Document ID: chunk:federal_register_of_legislation:F2023L01376:reg:2:p5
Version: federal_register_of_legislation:F2023L01376
Segment Type: reg
Provision Reference: reg 2 (pt 5/8)
Character Range: 29474–32332

with native bees being superior pollinators. Trees in orchards are rarely observed to produce seed from self-pollination (Neal 2007).
Seed dispersal is by small rodents, cockatoos and gravity fall, probably with some assistance from local stream flooding. The role of seed predators such as cockatoos and rodents in effecting seed dispersal is likely to be limited. Studies of the caches of the introduced black rat – a common predator of trees in orchards, backyards and wild populations close to urban areas – found they did not contain any undamaged nuts; thus, germination of the dispersed seed is unlikely (Elmouttie and Wilson 2005).
Hybridisation has been documented between M. integrifolia and M. ternifolia, and between M. integrifolia and M. tetraphylla in areas of range overlap where both species co-occur within the same rainforest patch.
Genetic studies have been carried out on wild M. integrifolia DNA using RAFs (Radioactive Amplified DNA Fingerprinting) microsatellites and isozymes techniques. Both molecular marker evidence and evidence from variation for horticultural traits indicates there is moderate to high genetic diversity within the species and among populations (Neal 2007; Hardner et al. 2009).
The latest paper on the phylogenetic structure of M. integrifolia confirms a deep divergence between northern and southern clades of the species, suggesting a historical barrier to seed dispersal north of Brisbane, between the Brisbane and Mary catchments (Nock et al. 2019). This is consistent with two subtropical refugia as defined by Weber et al. (2014). Each of the northern and southern clades forms two distinct sub-clades – Mt Bauple and Gympie for the northern clade and for the southern clade, a division by the Brisbane River valley into sites to the north-west of Brisbane and sites south of Brisbane to the Gold Coast (Nock et al. 2019). A fifth sub-clade was identified by Nock et al. (2019) which was only represented by three old trees transplanted from the wild. It is hoped that further surveying and DNA testing will find other trees from this sub-clade and reveal their geographic origin, but it may be that they are from a population that is now extinct in the wild (Nock et al. 2019).
Evidence from paternity studies indicates presence of current gene flow by pollen between populations up to approximately 3 km in a highly fragmented landscape (Neal 2007). These data indicate that the species may survive small population size if there is a network of small populations within a region (meta-population) that enable the maintenance of genetic diversity. Neal et al. (2010) investigated the impact of habitat fragmentation on reproduction and growth of new trees in wild M. integrifolia populations, finding that fragmentation is not necessarily detrimental to reproduction in the short term, possibly because