The problems caused by the extensive prickly pear (O. stricta) infestations in Queensland in the early 20th century are well known, and help identify opuntioid cacti as significant weeds, while the success of the O. stricta biological control program will drive community expectation that biological control programs for other opuntioid cacti will be equally successful. The recently-acquired WoNS status of the opuntioid cacti will help reinforce the community’s perception of their weed status. 3.4 Impact assessment for opuntioid cacti An impact assessment was conducted on four opuntioid cacti species and the entire genus Opuntia as part of a process to undertake Benefit Cost Analysis for all declared plants and WoNS weeds present in WA (Petersen et al., 2013). This assessment involved an expert panel approach, where weed specialists used their knowledge of the benefits of control to score each plant on a scale of 1 to 5, using the key shown in Table 4. A total of 73 declared plant species were assessed. Agricultural and environmental benefits were scored separately. Both private (landholder) and public (government and the community) benefits were considered. The agricultural and environmental benefit score given by all experts was averaged (that is, given equal weight in terms of benefits) to calculate an Impact Score as shown in Table 5. Table 4. Scoring key for measuring benefits of plant control Agricultural benefits Environmental benefits 1 Uncontrolled plant has 1 Uncontrolled plant has – – very little impact on profit very little impact on environment 2 2 3 Moderate 3 Moderate – – 4 4 5 Uncontrolled plant has 5 Uncontrolled plant has – – significant impact on significant impact on profit environment 5. Impact scores and rankings for opuntioid cacti Common Scientific name Agric Ranking Enviro Ranking name(s) (out of impact (out of impact 73) 73) Cane or Austrocylindropuntia 3.0 16= 3.5 28= cactus cylindrica
The problems caused by the extensive prickly pear (O. stricta) infestations in Queensland in the early 20th century are well known, and help identify opuntioid cacti as significant weeds, while the success of the O. stricta biological control program will drive community expectation that biological control programs for other opuntioid cacti will be equally successful. The recently-acquired WoNS status of the opuntioid cacti will help reinforce the community’s perception of their weed status. 3.4 Impact assessment for opuntioid cacti An impact assessment was conducted on four opuntioid cacti species and the entire genus Opuntia as part of a process to undertake Benefit Cost Analysis for all declared plants and WoNS weeds present in WA (Petersen et al., 2013). This assessment involved an expert panel approach, where weed specialists used their knowledge of the benefits of control to score each plant on a scale of 1 to 5, using the key shown in Table 4. A total of 73 declared plant species were assessed. Agricultural and environmental benefits were scored separately. Both private (landholder) and public (government and the community) benefits were considered. The agricultural and environmental benefit score given by all experts was averaged (that is, given equal weight in terms of benefits) to calculate an Impact Score as shown in Table 5. Table 4. Scoring key for measuring benefits of plant control Agricultural benefits Environmental benefits 1 – Uncontrolled plant has very little impact on profit 1 – Uncontrolled plant has very little impact on environment 2 2 3 – Moderate 3 – Moderate 4 4 5 – Uncontrolled plant has significant impact on profit 5 – Uncontrolled plant has significant impact on environment 5. Impact scores and rankings for opuntioid cacti Common name(s) Scientific name Agric impact Ranking (out of 73) Enviro impact Ranking (out of 73) Cane or cactus Austrocylindropuntia cylindrica 3.0 16= 3.5 28=
Opuntioid%20cacti%20situation%20report%2031%20March.docx