Species-Area Curves and Growth-Form Spectra for Some Herb-Rich Woodlands in Western Victoria, Australia
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Australian Journal of Ecology (1990) 15, 155-161 Species-area curves and growth-form spectra for some herb-rich woodlands in western Victoria, Australia IAN D. LUNT George et al. 1979; Rice & Westoby 1983a, b; Department of Botany, La Trobe University, Lamont et al. 1984). At scales of up to 0.1 ha, Bundoora, Victoria 3083, Australia kwongan (sclerophyllous shrubland in south- western Australia) is one of the most diverse communities in the temperate world (Lamont Abstract et al. 1984), with up to 103 vascular species in 0.1 ha (Brown & Hopkins 1983), a high species Species-area curves are presented for three turnover (Griffin et al. 1983; Hopkins & woodlands with herbaceous understoreys in Griffin 1984), and considerable endemism western Victoria, Australia. Up to 93 species of (Lamont et al. 1984). By contrast, woodlands vascular plant were recorded from 128 m2, with herbaceous understoreys are generally making these woodlands one of the richest thought to be relatively poor in species: terrestrial vegetations recordedfrom temperate Whittaker et al. (1979) recorded a mean of only Australia. Species richness at this scale is 53 species in 0.1 ha in mallee. comparable with that recorded from kwongan The original grasslands and grassy wood- (sclerophyllous shrubland) in south-western lands oftemperate Australia were dramatically Australia. Up to 45 species were recorded from altered and fragmented by agricultural 1.0 m2. At this scale the woodlands are the development and, presently, are poorly richest terrestrial vegetation recorded from represented in conservation reserves (Specht Australia, and among the richest in the world, 1981a; Frood & Calder 1987; Kirkpatrick et al. being comparable with the renowned chalk 1988). Consequently, relatively little is known grasslands of Europe. The growth-form spectra of their composition, variation or ecology. of these woodlands differ dramatically from Recent floristic surveys in western Victoria those of other species rich communities in have, however, described woodlands with temperate Australia due to the abundance of herbaceous understoreys that are exceedingly herbs and dearth of woody species. In contrast to rich in vascular plants, with up to 96 species in species rich woodlands in Israel and California, 0.09 ha (Lunt et al. 1987; Brown et al. 1988). perennial herbs rather than annuals pre- Both surveys underestimated richness by dominate. Although the woodlands studied are once-only sampling, and neither gathered protected in conservation reserves, regional information on species richness at smaller floristic surveys are required to determine the scales, from 1 to 100 m2• The aim of this study geographic extent, floristic variability and con- was to compile species-area curves to docu- servation status of herb-rich woodlands in ment the patterns of richness within these Victoria. woodlands and to present growth-form spectra to describe their composition. Introduction Methods The richest plant communities in temperate Three permanent plots of nested quadrats were Australia are widely considered to be shrub- established, two in the Grampians National lands and woodlands with sclerophyllous Park (Zumsteins and Victoria Valley) and one understoreys (Parsons & Cameron 1974; in Langi Ghiran State Park. Quadrats in- creased geometrically in size from 0.25 m2 to ·Present address: Flora and Fauna Survey Group, 2 Department of Conservation, Forests and Lands Victoria, 128 m and each plot included at least one 378 Cotham Rd, Kew, Vie. 3101, Australia. mature individual of the dominant species of 156 I. D. Lunt Eucalyptus. Plots were visited repeatedly from abundance in recent times and may have September 1988 to April 1989 and all species dominated the understorey prior to European of vascular plant were recorded. settlement. Plant growth-forms were determined from The Langi Ghiran site (37°17' 45"S, field observation and reference to Willis (1970, 143°04'50"E, 13 km east of Ararat, 380 m 1972), Cunningham et al. (1981) and Jessop a.s.l.) was on a flat outwash plain below Mt and Toelken (1986). Plant nomenclature Langi Ghiran (922 m a.s.I.). The soil was a follows Forbes and Ross (1988) except uniform, coarse loamy sand (pH = 6.0), 1.0 m Gnaphalium which follows Jessop and Toelken in depth, above weathered bedrock of (1986). Voucher specimens are lodged with the Devonian granite. Such soils are of high per- National Herbarium of Victoria (MEL). meability but low fertility and water-holding capacity (Land Conservation Council, Site descriptions Victoria 1980). Eucalyptus melliodora formed an open woodland above an herbaceous The Victoria Valley and Zumsteins sites were ground stratum with scattered sub-shrubs subjectively placed in stands described as Red including Lissanthe strigosa, Astroloma Gum (Eucalyptus camaldulensis) Forest (Lunt humifusum and Acrotriche serrulata. et al. 1987) and Yellow Box (Eucalyptus Few climatic data are available for the melliodora) Woodland (Brown et al. 1988), Grampians. The average annual rainfall at respectively. The Langi Ghiran site was sub- Halls Gap on the eastern edge of the jectively placed in a woodland that appeared Grampians is 916 mm, with a maximum of similar in structure and floristics to the 118 mm in June and August and minimum of previously mentioned red gum forest. 