Kroombit Threatened Frogs

Summary of Queensland Frog Society’s Kroombit Threatened Frogs Community Sustainability Action Grant Project

Situated 70 km southwest of Gladstone, Kroombit Tops National Park is home to the critically endangered Kroombit tinkerfrog and Kroombit treefrog, both of which are known only from areas of wet forest habitat at Kroombit Tops.

Over the past four years – with support from the Queensland Government’s Community Sustainability Action (CSA) Grant Program – Queensland Frog Society (QFS) volunteers have been actively involved in efforts to recover these critically endangered species.

Activities funded by the CSA Grant Program, undertaken by QFS in collaboration with the Queensland Parks and Wildlife Service (QPWS) during this time, included:

• Eight week-long surveys targeting threatened frog species (once in spring/summer and once in summer/autumn during the 2019/20, 2020/21, 2021/22, and 2022/23 wet seasons).
• Annual collation and analysis of data from acoustic recorders deployed between spring and summer surveys for each year of surveys.
• Construction of 0.2 km of pig exclusion fencing around a key Kroombit tinkerfrog breeding site.

The results of surveys and monitoring over the past four wet seasons (and previous surveys/monitoring undertaken by QPWS) show a significant and continuing decline in the abundance and distribution of the Kroombit tinkerfrog since the early 2000s, with the species now likely confined to two rainforest patches with a total area of about 70 ha.

Survey and acoustic monitoring data from QFS monitoring/surveys show numbers of this species remain critically low, with the total number of adult animals remaining in the wild likely less than 250 individuals.

Observations of pig damage (diggings, rooting, and wallows) made during surveys show that pigs remain a significant threat to the Kroombit tinkerfrog, and ongoing control/management is important for securing the survival of the species.

Data from surveys and monitoring undertaken by QFS demonstrated the persistence of the Kroombit treefrog at historical presence sites on plateau streams in the east of Kroombit Tops. Numbers of this species, however, appear lower overall compared with the late 1990s and 2000s.

Data collected by QFS volunteers for this project have helped to clarify the current status of the critically endangered Kroombit tinkerfrog and Kroombit treefrog and also provided information on weed spread and habitat disturbance/destruction by feral pigs being used to guide management of these threats at Kroombit Tops NP.

Information from surveys and monitoring conducted by QFS volunteers has also helped inform the translocation of captive-bred Kroombit tinkerfrogs to the wild (part of ongoing efforts to recover the species by QPWS and Currumbin Wildlife Sanctuary). Acoustic monitoring data collected as part of this project will serve as a baseline for assessing the effectiveness or otherwise of these translocations.

While CSA Grant funding of QFS surveys and monitoring of the Kroombit tinkerfrog and Kroombit treefrog has come to an end, QFS will continue to support efforts to recover the Kroombit tinkerfrog by providing acoustic recorders (purchased using CSA grant funds) to monitor changes in tinker frog numbers at release sites.