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

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Vertebrates Many stipoid grasses are readily eaten by livestock, including N. neesiana. In the Great Basin region of the USA Stipa spp. sens. lat. are considered “for the most part valuable forage plants” (Hitchcock and Chase 1971 p. 445). N. neesiana is readily eaten by sheep, cattle and horses in Argentine pastures in winter and spring, but consumption is much reduced when the plant is flowering and seeding, except under drought conditions or when stocking rates are high (Gardener et al. 1996b, Gardener 1998). It has been rated as one of the most valuable winter pasture species in the pampas (Gardener et al. 1996b). Grasses defend themselves against grazing mammals in a variety of ways, including adaptations of form, habit and phenology, presence of indigestible structural compounds and presence of toxic chemicals. Very few grass species contain toxic secondary metabolites that deter grazing and herbivory: less than 0.2% contain alkaloids, and the presence of noxious terpenoids and cyanogenetic compounds is rare (Tscharntke and Greiler 1995, Witt and McConnachie 2004), although McDonald (1991) claimed that defensive metabolites are common in cereal and other grasses. Records of toxic effects of stipoids on livestock are scarce. According to Quattrocchi (2006 p. 1361) “Some” Nassella species “have caused poisoning to mammals”. Randall (2002) stated that N. neesiana has been recorded as toxic, and the US Food and Drug Admimistration Poisonous Plants Database (USFDA 2006) lists N. neesiana, citing Kellerman et al. (1988). Probably most cases of toxicity attributed to grasses are the result of grass fungi. Possibly the best known example is ergot, Claviceps purpurea, which infects cultivated Secale cereale L., other cereals, and other grasses, the toxic effects of which have resulted in mass human poisonings (Gair et al. 1983, Wink and Van Wyk 2008). However none of the many Claviceps species affect Stipeae (Wink and Van Wyk 2008). The Mexican and southwestern USA Achnatherum robustum (Vasey) Barkworth (= Stipa vaseyi Scribn. = Stipa robusta (Vasey) Scribn.), known as Sleepy Grass, allegedly acts as a “narcotic”, especially on horses (Hitchcock and Chase 1971) due to infection with endophytic Acremonium fungi. The active principles were identified by Petroski et al. (1992), the dominant one, lysergic acid amide, likely being responsible for a reportedly extreme “sedative” effect on animals. However lysergic acid and its derivatives are generally considered to be hallucingens, producing delerium but not sedation (Wink and Van Wyk 2008). Achnatherum inebrians (Hance) Keng of China and Mongolia, known as Drunken Horse Grass, probably affects animals by ergot alkaloids produced by the endophytic Neotyphodium gansuense Li and Nan (Clavicipitaceae) (Moon et al. 2007). The ergot alkaloids consist of two main series, clavine alkaloids and the lysergic acid amides (Wink and Van Wyk 2008). Such fungal endophytes occur widely in grasses (see section on “Other biotic relationships” below) and produce a variety of poisonous secondary metabolites that effectively deter pathogen attack and grazing, and sometimes poison mammals (Tscharntke and Greiler 1995, Jallow et al. 2008), and are thus generally considered to be symbionts, rather than pathogens (Wink and Van Wyk 2008). Grass poisoning can also be caused by organic acids, which irritate skin and mucous membranes (Wink and Van Wyk 2008). Stipa capensis contains glycosides producing a strong acid that can harm cattle (Tsvelev 1984). Specialist granivorous birds, of which the most important are finches, parrots and pigeons, probably commonly consume stipoid seeds, however there appear to be few relevant records. Twigg et al. (2009) found from anyalysis of stomach contents that seeds in the diets of Australian finches (two Emblema spp.) and Alcedinidae (three dove and pigeon spp.) were predominantly
y increased importance of ant granivory. Specific information on mammal granivory in areas where N. neesiana is native appears to be lacking and no information is availabe about rodent granivory in Australian native grasslands. Pathogens A wide range of pathogenic fungi attack grasses. These are often highly host-specific, notably head smuts and rusts, with specificity often being confined to particular host biotypes (Witt and McConnachie 2004). Wapshere (1990) mentions, in addition, the genera Phyllochora (Ascomycetes), Cercospora (Hyphomycetes) and Stagonospora (Coelomycetes) as having, on a world basis, a high proportion of their species known from only a single grass genus. N. neesiana has a rich pathogenic fungal flora in South America (Briese et al. 2000, Anderson et al. 2004), including the following taxa: Powdery mildew (Anderson 2002b) Septoria leaf spot (Anderson 2002b) Teliomycetes (Rusts) Puccinia digna Arth. and Holw. (Greene and Cummins 1958) Puccinia graminella Diet. and Holw.- damaging infestations in central Argentina (Briese et al. 2000) Puccinia nassellae Arth. and Holw. var. platensis Lindquist (Briese and Evans 1998, Briese et al. 2000, Anderson et al. 2004 2008 ) Puccinia saltensis var. saltensis (Briese et al. 2000) Puccinia aff. avocensis (Anderson et al. 2002) Uromyces pencanus Arth. and Holw. (Greene and Cummins 1958, Anderson 2002a, Anderson et al. 2006 2008) Uredo sp. (Briese et al. 2000) Ustomycetes (Smuts) Tranzscheliella hypodytes (Schltdl.) Vánky & McKenzie (= Ustilago hypodytes (Schlecht.) Fr., sensu lato (Briese et al. 2000, Anderson 2002a, Anderson et al. 2004), listed as Ustilago sp. by Anderson et al. (2002). However some populations in Argentina are free of pathogens including Entre Rios Province where in one survey “many huge and dense populations ... were completely devoid of disease” (Anderson 2002b). Knowledge of these pathogens has been greatly enhanced by studies undertaken for an Australian biological control program for Nassella spp., initiated in 1999 (Anderson et al. 2008). Puccinia graminella is known from western and southern South America and California, and also attacks N. hyalina (Greene and Cummins 1958). It was found to be damaging N. neesiana populations in central Argentina by Briese et al. (2000). During one survey P. graminella was found at 12 of 14 sites and was killing N. neesiana leaves at 4 sites (Anderson et al. 2002). It was initially thought to cause little damage to N. neesiana (Anderson 2002b) but can cause mortality under wet conditions (Anderson et al. 2004) and severe