Phalaris coerulescens Desf

Title: Phalaris coerulescens Desf

Scientific Name:

Phalaris coerulescens Desf

Common Names:

blue canary grass, sunol grass

Image via GBIF

Distribution:

Distribution map via GBIF

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? No information in the literature outlines the germination requirements for this grass.

2. Establishment requirements? Phalaris spp. grasses are able to establish on a wide range of soil types including soils in low rainfall areas and poorly drained soils subject to occasional inundation (Anderton et al., 1999). P. coerulescens is commonly noted in the literature to establish in moist well drained soils (Colegate et al, 1999) and living in slightly wet soils (Herbario Virtual). In Victoria, it is associated with native and exotic grasses on disused pasture (Walsh and Entwisle 1994). For successful establishment the species seems to primarily require moist soils but may have the capacity to establish in drier areas. The ability to grow in disused pasture suggests that it can establish under moderate cover.

3. How much disturbance is required? When the species was first found and identified in Australia it was associated with native and exotic grasses on disused pastures (Walsh and Entwisle, 1994). In its native, Mediterranean Europe, it is usually found along rivers, lakes and streams or in damp depressions (McLaren and Turner, 1999; Colegate et al., 1999). It has also been found to establish in waste areas, path and road-sides, disturbed zones, edges of cultivated fields, cultivated ground/fields, along field boarders and mainly on clay soils with periodic inundation (Baldini, 1995; HerbarioVirtual; Tutin et al., 1980). It is noted as a minor component of pastures in several areas of Victoria and is reported to be present in NSW and NT (Blackstock). The species is able to establish in relatively disturbed areas and has been more commonly attributed to establishing in pasture, not cultivated fields in Australia.

GROWTH / COMPETITIVE

4. Life form? It is a hemicryptophyte grass belonging to the family Poaeace/Gramineae (Baldini, 1995; GRIN, Herbario virtual). The adult plants grow to heights of 30-150 cm tall (Davis, 1985; McLaren and Turner, 1999).

5. Allelopathic properties? After all the literature reviewed there was no reference to any allelopathy properties relating to the species. However little information exists on this species.

6. Tolerates herb pressure? Grazed by horses, sheep and cattle (Colegate et al, 1999). Arevalo et al (2007) conducted a study in pastures in its native Tenerife under a goat grazing management system found that P. coerulescens was the dominant species. It is noted as a minor component of pastures in several areas of Victoria and is reported to be present in NSW and NT (Blackstock). It is a pasture grass that is able to persist within moderate grazing systems.

7. Normal growth rate? The plant undergoes rapid germination with vigorous seed growth and high production in its seedling year (Anderton et al, 1999, Colegate et al, 1999). It has been noted to be similar to the growth rate of native and exotic grasses on disused pastures (Walsh and Entwisle 1994). It is a rapid growing, competitive species with other perennial grasses.

8. Stress tolerance to frost, drought, w/logg, sal. etc? The plant establishes in slightly wet soils near waterways (Under Control, 1999; Baldini, 1995, McLaren and Turner, 1999). Furthermore the genus is likened to establish in areas that receive regular inundation (Anderton et al, 1999). Therefore the species may have a degree of tolerance to waterlogging. No information on other tolerances was found.

REPRODUCTION

9. Reproductive system? The grass reproduces by seed. Seeds are 2-4 mm long and 0.7-1.4 mm wide (McLaren and Turner, 1999; Undercontrol, 1999). Plants are bisexual and flowers from September to December. The Phalaris genera has been described as being bisexual with bisexual spikelet with hermaphrodite florets with the spikelets of sexually distinct forms on the same plant (rarely), or all alike in sexuality (Watson and Dallwitz, 1985). The species is sexual with either cross and/or self pollination.

10. Number of propagules produced? 6-8 fertile spikelets falling from panicle when mature (Davis, 1985) fruit is dry seed-like fruit (grain). However it is difficult to determine from the available literature on the species biology on how many propagules the grass produces.

11. Propagule longevity? No information was found in the literature.

12. Reproductive period? Annual herb. Produces propagules for only one year. (Parsons and Cuthbertson, 2001)

13. Time to reproductive maturity? After all of the literature reviewed no information time to reproductive maturity of the grass was found.

DISPERSAL

14. Number of mechanisms? Escape from cultivation in the Armidale area in Australia (Harden, 1993). Possible introduction into Victoria as an accidental contaminant of stock fodder (McLaren and Turner, 1999). Suggesting that it is likely that the seed has been dispersed by humans possibly unintentionally such as, through the transport of hay containing seeds from one property to another (Bladstock). Also dispersal through vehicles may also be implicated. Other dispersal mechanisms of the species have not been discussed in the literature reviewed.

