Buffel grass (Cenchrus ciliaris)

Assessment ID: 4592
Jurisdiction: North Territory
Methodology: Northern Territory Weed Risk Management System - terrestrial
Management area: Katherine Region

Notes: Assessment conducted by the NT Weed Risk Technical Committee 2010 and reviewed 2022. Technical report available from: https://environment.nt.gov.au/landresources/publications2/weed-management-publications/management-guides/weed-risk-assessment-technical-reports

Status: PUBLISHED
Last updated: 23/10/2026 11:11:45 am AEST

Questions answered: 39 / 47

Weed Risk: 593.23 (Very high)
   Invasiveness (raw/adjusted): 11.00 / 9.163
   Impacts (raw/adjusted): 13.00 / 6.838
   Potential distribution (raw/adjusted): 18.00 / 9.468

Feasibility of Control: 125.82 (High)
   Control costs (raw/adjusted): 6.00 / 5.454
   Current distribution (raw/adjusted): 5.00 / 5.000
   Persistence (raw/adjusted): 6.00 / 4.614

Result: Prevent entry, contain regional spread, protect priority sites

Invasiveness

A1. What is the ability of the plant to establish amongst intact native environments?
Answer: Very High

Comments: 
Agronomists have carried out studies concluding that soil fertility and competition from other plants affect the success of the recruitment and spread of Buffel grass. Buffel grass has medium to high requirements for phosphorus and a number of studies have linked the performance of Buffel grass to soil fertility and phosphorous supply. The competitive ability of Buffel grass seedlings and the competition offered by existing vegetation is another possible factor.While Buffel grass is strongly competitive as an established plant, some studies suggest that it is only weakly competitive as a seedling. Hence it can establish where there is little competition and colonise bare areas but it cannot invade established vegetation (Christie & Moorby 1975, McIvor 2003).

Buffel grass has also proved problematic in Uluru-Kata Tjuta National Park and the McDonnell Ranges in the Northern Territory (Pitts & Albrecht 2000).

It has been recorded in many conservation reserves in Western Australia (Pigott 1995).

The efficiency with which the exotic and widespread pasture species buffel grass (Cenchrus ciliaris) acquires nutrients may be a key factor allowing it to out compete native grasses and to invade savanna (Fairfax & Fensham 2000).

The high seed yielding ability and the light fluffy seed allows it to spread rapidly on the wind and in water. Because of this high level of natural spread, the grass is now regarded as naturalised (Hall 2001).

This report describes Buffel grass as a major environmental threat to biodiversity in central Australia and that it is rapidly expanding its distribution in National Parks and other areas of conservation significance (Puckey et al. 2004).

More references available at https://territorystories.nt.gov.au/10070/895155

A2. What is the reproductive ability of the plant?

(a) Time to seeding
Answer: 1 year or less

Comments: 
Personal observations and experience in central Australia have found that the longest time that it takes to drop mature seed on the ground from time zero, (seedling) is about three months, in summer two months. But an adult plant can do it in as short a time as two weeks after rain breaks its dormancy (P. Latz [botanist, Alice Springs] 2007, pers. comm.).

Personal experience and observations in the Longreach region in Queensland suggest that if it rained on a small buffel plant it could seed within a week on red country (J. Milson [Qld Department of Primary industries and Fisheries] 2007, pers. comm.).

(b) Annual production of viable seed /m2 or /plant
Answer: High

Comments: 
Prolific seed production has been recorded up to 440,000 seeds per kg (O'Reilly & Arthur Yates & Co 1975).

Seed production from sown Buffel grass in the NT near Darwin was measured by DBIRD. Buffel was planted in 1988/89 wet season and was well fertilised each year until July 1991 when seed was harvested. In these trials the highest yield from Buffel grass was 762 kg/ha, harvested late February following a wet season when rainfall was 1284 mm. The quality of seed harvested was good to excellent and all lots exceeded the minimum standard of 20% germination (Cameron 2004).

