Declared Plant Policy under the Natural Resources Management Act 2004




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Declared Plant Policy

under the Natural Resources Management Act 2004

Mexican feathergrass (Nassella tenuissima)


Mexican feathergrass is a perennial tussock grass resembling the native spear grasses, Austrostipa species. It is known to have been cultivated in South Australia as a garden ornamental.


Management Plan for Mexican feathergrass




Outcomes





  • Pasture and native vegetation protected from degradation by invasive, unpalatable grasses.



Objectives





  • To prevent the establishment of Mexican feathergrass in South Australia.



Implementation





  • Inspection of gardens and nurseries for Mexican feathergrass as part of routine surveillance by NRM authorities.




  • Destruction of any infestations found in accordance with NRM board regional management plans.


Regional Implementation
Refer to regional management plans for further details.


NRM Region

Actions

Adelaide and Mount Lofty Ranges

prevent entry or sale; destroy if detected

Alinytjara Wilurara

prevent entry or sale; destroy if detected

Eyre Peninsula

prevent entry or sale; destroy if detected

Kangaroo Island

prevent entry or sale; destroy if detected

Northern and Yorke

prevent entry or sale; destroy if detected

South Australian Arid Lands

prevent entry or sale; destroy if detected

South Australian Murray Darling Basin

prevent entry or sale; destroy if detected

South East

prevent entry or sale; destroy if detected


Declaration

To implement this policy, Mexican feathergrass is declared under the Natural Resources Management Act, 2004 throughout the whole of the State of South Australia. The movement or transport of the plant on a public road by itself or as a contaminant, its entry to South Australia, or the sale by itself or as a contaminant are prohibited. Notification of infestations is necessary to ensure these are destroyed. Land owners are required to destroy any Mexican feathergrass plants growing on their land. NRM authorities are required to destroy plants on road reserves, and may recover costs from the adjoining land owners.


Mexican feathergrass is declared in category 1 under the Act, for the purpose of setting maximum penalties and for other purposes. Any permit to allow its movement or sale can only be issued by the Chief Officer pursuant to section 188. Under the Natural Resources Management (General) Regulations 2005, the transport or movement of grain for milling or wool for cleaning is exempt from the operation of sections 175 and the sale of wool or grain is exempt from section 177(2) if at the time of the sale the person believes on reasonable grounds that the purchaser will remove the plant from the wool or grain before any re-sale.
The following sections of the Act apply to Mexican feathergrass throughout each of the NRM regions noted below:


Region

Sections of Act



AMLR

AW

EP

KI

NY

SAAL

SAMDB

SE

175(1) Prohibiting entry to area

X

X

X

X

X

X

X

X

175(2) Prohibiting movement on public roads

X

X

X

X

X

X

X

X

177(1) Prohibiting sale of the plant

X

X

X

X

X

X

X

X

177(2) Prohibiting sale of contaminated goods

X

X

X

X

X

X

X

X

180 Requiring notification of infestations

X

X

X

X

X

X

X

X

182(1) Landowners to destroy the plant on their properties

X

X

X

X

X

X

X

X

182(2) Landowners to control the plant on their properties

























185 Recovery of control costs on adjoining road reserves

X

X

X

X

X

X

X

X



Review

This policy is to be reviewed by 2020, or in the event of Mexican feathergrass becoming established as a weed in SA.



Weed Risk
Invasiveness
Mexican feathergrass has very high seed production, and its small seeds are chiefly dispersed by wind or attached to animals. They have large curved awns that often intertwine to form balls that can roll before the wind like tumbleweeds.
Impacts
Mexican feathergrass is an unpalatable grass that can become dominant under continual heavy grazing pressure, greatly reducing the productivity of pasture in a similar way to serrated tussock. By replacing native grasses and other herbs, it may adversely affect native grasslands and grassy woodlands.
It is also expected to behave in a similar way to serrated tussock in urban areas, by invading roadsides, parks, waste ground, industrial sites and amenity areas. Heavy build-ups of dry biomass from these weedy grasses can increase fire risk and hazard.


