Survey of threatened plant species in South East Queensland biogeographical region queensland cra/rfa steering committee survey of threatened plant species in
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3.33 sophora fraseri Benth.3.33.1 SummarySophora fraseri is restricted to south-eastern Queensland and north-eastern New South Wales where it occurs from the Casino area north to near Miriam Vale. Most collections are from the Conondale, D’Aguilar and Taylor Ranges, and the Great Dividing Range south of Toowoomba in south east Queensland. There is no information available on population sizes at these sites. It grows mostly in hilly terrain at altitudes from 60 to 660 m on shallow soils along rainforest margins in eucalypt forests or in large canopy gaps in closed forest communities. Current or perceived threats to the continued survival of S. fraseri are considered to be inappropriate fire regimes and increased competition from exotic weeds. 3.33.2 Species description and identificationThe genus Sophora is placed in the pea family (Fabaceae). Sophora is widespread throughout the tropical and temperate regions of the world with approximately 50 species (Mabberley 1997). Sophora fraseri is one of two species of Sophora recorded in Australia. Sophora fraseri Benth. was formally described in 1864 from material collected from south east Queensland and northern New South Wales (Bentham 1864). The botanical description of Sophora fraseri is as follows: Sparsely branched shrub, 1-2 m high, softly pubescent. Leaves pinnate, with a terminal leaflet; petiole 10-20 mm long; rhachis 50-150 mm long; stipels absent; leaflets 17-39, oblong to ovate, 5-25 mm long, 3-10 mm wide, apex obtuse or retuse, margins entire, pubescent; petiolules 1-2 mm long. Flowers in terminal racemes 5-13 cm long; pedicels 5-10 mm long. Calyx 4-6 mm long. Corolla 9-15 mm long, pale yellow. Pod moniliform, indehiscent, 3-10 cm long, up to 8 mm diameter, sparsely hairy, irregularly constricted between seeds; seeds 2-7, approximately 6 mm long. For other descriptions of this species refer to Thompson (1961), Stanley and Ross (1983), Hacker (1990) and Harden (1991). Sophora fraseri is a fairly distinctive species with its pinnate leaves with numerous leaflets, yellow flowers, plump seeds and pods which are very constricted between the seeds, giving the appearance of a string of beads. 3.33.3 Current conservation statusSophora fraseri 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. 3.33.4 Distribution and abundanceSophora fraseri is restricted to south-eastern Queensland and north-eastern New South Wales where it occurs from the Casino area north to near Miriam Vale. S. fraseri was not surveyed during the present study. Details from Queensland Herbarium specimens of S. fraseri are listed in Appendix 1.32. Most of the collections have been made in the coastal ranges in south east Queensland. These include the Conondale, D’Aguilar and Taylor Ranges, and the Great Dividing Range south of Toowoomba. Other Queensland records come from the Kingaroy district (1, date unknown), Kilkivan district (1,1978) and near Miriam Vale (1, 1995). S. fraseri has been recorded in Brisbane Forest Park, Main Range National Park and four State Forests (SF 494 Fty 1309, SF 792 Fty 1681, SF 809 Fty 1630 SF 1355 Fty 1526) in south east Queensland. There is no information available on population sizes at these sites. S. fraseri has been reported to be rare to common at the collection sites. Unvouchered records have been reported from Bahrs Scrub, near Beenleigh (Quinn et al. 1995), Splityard Creek, Fernvale (Forster et al. 1991), Lamington National Park (Forster et al. 1991) and Darlington Range near Mt Tamborine (D. Halford, pers. obs.) 3.33.5 HabitatS. fraseri has been reported growing in hilly terrain on hillslopes and hillcrests at altitudes from 60 to 660 m, mostly shallow stony to shaly soils, of loam to clay texture derived from sandstone or basalt rocks. It has also been noted on sandy soil on a creek bank. It grows in open eucalypt forest and semi-evergreen vine forest. Where it grows in eucalypt forest frequent tree species are Corymbia citriodora, Eucalyptus carnea, E. microcorys, E. acmenoides, E. propinqua and Lophostemon confertus. Evidence suggests that it prefers to grow along rainforest margins, in eucalypt forests in the vicinity of rainforests or in large canopy gaps in closed forest communities. 3.33.6 Life history and ecologyThere have been no studies into the biology or autecology of Sophora fraseri. S. fraseri is in cultivation at Coff Harbours (Quinn, et al. 1995). S. tomentosa is cultivated and is propagated from scarified seed (Wrigley & Fagg 1996). Sophora fraseri is a shrub with an unknown life span. The main method of reproduction is by sexually produced seeds. S. fraseri has been recorded flowering in January, April and from September to December and fruiting in January, April, July, August and November. Possible pollinators were not recorded. However, the Fabaceae family is principally a bee-pollinated family (Kalin Arroya 1981). Unlike most other species in the family Fabaceae the fruit does not appear to spilt at maturity to release seeds. The pod seems to decay slowly and the seeds finally drop to the ground. The seed of S. fraseri lack any fleshy attachment which is known in many genera in the Fabaceae. It appears that Sophora fraseri in common with most leguminous plants releases its seed from the fruit in a dormant state (Wrigley and Fagg 1996). For most hard-seeded leguminous species the dormancy is due to seed coat impermeability. The germination of such seeds involves the breaking of seed dormancy by heat or the gradual decay of the seed coat. With these seed characteristics, S. fraseri would accumulate a persistent soil seed bank during inter-fire periods. The longevity of such a soil-stored seed bank is unknown. There is no information on the response of adult plants to fire. However, S. fraseri is suspected to be killed by fire. There is no evidence to suggest that it is capable of regenerating from the rootstock. 3.33.7 ThreatsWith our limited knowledge of the species it is difficult to determine the stability of the populations and what possible threats there are to the long term existence of Sophora fraseri in the wild. Its habitat on rainforest margins is susceptible to invasion by exotic weed species such as lantana (Lantana camara). The impact that such invasions could have on S. fraseri is unknown. However, it can be assumed that weeds would change the vegetation structure and lead to increased competition for available resources. Therefore a potential threat to the species is the invasion of weed species into the habitat. Anecdotal evidence suggest that fire may play a role in the maintenance of the population levels of S. fraseri in its habitat. However the lack of ecological information about this species makes it impossible to assess what would be an appropriate level of frequency and intensity for the long term benefit of the species. If fires are too frequent, the plants will have insufficient time to build-up a soil seedbank to replace plants that are killed in the fire, and this will lead to population declines. If fires are too infrequent then adult plants will become senescent and the soil seedbank may decline to the point where it is insufficient to maintain population levels. Therefore a potential threat to the species is an inappropriate fire regime. 3.33.8 Management, research and conservation measuresPreviously recorded sites should be examined to establish their size and extent. Areas of likely habitat in the vicinity of the known populations should be searched for further occurrences. Fire intensity, frequency and seasonality are important factors in determining the long term population levels of most hard-seeded leguminous species. It is important to understand the response of Sophora fraseri to differing fire regimes in its habitat. Research is required into the fire ecology, reproduction biology and the population dynamics of the species. |