Title: Agrostis capillaris L.

Scientific Name:

Agrostis capillaris L., Agrostis castellana Boiss & Reuter

Common Names:

bent grass



Source & more images

Habitat:

Cool, high-rainfall areas from sea level up to alpine regions, usually on poor acid soil types and in open habitats (Walsh and Entwisle 1994, Weiller et al. 1995). It is a common weed of pastures and roadsides (Weiller et al. 1995). Brown-top bent invades dry coastal vegetation, heathland and heathy woodland, lowland grassland and grassy woodland, dry sclerophyll forest and woodland, damp sclerophyll forest, riparian vegetation, freshwater wetland (seasonal), and alpine and subalpine vegetation (Carr et al. 1992).

Distribution:

 
Present Distribution - Australia (source: ALA)   Present Distribution - World (VIA CABI)




Invasiveness Assessment

ESTABLISHMENT


1. Germination requirements? In the field, seeds germinate in autumn and spring (HDRA 2006). Requires natural seasonal disturbances for germination.

2. Establishment requirements? Described growing in shaded situations (Dore & McNeil 1980) and as invading forest (Carr et al 1992). Could establish under a moderate canopy.

3. How much disturbance is required? It is described as being one of worst pasture weeds of the high rainfall zone of Victoria dominating in lightly grazed pastures (Hill et al 1996), suggesting it can establish with minimum disturbance such as in well established pasture. Also described as invading grassland (Edgar & Connor 2000), grassy woodland, sclerophyll forest/woodland, heathland & heathy woodland, riparian and alpine & subalpine vegetation (Carr et al 1992). Establishes in relatively intact natural ecosystems.

GROWTH / COMPETITIVE


4. Life form? Life form: Grass (Batson 1998)

5. Allelopathic properties? No evidence was found to suggest the presence of allelopathy within the species, or genus.

6. Tolerates herb pressure? Under severe grazing, common bent will soon appear in grassland and within 5 years it can make up a significant proportion of the sward (Spedding 1966). Adapts to heavy grazing by growing close to ground level. Bent grows slowly over winter/ early spring producing little feed for stock, but in late spring/early summer bent grass produces excess feed of poor quality which is not utilised by stock (Batson 1998b). Appears to be only preferred and grazed for part of the year.

7. Normal growth rate? A. castellana grows more vigorously by rhizomes than A. capillaris (Batson 1998) and is more competitive and chokes out ryegrass and clover (Batson 1998b). Grows slowly over cooler periods but in late spring and early summer produces excess feed (Batson 1998b). Although slow growing in winter, the literature suggests overall growth would equal competitive species of the same life form.

8. Stress tolerance to frost, drought, w/logg, sal. etc? Described as surviving waterlogged soils better than ryegrass and clover (Batson 1998b), dominating seasonally flooded grasslands (Sanchez & Peco 2004) and occurring in seasonal wetlands (Carr et al 1992). Hardy to European winters (Jones & Charles 1984) and occurs on subantarctic islands (Clayton et al 2007). Not tolerant of salinity (Marcum 2004). Exhibits some tolerance to burning (HDRA 2006) probably due to rhizome system. Likely to have some drought tolerance occurring in semi-arid grasslands (Vaquero et al 2003).

REPRODUCTION


9. Reproductive system? Reproduces sexually by seed (Hill et al 1996) and vegetatively via rhizomes (Batson 1998).

10. Number of propagules produced? Observed producing up to 298,000 seeds/m2 (Alexander 1995 in Batson 1999). It is likely that an individual plant would produce greater than 2000 seeds.

11. Propagule longevity? Thompson et al. (1993) suggest that based on seed character, common bent seed is likely to persist for longer than 5 years. Seed buried at 13cm depth retained 28% viability after 4 years (Lewis 1973 in HDRA 2006). Greater than 25% of seed may survive beyond 5 years.

12. Reproductive period? A perennial grass (Edgar & Forde 1991), therefore having the potential to produce propagules for several (3+) years.

13. Time to reproductive maturity? As a grass (Batson 1998), time to reproductive maturity is presumed to be less than 2 years.

DISPERSAL


14. Number of mechanisms? Spread by wind and attachment to animals (Carr et al 1992). Some seeds also likely to be accidentally ingested and dispersed internally by grazers (Janzen 1984).

15. How far do they disperse? Attachment and internal dispersal can spread seeds considerable distances (Janzen 1984), with free ranging introduced and native grazers able to disperse seeds greater than 1km.


Impact Assessment

RECREATION


1. Restrict human access? Perennial grass of height 20-80 cm (Tutin et al 1980). There is no information to suggest that A. castellana would restrict human access.

2. Reduce tourism? There is no information to indicate it would reduce tourism, and as a grass species (Edgar & Forde 1991) it is not likely to be obvious as a weed to the ‘average’ visitor.

3. Injurious to people? Nothing was found in the literature to indicate that A. castellana possesses any injurious properties.

4. Damage to cultural sites? Perennial grass of height 20-80 cm (Tutin et al 1980). No information found to suggest it would cause damage to cultural sites.

ABIOTIC


5. Impact flow? As a terrestrial species it is unlikely to impact on water flow.

6. Impact water quality? As a terrestrial species it is unlikely to impact on water quality.

7. Increase soil erosion? It produces rhizomes (Batson 1998) so may decrease the probability of erosion in some situations.

8. Reduce biomass? When displacing native vegetation (DECC 2004), there is potential for direct replacement of biomass, as it would most likely replace other grass species.

