) (ties) Transkei Coast Supratidal NERA (3) [NERA + Coastal Development] (ties) [Pollution] Natal Intertidal EMLRU (8) (ties) Natal Shallow Photic EMLRU (8) ((ties) [Pollution] Natal Deep Photic EMLRU (9) (ties) Natal Sub Photic EMLRU (9) Pollution (3)



Biozone name Greatest threat Second greatest threat KwaZulu-Natal Coast Supratidal Coastal development (5) (ties) [NERA] Delagoa Intertidal EMLRU (8) (ties) [Coastal Development] Delagoa Shallow Photic EMLRU (4) [EMLRU + Climate Change] (ties) Delagoa Deep Photic EMLRU (3) + NERA (3) [NERA] (ties) Delagoa Sub Photic EMLRU (3) (ties) [Climate change] West Indian Upper Slope EMLRU (3) (ties) [Climate change]

West Indian Lower Slope EMLRU (1) + Pollution (1) + Climate change (1) + Catchment issues (1) [EMLRU + Climate Change] (ties)



Do threats increase in the future? Figure 16.3 shows that according to the expert ratings, all threats increase in the future, in the order shown in Table 16.3 below. Table 16.3. The proportional increase in the nine threats in the future (threats summed across all biozones). Data are sorted from greatest to smallest increase. Threat % increase Alien invasive species 82 Mariculture 78 Climate change 76 Coastal development 49 Mining 33 Pollution 27 Non-extractive recreational activities 26 Extractive marine living resource use (EMLRU) 13 Catchment issues 10 Unfortunately, two of the threats with the greatest proportional increases in the future are practically beyond spatial or management mitigation measures (alien invasive species and climate change). The other threat that increases greatly is mariculture. The potentially negative effects of mariculture should thus be carefully managed and monitored. Note, however, that these three threats rate amongst the lowest of the nine threats in terms of their absolute values. Which depth strata face the greatest threats? As one moves from the land (supratidal) to the deep sea (abyss), the summed threats per depth stratum decrease, both now and in the future (Table 16.4). This trend is expected, since human access decreases as one moves further offshore. Table 16.4. The summed expert ratings of the nine threats per depth stratum, both now and in the future. The greatest threat in each depth stratum is also listed.

Depth stratum

Total rating

(current)

Total rating

(future) Greatest

current threat Greatest

future threat Supratidal 107 141 Coastal development Coastal development Intertidal 103 137 EMLRU EMLRU Shallow Photic 90 112 EMLRU EMLRU Deep Photic 84 109 EMLRU EMLRU Sub Photic 69 91 EMLRU EMLRU Upper Slope 30 40 EMLRU EMLRU Lower Slope 9 20 Pollution; Climate change EMLRU; Climate change Abyss 7 10 Catchment issues Climate change; Catchment issues



Currently, coastal development is the highest threat in the supratidal, whereas EMLRU is by far the highest threat from the intertidal to the upper slope (Table 16.4). Pollution and climate are the greatest threats on the lower slope, whereas catchment issues are the greatest threats in the abyss (geologists have noted accelerated deposition over past 100 years). In the future, the pattern is the same, except that EMLRU begins to affect the lower slope (it is assumed that methods of fishing, which currently extend to about 1600 m depth, will be able to penetrate even more deeply along the continental slope, R. Leslie, pers. comm.). In addition, climate change is assumed to play a bigger role in the abyss. How are threats distributed across the bioregions? Both current and future threats appear to be worse on the west coast (Namaqua and South-western Cape bioregions), followed by the south and east coasts (Agulhas and Natal bioregions), and then the northeast coast (Delagoa bioregion) (Figures 16.5-16.7). The exception is that the KwaZulu-Natal supratidal bioregion has a summed rating on a par with the west coast (Figure 16.5). Mining and EMLRU drive the high threats on the west coast, and EMLRU drives the high threats on the south and east coasts (Figures 16.5 and 16.6). The lower threats in the Delagoa bioregion result because of the presence of the St Lucia and Maputaland MPAs (but note that there is still heavy intertidal exploitation within parts of these MPAs).

Figure 16.5. Summed expert ratings of all threats per supratidal bioregion (each supratidal bioregion is also a single biozone). Both current and future scenarios are shown.

0

5

10

15

20

25

30

35

West Coast South-west Coast South Coast South-east Coast Transkei Coast KwaZulu-NatalCoast

Supratidal bioregion

Sum

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ratin

gs fo

r all

thre

ats

Current threats

Future threats



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Namaqua South-western Cape Agulhas Natal Delagoa

Inshore bioregion

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ats

Current threats

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0

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Atlantic South-west Indian (plus Indo-Pacific)

West Indian (plus Indo-Pacific)

Offshore bioregion

Sum

med

ratin

gs fo

r all

thre

ats

Current threats

Future threats

Figure 16.6. Summed expert ratings of all threats per inshore bioregion (each inshore bioregion contains 4 biozones). Both current and future scenarios are shown.

