Managing weeds under future scenarios for environmental flows in the Murray River

Summary

This project aims to determine site indicators that will clarify risk with respect to weed invasion, and how this risk is affected by patterns of flooding. This will assist in reducing the spread of weeds in riparian and floodplain environments and in restoring native vegetation in systems that are degraded.

Background

Many exotic weeds have colonized floodplain and riparian environments in Australia, including blackberry (Rubus spp.), willows (Salix spp.) bridal creeper (Asparagus asparagoides), cabomba (Cabomba caroliniana) and Lippia (Phyla canescens)). These weeds can have substantial negative impacts on the biodiversity values of riparian environments, and can spread away from the river banks to invade otherwise productive agricultural land. Flooding promotes growth and reproduction of many riparian plants, activates the sexual and asexual propagules of aquatic and semi-aquatic species and eliminates flood-intolerant species that colonize the floodplain during dry periods. Riparian and floodplain environments have been subject to many stressors due to land use changes in the past, but it is known that more significant changes will occur in the next decade. State and federal governments are co-ordinating to increase the amount of water released in Australia's largest river in the form of environmental flows. The primary goal of this program is to restore ecosystem health to the Murray river. At the same time must minimise negative consequences for productive land use. As such, a great challenge must be faced, how to release water in a manner that will maximise environmental benefits? For this study, the question is how is it possible to manage environmental flows in a manner that will not exacerbate weed invasion or trigger an increase in abundance of exotic species that are currently present as sleepers in the system?
 

Products and Publications