Document ID: chunk:federal_register_of_legislation:F2023L00138:front:0:p16
Version: federal_register_of_legislation:F2023L00138
Segment Type: other
Provision Reference: 
Character Range: 42206–45265

range and at different times of year, but the precautionary principle dictates that the threat category is determined by the population at highest risk. Population-wide threats are generally considered to present a higher risk.

   The risk matrix uses a qualitative assessment drawing on peer reviewed literature and expert opinion. In some cases the consequences of activities are unknown. In these cases, the precautionary principle has been applied. Levels of risk and the associated priority for action are defined as follows:
     •       Very High – immediate mitigation action required
     •       High – mitigation action and an adaptive management plan required, the precautionary principle should be applied

     •       Moderate – obtain additional information and develop mitigation action if required
     •       Low – monitor the threat occurrence and reassess threat level if likelihood or consequences change

             Categories for likelihood are defined as follows:
•       Almost certain – expected to occur every year
•       Likely – expected to occur at least once every five years
•       Possible – might occur at some time

•       Unlikely – such events are known to have occurred on a worldwide basis but only a few times

•       Rare or Unknown – may occur only in exceptional circumstances; OR it is currently unknown how often the incident will occur

             Categories for consequences are defined as follows:
•       Not significant – no long-term effect on individuals or populations
•       Minor – individuals are adversely affected but no effect at population level
•       Moderate – population recovery stalls or reduces

•       Major – population decreases
•       Catastrophic – population extinction

     Chapter 3

     Populations under particular pressure

   The actions described in this Recovery Plan are designed to provide ongoing protection for Australasian Bitterns throughout their Australian range. The meta-population structure of the species is largely unknown. Australasian Bitterns persist as at least two isolated, subpopulations in eastern and south western Australia. In recent decades, numbers in the previous strong-holds in the Murray–Darling Basin have declined, perhaps permanently due to pressure on water resources and thus now only rare inundation of floodplains. The Western Australian subpopulation has become more restricted with few records away from the south and south-east coasts and Lake Muir wetlands, which is part of the Muir-Byenup System Ramsar wetland (Pickering 2013). There have been few confirmed records from the Swan Coastal Plain since 1992 and surveys in 2007 and 2008 found that half the wetlands that supported the species in 1980 now retained no suitable habitat (Pickering and Gole 2008; Pickering 2013; DBCA 2018). Breeding in South Australia is confirmed from the Bool Lagoon, and the coast from Adelaide to Victorian border. There are few recent Queensland records (Barrett et al. 2003).

   All subpopulations covered by this plan have