(c) Vegetative reproduction
Answer: Infrequent

Comments: 
Buffel grass can reproduce either vegetatively through rhizome or stolon production, or sexually by seed (Tu 2002).

A3. Do propagules of the plant have properties that allow them to be dispersed long-distance by natural means?

(a) Flying animals (birds, bats)
Answer: No

Comments: 
Undigested seed may be spread by ground-feeding granivores such as the flock bronzewing (Phaps histrionica: Columbidae), which are known to collect undigested grass seed from cattle dung, especially during drought. However, there is no evidence to suggest that the seeds remain viable once they have passed through the cattle” (Best 1998, Frith 1988).

(b) Other wild animals
Answer: Yes

Comments: 
Buffel burrs contain 1-3 seeds and are covered with barbellate bristles which enable them to attach to animal fur (Puckey & Albrecht 2004).

Horses and cattle are viewed as the most effective animals at dispersing Buffel grass seed. A high number of Buffel grass seeds have been found germinating in horse dung and studies are currently being undertaken in Queensland to further examine this phenomenon (V. Bailey [Queensland EPA, Longreach] 2007, pers. comm.).

(c) Water
Answer: No

Comments: 
Flood waters are a major mechanism of dispersal of Buffel grass seeds (Humphries et al. 1991).

This study noted that Buffel grass was not reported as spreading in Australia until the 1970s, when high rainfall and floods lead to rapid colonisation along creek lines and alluvial flats (Griffin 1993).

Observational evidence confirms that dispersal units of Buffel grass are spread by water (Puckey & Albrecht 2004).

Light, fluffy seed allow C. ciliaris to spread readily via water (Hall 2001).

(d) Wind
Answer: Yes

Comments: 
Wind is a major mechanism of dispersal of Buffel grass seeds. Buffel grass seeds are adapted to spreading short to medium distances by wind (Smith 2002).

This study suggests that seed is spread via the action of wind. However there is no evidence to suggest that seed is carried over 100m (Griffin 1993).

Dispersal units of Buffel grass are spread by wind (Puckey & Albrecht (2004).

Light, fluffy seed allow C. ciliaris to spread readily via wind (Hall 2001).

Personal experience in the Longreach region of Queensland suggests that the light, feathery seed of Buffel grass could potentially be dispersed over 100m by wind although this is only anecdotal evidence (J. Milson [Qld Department of Primary industries and Fisheries] 2007, pers. comm.).

A4. How likely is long-distance dispersal by human-assisted means?

(a) Deliberate spread by people
Answer: Common

Comments: 
Buffel grass has been widely introduced in the dry tropics and subtropics primarily aimed at improving stockfeed, stabilising soil and revegetating bare and eroded areas (Bryant 1961, Humphreys 1967).

It is one of the most important pasture introductions in arid and semiarid Australia. It is very drought tolerant and responds more rapidly to rain than other species. In central Australia Buffel grass has been planted extensively Australia for erosion control and land rehabilitation (Humphries et al. 1991).

(b) Accidentally by people and vehicles
Answer: Common

Comments: 
Seed is also easily spread by humans as they readily adhere to trousers, socks and vehicles (Puckey & Albrecht 2004).

(c) Contaminated produce
Answer: Occasional

Comments: 
This website considers that Buffel grass makes reasonable quality hay when cut in the early flowering stage, yielding up to 2500 kg/ha per cut with a protein content of 6-10% of dry matter (Food and Agriculture Organisation of the United Nations 2005).

This seed company website explains that once the Buffel grass seed is harvested the pasture crop is then cut and baled for hay. The hay is sold throughout Queensland and is renowned for its quality with many sales coming from return customers (Riverslea Seeds 2004).

(d) Domestic/farm animals
Answer: Occasional

Comments: 
Domestic stock are a possible mechanism of dispersal for Buffel grass seed (Dixon et al. 2002).

Buffel burrs contain 1-3 seeds and are covered with barbellate bristles which enable them to attach to animal fur (Puckey & Albrecht 2004).

