Management Ofremnant Lowland Grasslands and Grassy Woodlands for Nature Conservation

Management of remnant lowland grasslands and grassy woodlands for nature conservation: a review Ian D. Lunt* Abstract Collectively, they encompassed about a A review is presented of recent third of the State (Fig. I). Sadly, the des- literature relevant to the conservation truction of grassy ecosystems has been so management of remnant lowland complete that today less than 0.5 percent grasslands and grassy woodlands, two of remain (Ministry for Planning and the most threatened ecosystems in temp.. Environment 1989). The situation is erate Australia. The long-term conserva- similar in New South Wales (Sim and tion of both ecosystems is dependent upon Urwin 1984),the Australian Capital Terri- increased reservation and informed tory (Groves 1979), South Australia management. Issues discussed include (Davies 1982, Williams and Goodwins grazing by stock and native herbivores, 1988) and Tasmania (Kirkpatrick et al. burning, ploughing, grading, mowing, 1988). The decimation of grassy eco- trampling, tree regeneration and planting, systems is not a peculiarly Australian herbicides, fertilizers, rehabilitation and phenomenon, but echoes the loss to agri- ecosystem re-creation. culture of the indigenous grasslands of Introduction other continents, including the prairies of Lowland (non-alpine) grasslands and North America, the pampas of South grassy woodlands are among the most America and the chalk grasslands of threatened ecosystems in Australia, with Europe (Koopowitz and Kaye 1983,Davis few examples in conservation reserves et al. 1986, Murphy and Ehrlich 1989). (Specht 1981). These communities Mack,(1989)observed that: originally covered vast areas of the low- 'In less than 300 years (and in most land plains of temperate, south-eastern cases, little more than 100years) much Australia. However, the fertile plains were of the temperate grassland outside the first areas to attract European settle- Eurasia ... has been irreparably ment, and agriculture and associated transformed by human settlement and development rapidly transformed the the concomitant introduction of alien native ecosystems to pastures, crops and plants. Few other changes in the towns. distribution of the earth's biota since Throughout south-eastern Australia, the end of the Pleistocene have been as native grasslands and grassy woodlands radical ... or as swift'. are now restricted to small, fragmented Unless remedial action is undertaken remnants, the best examples of which promptly, many of the distinctive com- commonly occur on rail and road ease- munities of lowland grasslands and grassy ments (Groves 1979, Scarlett and Parsons woodlands in Victoria, and many of the 1982, Frood and Calder 1987). In rare and threatened species they contain, Victoria, native grasslands and grassy will soon become extinct. A compre- woodlands originally dominated the hensive conservation program must Wimmera and Northern Plains, Dundas immediately be implemented if these Tablelands, Western Volcanic Plains, threatened ecosystems and species are to Gippsland Plains and other, smaller areas. survive. To succeed, such a program must include (1) the protection and mainten- ·Flora Group, Department of Conservation and ance of intact remnants, including those Environment. P.O. Box 406. Kew,3101 Present address: Botany Department, laTrobe containing rare or threatened species, (2) University. Bundoora, 3083 the establishment, in all regions of the 56 Victorian Nat. Fia. 1. Probable distribution of lowlandasslands~ and grassywoodlands prior to European settlement of Victoria.The mapped area In the Raak Plain in north-westVictoriacomprisesa mosaic of grasslandsand saline shrublands. Additional areas may occur in south Gippsland. Based on land-systemmaps prepared by Rowan (1988)for the Land Conservation Council (1988),seetext for details. state, of reserves large enough to remain management; the latter topic deserves a viable, and (3) the restoration of plant review of its own. The paper is an ex- communities and the re-estabiishnient of tended version of one presented earlier rare plants and animals within these (Lunt 1990a). Plant names follow Ross secure reserves (Frood and Calder 1987, (1990). Lunt in press). Unlike many vegetation types, lowland Although a comprehensive network of grasslands and grassy woodlands often re- large reserves is vital, reservation is but quire intensive management to maintain the first step in conserving these their biological values. Most Themeda threatened ecosystems. Ultimately, their grasslands, for instance, require burning conservation depends upon appropriate (or some other form of canopy removal) management. This problem is graphically every three to five years to prevent the illustrated in Hattah-Kulkyne National vigorous