33 mm in January. Zumsteins and Victoria The Victoria Valley site (37°17'S, Valley receive considerably less rain than Halls 142°24' 25"E, 18 km south-west of Halls Gap, Gap, however, and the annual average rainfall 240 m a.s.l.) was on an alluvial plain between at both sites is estimated to be 700-750 mm the Victoria and Serra Ranges of the central (Land Conservation Council, Victoria 1979). Grampians. The duplex soil, which was water- Rainfall data from Ararat are relevant to Langi logged in winter and spring, consisted of a fine Ghiran: the average annual rainfall is 616 mm, sandy loam (pH=6.5-7.0), 0.5 m in depth, with a maximum of 68 mm in August and above a heavy mottled clay (pH = 6.0). minimum of 31 mm in January (Land Con- Eucalyptus camaldulensis formed an open servation Council, Victoria 1980). There are woodland (sensu Specht 1981b) above an no temperature data for the Grampians but herbaceous ground cover, with scattered trees data from Ararat (about 35 km to the east) are and shrubs including Acacia mearnsii, Acacia relevant to all three study sites; the mean daily melanoxylon, Acacia verticil/ata and Lepto- temperature reaches a maximum of 27.7°C in spermum juniperinum. January and minimum of 4.0°C in July. The The Zumsteins site (3r06' IO"S, growing season at Buangor, II km south-east 142°22'55"E, 13 km west-northwest of Halls of Langi Ghiran, extends from April to Gap, 370 m a.s.l.) was on a rolling hill of October (Land Conservation Council, Victoria Devonian granite (Land Conservation 1980). Council, Victoria 1979) in the northern All sites have been grazed in the past by Grampians. The soil was a skeletal loamy sand European stock and are currently grazed by in- (pH = 6.0) between outcropping granitic troduced rabbits (Oryctolagus cuniculus) and boulders. Eucalyptus melliodora and Euca- grey kangaroos, Macropus giganteus and lyptus goniocalyx formed a woodland above Macropusjuliginosus in the Grampians and M. scattered Acacia mearnsii and Xanthorrhoea giganteus at Langi Ghiran (Gilmore et al. australis and scattered shrubs and sub-shrubs 1979; Lunt et al. 1987). (less than 0.25 m tall) including Bursaria spinosa, Astroloma humifusum and Astroloma Results conostephioides with an herbaceous ground cover between the boulders. Xanthorrhoea All three sites were extremely rich in vascular australis appeared to have declined in plants (Appendix I), with a mean of 89 species Herb-rich woodlands in Victoria 157 100 .• u.. :,}.. '0 ;;; D E z" o 8 16 32 50 64 100 128 Area (m2) FIG. 1. Species-area curves for three herb-rich woodlands in western Victoria, with selected data from other species-rich communities. 1 Eucalyptus melliodora woodland, Langi Ghiran State Park, western Victoria. 2 Eucalyptus camaldulensis woodland, Victoria Valley, Grampians National Park, western Victoria. 3 Eucalyptus goniocalyx - Eucalyptus melliodora woodland, Zumsteins, Grampians National Park. 4 Richest site, grazed limestone grassland, Netherlands (During & Willems 1984). 5 Heathland, Seal Creek, eastern Victoria (Parsons & Cameron 1974). 6 Richest kwongan site at 50 m2, south-west Western Australia (George et al. 1979). 7 Range and mean number of species, richest kwongan group, south-west Western Australia (Griffin et al. 1983). 8 Mean number of species, sclerophyllous woodlands, West Head, New South Wales (Rice & Westoby 1983a). (range: 83-93) in 128 m2• Species richness at and 29 in 1.0 m2• Naturalized aliens were the small scale was high (Fig. I). On average common, accounting for between 9 and 18 there were 30 species in 0.25 m2 (range 26 to species at each site. Notably, 20 of the 22 33) and 42 species in 1.0 m2 (range 38 to 45). naturalized species (91%) were annual, com- The flora was primarily herbaceous (Table I), pared with only 33 ofthe 142 natives (23%). with woody species accounting for a maximum of 12 species, at Zumsteins. Although annuals Discussion were abundant (up to 33 species at Victoria Valley), most species at each site were These herb-rich woodlands are richer in plant perennial; moreover 18 species (20% of species than any other vegetation recorded species) at Langi Ghiran were geophytes. The from south-eastem Australia, far surpassing number of perennial species