7.0 Final Ranking and Recommendation

The final ranking of the 71 weed species assessed is given in appendix 11. From this list and taking into consideration the limitations previously discussed, the National Weeds Strategy Executive Committee recommended that the top 20 ranked weed species form the inaugural list of WONS as shown in Table 9.

Some species of willows were excluded from WONS status. In the context of weediness, willows can be divided into two distinct groups. The first group — the non-weedy species — comprises those that cannot propagate sexually and are not brittle. The other group — the weedy species — has an outstanding propensity to colonise the banks of waterways and margins of water bodies. On this basis, Salix babylonica, S X calodendron and S X reichardtiji, were classed as non-weedy taxa and excluded from WONS.

Rank Common Name Scientific Name
1 Parkinsonia Parkinsonia aculeata
2 mesquite Prosopis spp.
3 blackberry Rubus fruticosus agg.
4 lantana Lantana camara
5 rubber vine Cryptostegia grandiflora
6 bitou bush / boneseed Chrysanthemoides monilifera
7 prickly acacia Acacia nilotica ssp. indica
8 hymenachne Hymenachne amplexicaulis
9 salvinia Salvinia molesta
10 mimosa Mimosa pigra
11 cabomba Cabomba caroliniana
12 Chilean needle grass Nassella neesiana
13 athel pine Tamarix aphylla
14 willows except weeping willows, pussy willow and sterile pussy willow Salix spp. except S. babylonica, S. X calodendron and S. X reichardtiji
15 serrated tussock Nassella trichotoma
16 parthenium weed Parthenium hysterophorus
17 pond apple Annona glabra
18 gorse Ulex europaeus
19 bridal creeper Asparagus asparagoides
20 alligator weed Alternanthera philoxeroides

Table 9. Inaugural list of weeds of national significance

The Standing Committees and Ministerial Councils endorsed this recommendation, but with the proviso that the twenty WONS be listed in alphabetical order as a group to avoid the public focusing on the ranking of individual species.

The authors acknowledge the limitations associated with compiling the final ranking in what is a complex task. It is hoped that the process will be further utilised by administrators and policy-makers involved at all levels of land management decision-making throughout Australia, and that future work will progressively refine the methodology.

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