The natural distribution of Eucalyptus species in Tasmania K.J. Williams and B.M. Potts Cooperative Research Centre for Temperate Hardwood Forestry, Department of Plant Science, University of Tasmania, GPO Box 252–55, Hobart 7001 email: [email protected]./[email protected] Abstract dispersed (E. cordata) or disjunct (E. archeri) occurrences. Most species that are rare in A summary is provided of the natural geographic Tasmania are endemics, with the exception of distributions of the 29 Tasmanian Eucalyptus E. perriniana and E. aff. radiata, although species. The work is based on over 60 000 the taxonomic status of the latter requires observations from numerous data sources. A map investigation. Unresolved issues relating to the on a 10 km x 10 km grid-cell scale is presented for natural distribution and taxonomic affinities of each species and is accompanied by graphs of the the Tasmanian eucalypt species are summarised. altitudinal range and flowering times, as well as descriptive notes on distribution and ecology, supplemented with a list of key references. The Introduction geographic pattern of species richness is examined at generic, subgeneric and series levels. Total In Tasmania and the Bass Strait islands, species richness is greater in the drier, eastern 29 native eucalypt species (one of which has regions compared to the wet, western regions of two subspecies) are recognised by Buchanan Tasmania, with highest concentrations of species (1995), from two informal subgenera, occurring mainly in the central east coast and Monocalyptus and Symphyomyrtus (Pryor and south-eastern regions. Monocalyptus species Johnson 1971). In the present study, we have occur in 8% more grid cells than Symphyo- treated all Tasmanian records of Eucalyptus myrtus species but are absent from King Island. globulus as E. globulus subsp. globulus. The At the series level, greatest species richness is other subspecies of E. globulus listed for reached by the Obliquae in the north-east, the Tasmania, subsp. pseudoglobulus, occurs only Piperitae in the south-east, the Ovatae on the in forms which intergrade with E. globulus central east coast, and the Viminales in highland subsp. globulus (Jordan et al. 1993) and we do areas of the south-east and Central Plateau. Series not include it here as a separate taxon. Obliquae species are absent from Flinders Island and are poorly represented in the south-west. The Tasmanian native eucalypts include 12 species from two series in the subgenus The general patterns of eucalypt distribution and Monocalyptus and 17 species from two series ecology are reviewed. Species are classified into nine in the subgenus Symphyomyrtus (Table 1)1. categories based on the grid cells they occupy within Seventeen taxa are known to be endemic their geographic range. The most widespread to Tasmania (Brown et al. 1983), including species are E. delegatensis, E. obliqua, E. ovata, E. delegatensis subsp. tasmaniensis (Boland E. viminalis and the endemic E. amygdalina. 1985). The Monocalyptus and Symphyomyrtus Most species with localised distributions have been nationally recognised as rare (i.e. E. barberi, 1 An alphabetical list of the Tasmanian eucalypt E. morrisbyi, E. perriniana and E. risdonii). species, including common names, is given in Rare species with regional distributions have either Table 2 (p. 47). Tasforests Vol. 8 39 December 1996 Table 1. Taxonomic classification of the Tasmanian Eucalyptus species (after the informal classification of Pryor and Johnson 1971). Authorities for nomenclature follow Chippendale (1988). Subgroupings of the series Viminales generally follow Jackson (1965) and Duncan (1989) except E. cordata which has closest affinities with the alpine white gum subgroup (Pryor and Johnson 1971). Common names for series groups follow Duncan (1989; see also Jackson 1965). Eucalyptus globulus subsp. globulus includes forms which intergrade morphologically with the mainland taxon E. globulus subsp. pseudoglobulus (Jordan et al. 1993). (* = Tasmanian endemic) SUBGENUS Monocalyptus SUBGENUS Symphyomyrtus Series Obliquae (Ash Group) Series Ovatae (Black Gum Group) * E. barberi L. Johnson & Blaxell * E. delegatensis R.T. Baker subsp. tasmaniensis Boland E. brookeriana A.M. Gray E. obliqua L’Hér. E. ovata Labill. E. pauciflora Sieber ex Sprengel subsp. pauciflora * E. rodwayi R. Baker & H.G. Smith E. regnans F. Muell. E. sieberi L. Johnson Series Viminales (White Gum Group) Series Piperitae (Peppermint Group) White gum subgroup E. dalrympleana Maiden subsp. dalrympleana * E. amygdalina Labill. E. rubida Deane & Maiden * E. coccifera J.D. Hook. E. viminalis Labill. subsp. viminalis * E. nitida J.D. Hook. * E. pulchella Desf. Yellow gum subgroup E. aff. radiata Sieber ex DC. * E. risdonii