Contributed by Stephanie Lymburner, Committee Member, Big Scrub Landcare.
The Richmond River Birdwing Butterfly was a reasonably common species when the Big Scrub rainforest once covered this region; its range extended from Grafton to the subtropical rainforest around Noosa in Queensland.
This range has been severely modified due to extensive habitat destruction for timber, dairy farming, habitation pressures and urban development over the past century.
During the 1960’s and 70’s there was a realisation that the numbers of butterflies had dropped to critical levels.
Programs were introduced in both New South Wales and Queensland to encourage rainforest remnant owners and householders to plant the host species plant, the Richmond River Birdwing Butterfly Vine (Pararistolochia pravenosa).
Specialist nurseries were set up in these areas to assist in broadening the range of the plants and butterflies and to raise community awareness of the decline and vulnerability of both vine and butterfly.
During this period, unfortunately, some other nurseries also propagated and sold the Dutchman’s Pipe – an unusual, attractive flowering vine with ‘kidney shaped’ soft pale green leaves and very large distinctive unusually shaped maroon flowers; the fruit is a ‘parachute like’ brown capsule parachute with numerous small brown seeds.
The vine has a very pungent unpleasant smell when cut, corky ridged stems that, if hand pulled, have a tendency to snap off at ground level on young plants and runners.
The ‘cut scrape and paint’ method of weed control has proved the most effective in small outbreaks, requiring regular follow up as it has large underground tubers that survive for a number of years, resprouting after heavy rain.
While Birdwing Butterfly Vine is of the same genus the Dutchman’s Pipe (Aristolochia elegans) the females are attracted to Dutchman’s Pipe plants, laying their eggs on the leaves, that are toxic to the emerging Birdwing Butterfly caterpillars!