Literature review: Impact of Chilean needle grass ... - Weeds Australia

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(Chan 1980). The region also contains large areas of native pasture and secondary grasslands (Sharp and Shorthouse 1996, ACT Government 2005). Despite the relatively high altitude of these tablelands grasslands, their vascular plant composition is more similar to the grasslands of the Victorian Volcanic Plains than to alpine grasslands (Lunt et al. 1998). T. triandra, Austrodanthonia auriculata, A. caespitosa, A. carphoides, A. laevis, Austrostipa bigeniculata, A. scabra, Bothrichloa macra, Poa labillardieri and P. sieberiana are generally the dominant native grasses (Sharp 1997). B. macra was dominant in some areas in the late 1970s (Groves 1979). Areas of the Monaro tablelands not dominated by Poa sieberiana were probably dominated by T. triandra, which was largely replaced under bovid grazing by less palatable Austrostipa spp. from the mid 1840s (Kirkpatrick et al. 1995). Similar to other areas, pasture improvement intensified dramatically from the 1940s, resulting in widespread losses of native grasslands or major modification of their components and structure, including massive incursions of weeds (Keith 2004). Exotic plants have been reported to comprise 29% of the Monaro grassland vascular flora (Kirkpatrick et al. 1995). Unlike the Victorian Volcanic Plains, rocks are not a common feature (Melbourne 1993, Kukolic 1994). Kirkpatrick et al. (1995) briefly described the following lowland grassland communities in the region: 1. Poa labillardieri – Austrostipa – Bothrichloa macra Monaro Basalt Grassland, a widespread, dense-tussock formation on clays in the ACT and NSW; 2. Poa sieberiana – Carex appressa – Juncus Monaro Grassland, probably best thought of a highland community; 3. Austrostipa scabra – Enneapogon nigricans Monaro Grassland, a mid-dense tussock grassland found mainly on upper slopes and ridges; 4. Themeda triandra – Poa sieberiana – Bulbine bulbosa Monaro Grassland, found on valley floors or slopes with a southerly aspect; 5. Themeda triandra – Eryngium ovinum – Carex inversa Canberra Grassland, largely confined to the ACT in valleys on limestone; Sharp (1997) provided an analysis of the floristic associations present in the ACT (Table 14) and previous floristic classifications. The Austrodanthonia association occurred on sites subject to historical levels of moderate to high disturbance on well drained clay soils with low nutrient levels, and had the largest areas of bare ground. A wet Themeda association occurred in areas with moderate to high historical disturbance regimes, on poorly drained (seasonally wet) sites with higher soil P and acidity levels. A dry Themeda assocation occurred on well drained sites with low levels of disturbance, and had high litter cover of c. 40% and low soil P (7.9 ppm). About 70% of vascular plant species present were forbs, with Asteraceae an important component (Sharp and Shorthouse 1996). No community had consistently higher exotic richness, but the wet Themeda association had the highest exotic cover in spring, and the dry Themeda association the lowest (Table 14). Table 14. Floristic characteristics of natural grassland floristic associations in the ACT from a survey of 39 sites (Sharp 1997). Association Mean spp. richness (per 10 m 2 ) Mean spp. richness (sites) % exotic cover Native Exotic Total Native Exotic Total (spring) Austrodanthonia 24.7 12.4 37.1 33.2 21.7 54.9 32.8 Wet Themeda 25.3 13.7 39.0 36.3 23.2 59.5 35.5 Dry Themeda 21.8 8.6 30.4 41.8 23.6 65.4 11.1 Remnant grassland on the Southern Tablelands is highly fragmented and adequate reservation was considered unlikely to be achievable (Sattler and Creighton 2002). Remaining remnants are in various states of degradation and exist in a matrix of exotic pasture (Keith 2004). Approximately 5% of the original 20,000 ha of grasslands in the ACT were in more of less natural condition (florisitically and structurally intact, with low weed cover) in 1996, with an additional 550 ha of low quality grassland (Sharp and Shorthouse 1996, Sharp 1997). Sharp and Shorthouse (1996) provided a map of the pre-European distribution and remaining remnants and estimated that c. 70% of the grasslands identified in the late 1970s had subsequently been destroyed by urban development, conversion to pasture or invasion by exotic plants. Less than 3% of the pre-European area remained in reasonable condition by 2005, reduced from 11% of the region pre-1750 to about 1% in 2000 (ACT Government 2005). Most had been destroyed by intensive agriculture and urban growth, and existing remnants were threatened by inappropriate management. Remaining sites were mostly
Woodlands and New England Grassy Woodlands (Benson 2004), by tree clearing and livestock grazing (Trémont 1994). Frequent aboriginal burning is believed to have opened up the woodlands and maintained grassy vegetation (McIntyre and Lavorel 1994b). The map of Moore (1993) included most of the Northern Tablelands as aTemperate Shortgrass (Austrodanthonia-Austrostipa-Enneapogon) community. The grasslands occur on soils derived from basalts, granite or sedimentary rocks, at altitudes from
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Literature review: Impact of Chilea
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Fire 49 Other disturbances 50 Shade
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Conventions and standards Botanical
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neesiana appears to be a habitat ge
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population densities of existing sp
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elated plants have similar defences
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For invasion to occur there must be
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As yet there appears to be no evide
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experimental manipulation of specie
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species tend to be those which tran
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Taxonomy and nomenclature Stipeae N
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Vernacular names ‘Needlegrass’
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to Bouchenak-Khelladi et al. 2009).
