9.3.3 Sources, scale and timing

The identified threats to the Region’s ecosystem and heritage values arise from a number of sources and are highly variable in scale and timeframe. Figure 9.3 links individual threats to their probable causes (that is, the factors identified in Chapter 6 as key influences on the condition of the Region’s values) and indicates the spatial scale and likely timing of each threat’s effect.

The threats identified as highest risk are currently affecting the ecosystem and heritage values at a broad, often Region-wide scale. Similar to 2019, most of the very high risk threats are associated with climate change and land-based runoff, with the remaining very high risks associated with coastal development and direct use of the Region (illegal fishing and extraction). The threats rated as high risk mostly relate to direct use, at both Region-wide and local or regional scales (such as damage to reef structure, discarded catch, extraction from spawning aggregations, extraction of particle feeders, marine debris). Overall, threats which have localised effects (such as dredging and noise pollution) are generally associated with direct use and are rated as having a lower risk.