3.7 Arthraxon hispidus (Thunb.) Makino
A. hispidus has a wide distribution from tropical Africa to Asia. In Australia it occurs from northern New South Wales to Taroom and the Sunshine Coast in Queensland. Currently there are no data on population size and minimal habitat information. This lack of data hampers any attempt to conserve this species. A potential threat to the survival of the species is weed invasion of the habitat.
3.7.2 Species description and identification
The genus Arthraxon is placed in the grass family (Poaceae). Arthraxon occurs in the topical and subtropical regions of the world with approximately seven species (van Welzen 1981). The genus is represented in Australia by two species. The botanical description of Arthraxon hispidus is as follows:
A slender, more or less tufted annual; stems decumbent, rooting at nodes; flowering culms ascending and up to approximately 60 cm tall, nodes hairy. Leaf sheaths with stiff spreading tubercular-based hairs; ligules short, ciliate; leaf blades narrowly ovate, apex acuminate, base cordate and stem-clasping, 2-6 cm x 0.7-1.5 cm long, glabrous or with tubercular-based hairs, margin scabrid or ciliate. Racemes 1-5, mostly 2-4 cm long, greenish to purple; sessile spikelet 4-5 mm long, lower glume as long as spikelet, approximately 9-nerved with tubercular-based bristles on nerves, upper glume scabrid on keel, lemma of lower and upper florets approximately 1/2-2/3 length of spikelet, lemma of upper floret with awn approximately 4-5 mm long; pedicellate spikelet reduced to pedicel or absent (Stanley and Ross 1983). For other descriptions and illustrations of this species refer to Vickery (1961), van Welzen (1981), Tothill and Hacker (1983) and Jacobs and Wall (1993a).
In Australia Arthraxon hispidus may be confused with Oplismenus aemulus. However, A. hispidus has digitate to subdigitate inflorescences whereas Oplismenus aemulus has racemose inflorescences.
3.7.3 Current conservation status
Arthraxon hispidus is presently listed on the schedule of the Queensland Nature Conservation Act 1992 as “vulnerable wildlife”. The species has been assigned a national conservation status of V (vulnerable) by ANZECC (1993). It is also listed on Schedule 1 Part 1 (endangered) of the Commonwealth Endangered Species Protection Act 1992.
Overseas A. hispidus has a wide distribution from tropical Africa to Asia. It has also been naturalised in Hawaii and eastern North and Central America (van Welzen 1981). In Australia it occurs between the North Coast and Northern Tablelands in New South Wales and Taroom and the Sunshine Coast in Queensland.
A. hispidus was not surveyed during the present study. Details from Queensland Herbarium specimens of A. hispidus are listed in Appendix 1.6. Fourteen specimens of A. hispidus have been collected in Queensland. It has been recorded from a number of scattered locations throughout south east Queensland. Most (11 of the 14) of the specimens were collected prior to 1960. The most recent collections have been made in 1995 on mound springs in the Taroom District and in 1997 from Carnarvon National Park in the Brigalow Belt South Biogeographical Region. It has been recorded from one State Forest (SF 274 Fty 1880) in the Kenilworth area in 1939 and from Noosa National Park in 1943 and 1946. There is an unvouchered record of A. hispidus occurring in Tewantin State Forest (SF 959 Fty 1295) at a locality with Prostanthera sp. (Mt Tinbeerwah P.R. Sharpe 4781) (C. Sandercoe pers. comm.).
In the South East Queensland Biogeographical Region, A. hispidus has been recorded growing around a freshwater spring in coastal foreshore dunes, in shaded small gullies, on creek banks and on sandy alluvium in creek beds in open forests. Tothill and Hacker (1983) reported that the species may be found growing on the fringe of rainforest or in more open, wet eucalypt forest. Habitat information from overseas records this species growing in open to shaded grasslands, wood clearings, waste areas and often as a weed in rice fields and along deserted seashores (van Welzen 1981).
3.7.6 Life history and ecology
A. hispidus is a slender inconspicuous tufted annual. It has been collected fertile from March to May and July. Jacobs and Wall (1993) report that this species flowers during summer and autumn. There is no other information available.
The lack of information about present populations levels of A. hispidus and precise habitat requirements make it difficult to assess threats to this species.
Weeds such as mist flower (Ageratina riparia), crofton weed (Ageratina adenophora) and lantana (Lantana camara) may pose a threat to this species along creeks in its forested habitats. Weeds are also a potential threat in coastal habitats. A number of naturalised exotic species have been observed near the collection site in Alexandra Bay, Noosa (Batianoff and Franks (in press)).
Leigh et al. (1984) reported that the available habitat for A. hispidus had decreased due to clearing for agriculture.
3.7.8 Management, research and conservation measures
A. hispidus requires detailed surveys to assess previously recorded localities and to collect information on habitat requirements. Such a survey would need to be carried out during the flowering period from March to July.
3.8 Bothriochloa bunyensis B.K. Simon
B. bunyensis is endemic to south east Queensland and occurs along the Great Dividing Range from Bunya Mountains to Mt Mistake. . The distribution of B. bunyensis has a range of approximately 140 km. There is currently no data on population sizes. The species appears to be fairly habitat specific growing on krasnozem soils derived from basalt in grassland or grassy woodlands at altitudes above 600 m. Potential threats to the survival of the species are weed invasion of the habitat and an inappropriate fire regime.
3.8.2 Species description and identification
The genus Bothriochloa is placed in the grass family (Poaceae). Bothriochloa is widespread in the tropical regions of the world with approximately 35 species (Mabberley 1997). In Australia the genus comprises 7 native and 2 naturalised species.