15. How far do they disperse? No information in the literature that explains seed dispersal of this species.

Impact Assessment

RECREATION

1. Restrict human access? The grass grows in tufts or clumps with tubers at base of stem generally above ground (Herbarium usu). The adult plant grows to heights of 30-150 cm tall (Davis, 1985; McLaren and Turner, 1999). The plant may not prevent human access but may be of a low nuisance value.

2. Reduce tourism? The adult plant grows to heights of 30-150 cm tall (Davis, 1985; McLaren and Turner, 1999). Therefore infestations of the species may have minor effects to aesthetics and most recreational activities will not be inhibited. The plants toxicity to horses (Bourke et al, 2003) may reduce horse related recreation.

3. Injurious to people? Of the literature consulted (Harden, G. 1993; McLaren, and Turner, 1999; Muyt A., 2001) none mentioned the grass being injurious to humans. Not known to be injurious to people, no prickles, spines or toxins present.

4. Damage to cultural sites? Presence of the plant is quite noticeable during flowering. It would have a moderate negative visual effect. (Parsons and Cuthbertson, 2001)

ABIOTIC

5. Impact flow? Despite the grass being often found near streams and lakes the species is terrestrial (Colgate et al, 1999) and is not known to invade the waterbody or streambed.

6. Impact water quality? Despite the grass being often found near streams and lakes the species is terrestrial (Colgate et al, 1999) and is not known to invade or have any effect on the waterbody or streambed. No measurable effect on water quality.

7. Increase soil erosion? The grass grows in tufts or clumps (Herbarium usu). The adult plants grow to heights of 30-150 cm tall (Davis, 1985; McLaren and Turner, 1999). It is a species that commonly invades already disturbed eroded areas such as disturbed pastures edges of cultivated fields and roadsides (Baldini, 1995; Herbario Virtual; Tutin et al, 1980).

Existing with other native and exotic grasses (Walsh and Entwisle 1994). It has the potential to dominate grasslands and pastures as experienced in Mediterranean grasslands (Troumbis et al, 2000). Therefore it is likely that the species can replace and displace exiting species of a similar life form and in the highly disturbed areas it colonises may contribute to soil stability.

8. Reduce biomass? Other Phalaris species (such as P. acquatica and P. paradoxa) are known to increase the biomass and fuel load of introduced areas. On the basis that P. coerulescens is closely related with both particularly P. paradoxa (Bourke et al, 2003; Davis, 1985; Richardson et al, 2006) it may have the capacity to displace other species and dominate infested areas, in turn increasing fuel load and biomass.

9. Change fire regime? Other Phalaris species are known to have a higher fuel load than the original native grasses (CFA, 2004). Phalaris species have a fuel load of 27.5 tonnes/hectare compared to 2.9 t/h for kangaroo grass (CFA, 2004). On this basis, dense stands of P.coerulescens increase biomass and fuel hazard and are likely to have a minor affect more so on fire intensity than frequency.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC= Plains Grassy Woodland (E); CMA=Port Phillip and Westernport; Bioregion= Victorian Volcanic Plains; VH Climate potential. Reported to grow in association with native and exotic grasses (Walsh and Entwisle 1994) some displacement and possible dominance due to it being a persistence and productive grass species (Anderton et al, 1999). It has the potential to dominate grasslands and pastures as experienced in Mediterranean grasslands (Troumbis et al, 2000).

10(b) Impact on medium value EVC? EVC= Grassy Dry Forest (D); CMA= Port Phillip and Westernport; Bioregion= Victorian Volcanic Plain; VH = Climate potential. Reported to grow in association with native and exotic grasses (Walsh and Entwisle 1994) some displacement and possible dominance due to it being a persistence and productive grass species (Anderton et al, 1999). It has the potential to dominate grasslands and pastures as experienced in Mediterranean grasslands (Troumbis et al, 2000).

10(c) Impact on low value EVC? EVC= Wet Forest (LC); CMA= Glenelg Hopkins; Bioregion= Glenelg Plain; MED Climate potential. Reported to grow in association with native and exotic grasses (Walsh and Entwisle 1994) in moist well drained soils (Colegate et al, 1999). Some displacement and possible dominance due to it being a persistence and productive grass species (Anderton et al, 1999). It has the potential to dominate grasslands and pastures as experienced in Mediterranean grasslands (Troumbis et al, 2000).

11. Impact on structure? Growing up to 150 cm affecting mainly the lower stratum and may have a minimal affect on the lower end of the mid stratum. Reported to be a competitive species therefore associated with other grass species (Under Control, 1999). The species has been found to be a persistence and productive grass species (Anderton et al, 1999). It has the potential to dominate grasslands and pastures as experienced in Mediterranean grasslands (Troumbis et al, 2000), suggesting that it can become a dominant species of the lower strata.

