Button Wrinklewort (Rutidosis leptorhynchoides)
A native daisy, the Button Wrinklewort (Rutidosis leptorhynchoides) was declared an endangered species in the ACT in 1996. It is listed as endangered internationally, nationally and in NSW and Victoria. The ACT has some of the largest and most viable remaining populations, with their conservation likely to be critical to the survival of the species.
All populations greater than 10 plants and their habitat are critical to the survival of the species. Nationally, 29 known populations occupy a total of about 13.4 hectares, with a further 11 populations having become extinct in recent times.
In the ACT region, the Button Wrinklewort occurs at 11 sites in the suburbs just south of Lake Burley Griffin, the Majura Valley, the Jerrabomberra Valley and at Crace Nature Reserve. The largest population, at Stirling Park, is about 49,000 plants, but most sites are less than 5000 and some less than 100.
It is found on the margins of stands of Yellow Box/Red Gum Grassy Woodland with a ground layer of various native grasses and other forbs, in secondary grasslands derived from that community, and in Natural Temperate Grassland. It prefers an open habitat and shallow stony red-brown clay loams.
In spring and summer the Button Wrinklewort produces multiple flowering stems 20–35 cm tall. The hemispherical yellow flowers appear between December and April. The stems then die back in late summer and autumn. New leaves appear at the base of the plant in early winter.
It is likely the species was once widespread but declined as grassland and woodland habitat was converted to grazing and urban development. Weed invasion poses a risk at many sites, as does shading and competition from eucalypt and shrub regeneration.
Small sites are more vulnerable to incidental damage associated with human activity, such as roadside maintenance, dumping of waste, inappropriate mowing and parking of vehicles. The effect of fire on populations is still not confirmed, but appears to be related to the time and intensity of the burn.
Erosion of genetic diversity and a reduction in fertilisation success due to genetic self-incompatibility in the species may compromise both short and long-term population viability, particularly in populations of fewer than 200 plants.
More frequent drought in south-eastern Australia is one of the predicted effects of climate change. This may adversely affect some populations, particularly through reduced survival or newly germinated plants due to dry conditions and/or increasing intervals between rain events.
Through the Button Wrinklewort Action Plan (2017), which updates the 2006 plan, and the ACT Native Grassland Conservation Strategy (2017), the ACT Government proposes to continue to maintain the conditions, in the long term, that encourage a viable, wild population.
There have been several attempts to establish new populations of Button Wrinklewort in the ACT. Only one has been successful, but recent research has found methods that may improve this outcome, including the development of a computer model that can be used to predict population trends and the effects of changes in demographic parameters.
Long-term conservation depends on keeping native grassy habitat in suitable condition, and the ACT Government will continue to liaise with the National Capital Authority and Department of Defence to encourage continued protection and management of populations on their land.
Conservation actions aim to help land managers maintain the sites for the best conditions for the Button Wrinklewort. They will focus on protecting larger and medium-sized populations as a cluster of sites. Small populations will be protected from unintended impacts and efforts directed to increasing their size, and hence viability, to 200 or more plants.
The species and its habitat will be managed to maintain the potential for evolutionary development in the wild. Management includes removing weeds, protecting populations from shade and competition from the regeneration of native trees and shrubs where necessary, and using controlled burns to open the sites. ParkCare groups have been important in helping manage several sites.
Long-term viability of populations will be encouraged through management of adjacent grassland to increase habitat area, and by establishing new populations.
Knowledge of the distribution and abundance of the species in the ACT will be refined from data collected during surveys for other plant species or from opportunistic observations by naturalists and other interested persons.
For an improved understanding of the species’ ecology, habitat and threats, the ACT Government will continue to collaborate with other states, universities, CSIRO, Australian National Botanic Gardens, other research institutions and non-government organisations such as Greening Australia.
- Button Wrinklewort Action Plan, 2017
- The ACT Native Grassland Conservation Strategy and Action Plans, 2017
- See the plant’s distribution at the ACTmapi website.
- Australian Government’s Conservation Advice