Serrated Tussock
This Weed Risk Management Assessment uses a series of questions to arrive at scores for weed risk and feasibility of coordinated control for this weed, and displays the necessary management actions derived from these scores.
This information is then used to make decisions about the introduction, prioritisation and declaration of this weed in New South Wales.
| Weed (Scientific name) | Nassella trichotoma | ||
| Weed (Common name) | Serrated tussock | ||
| Region | NSW | ||
| Management area | Tablelands | ||
| Landuse | 3.2 Grazing modified | ||
| Assumptions | also forests; natural ecosystems | ||
| Weed Risk | |||
|---|---|---|---|
| Invasiveness | Score Total | Answers | Source and comments |
| Q1. What is the ability of the weed to establish amongst existing plants? | 1.0 | Seedlings establish after moderate disturbance | see references at end |
| Q2. What is the weed's tolerance to average weed management practices in the land use? | 2.0 | Between 50 and 95% of weeds survive | |
| Q3. What is the reproductive ability of the weed in the land use? | 2.0 | ||
| (a) Time to seeding | 2.0 | 1 year or less | |
| (b) Annual seed production | 2.0 | High | |
| (c) Vegetative reproduction | 0.0 | None | |
| Q4. How likely is long-distance dispersal (>100m) by natural means? | 2.0 | ||
| (a) Flying animals | 0.0 | Unlikely | |
| (b) Other wild animals | 1.0 | Occasional | |
| (c) Water | 1.0 | Occasional | |
| (d) Wind | 2.0 | Common | |
| Q5. How likely is long-distance dispersal (>100 m) by human means? | 2.0 | ||
| (a) Deliberate spread by people | 0.0 | Unlikely | |
| (b) Accidentally by people and vehicles | 2.0 | Common | |
| (c) Contaminated produce | 1.0 | Occasional | |
| (d) Domestic/farm animals | 2.0 | Common | |
| Total | 6.0 | ||
| Impacts | Score Total | ||
| Q1. Does the weed reduce the establishment of desired plants? | 2.0 | 10 - 50% reduction | |
| Q2. Does the weed reduce the yield or amount of desired vegetation? | 3.0 | 25 - 50% reduction | |
| Q3. Does the weed reduce the quality of products, diversity or services available from the land use? | 2.0 | Medium | |
| Q4. What is the weed's potential to restrict the physical movement of people, animals, vehicles, machinery and/or water? | 1.0 | Low | |
| Q5. What is the weed's potential to negatively affect the health of animals and/or people? | 0.0 | None | |
| Q6. Does the weed have major positive or negative effects on environmental health? | 2.0 | ||
| (a) food/shelter | 1.0 | Major negative effect | |
| (b) fire regime | 1.0 | Major negative effect | |
| (c) altered nutrient levels | 0.0 | Minor or no effect | |
| (d) soil salinity | 0.0 | Minor or no effect | |
| (e) soil stability | 0.0 | Minor or no effect | |
| (f) soil water table | 0.0 | Minor or no effect | |
| Total | 5.3 | ||
| Potential distribution | Total | ||
| Q1. Within the geographic area being considered, what is the percentage area of land use that is suitable for the weed? | 6.0 | 40-60% of land use | |
| Comparative weed risk score | 189 | ||
| Weed risk category | High | ||
| Feasibility of coordinated control | |||
| Control costs | Score Total | ||
| Q1. How detectable is the weed? | 2 | ||
| (a) Distinguishing features | 1 | sometimes distinct | |
| (b) Period of year shoot growth visible | 0 | > 8 months | |
| (c) Height at maturity | 1 | 0.5 - 2 m | |
| (d) Pre-reproductive height in relation to other vegetation | 1 | similar height | |
| Q2. What is the general accessibility of known infestations at the optimum time of treatment? | 1 | medium | |
| Q3. How expensive is management of the weed in the first year of targeted control? | 4 | more expensive if aircraft used | |
| (a) Chemical costs/ha | 3 | high ($250-$500/ha) | |
| (b) Labour costs/ha | 3 | high ($250-$500/ha) | |
| (c) Equipment costs | 2 | medium | |
| Q4. What is the likely level of participation from landholders/volunteers within the land use at risk? | 1.0 | medium | |
| Total | 6.7 | ||
| Persistence | Score Total | ||
| Q1. How effective are targeted management treatments applied to infestations of the weed? | 3 | low | |
| Q2. What is the minimum time period for reproduction of sexual or vegetative propagules? | 2 | 6-12 months | |
| Q3. What is the maximum longevity of sexual or vegetative propagules? | 2 | > 5 years | |
| Q4. How likely are new propagules to continue to arrive at control sites, or to start new infestations? | 2.0 | ||
| (a) Long-distance (>100m) dispersal by natural means | 2 | frequent | |
| (b) Long-distance (>100m) dispersal by human means | 0 | rare | |
| Total | 8.2 | ||
| Current distribution | Total | ||
| Q1. What percentage area of the land use in the geographical area is currently infested by the weed? | 1.0 | 5-10% of land use | |
| Q2. What is the number of infestations, and weed distribution within the geographic area being considered? | 2.0 | widespread | |
| Total | 2.5 | ||
| Comparative feasibility of coordinated control score | 136 | ||
| Feasibility of coordinated control category | Negligible | ||
| Management priority category | Manage weed | ||
| Calculation of overall uncertainty score | 0% | ||
| Positive impacts | |||
| References/Other comments | |||
|
PlantNET (2009). Flora Online module of PlantNET. Royal Botanic Gardens and Domain Trust, Sydney. Online at http://plantnet.rbgsyd.nsw.gov.au/search/simple.htm Parsons, W.T. and Cuthbertson, E.G. (2001). Noxious Weeds of Australia. 2nd. Edition. CSIRO Publishing, Melbourne, 698pp. Weed Management CRC (2003). Serrated tussock (Nassella trichotoma). Weed Management Guide. 6pp. Campbell, M. H. and Vere, D.T. (1995). Nassella trichotoma (Nees) Arech. In : The Biology of Australian Weeds Vol. 1 . R.H. Groves, R.C.H.Shepherd and R. G. Richardson (eds.) Richardson, Melbourne. pp.189-202. | |||