Bothriochloa bunyensis was formally described in 1982 from material collected on the Bunya Mountains, approximately 160 km north west of Brisbane (Simon 1982). The botanical description of Bothriochloa bunyensis is as follows:
Rhizomatous, erect or ascending, up to approximately 60 cm tall; culms with few branches, nodes glabrous. Leaf sheaths with few often tubercular-based hairs, usually on margin; ligules up to approximately 1 mm long; leaf blades linear, apex attenuate, up to 14 cm long , 0.15-0.35 cm wide, glabrous. Racemes 2-4, digitate or subdigitate, 5-10 cm long, rachis and pedicels with long more or less spreading whitish hairs; sessile spikelet 8-9 mm long, with densely bearded callus at base, lower glume as long as spikelet, with row of bristles on keels, upper glume slightly smaller than lower, lower floret with lemma approximately half as long as spikelet, upper floret with lemma approximately 4 mm long, with geniculate awn approximately 2 cm long, palea approximately 1 mm long; pedicellate spikelet reduced to lower glume with inrolled scabrous margin, 1-1.3 cm long (Stanley and Ross 1983). For a more detailed description refer to Simon (1982). For an illustration see Stanley and Ross (1983).
Bothriochloa bunyensis is similar to B. biloba in having bilobed awned lemmas, but it can be distinguished by having longer internodes on the rachis.
3.8.3 Current conservation status
Bothriochloa bunyensis is presently listed on the schedule of the Queensland Nature Conservation Act 1992 as “vulnerable wildlife”. The species has been assigned a national conservation status of V (vulnerable) by ANZECC (1993). It is also listed on Schedule 1 Part 2 (vulnerable) of the Commonwealth Endangered Species Protection Act 1992.
3.8.4 Distribution and abundance
B. bunyensis is endemic to south east Queensland where it occurs in the Bunya Mountains north of Dalby and on the Main Range north and south of Toowoomba. B. bunyensis was not surveyed during the present study. Details from Queensland Herbarium specimens of B. bunyensis are listed in Appendix 1.7. A total of 11 specimens of B. bunyensis have been collected. Two sites are within State Forest lands (SF 1142 Fty 1126 SA 10 and SF 510 Fty 1416), one in the Main Range National Park and the rest within Bunya Mountain National Park. The distribution of B. bunyensis has a range of approximately 140 km. There is no information available on population sizes at these sites but B. bunyensis is reported to be relatively widespread in the grasslands on the Bunya Mountains (Fensham and Fairfax 1996b).
B. bunyensis grows in relatively fertile krasnozem soils derived from basalt on upper slopes and hillcrests at altitudes of 600-1100 m. Vegetation structure is a grassland or woodland with a grassy understorey. The grasslands are mostly dominated by tussock grasses. The most common species is Poa labillardieri. Other grass species recorded in these grasslands include Chloris ventricosa, Microlaena stipoides, Bothriochloa decipiens and Echinopogon nutans. A detailed list of species present in the grasslands of the Bunya Mountains is given by Fensham and Fairfax (1996b). In woodland communities the common dominant trees are Eucalyptus pilularis, E. saligna, Allocasuarina torulosa and Eucalyptus tereticornis. The common grass species in the woodland communities were Themeda triandra, Imperata cylindrica and Poa labillardieri.
3.8.6 Life history and ecology
B. bunyensis is a perennial grass with a rhizome. The main methods of reproduction are by sexually produced seeds and by vegetative division of the rhizome. It has been recorded flowering from January to May. There is no information available about the viability or longevity of the seed.
The species appears to tolerate some habitat disturbance such as moderate levels of short-term grazing (Fensham and Fairfax 1996a). The above-ground parts of B. bunyensis are killed by fire but the species is capable of regenerating from the rhizome.
Potential changes in the species’ major habitat which is the grasslands on the Bunya Mountains threaten the long term survival of B. bunyensis. The grasslands on the Bunya Mountains are gradually disappearing due to encroachment of the woody open forest and rainforest species (Fensham and Fairfax 1996a). Fensham and Fairfax (1996b) proposed that changes in fire regimes since European settlement have led to the increased decline in the grasslands.
The invasion of exotic plant species into the grasslands is also a threat to B. bunyensis. The introduced grasses kikuyu (Pennisetum clandestinum) and African lovegrass (Eragrostis curvula) are considered to have potential to become a major problem in maintaining the natural flora of the Bunya Mountain grasslands (Fensham and Fairfax 1996b). Kikuyu has already invaded two grassland patches displacing the native grasses and has been recorded in another two grassland patches (Fensham and Fairfax 1996b). Weed species present at SF 1142 (Fty 1128) that may threaten the integrity of the habitat of B. bunyensis are Pinus sp., moth vine (Araujia sericifera) and lantana (Lantana camara) (SMP DNR)1.
3.8.8 Management, research and conservation measures
Appropriate fire management of the grassland habitat of B. bunyensis is required. However, rational management presupposes knowledge of the effect of certain decisions. Research is required to determine the optimum fire regime for B. bunyensis and the grassland communities as a whole.
Fensham and Fairfax (1996) recommended that kikuyu and African lovegrass be eradicated where possible from the grassland communities. Ongoing monitoring of the impact of weeds on the communities is required.
The grasslands on leasehold and State Forest lands are grazed by domestic stock. Although B. bunyensis appears to tolerate moderate levels of grazing by domestic stock the effect of long term grazing on the species and its habitat is unknown. Monitoring and research is required to determine the effect of grazing on the species’ ability to maintain a viable population.