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Saving Australia's wetlands from tenacious willows



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M E D I A R E L E A S E

NERP Environmental Decisions Hub

Saving Australia’s wetlands from tenacious willows

January 29, 2013 - for immediate release

Scientists have developed a new way to rescue the Bogong High Plains and their

endangered alpine wetlands from invading European willows.

The new strategy calls for an exclusive focus on eradicating willows within the

threatened bogs - patches of muddy ground where the soil is always wet, says Dr

Joslin Moore from the National Environmental Research Program’s (NERP)

Environmental Decisions Hub and the Royal Botanic Gardens Melbourne.

“After a severe bushfire burned out most of the Bogong High Plains in 2003, the

seeds of the grey sallow willow, a highly invasive shrub, began to spread along

the Plains,” Dr Moore explains. “The willows have since become a major threat to

our alpine ecosystems, and this spells big trouble for the High Plains.

“They fight for water, space and nutrients with the native plants of our precious

bogs, and are highly resilient, which means they can invade different

environments, regenerate after fire and their seeds can disperse tens of

kilometres.”

While environmental managers have worked hard to destroy the tenacious

invaders, they were often unsure where to focus scarce control resources, Dr

Moore says.

“There are a lot of uncertainties in willow management - we don’t know how often

bushfires that encourage willow growth will occur, how far the willow seeds have

travelled and how long it takes bogs to recover after fire,” she says.

With an increase in fire frequency expected due to climate change, environmental

managers are having to devote more and more resources to eliminating willows.

So hub researchers have developed a sophisticated decision system that will help

them identify the best strategies for defeating the invaders. Using a modelling

program, they can project how different management strategies will affect the

amount of willows in the alpine landscape over the next 200 years, under 10,000

different scenarios.

“Our analysis shows that with the current budget, the most practical, long-term

approach is to protect the threatened bog communities, instead of trying to control

invaders across the region,” says Dr Moore.

“This is because there are many more seed sources than there are bogs, and

there aren’t enough resources to reduce the seed volume enough to diminish the

threat significantly.”

The researchers also found that learning more about fire frequencies, seed

dispersal distances and bog recovery rates is unlikely to improve the ability to

manage willows.

“While these factors determine the spread of willow, our program shows that

unless current budgets are increased substantially, the same strategy - only

treating willows in bogs - is optimal for the nearly all of the 10,000 scenarios,”

says Dr Moore.

“In this case where we have a small-to-medium budget, having more knowledge

is unlikely to help us,” she says.

“So instead of investing our resources on gaining more information, our first

priority is to manage willow populations in bogs and allocate effort elsewhere only

when the budgets are large enough.”

The research was carried out in collaboration with Parks Victoria and other land

managers in the region and will inform the development of an Alpine Bog

Recovery Plan.

The study “Combining structured decision making and value-of-information

analyses to identify robust management strategies” by Joslin L. Moore and

Michael C. Runge was published in Conservation Biology. See:

http://www.ncbi.nlm.nih.gov/pubmed/22862796

The Australian Government funds the National Environmental Research Program

(NERP) to inform evidence-based policy and sustainable management of the

Australian environment.

More information:

Dr Joslin Moore, NERP Environmental Decisions Hub and Royal Botanic Gardens

Melbourne, +61 (03)8344 3337 or +61 (0)421 939 894

Prof. Brendan Wintle, Deputy Director NERP Environmental Decisions Hub and

University of Melbourne +61 (0)3 8344 3306 or +61 (0)425 828 470

Karen Gillow, Science Communications, NERP Environmental Decisions Hub and

University of Qld, +61 (0)7 3365 2450 or +61 (0) 402 674 409 or

k.gillow@uq.edu.au

www.nerpdecisions.edu.au

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