Weeds and the Murray

Feb 15, 2011

(PhysOrg.com) -- A new study has revealed that human-induced changes in the flow of the Murray River has led to mass weed invasion and reduced biodiversity in wetlands along the riverbank, highlighting the need for a review into how we manage the river's flow.

The study, led by Dr Jane Catford from the University of Melbourne’s School of Botany, provides valuable information on how best to guide the delivery of water to combat environmental problems.

“We have always thought that the huge problem of weed invasion along the Murray River had something to do with the changes in flow but this is the first time we have been able to identify what kind of flow alterations have had most impact,” Dr Catford said.
The control of the Murray’s flow by dams and weirs has meant that floods that would have occurred every 10 years are now occurring every 24 years, Dr Catford said.

“And we found that altered flooding patterns, and particularly the reduction in the size of natural floods, has provided conditions that favour alien plants at the expense of native ones,” she said.

“The introduction of alien plants has dramatically changed the structure and function of these wetlands, which provide crucial habitat and food for a range of birds, fish, turtles and other animals and also play a critical role in filtering water.

“These functions contribute to an estimated $2.1 billion dollars annually for local regions and such changes to wetland flora has impaired these functions.”

Dr Catford surveyed plants in 24 wetlands between Albury and Echuca and then modeled the ’ flood histories, and assessed the effect of river regulation on the flora.

“I also examined the effect of human-mediated weed dispersal, grazing, soil and water characteristics, but flow regulation was the clearly the main factor driving weed invasion,” Dr Catford said.

As a result of the evidence, the scientists are now calling for a change in how we manage the flows that are allocated to go back into the environment.

“Environmental flows will help redress the balance between native and alien species,” Dr Catford said.

“Given that environmental water allocations are typically limited, it is essential that release decisions are science-based. We recommend that environmental water be used to augment natural floods that typically occur in spring.

“Increasing the size of mid-range floods in particular will kill most of the weeds and will encourage growth and reproduction of native plants.”

Explore further: Current residential development research is a poor foundation for sustainable development

Related Stories

Groundwater threat to rivers worse than suspected

Nov 02, 2010

Excessive groundwater development represents a greater threat to nearby rivers and streams during dry periods (low flows) than previously thought, according to research released today by CSIRO.

Fern's hunger-busting properties supported by research

Nov 15, 2010

Professor Roger Lentle, from the Institute of Food, Nutrition and Human Health at the Massey University, led a team that studied how an extract of the mamaku fern influenced stomach activity. Maori traditionally ...

Robotic glider to map Moreton Bay impacts

Jan 20, 2011

A $200,000 CSIRO coastal glider is bound for Queensland to be deployed in Moreton Bay to investigate the impact of the recent flooding on marine ecosystems.

Introduced plants 'becoming Australian'

Jan 31, 2011

(PhysOrg.com) -- A number of introduced plant species have become more like natives, suggesting rapid evolution could happen far more frequently than previously thought, according to new research from UNSW.

Recommended for you

Study provides detailed projections of coral bleaching

6 hours ago

While research shows that nearly all coral reef locations in the Caribbean and Gulf of Mexico will experience bleaching by mid-century, a new study showing in detail when and where bleaching will occur shows ...

Germany restricts fracking but doesn't ban it

12 hours ago

The German cabinet drew up rules Wednesday on the hitherto unregulated technology of "fracking" in Germany, narrowly restricting its use, but stopping short of an outright ban.

Life in the poisonous breath of sleeping volcanos

13 hours ago

Researchers of the University Jena analyze the microbial community in volcanically active soils. In a mofette close to the Czech river Plesná in north-western Bohemia, the team around Prof. Dr. Kirsten Küsel ...

Eggs and chicken instead of beef reap major climate gains

13 hours ago

Beef on our plates is one of the biggest climate villains, but that does not mean we have to adopt a vegan diet to reach climate goals. Research results from Chalmers University of Technology show that adopting ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.