A number of early collections were made from suburban areas where the species is now considered to be locally extinct. These areas include Kogarah (1884), Arncliffe (1897), Tempe (1898), Oatley (1899), Cooks River (1901), and Earlwood (1912). In the last ten years, sites have also been lost to residential development and road construction in Hornsby Heights (J. Slaven, Hornsby Council, pers. comm.), Bangor, and Menai (I. Drinnan, Sutherland Council, pers. comm.).
It is difficult to count individual plants within populations, because M. deanei is a clonal species. This means that an individual (or genet) may occur as a number of stem clumps (or ramets), which may appear as different plants (Myerscough 1998). Genetic analysis is the only means to determine the number of genetically distinct individuals in a population, but this has not yet been undertaken. Research by Felton (1993) suggests that for every 10-15 M. deanei ramets counted, two to three individuals may be present, while the NSW Scientific Committee (1999) notes that for this species ‘ramet counts may overestimate population size by two or three times’.
This difficulty with identifying genetically distinct plants needs to be considered when discussing the size of populations based on ramet counts (Table 2). It also explains why no attempt has been made to determine the size of 28% of all populations. Generally, it is likely that the number of genetically distinct plants is lower than the number of ramets counted. The numbers in Table 2 thus give rise to concern: at least 52% of the populations contain less than 50 ramets, and thus most likely even less individual plants. Only four populations contain more than 500 ramets. Of these four, only one occurs in the northern part of the species’ range, the other three are in the southern part.
Table 2. Size class distribution for the 94 known populations of Melaleuca deanei.
Table 3 shows tenures for the land on which M. deanei occurs, and Table 4 describes the zoning of such land. More than 50% of all sites occur in DECCW estate and are zoned as National Park or Nature Reserve. Holsworthy Military Reserve, contains 17 % of the known M. deanei population, including large populations that extend along the ridgelines in the central and western section of the area. This reserve is owned by the Department of Defence, and most of it is presently zoned as land for Environment Protection, with a small proportion zoned as ‘Special users’. Two large sites (both large populations) occur on land that is managed by the Sydney Catchment Authority, within the Nepean and Avon Dam catchments. The survival of the species has thus been largely dependent on the protection of lands that have not been subject to intensive land use or clearing.
Note that for the analysis in Tables 3 & 4, populations are counted as two different sites where they are distributed across two different tenures, and both tables thus list 100 sites (compared to the 94 populations in Table 1). More detail for these 100 sites is provided in Appendix 3. References to site numbers throughout this plan correspond to Appendix 3.
Table 3. Land tenures for 100 Melaleuca deanei sites.