Impacts

B1. What is the plant's competitive potential?
Answer: High

Comments: 
Buffel grass was identified as a category 1 weed (a terrestrial species capable of destroying an ecosystem) with an extensive distribution within Australia (Humphries et al. 1991).

The results from this study showed that Buffel grass is invasive in a semi-arid environment and that it changes floristic composition of vegetation. Invasibility appears to be related to both propagules pressure from sources along drainage and resource availability but the role of disturbance remains
equivocal. Cenchrus has steadily colonised the study site since 1976 when there were only a few records of its presence and its abundance was less than 5% in those plots. Since then Cenchrus has steadily increased its presence in plots and its abundance regularly exceeds 80%. This measured spread across two floodplains is mirrored in qualitative observations throughout floodplains of Central Australia (Clarke et al. 2005).

Photo plots in this study revealed increases in larger woody species throughout the study area corresponding to an increase in abundance of highly palatable shrubs in plots where C. ciliaris was absent (Clarke et al. 2005).

Buffel grass is known to reduce native plant diversity and interfere with natural ecosystems functions
(McIvor 2003).

Between 1987 and 1994 the area of Buffel grass increased in Epping Forest National Park from 13% to 54% respectively (Low 1997).

More references available at https://territorystories.nt.gov.au/10070/895155

B2. What is the plant’s potential to modify the existing fire behaviour and alter the fire regime?
Answer: Significant potential

Comments: 
The authors of this paper strongly believe that Buffel grass has the potential to alter fire regimes in arid and semi-arid areas because of increased fuel load and fuel continuity (Clarke et al. 2005).

This study conducted in central Australia, demonstrated that Buffel grass invasion was significantly correlated with increased fuel loads and increased burn severity. There was strong correlative evidence that greater Buffel grass abundance increased fuel loads, that increased fuel loads increased burn severity, that greater Buffel abundance resulted in higher burn severity and that higher burn severity resulted in greater mortality of woodland storey trees. These findings support the majority of assumptions of the exotic grass fire-invasion model proposed by D'Antonio and Vitousek (1992) (Miller 2003).

This study found that Buffel grass had double or triple the fuel loads of central Australian native grasses. These results were consistent with an unpublished long-term monitoring study at Simpson’s gap (Latz 1997, Miller 2003).

Buffel cover has been shown to increase two fold after fire relative to unburnt patches, consistent with the facilitation of a positive feedback between Buffel and fire (Butler & Fairfax 2003).

This study described the spread of buffel grass from a paddock to an adjacent conservation reserve... where buffel grass had invaded, fire intensity was appreciably greater and resulted in far higher mortality of native shrubs. Further more there was a positive feedback between fire and buffel dominance “…Buffel grass invasion, which increases ground fuel loads in Acacia woodlands, is facilitated by burning, producing positive feedback between Buffel grass and fire. The result is accelerating remnant degradation….” (Butler & Fairfax 2003).

More references available at https://territorystories.nt.gov.au/10070/895155

B3. What is the plant’s potential to restrict the physical movement of people, animals, vehicles, machinery and/or water?
Answer: None

Comments: 

B4. What is the plant’s potential to negatively affect the health of animals and/or people?
Answer: Low

Comments: 
This paper states that Buffel grass contains soluble oxalates in sufficient concentration to induce calcium deficiency in grazing animals. Oxalates react with calcium to produce insoluble calcium oxalate, reducing calcium absorption. This leads to disturbance in the absorbed calcium: phosphorous ratio, resulting in mobilisation of bone material to alleviate the hypocalcaemia (Cheeke 1995).

Sheep have been poisoned while grazing Buffel grass (Cheeke 1995).

B5. Does the plant potentially have negative effects on natural and cultural values?

(a) Reducing habitat quality for native animals?
Answer: High

Comments: 
Once native vegetation disappears many niche spaces for native animals will also disappear (Puckey & Albrecht 2004).

