CSGL24004 – Protecting Critical Weight Range Fauna in Torbay Catchment

Project Description:

The Torbay Catchment, and its greater surroundings, are known to host four EPBC-listed species, which are native Australian species currently protected under the Environment Protection and Biodiversity Conservation Act 1999 due to their threatened status, and a number of critical weight range (CWR) fauna species, which are Australian mammals with body masses falling between 35g and 5.5kg. The four EPBC-listed species include the Western Ringtail Possum (Pseudocheirus peregrinus occidentalis), the Baudin’s Black Cockatoo (Calyptorhynchus baudinii), the Forest Red Trailed Black Cockatoo (Calyptorhynchus banksia) and the Carnaby’s Black Cockatoo (Calyptorhynchus latiriostris). A number of CWR faunal species are found within the Torbay Catchment, including Rakali (Hydromys chrysogaster), Brush-tailed Phascogale (Phascogale tapoatafa), Quenda (Isoodon fusciventer) and more.

The ”Critical Weight Ratio (CWR)” hypothesis suggests that Australian mammals that fall within a specific range of body masses (35 grams to 5.5 kilograms) have been disproportionately susceptible to extinction and significant decline following European colonization.

Faunal attrition has been linked to feral predation, CWR, environmental changes, and low rainfall. As a climate refugia, or an area that has been relatively buffered from the effects of climate change allowing for certain species to persist in the face of ever-changing environmental conditions, facing WA’s driest year on record, managing threats to fauna and habitats is crucial to ensure the survival of these many threatened species.

Project Objectives:

This project will:

  • We will address knowledge gaps through the use of population monitoring, ground surveys, and data analysis to broaden our understanding of EPBC and CWR species populations within the Torbay Catchment. The Torbay Catchment Group will continue our ongoing population monitoring of the critically endangered Western Ringtail Possum by carrying out transect surveys within West Cape Howe National Park and Cosy Corner, while also commencing with new eDNA water sampling and transect surveys to gauge the presence/absence of the elusive Rakali throughout the waterways in Torbay. Bridging these knowledge gaps will allow us the ability to better target future conservation efforts towards our target species by building our understanding of their behavioural patterns.
  • We will reduce feral predators within our catchment through baiting, shooting, and trapping. Feral predators are known to have directly influence Australian native species being one of the main causes of significant declines and extinctions. We will be targeting control efforts throughout our catchment to decrease the total number of feral predators, which will hopefully have a positive impact on a number of native species.
  • Finally, we will be running a number of events and workshops over the course of this project to raise awareness surrounding several key focuses including Rakali, Frogs, Wetland Habitat, Feral Animal Management and more. We will also be providing opportunities for volunteers and members of our catchment to develop their skill sets when it comes to environmental field work, by running training sessions/workshops discussing how we as a catchment group carry out population monitoring and field work.

This project is supported by funding from the Western Australian Government’s State NRM Program.