26 Monitoring Threatened Species and Ecological Communities
2010). Furthermore, the status of some species is so poorly known that it is not
evident whether they are extinct or not: the Christmas Island shrew is such a case,
with only four records since 1908, including two in the mid-1980s.
Notwithstanding these caveats, monitoring of the rate of extinctions provides a
compelling account of biodiversity decline (Fig. 3.1), and can usefully chart the extent
to which management investment is achieving at least the basic conservation
objective of attempting to prevent extinction. For Australian native mammal species,
extinctions have been occurring at broadly the same rate (1–2 species per decade)
since the 1840s, with that rate showing no sign of easing, despite conservation
management improvements over recent decades (Woinarski et al. 2015).
Monitoring of Australian terrestrial mammals: an assessment
The assessment of the extent and adequacy of monitoring for the 167 extant
terrestrial mammal taxa considered to be of conservation concern is summarised
in Table 3.1 and Fig. 3.2. With a somewhat generous interpretation of what
sampling could be termed monitoring, some monitoring activity was located for
most (79%) of the considered mammal taxa, but no monitoring activity for the
remaining 21%. For the taxa with monitoring, most of this activity rated low for
most metrics of the evaluation framework. The monitoring metrics that scored
most poorly were: inclusion of demographic parameters (mean score 1.5 on a 0 to 5
point scale; most monitoring programs simply reported relative abundance); data
availability and reporting (1.8; most monitoring results were not readily accessible);
coordination (2.0; most monitoring involved idiosyncratic activity at different sites,
Fig. 3.2. Summary of the extent and adequacy of monitoring for 167 Australian terrestrial mammal taxa of
conservation concern. Shading on each horizontal bar (representing the named metric) indicates the
percentage of species in each score class, from 0 (no monitoring, palest shading) to 5 (optimal monitoring,
darkest shading).