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

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vegetation by fire, so as to render the new year’s growth serviceable”. Great fires across the pampas were reported in 1853 (Soriano et al. 1992). The fire history of Southern Brazil is “poorly known” but palynological studies indicate that fires were rare before c. 7400 years ago and then became frequent, possibly as a result of deliberate burning for hunting (Overbeck and Pfadenhauer 2007 p. 28). In southern Brazilian grasslands, where N. neesiana is native, fire became more frequent from the beginning of the Holocene, proabably as a result of the advent of human populations, and currently grazed native grasslands are burned approximely biannually, usually in August (Overbeck et al. 2007). Most of the grassland species of southern Brazil “seem to be adapted to frequent ... burning” (Overbeck et al. 2007 p. 107). Honaine et al. (2009) stated that winter burning, along with grazing, in the flechillar community of the Tandilia Range of Buenos Aires province, in which N. neesiana is a major component, led to the dominance of Achillea millefolium L. and Carduus acanthoides L. (Asteraceae). Historical observations suggest that fire occurred at intervals of 5 years in the stipoid dominated savannah grasslands of the more arid Caldenal, to the south and west of the Pampean region, before the introduction of livestock (Fernández et al. 2009). Bourdôt (1989) noted that in New Zealand “regular burning promotes the grass” and that after fire “tussocks quickly begin to reestablish from clandestine seeds present in old tiller bases”. Liebert (1996 p. 15, quoting Craig Bay on the plant’s behaviour at Organ Pipes National Park, Victoria) stated that it is “usually the first grass to resprout after fire”. Stewart (1996) recorded that dense N. neesiana quickly regained high cover after a wildfire at Broadmeadows Valley Park, Victoria, in December 1994, reaching 50% cover after approximately 6 months and 70% cover after 7 months, and reaching a height of over 50 cms after 11 months. Kirkpatrick et al. (1995 p. 35) considered that it “generally ... recovers more quickly than other species” and is “as well adapted to fire as the native dominant” T. triandra (op. cit. p. 82). However the precise timing of fire in relation to rainfall likely has a large influence on which plant species recover first. Young seedlings and small plants are possibly killed by fire, but larger plants lose most of their above-ground biomass and resprout from protected buds. In the classification used by Overbeck and Pfadenhauer (2007) the seedlings are “non-sprouters”, while tussucks are fire “resistors”, retaining some dead stem biomass after burning. The above-ground meristems are protected by the densely packed basal leaf sheaths (Overbeck and Pfadenhauer 2007), some of which burn, but many of which resist burning because of their high moisture content and tight packing and merely char on the outside. Thus, older tussocks are best adapted to frequent burns. Britt (2001) found that burning, after application of 1 litre of methylated spirits to square metre areas surrounded by a metal frame, eradicated adult plants in an infested pasture. Hocking (2005b) reported on small scale experimental burning of thickets at the Iramoo native grassland, Victoria, in late spring and summer 2002. Both early and late spring burning resulted in less than 10% of mature tussocks resprouting after the autumn break, much lower than unburnt treatments, a reduction of more than 75% in mature tussocks, but an increase in the number of small tussocks and very immature tussocks, likely resulting from fragmentation of what had previously been large plants. Late spring burning removed all viable seed from the site, reduced seed production in the subsequent fruiting period by c. 50% and appeared not to lead to any major seedling recruitment, up to and including the following spring. Early spring fire had no effect on subsequent seed production. As with other grasses, the specific effects of fires are likely to be dependent on the intensity, severity and precise timing of the fire. Seed that has found its way into the soil is likely to survive, presumably in a