Pacific Island Ecosystems at Risk (PIER)


Ischaemum polystachyum


RISK ASSESSMENT RESULTS: High risk, score: 20

Information on Risk Assessments


        Ischaemum polystachyum
A. History/     paddle grass
  Biogeography     team
1 Domestication/ 1.01 Is the species highly domesticated? If answer is 'no' go to 2.01 N
  cultivation 1.02 Is species naturalised where grown?  
    1.03 Does the species have weedy races?  
2 Climate and 2.01 Species suited to Australian climates (0-low; 1-intermediate; 2-high) 2
  Distribution 2.02 Quality of climate match data (0-low; 1-intermediate; 2-high) 2
    2.03 Broad climate suitability (environmental versatility) Y
    2.04 Native or naturalised in regions with extended dry periods Y
    2.05 Does the species have a history of repeated introductions outside its natural range? Y
3 Weed 3.01 Naturalised beyond native range Y
  Elsewhere 3.02 Garden/amenity/disturbance weed Y
  (interacts with 2.01 3.03 Weed of agriculture/horticulture/forestry Y
  to give a weighted 3.04 Environmental weed N
  score) 3.05 Congeneric weed Y
B. Biology/Ecology    
4 Undesirable 4.01 Produces spines, thorns or burrs N
  traits 4.02 Allelopathic N
    4.03 Parasitic N
    4.04 Unpalatable to grazing animals N
    4.05 Toxic to animals N
    4.06 Host for recognised pests and pathogens N
    4.07 Causes allergies or is otherwise toxic to humans N
    4.08 Creates a fire hazard in natural ecosystems N
    4.09 Is a shade tolerant plant at some stage of its life cycle N
    4.10 Grows on infertile soils Y
    4.11 Climbing or smothering growth habit Y
    4.12 Forms dense thickets N
5 Plant 5.01 Aquatic N
  type 5.02 Grass Y
    5.03 Nitrogen fixing woody plant N
    5.04 Geophyte Y
6 Reproduction 6.01 Evidence of substantial reproductive failure in native habitat N
    6.02 Produces viable seed Y
    6.03 Hybridises naturally N
    6.04 Self-fertilisation Y
    6.05 Requires specialist pollinators N
    6.06 Reproduction by vegetative propagation Y
    6.07 Minimum generative time (years) 1.0
7 Dispersal 7.01 Propagules likely to be dispersed unintentionally Y
  mechanisms 7.02 Propagules dispersed intentionally by people Y
    7.03 Propagules likely to disperse as a produce contaminant Y
    7.04 Propagules adapted to wind dispersal N
    7.05 Propagules buoyant N
    7.06 Propagules bird dispersed N
    7.07 Propagules dispersed by other animals (externally) Y
    7.08 Propagules dispersed by other animals (internally) N
8 Persistence 8.01 Prolific seed production Y
  attributes 8.02 Evidence that a persistent propagule bank is formed (>1 yr) Y
    8.03 Well controlled by herbicides Y
    8.04 Tolerates or benefits from mutilation, cultivation or fire Y
    8.05 Effective natural enemies present in Australia  
      Outcome: Reject
      Score: 20
  Statistical summary   Biogeography 12
  of scoring   Score partition:                       Undesirable attributes 1
      Biology/ecology 7
      Biogeography 8
      Questions answered:                       Undesirable attributes 12
      Biology/ecology 23
      Total 43
      Agricultural 18
      Sector affected:                                   Environmental 15
         
   A = agricultural, E = environmental, C =combined  

Risk assessment prepared 5 April 2000 by J. Denslow, B. Waterhouse, J. Space, D. Nelson


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This page new 14 January 2001.