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

Figure 4. Distribution of N. neesiana in New South
Wales (National Herbarium of New South Wales
2009).
Australian Capital Territory
Published information about early records of the grass in the ACT are scanty. Gardener (1998) dated the first record to 1960. The
ACT Weeds Working Group (2002 p. 2) vaguely noted that it was “known to have occurred in the ACT for some time, but was
not considered a species of concern until the late 1990s”. Vickery et al. (1986 p. 81) considered it was “now spreading” in the
ACT, and examined material from Burbong, Black Mountain, Commonwealth Gardens in Canberra, and O’Connor. Berry and
Mulvaney (1995) did not list the species as a significant weed in the ACT: it was not considered a “widespread or dominant”
environmental weed, nor a “common weed” of any major habitat type except grasslands and road verges, and was not recorded
from 40 or more 2.5’ x 2.5’ grid cells (c. 3.5 x 4.5 km), nor known to be dominant over an area of > 30 x 30 m. The weed
database at that time recorded zero locations for it in the ACT. In fact the species was not properly recognised in the ACT in this
period, and its presence was being overlooked (Sarah Sharp pers. comm. 11 October 2006). Berry and Mulvaney did note
however (1995 Vol. 2 Appendices p. 261) that it was a weed of grasslands in Canberra, “observed as a dominant in a small patch
of grassland in the Barton area ... also common along the bicycle path at Yarramundi” (at the western end of Lake Burley
Griffin).
Eddy et al. (1998) considered it common in the ACT. Bruce (2001) surveyed 39 sites in the ACT including natural grasslands,
parks and road verges in rural, urban and periurban areas and found N. neesiana to be widespread. It was most common in urban
and peri-urban areas subject to mowing and was present at all urban and peri-urban sites investigated, but at only 67% of rural
sites. Abundance data suggested that the invasion in the older urban areas was of longest standing and at a more advanced stage.
Lowest levels of abundance were found on agricultural land and grazed areas (whether or not managed for agriculture).
Further surveys from 2000 to 2002 (ACT Weed Working Group 2002, ?Sharp 2002) revealed expansion of known infestations at
numerous sites, plus numerous previously unrecorded patches and linear infestations along primary, secondary and semi-rural
roadsides leading outwards from major infestations. The Tuggeranong Valley contained the most noteworthy severe new
infestations. N. neesiana was found to be dominant in numerous areas in inner Canberra including most suburban nature strips
and roadsides, and around Parliament House. ACT Government (2005) recorded that it had spread dramatically in abundance
and distribution in the previous 10 years. The highest abundances in the ACT were in the central city and at Belconnen, with
lower abundances in the Jerrabomberra and Majura districts, Gunghalin, but was absent from sites examined in the Tuggeranong,
Tidbinbilla and Namadgi districts.
South Australia
The first known collection in South Australia was at Lucindale in the South East on 18 November 1988, where, according to J.P.
Jessop of the Adelaide Herbarium, it ‘did not seem to be causing any trouble’ (McLaren et al. 1998). Gardener (1998) mapped a
1988 record in the vicinity of Mallala (north of Adelaide). Gardener et al. (1996a) mentioned its presence in the Adelaide Hills,
and Gardener (1998) dated the first Adelaide area record as 1989. By 2000 it was recorded from the South East (Thorp and
Lynch 2000) and was known from the Okagparinga Valley by late 2000 (Obst and How 2004). Infestations at Belair National
Park were also identified. Field surveys in spring-summer 2003 enabled the mapping of all known infestations in Adelaide-
Fleurieu Peninsula (Iaconis 2006a). 53 infestations in the Mt. Lofty Ranges, Fleurieu Peninsula and greater Adelaide regions
totalling 14.0 hectares had been recognised up to December 2003, including Modbury (moderate to heavy, 0.07 ha), Adelaide
Parklands (5 plants removed by hand), Clarendon (one site, 0.02 ha, low density, grazed pasture) and Wirrina (several sites,
13.77 ha) (Obst and How 2004). Further surveys in 2004 located a few additional sites. During 2003-2005 the original survey
area was extended to include Randall Park and adjoining roads and railway infrastructure to Belair National Park, but no new
infestations were discovered (Iaconis 2006a). Jessop et al. (2006) recorded its presence in the Northern Lofty region (near
Bundaleer), Southern Lofty region and the South East.
Queensland
The presence of N. neesiana in Queensland may have been first recorded in published literature by Mallet and Orchard (2002).
Michael Hansford (in Iaconis 2003) noted its presence in “southern” parts of the State, in the Darling Downs. Extensive
surveying for N. neesiana was undertaken in 2005 and 2006 including roadside mapping in Clifton and Warwick Shires, with a
delimiting survey planned for the whole of the eastern Darling Downs (Iaconis 2006a). As of October 2006 infestations were
restricted to Clifton, Warwick and Cambooya Shires, and property management plans had been finalised for all known
infestations (Phil Maher, Queensland Department of Natural Resources and Mines, in Iaconis (2006b)). Infestations were
concentrated in the Darling Downs, with some along the Condamine River, and approximately 100 ha were known to be infested
by 2007 (Snell et al. 2007). The largest infestation was at Clifton Showgrounds and polo field where anecdotal evidence suggests
it may have been present since at least 1977 and have given rise to the other infestations (Snell et al. 2007). Additional
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