Figure 16.7. Summed expert ratings of all threats per offshore bioregion. The Atlantic offshore bioregion contains three biozones, and the South-west Indian, and West Indian offshore bioregions contain two each. Consequently, the data from the Indo-Pacific abyss biozone (which also forms the Indo-Pacific Offshore bioregion) was added to each of these, to bring the total number of biozones up to three each (to make them comparable with the Atlantic data).



Conclusions Extractive marine living resource use is the overriding threat to South African marine biodiversity, and it affects all bioregions and all depth strata. Pollution and mining are the next most serious threats, but mining is restricted to particular biozones, especially on the west coast. In fact, mining is the only current threat to be rated with the maximum score (ten) in any one biozone. It is responsible for the Critically Endangered status of the west coast biozones, from the supratidal to the deep photic (Figure 16.4). All threats are predicted to increase in the next ten years, especially alien invasive species, and mariculture. Threats decrease as one moves offshore, with the decrease in human access. Bioregionally, threats tend to decrease from the west to the east. This may be partly the result of the higher biomass (and exploitation) on the west coast, coupled with the presence of minerals (such as the diamonds, oil and gas). South Africa urgently requires an MPA on the west coast, to offset the problem that almost the entire region has been allocated to mining concessions (Clark et al. 1999).



17. Priority status of biozones For this chapter, please refer to Figure 7.1, which shows the biozones referred to here. The previous two chapters (protection and threat status of biozones) give a broad picture of the distribution of protected areas, and threatened areas, in South Africa’s marine environment. One could argue that these two variables (protection and threat) are not independent, and that areas are threatened because they lack protection. However, the broad scale of the threats analysis negates this argument, as threats were rated across entire biozones, irrespective of the presence of protected areas within them. Assuming that protection and threat status are independent, we plotted the biozones in two dimensions, with protection status on the X-axis and threat status on the Y-axis (Figure 17.1), using data for current threats only. The position of points in the graph then gives the priority status: the rationale is that any biozone that is extremely threatened, and also lacks any protection, requires priority intervention. Alternatively, a biozone that lacks any current threats and also enjoys a lot of protection, does not require immediate conservation intervention. All other biozones will fall somewhere in the middle, and depending on their position in the graph, can be grouped into classes, with different amounts of urgency required for conservation intervention. We defined six classes on the graph, and called them priority status. The classes were defined by dragging a Y=X line across the graph, and allowing clusters of points to define the classes. We then plotted these classes in Figure 17.2.

Figure 17.1. The priority status, for conservation intervention, of biozones in the South African marine environment. Biozones are illustrated in Figure 7.1. Priority status is numbered from 1-6 on the graph, and is mapped in Figure 17.2.

0

5

10

15

20

25

30

0 10 20 30 40

Biozone Protection Status (% in category 1 MPAs/PAs)

Bio

zone

Thr

eat S

tatu

s (c

urre

nt s

umm

ed ra

tings

/bio

zone

)

South-east Coast

Supratidal

All upper and lower slopes and abyssal biozones (except the Atlantic Upper Slope) Delagoa Sub Photic

Delagoa Shallow PhoticDelagoa Deep Photic

Delagoa Intertidal

South Coast Supratidal

South-west CoastSupratidal

KZN CoastSupratidal

Transkei CoastSupratidal

SW CapeIntertidal

Agulhas Intertidal

SW CapeShallow Photic

Namaqua Shallow PhoticNamaqua Intertidal

Namaqua Deep PhoticWest Coast Supratidal

Agulhas Shallow Photic

NamaquaSub Photic

SWCapeSubPhotic

Agulhas Sub Photic,SW Cape Deep Photic,Atlantic Upper Slope

Natal Intertidal,Natal Shallow Photic,Natal Deep Photic,Natal Sub Photic

Agulhas Deep Photic

12 3 4

5

6



Figure 17.2. The priority status, for conservation intervention, of biozones in the South African marine environment. Data are from Figure 7.1.

Conclusions These two figures clearly show that the west coast biozones not only have the least protection (zero actually), but also currently experience the greatest threats (mainly mining). Conservation intervention is required immediately. At the opposite end of the scale, the Delagoa shallow, deep and sub photic areas (i.e. the continental shelf), are the lowest priority, owing to the narrow shelf in this region (on average about 2 nautical miles offshore) and the St Lucia-Maputaland MPA complex (which extends 3nm offshore). The other two corners of the graph (Figure 17.1) show that although the slope and abyssal biozones have no protection, they are currently not as threatened as biozones closer inshore, and thus have a low priority status. At the top right of the graph, the South-west Coast Supratidal, and the KZN Coast Supratidal biozones may have a high protection status, but are still very threatened by coastal development and non-extractive recreational activities. Management intervention within these MPAs is thus required.

Biozone Priority Status1 (Highest priority)23456 (Lowest priority)

Intertidal

Deep photic

Shallow photic

Sub photic

Supratidal



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