Authors: Christie, Alec ;Martin, Philip ;Petrovan, Silviu ;Sutherland, William ;White, Thomas;

Wildlife conservation is severely limited by funding. Therefore, to maximize biodiversity outcomes, assessing financial costs of interventions is as important as assessing effectiveness. We reviewed the reporting of costs in studies testing the effectiveness of conservation interventions and find very low levels of cost reporting (8.8% of studies reported total costs). Even fewer studies broke down these totals into constituent costs, making it difficult to assess the relevance of costs to different contexts. We investigate trends in reporting by geography and type of intervention to see if some areas of conservation may be better. Without standardized, transparent information on costs, we risk misallocating conservation resources on suboptimal, or at worst ineffective, action. Yet our research is also highlighting the importance of financial costs and benefits in decision-making. I will finish by discussing opportunities for conservationists to improve future practice through encouraging systematic reporting and collation of intervention costs, using economic evaluation tools, and increasing understanding and skills in finance and economics.