Study reveals rich but vulnerable picture of Australia's island frogs and fish

A first database has been compiled of the frog and freshwater fish species on hundreds of Australian islands.

It was developed at The University of Queensland to help target conservation efforts across Australia’s 9,300 islands using information from multiple sources, including the Atlas of Living Australia platform and thousands of published wildlife surveys.

Researcher Samuel Ho from UQ’s School of the Environment said the study found that 536 Australian islands had freshwater habitats, ranging from deep lakes to wetlands and seasonal creeks.

“Across those islands, there are 102 amphibian species from 6 different families with a wide range of sizes and behaviours,” Mr Ho said.

“We recorded 95 freshwater fish species, some of which are endemic to a particular island along with 9 non-native species.”

The project looked at the environmental factors that influence the presence of frog and fish species on islands, their threat levels and risk of extinction.

“Frogs were more common on islands close to the mainland with humid climates and low temperature variability while the number of freshwater fish species was higher on larger islands,” Mr Ho said.

“Within the database, 14 of the recorded species are known to be threatened, most of them freshwater fish.

“While only 2.5 per cent of the Earth’s surface water is freshwater, these habitats are highly biodiverse.

“Freshwater ecosystems on islands are particularly vulnerable to human-induced threats such as habitat destruction and rapid climate change, and they are often understudied.

“We hope this database will help prioritise conservation efforts and pinpoint Australian islands that need more comprehensive surveys.” 

The project is part of a wider long-term study of Australia’s islands and their conservation by UQ’s Biodiversity Research Group, led by Professor Salit Kark.

Professor Kark said the research team had developed a database of threatened plant and animal species for all of Australia’s 9,300 islands.

“Islands are hotspots for species that do not occur anywhere else on Earth,” she said.

“But a combination of their isolation and human activity can lead to species becoming threatened on islands and indeed many extinctions have occurred on islands globally.

“This new database helps us better understand the patterns and processes at play on islands to help direct future conservation and management actions for these valuable and sensitive ecosystems, including highly threatened groups such as amphibians and freshwater fish.

“We hope the database will be used by local island communities, managers, researchers and other organisations to support island communities and biodiversity.”

The Australian islands amphibian and freshwater fish database is open access.

The research has been published in Diversity and Distributions.