similar way to that of Austrostipa. Other disturbances Weed invasion of natural communities is often facilitated by disturbance, and the more frequent, intense or prolonged that disturbance the greater the invasion is likely to be (Fox and Fox 1986, Carr et al. 1992, D’Antonio et al. 1999). According to Weber (2003 p. 280) in a survey of environmental weeds of the world, based on a very limited literature review, N. neesiana “invades mainly degraded and disturbed plant communities”. Bartley et al. (1990), commenting on the situation in Victoria, wrote that “prior disturbance does not appear to be necessary for invasion” for N. neesiana invasion of native grasslands. This was echoed by Kirkpatrick et al. (1995 p. 35), who nevertheless added that “its spread is certainly facilitated by soil disturbance”. According to Slay (2002a p. 4) N. neesiana “evolved under conditions of low disturbance”, however Gardener (Gardener 1998, Gardener et al. 1996, 1999, 2003b) found that N. neesiana seeds only germinate on bare ground, in gaps or areas bared by herbicides and other disturbances, and that seedlings only survive in bare areas. The plant survives well in the Rio de Plata grasslands where trampling by cattle “is the main anthropic disturbance” (Soriano et al. 1992). Bedggood and Moerkerk (2002) recorded regrowth of N. neesiana in wheel tracks after treatment of infestations with glyphosate using vehicle mounted wick wipers. Liebert (1996) recommended the avoidance of unnecessary soil disturbance to minimalise N. neesiana invasion. Bruce (2001) attempted to determine the importance of different types of disturbance in determining the level of N. neesiana infestation in native grasslands in the ACT. She assessed the current extent of four ‘disturbance types’ on a four point scale from absent (0) to high (5): bare ground, other exotic weed populations, soil disturbance (earthworks, erosion, cultivation, animal diggings etc.) and the amount of refuse dumping (garden waste, soil, rubbish). The literature contains numerous mentions of the importance of ‘bare ground’ to enable seedling establishment. The usual meaning appears to be soil lacking other vascular plants above ground and devoid of litter. Bruce (2001) found that N. neesiana had wide levels of abundance, from absent to dominant, where bare ground was present at low and medium levels. It had the largest range of abundances (0-5) at high weed levels, and the lowest (0-3) at low weed levels (perhaps suggesting that N. neesiana facilitates invasional meltdown). The single site with no soil disturbance had occasional patches of the weed, sites with low soil disturbance had a range of infestation levels (0-5) and sites with medium soil disturbance were overall more highly invaded (1-5). No sites had high soil disturbance. Infestation levels varied widely for all levels of dumping, but N. neesiana was observed to have established and be spreading from scattered piles of lawn clippings at one site. 50
Proximity to urban development appeared to be the most important predisposing factor for N. neesiana invasion in the ACT, and use of the land as urban open space appeared to almost guarantee that it would become infested, probably as a result of seed dispersal by mowing (Bruce 2001). No-one appears to have comprehensively evaluated past disturbance in relation to present N. neesiana infestations. Historical disturbance patterns are more difficult to determine and there are more difficulties in assessing their intensity, frequency and duration. Consensus opinion appears to be that disturbances of various types can facilitate invasions and it appears likely that in those cases where invasion has been recorded without disturbance, there has been inadequate appreciation of the effects of prior disturbances. The effects of various disturbances including fire, grazing and herbicides on N. neesiana establishment and survival are discussed in more detail below. Shade N. neesiana has been called a sun loving (“heliófilas”) species (Martín Osorio et al. 2000 p.39) but is adapted to moderate shade (Muyt 2001). It has considerable shade tolerance, up to medium level tree densities, e.g. in wooded areas around Bendigo, Victoria (Hocking 1998). Bruce (2001) found it was commonly