Central Australian vegetation has adapted to extremely unpredictable rainfall, and for many species recruitment, vegetative growth and flowering are generally associated with periods of higher rainfall. If rapid growth of Buffel results in fires at times outside of these major pluvial periods, native plant mortality may be greater because plants are already stressed, and the likelihood of subsequent germination is reduced (Miller 2003).

This paper outlines the major potential threats resulting from Buffel establishment. Potential threats include increased competition with native vegetation for nutrients, water, and light, allelopathic alteration of soil properties that inhibit germination and growth of other plants, alteration of
ecosystem processes such as fire regime and succession, and displacement of native animals through changes to habitat structure and competition (Puckey & Albrecht 2004).

In arid NT, Buffel establishment is in the very restricted habitats of the shaded cliffs and gorges brings it into direct competition with many of the regions rare and relict plant species (Griffin 1993).

This study, carried in central Queensland, found that numbers of Carnaby’s skink (Cryptoblephurs carnabyi) and Delicate mouse (Pseudomys delicatulus) declined as the cover of Buffel increased in eucalypt woodlands (Ludwig et al. 2000).

(b) Threatened species or communities
Answer: More than one

Comments: 
In Epping National Park in central Queensland, the area of Buffel grass increased to over 54% in 1994. This park is the last refuge of the Northern Hairy-Nosed wombat (Lasiorhinus krefftii) which now restricted to a tiny 300 ha range within the park. It is probably the rarest large mammal in the world and is critically endangered, with 70 to 100 individuals remaining. It has very little habitat left and the remaining 300ha has become infested with African Buffel grass, which out-competes the native grasses Yaminon prefers to feed on (Low 1997).

Introduced buffel grass, planted in the area for cattle feed, outcompetes the native grasses and forces the wombats (Northern Hairy-nosed) to travel further to find the native species they prefer to eat (Department of the Environment and Heritage 2004).

Buffel grass is listed as a Threatening Process (Vegetation Management Act 2005) for particular regional ecosystems in Queensland (EPA Queensland 2005).

The shrub Minuria tridens is a species restricted to arid NT. It is known from approximately nine locations. This species has been declared as vulnerable. Buffel grass has been identified as a potential threatening process due to competition and altered fire regimes (Kerrigan et al. 2002a).

Palm Valley Myrtle (Thryptomene hexandra) has a very restricted range, in the Finke Gorge National Park in several narrow steeply dissected valleys and it also occurs in Queensland. The NT populations are potentially threatened by Buffel grass invasion due to increased frequency of fire. The ‘fire response’ of this species is unknown but it is possible that altered fire regimes could destroy populations (Kerrigan et al. 2002b).

More references available at https://territorystories.nt.gov.au/10070/895155

(c) Sites of natural or cultural significance
Answer: More than one

Comments: 
Buffel grass is listed as one of 52 high priority weeds on Aboriginal lands in the Northern Land Council area. High priority weeds are those weeds capable of causing significant impacts on current land use. It is considered a severe threat in natural areas and little threat in pastoral areas. It is recorded in the Victoria River, Moyle River, Daly River, Finniss River, South Alligator River, Liverpool River, Roper River, Buckingham River, Walker River, Limmen Bight River, McArthur River and Wiso catchment areas (Smith (2001).

At Uluru-Kata Tjuta National Park rehabilitation was attempted to reduce the impact of erosion in sensitive areas in 1968 following a dramatic increase in visitor numbers. Structures to hold back water flow were built and exotic perennials were introduced in the hope of stabilising the soil quickly. Unfortunately, some of these exotics were more successful than anticipated, and a few, particularly Buffel grass (Cenchrus ciliaris), now dominate the most popular gorges at Uluru as well as the edges of roads and tracks (CSIRO 2006).

Buffel grass is currently impacting and threatening the conservation values of Watarrka National Park (Puckey et al. 2004).

B6. Is the plant presumed to have negative effects on environmental health?

(a) Soil chemistry/stability
Answer: Yes

Comments: 
Allelopathic inhibition the growth of Calotropis procera seedlings by Buffel grass have been reported by this study (Cheam 1984).