Potential distribution
Mexican feathergrass is adapted to climates matching the southern part of the agricultural zone in SA. It has wider ecological amplitude than serrated tussock and would extend further into drier climate zones. In other parts of the world it grows in grasslands, open rocky slopes, open dry woodlands and highlands up to 2900 metres altitude.
It tolerates a wide range of soil types from sands to heavy clay soils, as long as the soil dries out between waterings.
Feasibility of Containment
Control costs
There are no selective treatments for Mexican feathergrass in pasture, and control using herbicides such as glyphosate or fluazifop would take several years with the need to search for regrowth.
Persistence
Mexican feathergrass, like the other stipoid grasses, can persist unnoticed in native vegetation or unsown pasture because of its resemblance to many native grasses.
Current distribution
Not naturalised in SA. However, it is known to have been introduced under an incorrect name as an ornamental since the 1990s and planted in suburban Adelaide, towns on the Fleurieu Peninsula and Mount Gambier, and rare occurrences are still likely to persist.

State Level Risk Assessment

Assessment using the Biosecurity SA Weed Risk Management System gave the following comparative weed risk and feasibility of containment scores by land use:




Land use


Weed Risk

Feasibility of control

Response at State Level


Grazing - southern

medium

95


very high

1


contain spread

alert


Native vegetation

low

32


very high

1


monitor

Urban

negligible

11


very high

1


monitor


Considerations

Mexican feathergrass is native to a wide region of the Americas including Argentina, Chile, New Mexico and Texas. It was imported into Australia by production nurseries on many separate occasions from the mid 1990s to the mid 2000s in response to the fashion for ornamental grasses. Mexican feathergrass in particular has been promoted very widely as an ornamental on websites in the USA and Europe.


In 2008-2010 efforts were made, as part of a national eradication program, to trace and destroy all Mexican feathergrass plants that had been sold to the public. Although this grass is no longer in the nursery trade, a few specimens are likely to remain in gardens.
Risk assessment indicates containment as a management action; since Mexican feathergrass is present only as rare garden specimens in SA, containment is best implemented by preventing establishment in the wild or any further entry to the State while destroying any plants that remain in gardens. Due to its medium weed risk, presence in SA only as a rare cultivated plant, and very high feasibility of control, Mexican feathergrass is regarded as a State Alert Weed and a high priority surveillance target to increase the likelihood of early detection.

Synonymy
Nassella tenuissima (Trin.) Barkworth, Taxon 39: 612 (1990)
Basionym: Stipa tenuissima Trin., Bull. Sc. Acad. Petersb. i. 67 (1836)
Taxonomic synonyms:

Stipa cirrosa E.Fourn. & E.Fourn., Mexic. Pl. 2: 75 (1886)

Stipa geniculata Phil., Anales Univ. Chile 36: 204 (1870)

Stipa mendocina Phil., Anales Univ. Chile 27: 339 (1865)

Stipa oreophila Speg., Contr. Fl. Sierra Vent. 65 (1896)

Stipa subulata E.Fourn. & E.Fourn., Mexic. Pl. 2: 75 (1886)

Stipa tenuissima var. planicola Speg., Anales Mus. Nac. Montevideo 4: 155 (1904)
Other common names include Texas tussock grass, white tussock, ponytail grass, regal sensations and angels’ hair. In the nursery trade it may be found mislabelled as Stipa ‘Capriccio’, Stipa capillata, Stipa lessingiana, Stipa tenacissima or the native elegant speargrass (Austrostipa elegantissima).

References
Jacobs, S.W.L., Everett, J. & Torres, M.A. (1998) Nassella tenuissima (Gramineae) recorded from Australia, a potential new weed related to serrated tussock. Telopea 8: 41-46.

Hon Ian Hunter MP

Minister for Sustainability, Environment and Conservation
Date: 28 July 2014


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