Document ID: chunk:federal_register_of_legislation:F2025L00287:reg:3:p252
Version: federal_register_of_legislation:F2025L00287
Segment Type: reg
Provision Reference: reg 3 (pt 252/276)
Character Range: 920120–924336

(2010) found a total of 84 plants, including trees and a reasonable number of seedling. Mills (2012b) counted 12 plants at five locations, but noted that the species was not regenerating well, as most seedlings were not surviving.
The population estimate in 2021 had increased to 629 individuals, through planting and propagation as part of the Norfolk Island National Park threatened flora program.
The distribution is shown in Map 66.

Ecology
This species is possibly short lived and requires high light levels for establishment.

Habitat
Occurs in moist upland hardwood forest and pine-hardwood ridge forest (Invasive Species Council & TierraMar 2021), especially in protected, sunny, moist sites.

Threats
Threats to the species include weed invasion and competition from weeds, particularly red guava. Phytophthora cinnamomi is potentially a major risk. There has been unexplained death of many plants; the cause of this is unknown.
Map 66 Distribution of Wikstroemia australis
Green outlines indicate reserves within which the species occurs. Green shading shows plant communities within which the species may occur (Christian & Mills 2021).

Impact on other species
None known.

Risk assessment
Risk assessment undertaken for Critically Endangered trees/shrubs as a grouping. The risk assessment is shown in Table 151.
Table 151 Risk assessment for Critically Endangered trees/shrubs as a grouping
Risk                                                                                                               Likelihood of exposure    Consequence  Threat rating
1. Loss and fragmentation of native vegetation through past land clearing                                          Almost certain (91–100%)  Extreme      Extreme
2. Loss and fragmentation of native vegetation through current or future land clearing                             Rare (0–10%)              Negligible   Negligible
3. Degradation of native vegetation through past grazing or loss of nutrients                                      Almost certain (91–100%)  Extreme      Extreme
4. Degradation of native vegetation through current or future grazing                                              Possible (26–50%)         Moderate     Medium
6. Predation by rodents                                                                                            Almost certain (91–100%)  Major        Extreme
7. Predation by cats                                                                                               Rare (0–10%)              Negligible   Negligible
8. Predation or damage by chickens                                                                                 Likely (51–90%)           Moderate     Medium
9. Predation by swamphens                                                                                          Rare (0–10%)              Negligible   Negligible
10. Predation by Argentine ant                                                                                     Possible (26–50%)         Minor        Low
11. Competition from/change of habitat because of weed invasion                                                    Likely (51–90%)           Minor        Medium
12. Infection by pathogens already present                                                                         Possible (26–50%)         Moderate     Medium
13. Impacts of potential new invasive species or pathogens                                                         Unlikely (11–25%)         Minor        Low
14. Changes to vegetation, increased fire risk and/or direct physiological stress as a result of climatic changes  Possible (26–50%)         Moderate     Medium
15. Problems caused by small populations, including lack of genetic diversity                                      Likely (51–90%)           Moderate     Medium

Management actions
Continue propagation and planting in suitable areas. Undertake habitat protection and rehabilitation. Carry out targeted weed control and maintenance around existing populations to create gaps to allow the penetration of sunlight. Undertake research into the causes of plant death and treatment options.

Recovery target
The recovery target is shown in Table