The productivity of Buffel grass pastures slowly decline, indicated by thinning of the sward, lack of vigour and reduced seed production. Cattle live-weight gain can decline at the rate of 9 to 13 kg/head/year (Cavaye 1991).

Buffel has a high demand for available soil nitrogen and phosphorous and as Buffel assumes dominance, soil nitrogen is depleted and growth begins to decline in what has been described as the “run down” effect with an associated decline in cattle live-weight gain” (Puckey & Albrecht 2004).

This experiment aimed to determine whether leachate from Buffel grass reduced seed germination of other species. The results showed that leachate from Buffel grass root reduced germination of partridge pea more so than leachate from Buffel grass leaf and this study called for further field studies to determine potential impacts in the field (Nurdin & Fulbright 1990).

Over time nutrient run down occurs. The time frame and extent depend on the country. In poor Gidgee country for example, nutrient run down would occur after approximately 20 years (J. Milson [Qld Department of Primary industries and Fisheries] 2007, pers. comm.).

(b) Water quality
Answer: No

Comments: 
Buffel grass is not associated with water bodies, therefore no effect (No reference).

(c) Hydrology
Answer: Do not know

Comments: 
No specific information available, however the potential for impact exists as Buffel grass is associated with wetter parts of the landscape (NT Weed Risk Management Committee 2006).

Potential distribution

C1b. What is the Climatch suitability score (which indicates the proportion of the NT environment that is suitable for the plant)?
Answer: 9

Comments: 
The CLIMATE potential distribution map suggests that 93% of the Northern Territory is climatically suitable for Buffel grass (No reference).

Buffel now occurs in all mainland states of Australia (Best 1998).

By the year 2000, it was estimated that Buffel had naturalised between 30 and 50 million hectares in Queensland alone (Hannah & Thurgate 2001).

This study developed a map of the suitability of Australia based on climate and soil suitability. This model predicts that 25% of Australia is highly suitable and 43% is suitable for Buffel grass growth (Lawson et al. 2004).

Using climate only CLIMEX, 31% of mainland Australia is potentially highly suitable and 32% suitable for Buffel grass growth (Lawson et al. 2004).

C2. How many broad habitat types in the NT will the plant potentially naturalise in (up to 5)?
Answer: Five or more

Comments: 
It was noted that the distribution of Buffel grass is very dependent on soil type. The broad vegetation types that Buffel grass will potentially naturalise in include arid and semi-arid riparian, arid and semi-arid woodlands, arid and semi-arid shrublands, arid and semi-arid wetlands, spinifex grasslands, mitchell grasslands, tropical riparian and tropical open forests/savanna woodlands (NT Weed Risk Management Committee 2006).

The broad habitat types that Buffel grass will potentially naturalise in three assessment regions are -
Darwin: Tropical riparian areas, Tropical open forests/savanna woodlands and Mangroves/beaches.
Katherine: Tropical riparian areas, Tropical open forests/savanna woodlands, Mangrove/beaches, Mitchell grasslands and Spinifex grasslands.
Tennant Ck/Alice Springs: Mitchell grasslands, Spinifex grasslands, Arid and semi-arid woodlands, Arid and semi-arid shrublands, Arid riparian and Arid and semi-arid wetlands (NT Weed Risk Management Committee 2010).

C3. What is the potential of the plant to occur throughout its favoured habitat in the NT (as identified in question 2)?
Answer: Most

Comments: 
It was noted that the favoured habitat for the naturalisation of Buffel grass is arid and semi-arid riparian (NT Weed Risk Management Committee 2006).

Buffel grass' potential to occur throughout its favoured habitat in the three assessment regions are -
Darwin: Open forest (incidental)
Katherine: Open forest (Some)
Tennant Ck/Alice Springs: Arid and semi-arid riparian (most) (NT Weed Risk Management Committee 2010).

Control costs

A1. How detectable is the weed?

