Contribution of site assessment toward prioritising investment in natural capital

In prioritising investment in natural capital, site-scale indicators are increasingly used to capture fine-scale variation inherent in complex ecosystems. However, site assessment is costly, has high skill demand, and is time-consuming. We assess the marginal gain associated with including site-scale indicators in metrics typically used by agri-environmental stewardship schemes and payments for ecosystem services. We developed 18 landscape-scale and 14 site-scale indicators to prioritise sites for on-ground works in a real-world conservation auction in South Australia. We used the Analytical Hierarchy Process (AHP) to weight them and multi-attribute utility theory to combine them in quantifying site priority. Bid benefit was calculated as the product of impact of the proposed works and the site priority. Cost-utility analysis was used to rank and select bids with benefits calculated using: i) landscape-scale indicators, and; ii) both landscape- and site-scale indicators. We found that the inclusion of site-scale indicators has limited influence on the ranking and selection of bids for investment when cost of investment is included in the decision-making process. We suggest that, depending on the nature of costs and benefits, and if landholder engagement, information sharing, and trust-building can be achieved in more efficient ways, site assessment may not be necessary. Thereby a significant barrier to the adoption of cost-effective agri-environment schemes and payments for ecosystem services may be eliminated.