9. Change fire regime? Produces thick dry mats of coarse grass that are very sensitive to fire (Bernaldez 1991). Potential to increase fire frequency in some of the less fire prone ecosystems it invades, with a likely varying level of impact.

COMMUNITY HABITAT


10(a) Impact on composition of high value EVC? EVC= Plains Grassland (BCS= E); CMA= West Gippsland; Bioreg= Gippsland Plain; CLIMATE potential=VH. Described as a ‘very serious threat’ to several vegetation formations in Victoria (Carr et al 1992), and as displacing native vegetation (DECC 2004). Thick dry mats suppress annual herbs in pasture (Bernaldez 1991) and a similar affect is likely in natural systems, as it is documented dominating large areas of permanent grassland (Hubbard 1968). Potential for major displacement of some dominant species within the ground layer.

10(b) Impact on medium value EVC? EVC= Grassy Dry Forest (BCS= D); CMA= Corangamite; Bioreg= Central Victorian Uplands; CLIMATE potential=VH. Described as a ‘very serious threat’ to several vegetation formations in Victoria (Carr et al 1992) and as displacing native vegetation (DECC 2004). Thick dry mats suppress annual herbs in pasture (Bernaldez 1991) and a similar affect is likely in natural systems, as it is documented dominating large areas of permanent grassland (Hubbard 1968). Potential for major displacement of some dominant species within the ground layer.

10(c) Impact on low value EVC? EVC= Coastal Tussock Grassland (BCS= LC); CMA= West Gippsland; Bioreg= Gippsland Plain; CLIMATE potential=VH. Described as a ‘very serious threat’ to several vegetation formations in Victoria (Carr et al 1992) and as displacing native vegetation (DECC 2004). Thick dry mats suppress annual herbs in pasture (Bernaldez 1991) and a similar affect is likely in natural systems, as it is documented dominating large areas of permanent grassland (Hubbard 1968). Potential for major displacement of some dominant species within the ground layer.

11. Impact on structure? Displaces native vegetation (DECC 2004). Thick dry mats suppress annual herbs in pasture (Bernaldez 1991) and a similar affect is likely in natural systems, as it is documented dominating large areas of permanent grassland (Hubbard 1968). Potential for major effect on <60% of the floral strata.

12. Effect on threatened flora? Described as a ‘very serious threat to one or more vegetation formations in Victoria’ (Carr et al 1992) and as displacing native vegetation (DECC 2004). Its affect specific to threatened flora was not described.

FAUNA


13. Effect on threatened fauna? Described as a ‘very serious threat to one or more vegetation formations in Victoria’ (Carr et al 1992) and as displacing native vegetation (DECC 2004). Its affect on native flora is likely to lead to reduced habitat availability, however the possible impact on native fauna was not documented.

14. Effect on non-threatened fauna? Described as a ‘very serious threat to one or more vegetation formations in Victoria’ (Carr et al 1992) and as displacing native vegetation (DECC 2004). Its affect on native flora is likely to lead to reduced habitat availability, however the possible impact on native fauna was not documented.

15. Benefits fauna? Though described as having relatively low agricultural value (Hubbard 1968) and only nutritious to stock for part of the year (Hill et al 1996) it is likely to provide some food source to native grazing animals such as macropods.

16. Injurious to fauna? No information to suggest it would be injurious to fauna.

PEST ANIMAL


17. Food source to pests? Grazed by rabbits (Gillham 1955 in HDRA 2006). Supplies food to one serious pest.

18. Provides harbor? Not described as providing harbour to pests, and unlikely to being a relatively low growing grass (Tutin et al 1980).

AGRICULTURE


19. Impact yield? ‘…bent grass has become one of the worst pasture weeds of the high rainfall zone of Victoria. It was estimated to dominate over 1 million hectares (Siefert 1971) and, after rapid spread recently the authors consider that it now restricts production on a further 1 million hectares' (Hill et al. 1996). ‘It is not unusual for a perennial ryegrass and phalaris pasture dominated by bent grass to have its capacity to produce meat, milk or wool reduced by one third' (Lamp et al). Potential to decrease yield by >20%

20. Impact quality? No information found to suggest it would impact on the quality of agricultural yield.

21. Affect land values? Described as one of the worst pasture weeds of the high rainfall zone of Victoria (Hill et al 1996), it could affect the land value of grazing properties due to its capacity to restrict production, however, no specific reference was found in the literature.

22. Change land use? As a serious pasture weed (Hill et al 1996), and with significant effort and outlay required to renovate infested pastures (Batson 1998b) some pastures would be utilised less than others and there is potential for a downgrade of their priority land use to occur to one with less agricultural return.

23. Increase harvest costs? It is recommended that heavily infested pasture (>40%), undergo full renovation consisting of cutting, spraying, cultivating, re-sowing and fertilising (Batson 1998b), resulting in considerable time and cost outlay. In addition because stocking capacity is significantly reduced (Hill et al 1996), increased time allocation for stock movement would also be required. Potential for major increase in production costs.

24. Disease host/vector? Not found described as a host of agricultural disease or vector.



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Assessment ratings originally made by the Victorian Department of Primary Industries.
The entry of this assessment was made possible through the generous support of The Weed's Network.






Attachments:
Agrostis capillaris Potential Distribution.doc
Agrostis capillaris Present Distribution.doc
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distribution_map (8).png
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Date: 26 October 2009; 12:32:54 PM AEDT

Author Name: Jessica Mackay
Author ID: mackayj