12. Effect on threatened flora? The impact on threatened flora is indeterminable.

FAUNAu

13. Effect on threatened fauna? The impact on threatened fauna is indeterminable.

14. Effect on non-threatened fauna? Strong circumstantial evidence suggests that P.coerulescens is fatal to horses (Bourke et al, 2003). Sheep, goat and cattle seem to be unaffected by the species (Bourke et al, 2003). It can provide an alternate food source for livestock similar to other cultivated Phalaris species (Watson et al, 2000). It contains six alkaloids that may make it unpalatable to natives. No reports of toxicity to natives. The species can have a minor impact on structure and habitat and availability of food resources.

15. Benefits fauna? May provide an alternate, reliable food source for livestock or native animals. Particularly because it can tolerate herb pressure (Colegate et al, 1999). Areas of high infestations in combination with other grass species may provide cover for native animals (e.g. bandicoots).

16. Injurious to fauna? Contains toxic alkaloids poisonous to horses (Bourke et al, 2003). Alkaloids may render it unpalatable to native fauna. Found to have little or no effect on cattle and sheep but found that horses are most susceptible to poisoning once plant has been ingested due to the presence in P.coerulescens of methylated tryptamine and related beta-carboline alkaloids (Bourke et al, 2003). At the moment strong circumstantial evidence suggests that these deaths are associated with P. coerulescens. Toxicity to horses may suggest that it can have the same effect on native fauna however no reported effects on native fauna.

PEST ANIMAL

17. Food source to pests? Can be a food source to goats. In its native range Arevalo et al. (2007) studied P.coerulescens dominated pastures under a goat grazing system.

18. Provides harbor? Growing to heights of up to 150 cm (Davis, 1985; McLaren and Turner, 1999) large, dense infestations may provide temporary harbour to major pest specie such as rabbits. However nothing has been documented in the literature.

AGRICULTURE

19. Impact yield? P. coerulescens in its native range it is a known weed of cultivated fields (Baldini, 1995). The closely related P. paradoxa is a serious weed of cereal crops (Bourke et al, 2003). According to Global Compendium of Weeds it is considered an agricultural weed. In Portugal P. coerulescens amongst other Phalaris species infest a wide variety of crops but principally cereals and uncropped land (Costa, 1981). However in Australia it has not yet been documented as a weed of cultivated fields. Due to the similarities P.coerulescens shares with P. paradoxa (Bourke et al., 2003; Davis, 1985) it is possible that P. coerulescens can potentially invade cultivated fields (pers comm. David McLaren) however the impact is not yet known.

20. Impact quality? A known weed of cultivated pastures. However there is no information in the literature that indicates how this species impacts on the quality of produce.

21. Affect land values? A known weed of cultivated pastures (Baldini, 1995) however there is no information in the literature describing how this species could affect land values.

22. Change land use? Due to toxicity to horses (Bourke et al, 2003) can change grazing system of pastures and subsequently land use.

23. Increase harvest costs? Currently not a documented weed of cultivated pastures in Australia. There is no evidence that suggests that this species currently requires a control regime outside normal weed management.

24. Disease host/vector? Benigno and Brook (1972) reported P. coerulescens as a host for the Cocksfoot Mottle Virus. They are viruses transmitted by beetles prevalent in the Gramineae. Its closely related species P. paradoxa is susceptible to a number of viruses including barley stripe mosaic hordeivirus, maize dwarf mosaic potyvirus, and sugarcane mosaic potyvirus (Brunt et al, 1996). Diseases identified and prevalent in Phalaris species, that may affect P. coerulescens, include Ergot and Stem rust, Grass downy mildew fungus, wheat eye spot fungus, powdery mildew and a new disease identified in Victoria, Stagonospora foliicola (Watson and Bourke, 2000).

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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 Nature's Weeding Centre.

Attachments:

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referenced by (1)

wra825: Common Name - B (via blue canary grass)

Article: wra8448 (permalink)
Categories: :wra:p, :wra:inv1, :wra:invm, :wra:invmh, :wra:inv3, :wra:inv4, :wra:inv5, :wra:inv6, :wra:inv7, :wra:inv8, :wra:inv9, :wra:invml, :wra:inv10, :wra:inv11, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:impml, :wra:imp2, :wra:impmh, :wra:imp3, :wra:impl, :wra:imp4, :wra:imp5, :wra:imp6, :wra:imp7, :wra:imp8, :wra:imp9, :wra:imp10a, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imp12, :wra:imp13, :wra:imp14, :wra:imp15, :wra:imp16, :wra:impm, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 12 February 2023; 1:04:05 PM AEDT

Author Name: David Low
Author ID: adminDavid