Weeds of National Significance National Willows Program WILLOWS WORKSHOP Supported by the State Government of Victoria.

National, state and regional context Willow identification Willow sawfly in Australia Update regional maps highlighting where willows occur Workshop Game Plan

Willows - a Weed of National Significance Infest 1000s of km of waterways Approx. $30 million spent annually > 32 types of willows Spread in different ways Distribution, invasiveness and impacts of specific willows are poorly understood

Did you know? Q: Do willows consume more water than natives? Clue: it depends on where they are in the landscape A: Yes: if growing in the water No: if growing on the bank Can consume approx. 3 megalitres per crown hectare more water than river red gums

WILLOWIMPACTS? Primary production altered (algae) Nutrient transfer Leaf litter input Aquatic food webs Increased shading of stream Obstruct and divert floods Erode Riverbanks Sediment trapping around roots Change in vegetation & structure Terrestrial insects Change in higher trophic orders Emergent stream insects

Q: When sitting along a river, lazily fishing, how might you accidentally grow a new willow tree? Clue: what do you lean your fishing rod on? A: Stick a willow stem in the ground as a fishing rod holder Willows grow easily from stems How do you grow a willow?

How do willows spread? Seed up to 100km Twigs and branches Layering

Salix nigra (black willow) e.g. North East Victoria Salix cinerea (grey sallow) e.g. Sydney catchment Spread by seed

Early detection and eradication of seeding willows in Tasmania Don’t respect our borders

National Willows Taskforce SA CMAs Weeds CRC ACT NSW Tas Community NGIA Qld Local gov’t Vic Community

Did you know? Q: For what religious festivals are willows allowed to still be imported? Clue: they can be imported from Israel and the U.S.A A: Jewish festivals ‘cut flowers and foliage’ ‘only Rabbis may import the cuttings’ One of the Four Kinds taken on Sukkos: “The willow, which is inedible and lacks aroma as well, represents those people lacking both in Torah and good deeds”

National Willows Program National policy on importation –to prevent future problems Biological control and other research –protecting our investment for the future Education / awareness / communications –National Best Practice Management Guide –Nursery and Garden Industry –Increasing broad public awareness Mapping and weed risk assessment –can’t manage what we don’t know

Developing willow management priorities Workshops –create/update regional maps –training in mapping, sawfly and ID Weed risk assessment –risk, impacts, current and potential distribution and feasibility of control Priority actions for willow management –reports to each state and CMA/NRM region –maps of distribution and potential spread

Find out more... Website: National Willows Network Willow Strip Newsletter

Weeds of National Significance WILLOW MAPPING Supported by the State Government of Victoria.

Why map willows? Because you can’t manage what you don’t know! North East bushfires Tasmania

E.g. Wingecarribee Swamp

Why map willows? Eradication of all willows not feasible or desirable Need to set priorities for management Factors to consider: –Risk of further spread by seed or branches –Current impacts –Density and location of willows –Accessibility and cost of management –Community support

Did you know? Q: What industry in South Australia is impacted by willows growing along the River Murray? Clue: they float on water A: Houseboating Industry Nowhere to moor the boats in some sections

Weed risk management Weed risk is based on: –invasiveness (rate of spread) –impacts –current and potential distribution

Weed risk management One willow may rank more highly than another willow if: –its overall area and / or the number of ecosystems it can invade is greater (invasiveness); –it impacts more on social, environmental and agricultural values (impacts) –it is presently localised - but could spread much further (current:potential distribution)

Feasibility of coordinated control Total cost is a function of: –total area infested, –annual control cost per unit area and –number of years required to achieve the desired level of control.

Current : potential distribution

Potential Distribution Sample maps Australian climate match Salix aegyptiaca Australian climate match Salix fragilis