J.D. Hook. * E. johnstonii Maiden * E. tenuiramis Miq. * E. subcrenulata Maiden & Blakely * E. vernicosa J.D. Hook. Blue gum subgroup E. globulus Labill. subsp. globulus Alpine white gum subgroup * E. archeri Maiden & Blakely * E. cordata Labill. * E. gunnii J.D. Hook. * E. morrisbyi Brett E. perriniana F. Muell. * E. urnigera J.D. Hook. subgenera are reproductively isolated (Ellis This atlas of the natural geographic and et al. 1991) but, within subgenera, extensive altitudinal distribution of the Tasmanian hybridisation and intergradation may occur Eucalyptus species is a compendium of (Griffin et al. 1988). Recognised cases of annotated maps on a 10 km x 10 km grid- cell hybridisation and clinal variation amongst scale, collated from diverse information the Tasmanian eucalypts are summarised sources. Mapping has been the first stage by Duncan (1989; Figure 1). A field key for in screening for errors in a database that will the identification of Tasmanian eucalypts, ultimately be used for predictive analyses, which caters for the complex variation contribute to land management decisions and within and between species, is given by assist ecological research. The main impetus Duncan (1996). for publishing these distributional data is to Tasforests Vol. 8 40 December 1996 Figure 1. Species of Eucalyptus native to Tasmania, showing species which form clines and natural hybrids. Hybrids only occur within subgenera. For each species, follow horizontal and vertical axes. For example, E. barberi is known to hybridise with E. brookeriana and E. ovata (horizontal axis) and possibly with E. globulus, E. gunnii and E. cordata (vertical axis). † E. delegatensis is represented in Tasmania by an endemic subspecies. (Figure adapted from Duncan 1989) quantify current knowledge, to stimulate the Jackson (1965) are still the main overall source collection of herbarium voucher specimens of information on the distribution of eucalypt from new localities, and to encourage the species in Tasmania (e.g. Davidson et al. 1981; verification of outliers. It is important to Forest Resources 1995). Other publications clarify the natural distribution of Eucalyptus such as Boland et al. (1984) and Chippendale species in Tasmania as land clearing and (1988) include broad-scale maps of Tasmanian plantings for ornamental and forestry eucalypt species in the context of Australia- purposes will eventually confuse natural and wide eucalypt occurrences. Local texts such artificial occurrences. The maps and graphs as Kirkpatrick and Backhouse (1985) and the presented should allow clear assessment of atlas of Tasmanian endemics (Brown et al. whether an occurrence is novel and represents 1983) include eucalypts in the context of other an extension of the geographic or altitude Tasmanian plant species. Mapping at higher range of a species, or whether it represents a resolutions, such as the 1:500 000 distribution poorly verified or well-known location. maps of vegetation types (Kirkpatrick and Dickinson 1984), tall eucalypt forest types Previously published data on eucalypts (Forestry Commission 1988), and the specific studies of wet and dry eucalypt forests by Several previous studies have published Wells (1989) and Williams (1989) display the maps of eucalypt distributions at the level predominance of eucalypts in the landscape of species or vegetation type. The maps of (cf. Pryor and Johnson 1981). Regional and Tasforests Vol. 8 41 December 1996 local vegetation mapping has also contributed (Pannell 1992), rainforest (Jarman et al. 1984, significantly to our knowledge of eucalypt 1991), riparian vegetation (Askey-Doran occurrences. For example, Brown and Bayly- 1993), buttongrass moorlands (Jarman et al. Stark (1979a) mapped the vegetation of Maria 1988), and alpine vegetation (e.g. Kirkpatrick Island, Duncan (1983) mapped communities 1980, 1984a, b; Kirkpatrick and Harwood in the Douglas River region, Brown and 1980; Kirkpatrick and Whinam 1988). Other Duncan (1989) mapped the vegetation of purpose-specific flora inventory surveys Tasman Peninsula, Fensham (1989) encompass many local areas in particular reconstructed the vegetation patterns for regions throughout Tasmania; for example, the Midlands from extant and remnant the non-allocated Crown land surveys (e.g. community distributions, and Kirkpatrick and Duncan 1986; Neyland 1988a, b; Neyland and Balmer (1991) mapped the northern portion of Duncan 1988a, b; Slater 1988; Cullen 1990; the Cradle Mountain – Lake St Clair National Mendel 1991), the land system surveys (Richley Park (see also Corbett and Mackie 1994). 1978, 1984; Pinkard 1980; Pinkard and Richley 1984; Pemberton 1986, 1991; Davies 1988), and Geo-coded flora inventory surveys with the numerous unpublished environmental