Alectryon ramiflorus Photo: P Forster, Queensland Herbarium
Common name: Isis tamarind
Scientific name: Alectryon ramiflorus
Conservation status: Alectryon ramiflorus is listed as endangered in Queensland (Nature Conservation Act 1992) and nationally (Environment Protection and Biodiversity Conservation Act 1999). It is ranked as a high priority under the Department of Environment and Heritage Protection Back on Track species prioritisation framework.
A. ramiflorus is a tree that grows to about 16 m. Individual trees may be single or multi-stemmed, often branching low to the ground. It has light brown soft, flaky bark and bears clusters of individual flowers that are pale green, small and without petals. These grow on the older branches, and occasionally the younger shoots, during spring and summer. When its branches are damaged or come into contact with the soil A. ramiflorus can grow adventitious shoots.
Habitat and distribution
A. ramiflorus is known from a few small populations in south eastern Queensland. The main population exists at Cordalba Forest Reserve and consists of approximately 37 plants. Four other smaller populations of one to three plants grow on the roadside and in riverine remnants near Childers. These populations are very fragmented and surrounded by agricultural land.
In general, its habitat is confined to remnant microphyll vine forest growing on hillslopes, gullies and alluvial terraces with shallow pale brown, gravelly sandy clay soil. As these communities are fire sensitive, their distribution is affected by fire history patterns and the presence of natural fire barriers.
Life history and ecology
Little is known of the reproductive biology of A. ramiflorus. Observations suggest that it reproduces asexually by root suckering. Flowering and fruiting behaviour is variable and limited both from year to year and between plants. When flowering does occur, the flowers generally form in mid summer. The fruits of A. ramiflorus are between 5-9 mm and take three months to ripen. They contain brownish seeds half enclosed by a red aril (an appendage or covering of certain seeds).
At all locations A. ramiflorus is experiencing a number of threatening processes including:
- Loss of and fragmentation of habitat increasing its susceptibility to wind damage, insect predation and drought.
- Competition from weeds, in particular lantana, mother of millions and asparagus fern.
- Trampling of seedlings and juveniles by grazing animals.
- Inappropriate fire regimes inhibit its survival.
- Small population size and low reproductive success results in a restricted gene pool and a potential for inbreeding.
Three out of the four main invasive plant species adversely impacting on A. ramiflorus began their existence in Australia as ornamental plants in gardens. These pest plants - lantana Lantana camara, mother of millions Bryophyllum delagoense, asparagus fern spp. Asparagus africanus and A. asparagoides and guinea grass Panicum maximum - are all characterised by the ability to reproduce at an incredible rate, competing with native species by rapidly overtaking the land. Lantana even has the ability to release chemicals into the soil surrounding it so that it prevents germination by some other plant species, thereby avoiding competition.
The recovery plan for A. ramiflorus identifies objectives and actions for the species conservation. The habitat of the main population at Cordalba has been protected through the gazettal of the Cordalba State Forest, near Zillman Scientific Area. The Department of National Parks, Recreation, Sports and Racing (NPRSR) manage the area to limit any threats, principally from fire and invasive species.
Suggested management practices to recover the species include:
- Protect known habitat and populations.
- Actively manage habitat to control threatening process.
- Conduct public education on threatening processes to A. ramiflorus.
- Undertake surveys of habitat to locate new populations.
- Continue monitoring known individuals to detect the effects of management practices and allow a better understanding of the requirements of the species.
Barker M. and Barry S. 2003. National recovery plan for the Isis tamarind Alectryon ramiflorus 2003–2007. Report to Environment Australia, Canberra. Queensland Parks and Wildlife Service, Brisbane.
Department of Sustainability, Environment, Water, Populations and Communities (SEWPaC). 2012. Alectryon ramiflorus in the Species Profile and Threats Database. SEWPaC, Canberra.