Broad-headed Snake (Hoplocephalus bungaroides).  Photo: J. Webb

Human-related changes to natural habitats are a critical threat to biodiversity worldwide. We urgently require a better understanding of the links between habitat modification and population viability, and improved ways of restoring habitat.

The Broad-headed Snake (Hoplocephalus bungaroides) is a nocturnal, venomous snake.  It occurs on sandstone ranges around Sydney, NSW.   This area has been intensively urbanized, and populations of Broad-headed Snakes have declined dramatically since European settlement: it is now listed as Vulnerable under the IUCN Red List of Threatened Species.  Both the Broad-headed Snake and its prey are dependent on thin rock sheets for thermoregulation and shelter.

Key threatening processes for this species include:

1. The removal of exfoliated sandstone rocks and boulders for garden landscaping (including illegal collection from national parks).
2. The overgrowth of rock outcrops by encroaching vegetation (possibly due to changes in fire regimes).  
3. Loss of tree-hollows due to forestry and bushfires.
4. Illegal collection for the pet trade.

Zoos Victoria is partially funding a landscape-scale research project on the population demographics and distribution of the Broad-headed Snake, lead by Dr Rick Shine from the University of Sydney.  The project is also investigating ways of restoring Broad-headed Snake habitat.

AIMS

The research project aims to:

1. Conduct field-based tests of hypotheses about the threatening processes that have led to the decline of the Broad-headed Snake.  
2. Compare alternative approaches to habitat restoration for the Broad-headed Snake, by manipulating two critical factors (vegetation density and shelter-site availability).
3. Evaluate the ways in which abiotic factors (including fire history) affect the availability and faunal use of shelter-sites on rock outcrops.
4. Restore Broad-headed Snake habitat across its historical range, and so reverse the decline of this species.

RESULTS

In the field, more than 900 artificial rocks have been built and placed in the natural habitat of the Broad-headed Snake.  Regular monitoring shows that they are frequently used by native animals, including the Broad-headed Snake.  Artificially sun-exposed sites (created by removing shading vegetation) are also used regularly.

A major historical analysis of the changes in vegetation and a detailed phylogeographic study of the species have also been completed.  The research has also led to a greater understanding of how reptiles and invertebrates use retreat-sites such as rock crevices. 

As part of the broader conservation plan for this species, Zoos Victoria is continuing to develop improved reproductive techniques for the Broad-headed Snake.

PROJECT OUTCOMES

This research will provide a practical solution to a key threatening process that poses a serious threat to Australian ecosystems - bush-rock removal.  Novel ways of restoring degraded rock outcrops will not only benefit the Broad-headed Snake, but also the diverse assemblage of invertebrate and vertebrate species that use sandstone rocks for shelter and nest sites.

The research also contributes to conservation planning in a broader sense, because it will develop new collaborative science-based approaches to habitat restoration and species recovery.  Importantly, the methods developed will be ideally suited to implementation by local community groups to restore habitat in their local areas.

PROJECT PARTNERS

Research – University of Sydney, Australian National University, Stanford University, Forests NSW, Department of Environment & Conservation (NSW).

Captive Breeding – Zoos Victoria, Adelaide Zoo. 

FOR MORE INFORMATION

- on the conservation status of the Broad-headed Snake - click here.