Conservation

Ecological effects of roads and traffic on flora, fauna and ecological processes

R. van der Ree

In fragmented landscapes, wildlife need to move between habitat patches to exchange genes, increase the size of declining populations and recolonise areas were animals have become extinct. For many species, roads may act as barriers that prevent or limit dispersal, potentially isolating some habitats and populations. The disruption to normal movement patterns and behaviour may increase the risk of mortality, as well as threatening populations and species with extinction. Roads are clearly critical to the social and economic health of all Australians. However, conflict often arises in rural and regional Australia where highways dissect relatively intact habitat (e.g. through National Park or wilderness area) or in areas where the cumulative effect of numerous relatively minor roads (e.g. in areas of high road density such as urban or urban-rural fringe areas) exceeds threshold levels.

Dr Rodney van der Ree with colleagues Prof Mark Burgman, Dr Paul Sunnucks, and Dr Andrea Taylor have recently received funding from the Australian Research Council to study the ecological effects of roads and traffic on wildlife. In collaboration with VicRoads, they aim to quantify the extent to which major highways in regional Australia form a barrier to the movement of different groups or species of wildlife that include vertebrates and invertebrates. They will then test the effectiveness of measures that may facilitate safe crossing by measuring their rate of use, reduction in road kill and increase in population viability. This information can then be used to construct major roads that are more environmentally sustainable.

Selected road ecology references

Revegetation

L. Hynes, M. McDonnell and N. Williams

ARCUE students and staff have worked cooperatively with the Merri Creek Management Committee (MCMC) to determine the efficacy of their riparian revegetation efforts over the past decade. The objectives of the project were to develop techniques to assess the success of riparian revegetation projects and use them to evaluate the restoration sites created and maintained by the Merri Creek Management Committee (MCMC). The results of the study suggest that changes in planting design could be made for existing and future restoration projects to better replicate remnant vegetation communities. Most revegetation teams plant indigenous species on their sites, however they also need to position them appropriately in the landscape so that communities faithfully represent remnant habitats. This will also help to ensure the survival of individual plants. This project demonstrated that the application of sound ecological knowledge and techniques to restoration projects could save money and resources while providing a more successful outcome.

Revegetation on bank of Merri Creek

Above: Revegetation along a bank of the Merri Creek, Melbourne.

Spread of Non-indigenous Plants

B. Hamilton and M. McDonnell

As part of a research partnership program with Parks Victoria, students and staff at ARCUE examined the ecology of Spartina anglica in south-eastern Victoria. Spartina anglica is an introduced threatening weed that has the ability to spread rapidly choking estuaries and bays and causing sediment accretion, channelization and altered hydrology. An assessment of the threat that Spartina poses to the mudflats of the Bass River region of Western Port Bay was conducted by determining the identity of the species, its current distribution and potential distribution. Spartina anglica has spread approximately 3 km either side of the mouth of the Bass River. A transplantation experiment indicated that S. anglica is capable of surviving to distances of at least 500 m from the upper edge of the mudflats, out onto the open mudflats of Western Port Bay. These data were shared with Parks Victoria to facilitate the management and control of this weed species in Victoria.