Regional Threats, Actions and Priorities the Previous Sections Provided Detailed Information for Each of the 46 Cells
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Bryars (2013) Nearshore marine habitats of the AMLRNRM region: values, threats and actions Regional threats, actions and priorities The previous sections provided detailed information for each of the 46 cells. However, those individual cell descriptions did not provide information at a more regional scale that may be useful in terms of catchment management, local government area management and identifying generic threats, and they also do not consider cumulative threats within each cell. In an attempt to address these issues, the present section provides information on threats, actions and priorities at a more regional scale. In order to account for cumulative threats within each cell, a cumulative risk score was calculated by summing all of the risk values for all habitats and issues within each cell (Table 7). These cumulative risk scores were then categorised as none (=0), low (1–15), medium (16–30) and high (>30) to provide a visual summary of regional threats (Figure 4). The highest cumulative risk scores were located off the Adelaide metropolitan coast (Cells MA8–10 and MA12–19), in Rapid Bay (Cell F21) and in Encounter Bay (Cells F10–11) (Figure 4, Table 7). Regions with medium cumulative risk scores were located off southern metropolitan Adelaide, in Yankalilla Bay, from Cape Jervis to Rapid Head and in Encounter Bay (Figure 4). Outside of these areas, threats were low to none (Figure 4). The high cumulative risk scores for the Adelaide region were due to a combination of stormwater, catchment water and wastewater as well as various other issues that threaten the reef, seagrass and sand habitats (see individual cell summaries). The high score for Rapid Bay was mainly driven by the extreme risk rating (RV=24) given to ongoing smothering of reef habitat from the Rapid Bay quarry gravel train (see Cell F21). The high and medium scores for Encounter Bay were mainly due to the threat to reef and seagrass habitats from stormwater and catchment water via the Hindmarsh and Inman Rivers (see Cells F10 and F11). The medium scores for Yankalilla Bay were mainly due to the threat to reef and seagrass habitats from stormwater and catchment water via the Yankalilla River, Bungala River and/or Carrickalinga Creek (see Cells F22–26). Using a similar rationale to Bryars (2003) in the Fish Habitat Inventory, the AMLRNRM region was divided into six geographical areas (Table 8, Figure 5). These geographical areas enable a more holistic approach to threat mitigation in terms of catchment management, generic threats and local government area actions (Figure 5). It is apparent that five of the six geographical areas have a high level of cumulative threats to nearshore marine habitats: northern Adelaide, Holdfast Bay, southern Adelaide, Yankalilla Bay and Encounter Bay. The southern Fleurieu area has a relatively low level of cumulative threats to nearshore marine habitats. Table 9 provides a summary of issues, proposed actions, priority of actions and key players across the six geographical areas based upon the combined information from the 46 individual cell descriptions. When summarising this information across a geographical area, generic issues were combined and the highest priority rating (Low, Medium or High) across the cells within a given area was presented for each issue. While each geographical area has a differing number of issues, many of the issues are consistent across areas, e.g. sediments and nutrients from catchment water and stormwater (Table 9). Nonetheless, the priority of action for such issues often differs between geographical regions (Table 9). Table 10 provides a list of those marine cells that are adjacent to each local government area with a coastal boundary (see also Figure 5). It is apparent that some local government areas are adjacent to 311 Bryars (2013) Nearshore marine habitats of the AMLRNRM region: values, threats and actions just one or two marine cells, while others are adjacent to many cells (e.g. City of Onkaparinga). Table 11 then provides a list of which local government areas are relevant to the six broad geographical areas; these local government areas include both those with coastal boundaries (as in Table 10) and those that lie inland but within a catchment that connects to the coast within that geographical area. When this information is used in conjunction with the identified marine cell and regional threats/issues, local government areas can gain some insight to their links with (and responsibilities to) the marine environment. It is apparent that the Encounter Bay, Southern Fleurieu, Yankalilla Bay and Southern Adelaide geographical areas are each associated with few local government areas, but