Taxonomic name: Nassella neesiana (Trin, & Rupr.) Barkworth
Synonyms: Stipa neesiana Trin. & Rupr.
Common names: Chilean needle grass (English)
Organism type: grass
Nassella neesiana (Chilean needle grass) threatens the ecological integrity of affected natural ecosystems and also causes significant devastation in agricultural areas due to the reduction in pasture palatability and also direct damage to stock.
Perennial tussock forming C3 grass of up to 1m high. Flat leaves 1-5mm diameter, strongly ribbed on adaxial surface with rough margins. Infloresence an open panicle; stem seeds (cleistogenes) are also produced (Gardner, 1998).
Nassella charruana, Nassella hyalina, Nassella lecotricha, Nassella tenuissima, Nassella trichotoma
agricultural areas, natural forests, range/grasslands, riparian zones, ruderal/disturbed, scrub/shrublands, water courses
In Australia it invades disturbed grasslands and grassy woodlands of temperate regions with more than 500mm rainfall (Gardner, 1998)
Nassella neesiana has the tendency to replace native flora (Agriculture and Resource Management Council of Australia and New Zealand et al., 2000; Ens, 2002), reduce ant abundance and alter the entire invertebrate community composition in conservation areas (Ens, 2002). Potential distribution overlaps an array of threatened species in Australia (Thorpe and Lynch, 2000). Agricultural productivity is thwarted by the replacement of palatable ground cover, injury to stock, reduction of produce quality and increased management costs (Thorpe and Lynch, 2000). Some sheep graziers in eastern Australia have been forced to switch to beef production (Thorpe and Lynch, 2000).
Good stock feed during winter only
Nassella neesiana was previously known as Stipa neesiana. It is difficult to distinguish from native Stipas.
Native range: Native to South American countries of Chile, Argentina, Bolivia, Ecuador, Uruguay and Southern Brazil.
Known introduced range: Naturalised populations now occur in Australia (Gardner and Sindel, 1998), New Zealand (Bourdot and Hurrell, 1992) and England (Stace, 1977).
Preventative measures: A combination of chemical, mechanical, rehabilitation, competition, grazing management, biological control techniques and hygiene regimes are required to eradicate Chilean Needle Grass (Agriculture and Resource Management Council of Australia and New Zealand et al., 2000). As yet there is an absence of an effective herbicide (Agriculture and Resource Management Council of Australia and New Zealand et al. 2000).
Reproduces by sexual (chasmogamous) and asexual (cleistogamous) seed production. The cleistogenes are formed in the leaf sheaths and culms while the chasmogenes are found in the infloresence (Gardner, 1998). Up to 22,000 chasmogamous seeds/plant/year can be produced (Bourdot and Hurrell 1992). Production of the asexual seeds is a common response following slashing, grazing or fire (Gardner, 1998).
Peak flowering of Chilean needle grass in Australia occurs between November and February (Gardner, 1998), however it has the ability to flower all year round (Ens, 2002). The seed bank has been estimated to potentially persist in the soil for up to 12 years even with annual glyphosate application (Bourdot and Hurrell 1992)!
Reviewed by: Emilie-Jane Ens, PhD candidate University of Wollongong, Australia.
Compiled by: Emilie-Jane Ens, PhD candidate University of Wollongong, Australia.
Last Modified: Wednesday, 16 November 2005