Re-establishing the endangered grassland herb Trioncinia retroflexa (Asteraceae)

Abstract

The endangered perennial herb Trioncinia retroflexa was re-established within suitable grassland habitat in central Queensland. The trial included direct seeding and transplanting nursery-grown seedlings during the wet season. Successful establishment may be contingent on moist surface soils at the time of planting and the maintenance of this moisture by adequate follow-up rain in the month after planting. Five years after planting there were a total of 22 mature plants and eight infertile plants within two small areas of the re-establishment trial. The established plants are now reproducing and several generations of seedlings have become established. Topographic position (ridges or swales) and post-planting fires had no significant effect on the density of the re-established population. There have been substantial fluctuations in the re-established population in concert with seasonal rainfall patterns. A patchy and small fe-established population could be expected given the patchiness of the largest natural population and the relatively low rainfall of the introduction site.