(a) Distinguishing features
Answer: Sometimes distinct

Comments: 
Sometimes distinct, as a layman could confuse it with other Cenchrus spp, or other Pennisetum spp. (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

Cenchrus ciliaris (Buffel grass) is an erect, deep-rooted perennial grass to 1m tall, forming dense tussocks. Leaves hairy flat or folded, tips pointed. Sedd heads dense, in a spike-like raceme up to 15cm long, white to pale purple, covered with clusters of bristles giving it a fluffy appearance. Flowers/fruits mainly Nov-May or sporadically following rain (Smith 2001).

(b) Active growth period
Answer: 4-8 months

Comments: 
In the Alice springs region Buffel grass is likely to grow for approximately 4 months, but this is moisture dependent (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

In the Tennant Creek region and the Victoria River District, Buffel grass can grow for 4-8 months, depending on the soil moisture (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

(c) Height at maturity
Answer: 0.5 - 2 m

Comments: 
Grows up to 1 metre high (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

Cenchrus ciliaris (Buffel grass) is an erect perennial grass to 1m tall (Smith 2001).

A2. What is the general accessibility of infestations at the optimum treatment time?
Answer: Medium

Comments: 
Most infestations are readily accessible at most times of the year, or may require some additional equipment e.g quad bike (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

Most of work with 4WD quadbikes. Note: This weed is not actively controlled and this is an estimate only (C. Brown [NT Weed Management Branch, Alice Springs] 2007, pers. comm.).

A3. How expensive is control of the weed in the first year of targeted control, for an infestation that has reached maximum weed density?

(a) Chemical costs
Answer: Low

Comments: 
To control buffel grass you would use approximately 6 L/ha of glyphosate, so it would cost about $30-40 per ha. However you often get only 70-80% control of buffel as it can already be a little water stressed when you get to spray it. Note: This would place Buffel grass control in the low (<$100 /ha) chemical costs category (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

$100/Ha. Note: This weed is not actively controlled and this is an estimate only (C. Brown [NT Weed Management Branch, Alice Springs] 2007, pers. comm.).

(b) Labour cost
Answer: Medium

Comments: 
$100-$250/ha (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

$100-$250/ha. Note: This weed is not actively controlled and this is a best estimate only (C. Brown [NT Weed Management Branch, Alice Springs] 2007, pers. comm.).

(c) Equipment cost
Answer: Medium

Comments: 
Vehicle, or quadbike (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

Vehicle, or quadbike. Note: This weed is not actively controlled and this is an estimate only (C. Brown [NT Weed Management Branch, Alice Springs] 2007, pers. comm.).

A4. What is the general community perception of this weed within the region?
Answer: Medium

Comments: 
Across all the regions considered (Alice Springs, Tennant Creek and Victoria River District), Buffel grass would be considered Medium for community perception, this is a conflict weed (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

Current distribution

B1. What is the current pattern of the species’ distribution across the weed management region?
Answer: Scattered

Comments: 
Buffel grass is widespread in the Alice Springs and Tennant Creek regions, but scattered in the Darwin and Katherine Weed Management Regions (A. Cameron [NT Department of Resources] 2010, pers. comm.).

In the Tennant Creek and Alice Springs regions, and the Victoria River District, Buffel grass is widespread (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

Persistence

C1. How long will it take to reach the maintenance period?
Answer: Medium

Comments: 
In the Alice Springs region the likelihood of long-term control is low, as it will take >5 years to reach the maintence period. Buffel grass will keep reinfesting the area (from within the control area) (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

In the Tennant Creek region and the Victoria River District, the likelihood of long-term control is low, as it will take >5 years to reach the maintence period. Buffel grass will keep reinfesting the area (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

C2. What is the minimum time period for reproduction of sexual or vegetative propagules?
Answer: <1 growing season

Comments: 
The minimum time period for reproduction is less than one growing season (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

Personal observations and experience in central Australia have found that the longest time that it takes to drop mature seed on the ground from time zero, (seeding) is about three months, in summer two months. But an adult plant can do it in as short a time as two weeks after rain breaks its dormancy (P. Latz [botanist, Alice Springs] 2007, pers. comm.).

