Document ID: chunk:federal_register_of_legislation:F2023L01713:body:0:p33
Version: federal_register_of_legislation:F2023L01713
Segment Type: other
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Character Range: 160944–163979

pit in New Guinea (Hitchcock 1998). Concurrent box trap surveys failed to detect the water mouse at the Arnhem Land site or in nearby mangrove, saline floodplain or freshwater swamp sites (Woinarski et al. 2000). As such, pitfall traps may be a useful – and potentially highly effective – method for surveying water mouse where environmental conditions ensure animal safety is not compromised.
It is possible to spotlight the water mouse foraging in open grey mangrove forests, where it can be positively identified by the distinctive white belly and dull mauve eye shine (Van Dyck 1996). However, spotlighting is generally not a cost-effective survey method for this species, with 32 person-hours of effort resulting in one detection in the Mackay region (Ball 2004).
The presence of an active or inactive mud shelter (Section 3.5) or conclusive feeding sign (Section 3.6) are effective ways to identify a likely water mouse occurrence. The use of detection dogs also holds much potential. Follow-up trap or camera surveys are recommended in locations where water mouse mud shelters, feeding sign and/or positive scent indications from a detection dog are suspected (e.g. Ball 2004; Ball & Mitchell 2018).

3.13            Intermittent detectability
The water mouse is not always detectable at known sites, suggesting unknown factors drive temporal variation in occurrence (Ball 2004; Gynther 2011).
Cameras monitoring water mouse shelters along the southern Queensland coast detected what appears to be water mouse torpor, with a frenetic feeding period just prior to the cold season followed by significantly reduced activity (Kaluza 2021 pers. comm.). Surveys for feeding sign, remote camera surveys, and box trap surveys may not detect this species during cooler months in this region.
The water mouse may also be temporarily absent from potential or confirmed habitat due to interannual, annual, monthly or daily wetland saturation conditions and prey availability (Woinarski et al. 2000; Gynther 2011), or recent disturbance from cyclone, extreme flooding and/or mangrove dieback (see Sections 4.2 and 4.3).

    4               Threats
There are very few areas where water mouse presence and/or abundance trends are monitored, and none where they are systematically monitored using standardised methods and/or in relation to threat dynamics or the effectiveness of management actions. This creates challenges in understanding natural water mouse population dynamics, the severity of known and potential threats, and the effectiveness of threat mitigation programs.

4.1                  Coastal development (urban and commercial)
The primary threat to the national water mouse population is from unsustainable urban and coastal development that removes, degrades, and fragments habitat and areas supporting recovery (Woinarski & Burbidge 2016; CITES 2019). Coastal development includes – but is not limited to – urban and industrial estates, mining, sea- and air-ports, and infrastructure to support the built environment. Land