Document ID: chunk:federal_register_of_legislation:F2023L01376:reg:3:p3
Version: federal_register_of_legislation:F2023L01376
Segment Type: reg
Provision Reference: reg 3 (pt 3/13)
Character Range: 91880–94969

flow via pollen of 2.8 km has been documented for M. integrifolia (Neal 2007). Nearest neighbour distance calculations among recorded Macadamia populations show that for each species, many populations are located within 3 km of their two nearest neighbours, especially those located within areas of clusters of populations. Macadamia species appear to maintain themselves via a meta-population structure rather than acting as isolated independent populations.
Whilst pollen exchange between close populations may assist with maintaining genetic diversity, the available data for wild Macadamia species suggest that reproduction is inhibited by a lack of pollinators (Neal 2007; Pisanu et al. 2009). Macadamias are weakly self-compatible, but not capable of autogamy, i.e., they require a pollinator to effect fertilisation; further, outcrossed pollen results in greater seed production (Pisanu et al. 2009). The combined impact of these three factors is to limit seed production by Macadamias. When compounded by the impact of abundant seed predators, such as rats, the result is very low seed germination; this was evident in surveys of wild populations across SEQ undertaken for the Macadamia Conservation Trust during 2015–16 (L. Gould pers. comm. 2017). Further surveys and long-term monitoring are required to understand the likely impact on population persistence.
Macadamias belong to a group of regional subtropical rainforest tree species that produce large hard-shelled seeds and have limited dispersal ability (Rossetto et al. 2008). Whilst in-situ Macadamia populations may be able to maintain themselves in a fragmented landscape better than some other species, there is less evidence that populations are able to be recolonised or restored by neighbouring populations (typical of a meta-population structure). Actions which enhance or at least maintain connectivity between populations and facilitate pollinator movement, may improve interpopulation gene flow through pollen exchange, potentially mitigating some of the impacts of habitat loss and fragmentation (though as noted above, this may not be sufficient to redress the compounded effects of poor germination).

Weed species
Weeds can displace native flora, compete for resources (such as pollinators, light, nutrients and water) and create habitats that are conducive to other exotic species. They can also alter the composition of vegetation communities, patterns of pollination and native seed dispersal. The interface between bushland and other land uses is particularly susceptible to the spread of exotic species that flourish in this altered environment.
Weed species that pose a direct and significant threat to Macadamia habitats are lantana (Lantana camara) and exotic vines such as cat's claw creeper (Dolichandra unguis-cati) and Madeira vine (Anredera cordifolia). All three species were introduced to Australia as garden plant and are now classified as weeds of national significance (WoNS). Cat's claw creeper and Madeira vine pose a significant medium-term threat to Macadamia species as they have the