present in shaded areas in the ACT , e.g. in windbreaks, very open woodlands, under oak trees, pines, eucalypts including Eucalyptus melliodora A. Cunn. Ex Schauer, Acacia spp. and shrubs. It grew in both shaded and unshaded locations at 59% of sites investigated (Bruce 2001). In the Sydney region it occurs in woodlands with Eucalyptus moluccana Roxb. and E. tereticornis Sm. (Benson and McDougall 2005). In New Zealand, N. neesiana plants growing under 25 year old Pinus radiata are generally weaker than plants growing in the open and have reduced seeding potential (Slay 2002a). N. neesiana was present in 3 of 6 treed paddocks examined by Bourdôt and Hurrell (1989a) in New Zealand. In the Canary Islands it “thrives” under the evergreen Laurus azorica (Seub.) Franco and the deciduous Castanea sativa Mill. (Verloove 2005). The literature appears to contain no precise informat.ion on the effects of solar radiation levels. N. neesiana plants growing under Eucalyptus in the ACT in early-mid summer were much greener and in an earlier reproductive stage than those in the open (Bruce 2001). Plantations with 2500 trees per ha have been established in New Zealand to examine the effects of shading as a possible control option (Slay 2002a 2002c). Soils and nutrients N. neesiana occupies areas on a wide range of geological substrates with a diversity of soil types. The soils may heavy or light textured (Cook 1999) and have low or high fertility (Muyt 2001, Slay 2002c). In Argentina it is found on well-drained, drought-prone soils (Bourdôt and Hurrell 1989b citing Cabrera and Zardini 1978, Lewis et al. 1985). In the Argentine pampas it is found on deep, generally fertile loessic silts and clays (Gardener 1998). These soils were formed on very deep (>c. 300 m) deposits of silt or loess, rich in swelling clays, and are mainly mollisols (commonly very deep, high fertility argiudolls) or frequently vertisols, of very young age (Soriano et al. 1992). In the Flooding Pampa t is not a component of the floristic groups characteristic of deep, non-saline, well-drained soils, nor the group that characterises areas subject to long flooding, nor in areas with saline alkaline soils (Perelman et al. 2001). It is most frequent in areas with higher topographic position, being scarce in depressions and lower lying areas, and occurs over a pH range of c. 6-8.2, disappearing in the more alkaline soils that occur in wetter depressions and are correlated with salinity (Perelman et al. 2001). In the Ventania land system in south-west Buenos Aires Province the soils are formed on a more complex mosaic of Palaeozoic sedimentary rocks (Soriano et al. 1992) and are“Typic and Lithic Argiudolls and Hapludolls developed from pure loess sediments or mixed with rock detritus”, slightly acid (pH 6.4-6.8), a high saturation with bases, organic carbon levels > 5.5. g kg -1 and total N > 0.4 g kg -1 (Amiotti et al. 2007 p. 535). In the Gualeguay area of Entre Rios province it is found on light loam, with much organic matter to a depth of 40-60 and pH in the range 5-6.8 (Marco 1950). In the Tandilia Range it occurs on soils derived from loess over quartzite, that are typic Haludolls 10-25 cm deep and Argiudolls 20-70+ cm deep with organic horizons less than 5 cm deep (Honaine et al. 2009). Although widely dominant in the Rolling Pampas, it is replaced by Sporobolus spp., Jarava plumosa and other plants where the soils are slightly alkaline (Soriano et al. 1992). Mollisols and vertisols predominate also in the southern campos (Soriano et al. 1992). Soils of the Southern Pampa and Flooding Pampa are noteably deficient in P (Soriano et al. 1992). In Europe it is generally found on well-drained, “sometimes slightly eutrophic” soils and on rocky slopes (Verloove 2005 p. 108). On Tenerife, Canary Islands, it prefers the nitrogen-enriched ruderal areas of fringe roads (Martín Osorio et al. 2000). In New Zealand the substrate rock types are loess, mudstones, and sandstones on slopes commonly 16-25° (Bourdôt and Hurrell 1989a), and it prefers acidic soils, low in phosphate, calcium and summer moisture (Esler et al. 1993, Champion 1995). It is recorded from Yellow Grey Earths, particularly when acidic or low in P, Ca or summer moisture (Bourdôt and Hurrell 