Data_Sheet_1_Threats, Costs, and Probability of Success: Informing Conservation Choices.docx

Threat classifications allow conservationists to categorize threatening processes faced by species of conservation concern, but lack of information on threat severity hampers efforts to establish the cost-effectiveness of conservation management actions. Actions and funds are often prioritized according to the prevalence of a threat; however, probability of success of threat management is little considered. Using data from three countries, New Zealand (NZ), Australia, and the United States, we identified which threats are more prevalent, more expensive to manage, and more likely to be successfully managed. In two of the countries, NZ and Australia, invasive species is the most prevalent, and costly threat, and actions to address it have the lowest probability of success. Thus, prioritizing actions based on prevalence rather than severity of threat may reduce efficiency. These findings provide general guidelines to agencies attempting to carry out cost-effective conservation of threatened species with limited resources.