Distribution, Habitat Characteristics and Conservation Status of the Forest Wire-Grass Ehrharta Juncea (R

Distribution, habitat characteristics and conservation status of the forest wire-grass Ehrharta juncea (R. Br.) Sprengel (Poaceae) in Tasmania M. Wapstra1*, B. French1 and T. Ashlin2 1Forest Practices Board, 30 Patrick Street, Hobart 7000 2Forestry Tasmania, PO Box 68, Burnie 7320 Abstract 1999). The genus includes the familiar weeping grass E. stipoides, common in native Ehrharta juncea (forest wire-grass) has a disjunct pastures throughout the State. Ehrharta distribution across northern and western juncea (R. Br.) Sprengel, commonly known Tasmania. Key sites for the species are the as forest wire-grass, occurs in Tasmania, Crayfish Creek area in north-western Tasmania, Victoria, New South Wales and Queensland the Claytons Rivulet area in the central north, (Curtis and Morris 1994; Walsh 1994). In the Dazzler Range in the West Tamar area and mainland States (and most literature), the the Mt Maurice area in the north-east. It occurs species is included in the genus Tetrarrhena predominantly in wet sclerophyll forest on a (as T. juncea). In Tasmania, the species’ range of substrates, mainly in coastal and distribution is described as ‘apparently subcoastal hinterlands, although the occurrence uncommon but locally forming extensive at Mt Maurice is inland at higher altitudes. The colonies scrambling over understorey species’ distribution is strongly associated with vegetation in eucalypt forest in coastal disturbance, including fire, logging, and clearing areas’ (Curtis and Morris 1994). for easements such as roads and pipelines. Most known sites occur on Crown Land or State forest. In Victoria and New South Wales, the Ehrharta juncea occurs in several reserves species is abundant in a range of forest including Crayfish Creek Forest Reserve, Mt types, including wet forests, heaths, and Maurice Forest Reserve, Little Peggs Beach State woodlands (Willis 1970; Walsh 1994; Lamp Reserve and the Arthur–Pieman Conservation et al. 2001). Forest research and inventories Area. An assessment of the conservation status in mainland States (mainly Victoria) have of the species suggests that its current Rare shown E. juncea to be tolerant of major status may be unwarranted but that the species' disturbance, including wildfires, prescribed response to disturbance should be monitored. burning and forestry activities (e.g. Rawson and Rees 1981; Loyn et al. 1983; Harris 1989; Stuwe and Mueck 1990; Ough and Ross Introduction 1992; Murphy and Ough 1997; Ashton and Chinner 1999; Ough and Murphy Ehrharta is a genus of grasses represented by 1999; Bauhus et al. 2001). 10 species in Tasmania, including six native and four introduced species (Buchanan Ehrharta juncea is currently listed on Schedule 5 (Rare) of the Tasmanian Threatened Species * Corresponding author Protection Act 1995, presumably because at e-mail: [email protected] the time of the listing it was known only Tasforests Vol. 14 77 May 2003 Figure 1. Locations of Ehrharta juncea in Tasmania. from a few scattered localities. The species Methods is now known from several disjunct sites in northern Tasmania: the Crayfish Creek Collation of known records area near Smithton, the Claytons Rivulet area near Ulverstone in the central north, Records for E. juncea were collated from the Dazzler Range in the West Tamar area, a variety of sources, including database the Mt Maurice area in the north-east, and searches (DPIWE’s GTSpot database, scattered localities in the north-west and Forestry Tasmania’s Conserve database), on the west coast (Figure 1). Ehrharta juncea Tasmanian herbaria (collections of the is not considered threatened in other States Tasmanian Herbarium at Hobart and the and, in Victoria, the species is the subject Queen Victoria Museum and Art Gallery at of actions to control its abundance, mainly Launceston), scientific reports, and personal for fire management purposes because of communications with numerous botanists, the fire risk presented by its elevated fuel naturalists and other field workers. (Rawson and Rees 1981; Buckley 1993). Comments are made on the accuracy of certain records. This paper presents information on the known distribution, habitat characteristics Field surveys and conservation status of E. juncea in Tasmania. The distribution and habitat Intensive surveys were conducted in the characteristics of the species in State Crayfish Creek area of the north-west (see forest in the Crayfish Creek area of north- Ashlin 2002; described below). Limited western Tasmania were reported by Ashlin surveys were conducted in the Dazzler (2002), and this paper formally presents Range and Claytons Rivulet area (B. French, that information. M. Wapstra), based around known localities. Tasforests Vol. 14 78 May 2003 Figure 2. Map showing survey boundary, plot sites and Ehrharta juncea locations recorded by Ashlin (2002) in a survey in the Crayfish Creek area in north-western Tasmania. No additional surveys were