Building Weed Risk Assessments. Mindy Wilkinson Invasive Species Coordinator

Transcription

1 Building Weed Risk Assessments Mindy Wilkinson Invasive Species Coordinator

2 Is this plant a weed?

3 Is this plant going to be worse than other weeds I manage? What impacts will this plant have? Is this plant sold in the nursery trade? Is this plant a weed? Has the pathway for introducing this plant been managed? Should I control this plant? How widespread will this plant become? Is this plant widespread in cultivation?

4 Is this plant a weed? What kind of information do you need to make predictions? Invasive elsewhere? Impacts on valued resources? Biological characteristics - especially fecundity. Lots of models will get you there

5 The most reliable model.

6 Benefits 1. Widely tested Users of the modified Australia Weed Risk Assessment

7 Benefits Weed Risk Assessment 2. Known accuracy Invasive Plants 95% Non-invasive Plants 85% Correct Incorrect

8 Weed Risk Assessment Benefits 3. You don t need to know everything about the plant. Answers only some of the 49 questions of the questions is sufficient for an accurate score. Section Minimum #? s A 2 B 2 C 6 Total 10

9 When do you use the WRA? After checking to see if a plant has already been assessed Before import Evaluating new horticultural accessions Possible rapid response targets

10 Purple loosestrife (Lythrum salicaria)

11 Five-leaved akebia (Akebia quinata)

12 What do you need to know? Section A Domesticated? Does it naturalize? Will it survive in your climate? Quality of climate match? How often has it been introduced outside its native range? Is it a weed of: Gardens or disturbed areas? Horticulture, forestry or agriculture? Is it an environmental weed?

13 What do you need to know? Section B Does it produce weapons (thorns, spines, burrs or allergens)? Is it allelopathic or parasitic? Would you want it in a pasture? Is it a host for pests or pathogens? Alters the local fire or nutrient cycle? Grows in shade? Forms thickets or is a vine?

14 What do you need to know? Section C Is it a grass or aquatic plant? Does it fix nitrogen? Geophyte? Tends to be kept in check by predators? Produces viable seeds? Hybridizes naturally? Fertility factors (pollinators, self fertile) Dispersal factors (water, wind, birds) Fecund? Resistant to available control methods?

15 How do you read a WRA score? 49 Questions Climate/distribution Domestication Weed elsewhere Undesirable traits Plant type Reproduction Dispersal Persistence attributes Prediction < 1 Not a pest 1-6 Evaluate >6 Pest About 30% evaluate further

16 Further assessment (species scoring between 1 and 6) Vines must pass both tests! Trees and Tree-like shrubs A) Shade tolerant OR known to form dense stands AND B) Bird OR clearly wind-dispersed Herb or low stature shrubby form Reported as a weed of cultivated lands? YES YES Life cycle < 4 years? NO Not a Pest Pest Unpalatable to grazers OR known to form dense stands NO Evaluate Further Daehler et al Cons Biol 18: Evaluate Further

17 So what does this look like? Tolerates, or benefits from, mutilation, cultivation, or fire Effective natural enemies present locally (e.g. introduced biocontrol agents) y=1, n=-1 y y=-1, n=1 n "It is also fire adapted and can sustain fires that spread quickly into adjacent areas." [dense infestations in Hawaii] /im/monitor/docs/inv_kisc2 003ActionPlan.pdf Total score: 26

18 Variants on the WRA New Zealand: Aquatic Weed Risk Assessment Model AWRAM (Champion & Clayton 2000)

19 Isn t this what USDA does? Import of Plants for Planting regulation Uses a Not Authorized Pending Pest Risk Analysis (NAPPRA) Q37 as of 05/27/2011 List 41 species for evaluation Use their own model

20 Who generates WRAs? Experts with botanical training Access to references and grey literature Estimated time per assessment ~6 hours

21 Which species to prioritize for screening with the WRA? New imports or introductions Requests from growers Early Detection finds Botanical garden collections Random suggestions

22 Why staff the WRA? Cost per year for 1.0FTE ~ $70k Link to horticulture Resource for quick decision making Consistency and transparency

23 Where can I read more? Environmental Protection and Biodiversity Conservation Act 1999 Weed assessment of new plant imports International Weed Risk Assessment Workshops 1999 &

24 Mindy Wilkinson Invasive Species Coordinator (608)