Personal experience and observations in the Longreach region in Queensland suggest that if it rained on a small buffel plant, it could seed within a week on red country (J. Milson [Qld Department of Primary industries and Fisheries] 2007, pers. comm.).

C3. What is the maximum longevity of sexual or vegetative propagules?
Answer: 2-5 years

Comments: 
Our experience has shown that the longevity of Buffel grass is between 2-5 years - especially if it is dry in the soil (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

Seeds can maintain their longevity for at least three years (Dixon et al. 2002).

C4. What is the threat of reinfestation from outside the management region?

(a) Long-distance (>100m) dispersal by natural means
Answer: Rare

Comments: 
Long distance spread by natural means is likely to be rare (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

Undigested seed may be spread by ground-feeding granivores such as the flock bronzewing (Phaps histrionica: Columbidae), which are known to collect undigested grass seed from cattle dung, especially during drought Frith, 1988). However, there is no evidence to suggest that the seeds remain viable once they have passed through the cattle (Best 1998, Frith 1988).

Buffel burrs contain 1-3 seeds and are covered with barbellate bristles which enable them to attach to animal fur (Puckey & Albrecht 2004).

Horses and cattle are viewed as the most effective animals at dispersing Buffel grass seed. A high number of Buffel grass seeds have been found germinating in horse dung and studies are currently being undertaken in Queensland to further examine this phenomenon (V. Bailey [Queensland EPA, Longreach] 2007, pers. comm.).

Flood waters are a major mechanism of dispersal of Buffel grass seeds (Humphries et al. 1991).

This study noted that Buffel grass was not reported as spreading in Australia until the 1970s, when high rainfall and floods lead to rapid colonisation along creek lines and alluvial flats (Griffin 1993).

Observational evidence confirms that dispersal units of Buffel grass are spread by water (Puckey et al. 2004).

Light, fluffy seed allow C. ciliaris to spread readily via water and wind (Hall (2001).

Wind is a major mechanism of dispersal of Buffel grass seeds. Buffel grass seeds are adapted to spreading short to medium distances by wind (Smith 2001).

This study suggests that seed is spread via the action of wind. However there is no evidence to suggest that seed is carried over 100m (Griffin 1993).

Dispersal units of Buffel grass are spread by wind (Puckey & Albrecht 2004).

(b) Long-distance (>100m) dispersal by human means
Answer: Frequent

Comments: 
Buffel burrs contain 1-3 seeds and are covered with barbellate bristles which enable them to attach to animal fur (Puckey & Albrecht 2004).

Long distance spread by human means means is likely to be frequent (P. Jeffery, M. Fuller & G. McSkimming [NT weed control contractors] 2007, pers. comm.).

Buffel grass has been widely introduced in the dry tropics and subtropics primarily aimed at improving stockfeed, stabilising soil and revegetating bare and eroded areas (Bryant 1961, Humphreys 1967).

It is one of the most important pasture introductions in arid and semiarid Australia. It is very drought tolerant and responds more rapidly to rain than other species. In central Australia Buffel grass has been planted extensively Australia for erosion control and land rehabilitation (Albrecht & Pitts 1997, Allan 1997, Humphries et al. 1991, Jackson 2005).

Seed is also easily spread by humans as they readily adhere to trousers, socks and vehicles (Puckey & Albrecht 2004).

This seed company website explains that once the Buffel grass seed is harvested the pasture crop is then cut and baled for hay. The hay is sold throughout Queensland and is renowned for its quality with many sales coming from return customers (Riverslea Seeds 2004).

Domestic stock are a possible mechanism of dispersal for Buffel grass seed (Dixon et al. 2002).

References

Reference list available in the Cenchrus ciliaris (Buffel Grass) NT Weed Risk Assessment Technical Report 2022. Available here: https://environment.nt.gov.au/landresources/publications2/weed-management-publications/management-guides/weed-risk-assessment-technical-reports