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1 m (Walsh 1994), ca. 90 cm (Verloo
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Figure 2. Anatomy of the seed of N.
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are the seeds larger/smaller, longe
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also based on a misunderstanding of
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Table 2. Modified Feekes Scale for
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Argentina, in the provinces of Chac
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Figure 3. Recorded distribution of
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1994). Only 3 of 186 exotic grasses
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According to Morfe et al. (2003) th
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populations have been found in the
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(Honaine et al. 2006). The flechill
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In Australia the altitudinal range
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Proximity to urban development appe
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In the southern Brazilian campos of
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arundinacea (Gardener et al. 2005).
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al. 2008). Cues for masting may be
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Approximately 200 alien grass speci
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Dispersal of seed in contaminated s
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In New Zealand, Hurrell et al. (199
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No emergence was observed in undist
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and high impact (“ability to caus
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also noted that despite a wide rang
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a small reduction in seedhead produ
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Slashing and mowing Slashing can re
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Themeda re-establishment McDougall
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species (Lawton and Schroder 1977 p
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y increased importance of ant grani
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BIODIVERSITY “Biodiversity ... on
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According to Woods (1997 p. 61) “
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2004, Richardson and van Wilgen 200
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negative depending on the particula
Page 89 and 90: Competition with native plants Comp
Page 91 and 92: asexual seed production, so local f
Page 93 and 94: GRASSLANDS Grasses: “... the most
Page 95 and 96: susceptible to N. neesiana invasion
Page 97 and 98: Floristic composition, vegetation s
Page 99 and 100: proportion of the flora then presen
Page 101 and 102: tussock space (Stuwe and Parsons 19
Page 103 and 104: Like vascular plant diversity, comm
Page 105 and 106: Opinions differ on the nature and i
Page 107 and 108: Species Common Name Family Aust ACT
Page 109 and 110: in shifting the distribution, exten
Page 111 and 112: of these systems is largely explain
Page 113 and 114: pasture. The least understood trans
Page 115 and 116: tend to benefit more from relaxed c
Page 117 and 118: Bovids crop their food between the
Page 119 and 120: are therefore less likely to distur
Page 121 and 122: esult in a “short-term flush” o
Page 123 and 124: Fire effects on weeds Moore (1993 p
Page 125 and 126: Table 8. Typical nutrient levels in
Page 127 and 128: grasses produced sigificantly more
Page 129 and 130: Fossorial vertebrates are or were o
Page 131 and 132: (Rosengren 1999). Approximately one
Page 133 and 134: Table 12. Areal extent and conserva
Page 135 and 136: Foreman (1997) investigated the eff
Page 137 and 138: Willis (1964) considered that the f
Page 139: Austrostipa-Enneapogon) from around
Page 143 and 144: Thylogale billardierii), Peramelida
Page 145 and 146: Its original habitat on the mainlan
Page 147 and 148: Table 17. Endangered reptile specie
Page 149 and 150: equirement, but unlike plants and v
Page 151 and 152: e assigned the same biodiversity sc
Page 153 and 154: Nematodes are mostly minute animals
Page 155 and 156: found in all mainland states, O. co
Page 157 and 158: Keyacris scurra, Melbourne (1993) o
Page 159 and 160: was once widespread in south- easte
Page 161 and 162: eing sluggish and wingless, and exi
Page 163 and 164: estoration and, if Australia follow
Page 165 and 166: close to the plant are able to bury
Page 167 and 168: Species *Chirothrips mexicanus Craw
Page 169 and 170: Table A2.1 (continued) Species Life
Page 171 and 172: Table A2.1 (continued) Species *Het
Page 177 and 178: Nematodes of grasses and grasslands
Page 179 and 180: REFERENCES Aceñolaza, F.G. (2004)
Page 181 and 182: Benson, D. and McDougall, L. (2005)
Page 183 and 184: Chan, C.W. (1980) Natural grassland
Page 185 and 186: DNRE (Department of Natural Resourc
Page 187 and 188: Fuhrer, B. (1993) A Field Companion
Page 189 and 190: Groves, R.H. and Whalley, R.D.B. (2
Page 191 and 192:
Iaconis, L. (2004) Chilean needle g
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Levine, J.M., Adler, P.B. and Yelen
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McDougall, K.L. (1987) Sites of Bot
Page 197 and 198:
Morfe, T.A., McLaren, D.A. and Weis
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Perelman, S.B., León, R.J.C. and O
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Saunders, D.A. (1999) Biodiversity
Page 203 and 204:
Thellung, A. (1912) La flore advent
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Weiss, J. and McLaren, D. (2002) Vi
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