for the Holdfast Bay and Port Adelaide areas, the situation is more complicated due to the higher number of relevant local government areas. Table 7. Cumulative risk scores and ratings for the 46 marine cells based upon individual risk values for all habitats and issues within each cell. Marine cell Cumulative Cumulative Marine cell Cumulative Cumulative risk score risk rating risk score risk rating F4 0 None F27 14 Low F5 0 None MA1 12 Low F6 11 Low MA2 7 Low F7 0 None MA3 24 Medium F8 15 Low MA4 11 Low F9 12 Low MA5 6 Low F10 33 High MA6 14 Low F11 45 High MA7 20 Medium F12 21 Medium MA8 38 High F13 12 Low MA9 37 High F14 3 Low MA10 54 High F15 2 Low MA11 16 Medium F16 4 Low MA12 80 High F17 6 Low MA13 86 High F18 12 Low MA14 86 High F19 9 Low MA15/16/17 70 High F20 19 Medium MA18 80 High F21 35 High MA19 44 High F22 17 Medium MA20 4 Low F23 19 Medium MA21 8 Low F24 19 Medium MA22 8 Low F25 19 Medium MA23 12 Low F26 6 Low MA24 12 Low 312 Bryars (2013) Nearshore marine habitats of the AMLRNRM region: values, threats and actions Adelaide Yankalilla Bay Rapid Bay Rapid Head Cape Jervis Encounter Bay Risk scores and ratings Figure 4. Distribution of cumulative risk scores and ratings for each of the 46 marine cells across the AMLRNRM region. See Figures 1 and 2 for cell details and Table 7 for exact scores. 313 Bryars (2013) Nearshore marine habitats of the AMLRNRM region: values, threats and actions District Light Council of Regional Mallala Council TG Barossa City of Playford Council ‘Northern Adelaide’ City of City of Salisbury Tea Tree CPAE Gully Adelaide Hills CP CCC CCS CTW Council CN ACC ‘Holdfast Bay’ CWT CU CB CH CMi CMa District Council of Mount Barker City of ‘Southern Adelaide’ Onkaparinga ‘Yankalilla Bay’ Alexandrina Council City of Victor Harbor District Council of Yankalilla ‘Encounter Bay’ ‘Southern Fleurieu’ Risk scores and ratings CPAE = City of Port Adelaide Enfield CU = City of Unley CN = City of Norwood Payneham & St Peters CH = City of Holdfast Bay CCS = City of Charles Sturt CB = City of Burnside CP = City of Prospect ACC = Adelaide City Council CWT = City of West Torrens CMa = City of Marion CCC = Campbelltown City Council TG = Town of Gawler CTW = Corporation of Town of Walkerville CMi = City of Mitcham Figure 5. Distribution of cumulative risk scores and ratings across the AMLRNRM region in relation to geographical areas, local government areas and catchments. 314 Bryars (2013) Nearshore marine habitats of the AMLRNRM region: values, threats and actions Table 8. Geographical areas within the AMLRNRM region showing their associated marine cells and equivalent fisheries habitat areas from Bryars (2003) Geographical area Associated marine cells Equivalent fisheries habitat area (from Bryars 2003) Encounter Bay F4–F13 Encounter Bay Southern Fleurieu F14–F20 Tunkalilla Beach Yankalilla Bay F21–F27 Yankalilla Bay Southern Adelaide MA1–MA11 Port Noarlunga Holdfast Bay MA12–MA14 Holdfast Bay Northern Adelaide MA15–MA24 Port Adelaide Table 9. Regional issues, proposed actions, priority of actions and key players Geographical Issue Proposed action Priority Key players area of action Sediments and nutrients Support initiatives for Medium Alexandrina Council from catchment water catchment revegetation and / City of Victor and stormwater improved land management Harbor / AMLRNRM practices (e.g. see Victor Board Harbor Environmental Management Plan 2010– 2014, Inman River Catchment and Landcare Group) Support initiatives to collect Medium Alexandrina Council Encounter and reuse stormwater (e.g. / City of Victor Bay see Victor Harbor Harbor / AMLRNRM Environmental Management Board Plan 2010–2014, Alexandrina Council’s Stormwater Detention and Retention Standards) Erosion of beach at Victor Support initiatives to mitigate Medium City of Victor Harbor beach erosion (e.g. see Victor Harbor / AMLRNRM Harbor Environmental Board Management Plan 2010– 2014) Sediments and nutrients Support initiatives for Low City of Victor from cliff top erosion and catchment revegetation and Harbor / District small creeks improved land management Council of Yankalilla Southern practices (e.g. see Victor / AMLRNRM Board Fleurieu Harbor Environmental Management Plan 2010– 2014, District Council of Yankalilla Development Plan 2013) 315 Bryars (2013) Nearshore marine habitats of the AMLRNRM region: values, threats and actions Table 9 (cont.). Regional issues, proposed actions, priority of actions and key players Geographical Issue Proposed action Priority Key players area of action Sediments and nutrients Support initiatives for Medium District Council of from cliff top erosion and catchment revegetation and Yankalilla / small creeks improved land management AMLRNRM Board / practices (e.g. see District Adelaide Brighton Council of Yankalilla Cement / EPA Development Plan 2013) Smothering by gravel Support initiates