1989b). Slay (2002a p. 4) considered it “apparently better adaptated to low fertility sites” in that country. Gardener (1998 p. 10) considered it was then generally found in Australia on “more fertile ... predominantly volcanic” soils, but noted its presence on granitic soils at Tenterfiled and Emmaville, NSW, on rich clay at Lucindale, South Australia, and alluvial soils near Melbourne. Infestations are widespread on the primarily heavy clay soils derived from basalts on the Victorian Volcanic Plains. Liebert (1996) found infestations on granitic and sedimentary soils in North Central Victoria. In the ACT it does not tend to establish on slopes with westerly aspects and shallow soils (Bedggood and Moerkerk 2002). In the Sydney region it occurs on clays on shale substrates with medium nutrient levels (Benson and McDougall 2005). According to Bedggood and Moerkerk (2002 p. 6) N. neesiana “does not establish well where nutrient levels are really low such as hillsides”, but “does better on flats where nutrient levels are moderate”. When P is added to pastures, desirable pasture grasses respond better than N. neesiana (Bedggood and Moerkerk 2002) and increase their basal cover at its expense, with the effect apparent with or without strategic grazing at 300 DSE ha -1 (McWhirter et al. 2006). Grech (2007a 2007b) found that N. neesiana responds to phosphorus fertilisation. 51
Page 1 and 2: Literature review: Impact of Chilea
Page 3 and 4: Fire 49 Other disturbances 50 Shade
Page 5 and 6: Conventions and standards Botanical
Page 7 and 8: neesiana appears to be a habitat ge
Page 9 and 10: population densities of existing sp
Page 11 and 12: elated plants have similar defences
Page 13 and 14: For invasion to occur there must be
Page 15 and 16: As yet there appears to be no evide
Page 17 and 18: experimental manipulation of specie
Page 19 and 20: species tend to be those which tran
Page 21 and 22: Taxonomy and nomenclature Stipeae N
Page 23 and 24: Vernacular names ‘Needlegrass’
Page 25 and 26: to Bouchenak-Khelladi et al. 2009).
Page 27 and 28: 1 m (Walsh 1994), ca. 90 cm (Verloo
Page 29 and 30: Figure 2. Anatomy of the seed of N.
Page 31 and 32: are the seeds larger/smaller, longe
Page 33 and 34: also based on a misunderstanding of
Page 35 and 36: Table 2. Modified Feekes Scale for
Page 37 and 38: Argentina, in the provinces of Chac
Page 39 and 40: Figure 3. Recorded distribution of
Page 41 and 42: 1994). Only 3 of 186 exotic grasses
Page 43 and 44: According to Morfe et al. (2003) th
Page 45 and 46: populations have been found in the
Page 47 and 48: (Honaine et al. 2006). The flechill
Page 49: In Australia the altitudinal range
Page 53 and 54: In the southern Brazilian campos of
Page 55 and 56: arundinacea (Gardener et al. 2005).
Page 57 and 58: al. 2008). Cues for masting may be
Page 59 and 60: Approximately 200 alien grass speci
Page 61 and 62: Dispersal of seed in contaminated s
Page 63 and 64: In New Zealand, Hurrell et al. (199
Page 65 and 66: No emergence was observed in undist
Page 67 and 68: and high impact (“ability to caus
Page 69 and 70: also noted that despite a wide rang
Page 71 and 72: a small reduction in seedhead produ
Page 73 and 74: Slashing and mowing Slashing can re
Page 75 and 76: Themeda re-establishment McDougall
Page 77 and 78: species (Lawton and Schroder 1977 p
Page 79 and 80: y increased importance of ant grani
Page 81 and 82: BIODIVERSITY “Biodiversity ... on
Page 83 and 84: According to Woods (1997 p. 61) “
Page 85 and 86: 2004, Richardson and van Wilgen 200
Page 87 and 88: 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 and 140:
Austrostipa-Enneapogon) from around
Page 141 and 142:
Woodlands and New England Grassy Wo
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 173 and 174:
Page 175 and 176:
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
Page 193 and 194:
Levine, J.M., Adler, P.B. and Yelen
Page 195 and 196:
McDougall, K.L. (1987) Sites of Bot
Page 197 and 198:
Morfe, T.A., McLaren, D.A. and Weis
Page 199 and 200:
Perelman, S.B., León, R.J.C. and O
Page 201 and 202:
Saunders, D.A. (1999) Biodiversity
Page 203 and 204:
Thellung, A. (1912) La flore advent
Page 205 and 206:
Weiss, J. and McLaren, D. (2002) Vi
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