Isis tamarind
Common name: Isis tamarind
Scientific name: Alectryon ramiflorus
Conservation status: The Isis tamarind is listed as endangered both in Queensland (Nature Conservation Act 1992) and the Commonwealth (Environment Protection and Biodiversity Conservation Act 1999).
Description: The Isis tamarind is a tree that grows to about 16m. It is 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.
Not a great deal is known about its reproductive biology. However, its flowering and fruiting behaviour is very limited and highly variable, both from year to year and between plants.
Distribution and habitat: The Isis tamarind has very few populations and all are considered to be critical habitat for its conservation. 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 vineforest growing on hillslopes, gullies and alluvial terraces with red loam or sandy clay loam soils. As these communities are fire sensitive, their distribution is affected by fire history patterns and the presence of natural fire barriers.
Threatening processes: The Isis tamarind is experiencing a number of threatening processes. Further loss of habitat and continued fragmentation of existing patches are increasing the susceptibility of the habitat and individual A. ramiflorus individuals to wind damage, insect predation and drought. Grazing and trampling of seedlings and juveniles occurs by both introduced and native animals such as cattle and wallabies. Also inhibiting its survival are inappropriate fire regimes and road maintainence activities as well as competition from invasive plants, particularly lantana, asparagus fern, mother of millions and guinea grass.
Be Alert, Be Aware…
Three out of the four main invasive plant species adversely impacting on the Isis tamarind began their existence in Australia as ornamental plants in gardens. These pest plants - lantana (Lantana camara), mother of millions (Bryophyllum delagoense) and asparagus fern spp. (Asparagus africanus, A. asparagoides, densiflorus and A. setaceus) 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 that prevent germination by some other plant species, thereby avoiding competition!These factors, coupled with the Isis tamarind's low population size, low rates of natural regeneration and restricted habitat availability have resulted in its current threatened status.
Recovery actions: A recovery plan exists for the Isis tamarind that identifies objectives and actions for its conservation. The habitat of the main population at Cordalba has been protected through the gazettal of the Zillman Scientific Area. Queensland Parks and Wildlife Service manage the area to limit any threats, principally from fire and invasive species.
The current populations are being monitored, while at the same time propagation is occurring and further study is being done, both to better understand the requirements of the species as well as in an effort to locate new populations. Public education and liaison with local land holders is also occurring.
Further information:
Recovery Plan for the Isis Tamarind (Alectryon ramiflorus)2003-2007
Last updated: 31 August 2005