Chapter 6 Impacts on the Values
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Chapter 6 Impacts on the values 6.8 Cumulative impacts .................... 6–67 6.8.1 Qualitative models ......................... 6–67 6.8.2 Spatial approaches ........................ 6–71 6.8.3 Outcomes of cumulative impact assessments ................................. 6–79 6.9 Effects on matters of national environmental significance ........ 6–81 6.9.1 World heritage properties ............... 6–81 6.9.2 Great Barrier Reef Marine Park ....... 6–81 6.9.3 National heritage places ................. 6–82 6.9.4 Commonwealth marine area ........... 6–82 6.9.5 Listed migratory and listed threatened species ......................................... 6–82 6.9.6 Wetlands of international importance .................................... 6–83 6.10 Key information gaps .................. 6–83 6.10.1 Biodiversity .................................... 6–83 6.10.2 Geomorphological features ............. 6–84 6.10.3 Indigenous and historic heritage values ........................................... 6–85 6.10.4 Community benefits of the environment .................................. 6–85 6.10.5 Cumulative impact assessment ....... 6–85 6.10.6 Processes to address information gaps ............................................. 6–86 6.11 Summary of outcomes ................ 6–87 References .................................................. 6–91 Table of contents 6 Impacts on the values ..................... 6–3 6.1 Background ................................... 6–3 6.1.1 Context ........................................... 6–3 6.1.2 Challenges in assessing impacts ...... 6–3 6.1.3 Terminology .................................... 6–4 6.2 Impacts considered ...................... 6–5 6.2.1 Identifying likely past and present impacts ........................................... 6–5 6.3 Legacy impacts ............................. 6–9 6.4 Impacts on biodiversity values . 6–11 6.4.1 Climate change impacts ................. 6–11 6.4.2 Catchment run-off .......................... 6–18 6.4.3 Degradation of coastal ecosystems . 6–32 6.4.4 Direct use ..................................... 6–35 6.4.5 Assessment of impacts on biodiversity .................................... 6–56 6.5 Impacts on geomorphological features ........................................ 6–59 6.6 Impacts on Indigenous and historic heritage values ............................ 6–62 6.6.1 Indigenous heritage values ............. 6–62 6.6.2 Historic heritage values .................. 6–66 6.7 Impacts on community benefits of the environment .......................... 6–66 Cover page image: Aerial view of Townsville . 6–2 Great Barrier Reef Region Strategic Assessment | Strategic Assessment Report | Draft for public comment Extract from Great Barrier Reef Region Strategic Assessment terms of reference 3. Assessment of impacts on matters of national environmental significance 3.1 Actual and potential impacts ……….. b) describe and analyse the actual and potential impacts on the relevant matters of national environmental significance, including the outstanding universal value of the Great Barrier Reef World Heritage Area, in the strategic assessment area, including: i. impacts from past, present and future activities ii. direct, indirect, consequential and cumulative impacts iii. the likely impacts of climate change c) describe the spatial and temporal scale at which impacts and their effects on the relevant matters of national environmental significance, including the outstanding universal value of the Great Barrier Reef World Heritage Area, are occurring or are likely to occur d) identify key information gaps and processes to address critical information needs. 6 Impacts on the values 6.1 Background 6.1.1 Context The Great Barrier Reef Region is a large and complex natural system with multiple uses that is subject to many impacts. The state of the Region’s biodiversity, geomorphological features and Indigenous and historic heritage values, and the benefits derived from the environment, are constantly changing in response to a complex suite of interactions between drivers, activities and impacts. To develop a full understanding of the impacts and their effects on the Region’s values the individual and cumulative effects of all impacts are considered in the chapter. The focus is on the impacts on the ecological system (that is, its biodiversity values) as this is fundamental to the matters of national environmental significance in the Region. An assessment of the impacts on key biodiversity values informs the assessments of impacts on geomorphological features and Indigenous and historic heritage values. Flow-on effects on the community benefits derived from the environment are also described. To date, understanding of cumulative impacts in the Region has been limited. The assessment of management effectiveness for the Great Barrier Reef Outlook Report 2009 identified the extent to which cumulative impacts are being addressed as “the weakest indicator across the entire management effectiveness assessment”1. The independent review of the Authority’s current management arrangements, carried out as part of the strategic assessment process (refer to Chapter 8), arrived at the same conclusion and further stated that processes to address cumulative impacts were “problematic for most issues”. Both qualitative and spatial modelling are employed in this chapter to consider cumulative impacts (see Section 6.8). 6.1.2 Challenges in assessing impacts Specific challenges in assessing impacts, and cumulative impacts in particular, in the Great Barrier Reef Region include: the diversity of values and attributes underpinning matters of national environmental significance relevant to the Region the availability of information on the condition and trend of a number of values and attributes to allow development of a ‘baseline’ for the assessment the complex interactions, processes and relationships of the hugely diverse species, habitats and bioregions that make up the ecosystem Impacts on the values 6–3 the number of drivers, activities and impacts acting on the values and attributes limited understanding of the relationships between the ecological and human systems the multiple scales at which processes and impacts occur and interact with ecological and human systems limited understanding of the cause-and-effect relationships of multiple or ‘compounding’ impacts on the Region’s values the dynamic nature of systems and the rapid pace of change the delayed response time of species, habitats and systems to change a limited understanding of the thresholds for species, habitats and ecosystem health. 6.1.3 Terminology In describing and assessing impacts, the following types are considered, adapted from A guide to undertaking strategic assessments2: Direct impacts — where the loss or modification of values is a direct result of an action within the strategic assessment area (for example, dredging and disturbing wildlife). Indirect impacts — can be either: o from actions outside the strategic assessment area with ‘downstream’ effects in the area (for example, modifying supporting terrestrial habitats, urban and industrial discharge) o as a result of another direct impact (for example, an oil spill resulting from the grounding of a ship). Consequential impacts — where the impact arises from an action made possible by an initial direct impact (for example, anchor damage from ships now able to visit an area after dredging). Cumulative impacts — the successive and combined effects of impacts on the environment, taking into account direct, indirect and consequential impacts and the incremental and compounding effects of these impacts over time. Direct, indirect and consequential impacts are diagrammatically represented in Figure 6.1. Figure 6.1 Direct, indirect and consequential impacts The strategic assessment considers all types of impacts on the Region’s values. Using ports and shipping as an example: dredging to deepen a port channel is a direct impact, a plume of sediment from that dredging is an indirect impact, and any anchor damage to the seafloor as a result of a ship visiting the port following the dredging is a consequential impact. 6–4 Great Barrier Reef Region Strategic Assessment | Strategic Assessment Report | Draft for public comment 6.2 Impacts considered 6.2.1 Identifying likely past and present impacts The set of past, present and future impacts affecting or likely to affect the Region’s values was developed by consolidating the outcomes of: the Outlook Report 20091 the analysis of drivers and activities within and adjacent to the Region presented in Chapter 5 workshops involving managers and technical experts in relation to future monitoring needs for the Region. The descriptors used are based on those used in the Outlook Report 2009, with some amendments and updates. The final 40 impacts considered are listed in Table 6.1 and matched to their likely causes, either direct drivers or activities, in Table 6.2. Each of the impacts is individually assessed in relation to its effects on biodiversity (Section 6.4), geomorphological features (Section 6.5) and Indigenous and historic heritage values (Section 6.6). The flow-on effects on community benefits, including aesthetics, is discussed in Section 6.7. The focus is on the impacts on the ecological system (that is, its biodiversity values) as this is fundamental to the matters of national environmental significance in the Region. It is important to recognise that there is great variation in the spatial extent of the impacts — some operate