Callitris oblonga occurs in three widely separated areas in Australia. In northern New South Wales it is found in a few localities in the New England Tablelands at altitudes ranging from 800 to 1300m above sea-level. In southern New South Wales, (over 500km south) there is a single locality along the Corang River at altitudes ranging from 570 to 630m above sea-level. In Tasmania, over 800km further south, it is restricted to two small areas in the northeast part of the state at altitudes ranging from 10 to 230m above sea-level. No intervening localities have been recorded. The estimated extent of occurrence (EOO) is 5835km², based on recent herbarium specimens. This EOO is a cumulative total from each area (Northern Tablelands: 4700km²; Southern Tablelands: 12km²; Tasmania: 1123km²). In Tasmania the EOO includes an outlying locality more than 60km from any other locality: the actual area of occupancy is estimated to be as little as 448 hectares. Its overall area of occupancy has not been calculated but it is certainly less than 500km² as the New South Wales subpopulations are small and localised.
Overall the population size is unknown although in Tasmania there are estimated to be 3000–4000 individuals. Although floods and fires may eliminate mature individuals, most subpopulations regenerate in the absence of competition from exotic weeds, feral animals and overgrazing.
Habitat and Ecology
A tall shrub or small tree. In New South Wales it occurs along sandy watercourses, shrubland, open woodland in granite country, and dry sites, such as exposed ridges at relatively high altitudes. In Tasmania, it occurs much closer to sea level, in scattered stands along creeks and rivers. Throughout its range it is fire sensitive: mature individuals are usually killed but there may be substantial regeneration from the release of seed contained within the serotinous cones in the canopy. In northern New South Wales, fire intervals of at least 11 years are required to allow regeneration (Clarke et al., 2009). Regeneration may also occur after flooding. Seedlings are shade intolerant and require open ground for establishment.
The estimated extent of occurrence (EOO) for Callitris oblonga is 5835km² based on recent herbarium specimens. This is a cumulative total from each area (Northern Tablelands: 4700km²; Southern Tablelands: 12km²; Tasmania: 1123km²). Although the area of occupancy has not been calculated, it is likely to be less than 500km² as subpopulations are relatively small and localised. Despite the great geographic disjunctions between the three main areas, individual subpopulations are not considered severely fragmented in the IUCN context. Nine locations have been identified based on common threats within geographical areas. In some parts of the range there is a continuing decline in quality of habitat due to the impact of exotic weeds, feral animals and habitat conversion.On this basis, C. oblonga is listed as Vulnerable under Criterion B.
Primary threats include clearing, degradation and fragmentation of habitat for agriculture; frequent fire; grazing by domestic stock, rabbits (Oryctolagus cuniculus) and feral goats (Capra hircus); weed invasion, particularly by Blackberry (Rubus fruticosus), Broom (Cytisus sp.) and Gorse (Ulex europaeus); destruction and disturbance of habitat for road works and roadside maintenance activities and erosion through removal of streamside vegetation (Threatened Species Unit, 2004; Threatened Species Scientific Committee, 2007). In northeast Tasmania temperature rise and changes to rainfall and other climatic factors associated with anthropogenic climate change is predicted to affect the environmental range of the community in which C. oblonga occurs as well as increasing the risk of stochastic events such as fire and flood (Threatened Species Unit, 2004).
At a federal level, C. oblonga is listed as Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). Prior to this it was also listed as Vulnerable under Schedule 1 of the Endangered Species Protection Act 1992. In New South Wales the species is listed as Vulnerable on the Threatened Species Conservation Act 1995 (NSW) while in Tasmania the subspecies Callitris oblonga subsp. oblonga is listed as Endangered on the EPBC Act and as Vulnerable on the Threatened Species Protection Act 1995 (Tasmania). In addition to these listings, the Eucalyptus ovata - C. oblonga forest ecological community in Tasmania is listed as Endangered under the federal Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). In New South Wales subpopulations that occur within the Montane Peatlands and Swamps of the New England Tableland, NSW North Coast, Sydney Basin, South East Corner, South Eastern Highlands and Australian Alps bioregions have been listed as an Endangered ecological community under state legislation. Listing under the various state and federal laws requires that monitoring and recovery plans are designed and put into place. These plans involve a range of strategies and actions to counter the main threats from exotic weeds and animals, clearing of vegetation and inappropriate fire regimes.
In Tasmania C. oblonga is known from the Douglas Apsley National Park. In other areas, some stands are under either local government protection or are subject to conservation covenant agreements with local landowners. Addtionally there is a moratorium on any further clearing of the threatened forest community in which it occurs (Threatened Species Unit, 2004). In New South Wales, two subpopulations are known from within Werrikimbe and Guy Fawkes National Parks. While most are on private land, many of these are subject to conservation covenant agreements.