Ponded pasture species in Northern Australia: the complexities of control and management. Lynise Wearne and Tony Grice CSIRO Sustainable Ecosystems

Transcription

1 Ponded pasture species in Northern Australia: the complexities of control and management Lynise Wearne and Tony Grice CSIRO Sustainable Ecosystems

2 A brief step back in time. Development of ponded pastures in 1970 s Introduction of ponded pasture species Para grass (Urochloa mutica) Aleman grass (Echinochloa polystachya) Olive Hymenachne (Hymenachne amplexicaulis) All plants now considered environmental weeds

3 Ponded Pasture Species. Para Grass Introduced late 1800 s Invasive plant shallow wetlands Declared environmental weed Current estimates of 100,000 hectares in QLD Considered valuable for cattle grazing Cannot cultivate but no removal

4 Ponded Pasture Species. Aleman Grass & Olive Hymenachne Both introduced 1988 (controversial decision) Both grow in deeper water than Para Grass Local shires encouraged and promoted the use Hymenachne widely planted Northern NSW, QLD, NT Available evidence indicates to us that these plants will return to haunt us as weeds of the freshwater systems in years to come (P.Fisk 1991) Based on the demonstrated behaviour of introduced aquatics there is little doubt that the deep water grasses Hymenachne amplexicaulis and Echinochloa polystachya will spread beyond the pasture system (J.Clarkson 1991)

5 Predictions were proven correct H.amplexicaulis spread rapidly into surrounding water ways/wetlands/sugar cane paddocks/ water storage plants 1999 declared WONS species Legislated for removal (Class 2 Pest Plant) reasonable attempt to keep land free in 2003

6 Predictions were proven correct H.amplexicaulis is regarded as one of Australia s worst weeds because of its invasiveness, potential for spread, and socioeconomic and environmental impacts (Hymenachne Management Report 2006) Hymenachne now covers an area of approx 8000 hectares QLD Neither Para Grass or Aleman grass are currently declared pest plants

7 Complex management issues H.amplexicaulis only species declared and actively managed Control Socioeconomic Chemical spray limited Site access difficult Many weed species Limited funding/ short term funding Management Complexities Many pastoralists do not control, previously encouraged to plant Control not enforced as pest officers encouraged planting Still actively promoted Varying options on cost/benefits of species Sectoral responsibility

8

9 How do we deal with these issues?? Discuss two different case studies: 1/ Burdekin Shire Council (Ayre) 2/ Hinchinbrook Shire Council (Ingham)

10 Can management work? Case Study 1: Burdekin Shire Council Identified priority areas for control - Horse Shoe Lagoon (5 landholders) - Healy s Lagoon (7 landholders) - Sheep station Creek (30 landholders) Multiple partners within each lagoon - Council, Sunwater, North Burdekin Water Board Landholders sign Land Holder Agreement agreement (legally binding attached to the land)

11 What are the commitments Horse Shoe Lagoon (5 landholders): $300 pa Healy s Lagoon (7 landholders): $700 pa Sheepstation Creek (30 landholders):?? Successful bid by Burdekin Shire Council for Australian Government funding 2001 Management committee formed (different stakeholders) Landholders agreed and committed to management plan Initial control undertaken by Council Follow up by both council and landholders Landholders provided with chemical subsidies Highly successful

12 Horseshow Lagoon - success Lagoon infested with Hymenachne Lagoon following treatment

13 Key lessons learnt Never clean a water body until all stakeholders sign up and contribute Be willing to use legislation where landholders do not commit Showcase the water body: use science (water quality, fish, birds have returned) TIME!! And COMMITMENT!!

14 Case 2: Hinchinbrook Shire Council Provided government funding for Hymenachne control Undertook extensive management (aerial spraying off label permit required) Extensive monitoring requirements No follow up funding Currently no active management of Hymenachne

15 What is happening in other locations Control has begun in Northern NSW Highlighted in NT but limited control still considered useful for Mimosa control In QLD shire dependent

16 Current ongoing Issues. Para Grass and Aleman grass not currently declared Currently undergoing weed risk assessment Not actively being managed.

17

18 Other introduced pasture species Issues not isolated to introduced ponded pasture species Gamba Grass (spreading rapidly), Buffel Grass (already widespread) similar issues

19 Key management solutions Declaration can be useful (Aleman Grass) Accountability and Awareness Sectoral responsibility Planning (areas of high conservation value)

20 Where to from here Review of weed risk assessment procedures how long does it take?? Cost/Benefit Analysis different opinions on the benefit of species Engagement of landholders ACTION!!!

21 Thankyou John Clarkson, Matt Buckman and Merv Pyott for interesting discussions on management and legislation issues!!