damage in the field (Anderson et al. 2008). It appears to have restricted host-specificity, is autoecious and completes its lifecyle on N. neesiana, with both uredina and telia having been recorded on the plant (Anderson et al. 2004 2006). However N. neesiana appears to have qualitative resistance to infection and a pure culture has not been established (Anderson et al. 2008). Puccinia nassellae is known from Argentina, Bolivia and Chile (Greene and Cummins 1958). Two strains have been investigated as potential biological control agents, specific to N. neesiana and N. trichotoma. The strain on N. neesiana commonly forms telia and produces pustules that are plain to see on open leaf lamina. It is virulent (Anderson et al. 2008), easy to rear, probably host-specific, hemicyclic (urediniospores and teliospores on N. neesiana, but possible other stages unknown), but probably not autoecious (Anderson 2002a) with Clematis montevidensis, Solidago chilensis, Cestrum parqui, Verbesina sp. and Morrenia sp. found with aecial rust infections, although none appear to be solid candidates as alternate hosts (Anderson 2002b). It has not infected Austrostipa spp. and Stipa spp. that have been tested, but of the strains collected in the wild, only one has been able to infect 3 of 6 Australian N. neesiana accessions, so there is high specificity at the subspecific level (Anderson 2002a, Anderson et al. 2002 2006). Trap plants of N. neesiana obtained in the Australian Capital Territory became infected with strain NT27 in Argentina (Anderson 2002a). Puccinia digna is known from Bolivia and Chile (Greene and Cummins 1958) and has not been studied for biological control purposes. Uromyces pencanus is known from Argentina and Chile (Greene and Cummins 1958), appears to be host-specific and can be very damaging to N. neesiana in Argentina, but its lifecyle on the plant is incompletely understood (Anderson et al. 2006 2008). It is easy to rear and has infected 5 of 6 Australian accessions of N. neesiana. Isolate Up27, virulent against most Australian accessions of N. neesiana, has been found not to infect N. hyalina, Austrostipa aristiglumis (F. Muell.) S.W.L. Jacobs & J. Everett and a range of economically important agricultural grasses (Anderson et al. 2008). Mixed species rust infections are not uncommon in Argentina and appear to be particularly damaging to the plant (Anderson et al. 2006). The smut Tranzscheliella hypodytes is a cosmopolitan species (Vánky and Shivas 2008) and infects a number of Austrostipa species (Briese and Evans 1998) in south-eastern Australia and Dichelachne crinita (L.f.) Hook. in NSW and Victoria, but does not appear to have been recorded on Australian N. neesiana (Vánky and Shivas 2008). It infests upper culm internodes of N. neesiana in Argentina, preventing most seed production when plants are severely attacked, and infection occurs at germination (Anderson et al. 2002). It is not known if strains found on N. neesiana can infect N. trichotoma and vice versa (Anderson 2002a). Conditions for infection appear to be uncommon in nature (Anderson et al. 2004) and the species has been found only at very low incidence in Argentina (Anderson 2002b). Knowledge of the fungal flora of N. neesiana in its introduced ranges is limited. Slay (2002a) summarised results of a Landcare Research survey of N. neesiana fungi at five sites in New Zealand. Fourteen species were identified, of which six were 79
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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).
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 and 50: In Australia the altitudinal range
Page 51 and 52: Proximity to urban development appe
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: species (Lawton and Schroder 1977 p
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
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Fossorial vertebrates are or were o
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(Rosengren 1999). Approximately one
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Table 12. Areal extent and conserva
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Foreman (1997) investigated the eff
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Willis (1964) considered that the f
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Austrostipa-Enneapogon) from around
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Woodlands and New England Grassy Wo
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Thylogale billardierii), Peramelida
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Its original habitat on the mainlan
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Table 17. Endangered reptile specie
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equirement, but unlike plants and v
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e assigned the same biodiversity sc
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Nematodes are mostly minute animals
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found in all mainland states, O. co
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Keyacris scurra, Melbourne (1993) o
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was once widespread in south- easte
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eing sluggish and wingless, and exi
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estoration and, if Australia follow
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close to the plant are able to bury
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Species *Chirothrips mexicanus Craw
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Table A2.1 (continued) Species Life
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Table A2.1 (continued) Species *Het
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Page 175 and 176:
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Nematodes of grasses and grasslands
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REFERENCES Aceñolaza, F.G. (2004)
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Benson, D. and McDougall, L. (2005)
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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
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
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Saunders, D.A. (1999) Biodiversity
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Thellung, A. (1912) La flore advent
Page 205 and 206:
Weiss, J. and McLaren, D. (2002) Vi
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