Border Ranges lined fern
Scientific name: Antrophyum austroqueenslandicum D.L Jones
Status: Critically Endangered
The Border Ranges lined fern, also known as the Lamington ox tongue fern, has small fronds that have a prominent, narrow winged stripe 2–7cm long. This species is unlikely to be confused with other ferns due to the oblanceolate shape of the fronds and the diagnostic sporangia pattern following veins on the underside of fertile adult fronds.
Habitat and distribution
The Border Ranges lined fern only occurs within restricted microhabitats within lowland subtropical rainforest, specifically as a lithophyte on andesite boulders and rarely as an epiphyte on lower parts of tree trunks. It is thought that the location of boulders with a small stream at its foot, but close to a larger stream that floods to high levels, is critical for its survival.
It was first discovered in 1983 when a small population of about 5 individuals of an unnamed fern was found in Woonoongoora (Lamington National Park), Queensland. It was subsequently considered extinct but then rediscovered in 2015 at two sites in New South Wales: near Tyalgum in the Border Ranges and Mount Jerusalem National Park. It was also then found at another site in the Huonbrook Valley in 2020. In surveys conducted in 2022 across the three known sites, a total of 275 individuals were counted.
Life history and behaviour
Little is known about the lifespan of the Border Ranges lined fern. However, it is estimated to be less than 30 years with sexual maturity between 3–10 years, more rarely up to 15 years. The ecology of this fern is also not well known but it appears to require a highly specific microclimate and microhabitat with constant high humidity and air movement.
The following threats have contributed to the decline of the Border Ranges lined fern.
- A reduction in the rainforest habitat for the species due to past logging and land clearing. The habitat conversion due to agriculture has caused changes to hydrology and the introduction and spread of weeds
- Infrastructure maintenance near populations.
- Natural disturbances such as fire, floods and landslides can damage existing habitat and wash away plants. Individuals have been documented to be lost during flood events. Fire mapping in December 2019 found that this species had not been adversely affected by the 2019–2020 bushfires.
- Weed invasion. Lantana camara (Lantana) and other weeds negatively impact the fern by changing the light environment, competing for available habitat and nutrients, and potentially smothering ferns.
- Illegal collection remains a constant threat to the population and is considered to be the cause of extinction of the Woonoongoora population.
A Recovery Action Plan is expected to be finalised and published in early in 2023 and will include actions for the reestablishment of the species in Queensland.
Existing conservation measures
No previous Recovery Plans exist for this species, however a Conservation Advice was adopted, effective from 2020. The Border Ranges lined fern subpopulation within Mount Jerusalem National Park is protected and managed. The subpopulation near Tyalgum is on private land, where land management and weed control is undertaken by the landholders. The subpopulation at Upper Huonbrook is on private property subject to an in-perpetuity conservation covenant with the Nature Conservation Trust of New South Wales.
- Threatened Species Scientific Committee (2020). Conservation Advice Antrophyum austroqueenslandicum Lamington Ox Tongue Fern. Canberra: Department of Agriculture, Water and the Environment.
- Jones DL (1998) Vitta Vol. 48: Ferns, Gymnosperms and Allied (Eds AE Orchard, PM McCarthy) pp. 292. (ABRS/CSIRO Australia).
- Silcock, J., Collingwood, T., Llorens, T., Fensham R. 2021. Action Plan for Australia's Imperilled Plants. NESP Threatened Species Recovery Hub, Brisbane.