Kangaroo Grass (Themeda Park, where intensive· grazing by large triandra) from smothering smaller native populations of Western Grey Kangaroos herbs (Stuwe and Parsons 1977, (Macropus fuliginosus) continues to McDougaIl1989a). degrade 'protected' plant communities such as Pine-Buloke woodland, by Ecosystem definition consuming and preventing the Lowland grasslands and grassy wood- regeneration of many species, including a lands are non-alpine ecosystems, in which number of rare plants (Cheal 1986,Mueck mature trees are absent or scattered 1988). (generally with less than 30% cover). The The aim of this paper is to review recent ground layer is dominated by native literature relevant to the conservation grasses, and herbaceous plants management of lowland grasslands and predominate. Few ferns occur, and small- grassy woodlands. The paper is not in- leaved 'heathy' shrubs are typically un- tended to provide pithy prescriptions for common. 'Typical' Australian families site management. Attention is focussed on such as Myrtaceae, ProteaCeae and Epa- flora and vegetation rather than fauna cridaceae are poorly represented. Lowland Vol. 108 No.3 (1991) 57 grasslands and grassy woodlands are most grassy woodlands. Within four years of extensive in flat to gently undulating European settlement, Robinson (in Bride landforms, on relatively fertile, heavily- 1898, Conley 1984) reported that Kang- textured soils. Collectively, 'lowland aroo Grass was replaced by a 'silk-grass' grasslands and grassy woodlands' (thought by Moore (1959) to be the exotic correspond to the 'Savannah' land sys- Squirrel-tailed Fescue, Vulpia bromoides). tems, which Specht (1972) described trom The ecological effects of grazing in- South Australia. In Victoria, these crease exponentially with grazing intensity ecosystems are almost totally confined to (Robinson and Dowling 1976). Morcom the lowland plains below 500 m altitude, (1990) demonstrated a progressive except for a series of isolated occurrences reduction in the number of native plant in inter-montane basins in the east of the species and a concomitant increase in the State, as at Buchan, Benambra and Omeo. cover and percentage of exotic species, with increasing grazing intensity. Original distribution As grazing pressure increases, tall, It is difficult to accurately map the pre- native perennial grasses such as Kangaroo European distribution of lowland grass- Grass and Silky Blue-grass (Dichantheum lands and grassy woodlands due to the sericeum) are replaced by small tussock- paucity of historical records and the near grasses such as Spear-grasses (Stipa total destruction of the ecosystems. The species) and Wallaby-grasses (Danthonia lack of recent vegetation surveys com- species), and then by introduced, annual pounds the problem. Recent maps of grasses and herbs (Moore 1962, 1964; Victorian vegetation (e.g. Paine 1982, Robinson and Dowling 1976).The overall Forests Commission Victoria 1984, Land change is from tall, summer.growing, Conservation Council 1988) either fail to perennial, native grasses to short, winter- distinguish lowland grasslands from growing, annual, introduced species. Such cleared pastures or fail to distinguish changes are accentuated by soil grassy woodlands from sclerophyllous for- disturbance and the application of fertil- ests, particularly in central Victoria. The izers (Robinson and Dowling 1976). map of lowland grasslands and grassy Grazing may also cause genotypic changes woodlands shown in Fig. 1is derived from within grazing-tolerant species, for ex- land-system maps prepared by Rowan ample, by selecting for short over tall (1988) for the Land Conservation Council Wallaby-grasses(Scott and Whalley 1984). (1988). It shows those areas which are Grazing by sheep is mote destructive than most likely to have supported grassy eco- grazing by cattle (Moore and Biddiscombe systems prior to settlement: principally, 1964) as sheep are more selective of pala- Rowan's (1988) 'plains' land-forms of fine- table plant species and graze more textured soils. Relevant vegetation maps uniformly and closely than cattle (Wells (e.g. Land Conservation Council 1987) 1969). and regional land system reports (e.g. Although Kangaroo Grass is sensitive Gibbons and Downes 1964) were also to grazing, and may rapidly decline under consulted. As shown in Fig. 1, lowland grazing pressure, it is not particularly pala- grasslands and grassy woodlands occupied table to stock except when it is young about eight million hectares, over a third (Leigh and Holgate 1978, Whalley etal. of Victoria, prior to European settlement. 1978). Thus, initial grazing pressure is often directed, not at the dominant grasses Grazing by stock such as Kangaroo Grass, but at less Grazing by domestic stock has had an common components

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