Document ID: chunk:federal_register_of_legislation:F2025L00287:reg:3:p55
Version: federal_register_of_legislation:F2025L00287
Segment Type: reg
Provision Reference: reg 3 (pt 55/276)
Character Range: 220874–223683

introduced (Mills 2012a). Most of these are found in the Kingston Common, Lower Watermill Creek and dam, and Lower Cascade Creek. One of the worst wetland weeds is water hyacinth (Eichhornia crassipes), which is highly abundant (to the point of choking) in Kingston and several other wetland areas.
Details of the principal terrestrial weed species affecting the islands are given below. CSIRO have produced probability maps and GIS layers for the distribution of red guava and African olive, which are available via the CSIRO Data Access Portal (Levick and Johnson 2023).

Red guava/porpay (Psidium cattleyanum var. cattleyanum)

Red guava is native to Brazil and has been present on Norfolk Island for over 150 years, where it poses a significant threat to native vegetation (Sykes & Atkinson 1988; Lowe et al. 2000). The plant produces an edible fruit and establishes in dense bush thickets with wide ranging root systems that restrict the growth of surrounding native plants. These thickets form rapidly, reduce light penetration to the understorey and produce numerous seeds which are then widely dispersed by birds and cattle (Director of National Parks 2008). Fruit dropped from the plants also negatively impact the environment by altering the chemical composition of downstream soil as they degrade, affecting the germination of native plant species (Christian 1999; Lowe et al. 2000). Areas infested with red guava tend to have lower surface soil moisture, and where dense stands occur along creek gullies there is little sign of regeneration of native ferns (Davidson et al. 1994). The impact is amplified in times of low rainfall when competition for moisture is more intense. A high abundance of woody weed species like the red guava can result in mortality of mature Norfolk Island pines due to competition for moisture (Parks Australia, unpublished data).
Red guava is present throughout much of the Mt Pitt section of the national park and across Norfolk Island, though not on Phillip Island. Extensive woody weed removal in the national park over the past decade has considerably reduced its cover (Parks Australia, unpublished data), suggesting that it is possible to control the impact of this weed.

African olive (Olea europaea cuspidata)

African olive is native to Mediterranean regions in North Africa but has become a widespread invasive species in Hawaii, New Zealand and eastern Australia (Starr et al. 2003; Cuneo & Leishman 2006). It is believed to have been introduced to Norfolk Island by the Melanesian Mission to provide wind breaks (R Ward 2024, pers comm 11 January) and on Phillip Island following the removal of rabbits. As native vegetation was cleared on Norfolk Island, African olive established as a major weed, and it is the main weed species found on Phillip Island.