conducted in • Crayfish Creek area (north-western Tasmania) the Mt Maurice or west coast areas. The survey area of Ashlin (2002) included Field surveys involved visual assessments State forest encompassed by Mawbanna, of the density of E. juncea rather than an Speedwell, Loosemores and Mathers Roads estimate of absolute numbers in each (Figure 2). A combination of the known population. This is mainly because the distribution of E. juncea at the time of the growth habit of the species makes it very survey, logistical constraints (e.g. time, difficult to accurately estimate how many access, tenure) and Forestry Tasmania plants are present at a particular site. When District priorities were used to define only a single ‘clump’ of grass is present at a the survey area. site, it is easier to count individual plants, but where the species forms extensive The majority of the survey area supports swards (which is the situation at most sites), regrowth wet sclerophyll forest, with creek it is virtually impossible to trace individual lines supporting swamp forest or more culms through the dense undergrowth. mature wet sclerophyll forest. Forest in Tasforests Vol. 14 79 May 2003 Table 1. Details of populations of Ehrharta juncea. No. of sites No. of individuals Area occupied Population Locality (minimum) (minimum) (minimum) North-west 1 Mawbanna Road 1 ~20 0.01 ha 2 Little Hell Gully 5 1000s < 10 ha 3 Crayfish Creek area* 70+ 10 000s 10s ha 4 Pipeline Road 1 ? ? 5 Dip Road 1 1000s 0.4 ha 6 Pine Corner Road East 2 250–1000 0.075 ha 7 Pine Corner Road West 2 > 250 0.065 ha 8 Black River South 2 < 100 < 1 ha 9 Black River North 3 ? ? 10 Detention River 4 1000s ~ 2 ha 11 Lake Mikany 2 ? ? Claytons Rivulet (central north near Ulverstone) 12 Stubbs Road 4 1000s 1 ha+ 13 Lasts Road 1 dense ~15 m2 Dazzler Range (West Tamar area) 14 Dazzler Range 4 1000s Mt Maurice (north-east) 15 Mt Maurice FR 2 < 100 West coast 16 Wild Wave River 1 ? < 1 ha 18 Temma Road 1 ? ? 19 Linnanes Road 1 ? ? 20 Ekberg Creek 1 ? ? * The Crayfish Creek area is treated as a single population because there are few records that are greater than 1 km apart. the Crayfish Creek area has been subject to are 500 m apart). The grid size was chosen several wildfires during the 1900s, the most because it sampled the typical variation in notable being an intense fire of large extent topography and forest type in a standard in the summer of 1938/39. Most of the coupe of 50–100 ha. Information collected area has a long history of forestry activities. included grid reference, altitude, slope, Early selective logging used bullocks. aspect, landform, geology (from Land More recent activities have included more Systems of Tasmania Region 3 map), PI-type extensive road construction, native forest (from Forestry Tasmania’s MDC mapping operations using clearfell, burn and sow system; Stone 1998), rock cover, drainage, techniques, and some conversion of ground litter cover, and bare ground cover. native forest to hardwood plantations. Vascular plant species in each plot were recorded and notes made on the structure of Within the survey area, sixty-two 25 m the vegetation. Notes were also made on the radius plots were located systematically disturbance history of the site, including fire using a 25 ha square grid (i.e. the plot points and logging history. The presence/absence Tasforests Vol. 14 80 May 2003 of E. juncea was recorded, along with notes a network of forestry tracks and roads, with on its density and habit. a long history of logging and recreational activities. An initial survey of the known Because of the species’ apparent preference sites showed the species was abundant for disturbed sites, accessible roads and along several hundred metres of gravelled tracks within the survey area were driven road but did not extend many metres into at about 20 km/h (the efficacy of this speed surrounding vegetation. A ‘windscreen’ was tested at known sites) to check for the survey was considered the most practical species. Discrete sections of roads/tracks and efficient means of mapping the extent supporting the species were identified and of the species in this area. Most driveable measured and a grid reference allocated to roads within about 5 km of the original the approximate centre of the site. A total known site were surveyed. Some of 32 km of road was surveyed. impassable roads and tracks were walked. Additional sites in the Crayfish Creek area Reservation and conservation status and the broader north-west were collated from database records and from more recent The assessment of the reservation and surveys (including those conducted by the conservation status of E. juncea used the authors, and those of North and Mallick (2001). criteria of the Tasmanian Threatened Species Protection Act 1995 (DPIWE 2002). • Claytons Rivulet (near Ulverstone) Three database records indicated the species’ Results presence on private property in a remnant forest area south of Ulverstone.

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