A framework for maximizing the benefit from retaining regrowth on private land.

Conservation interventions often have lower-than-desired positive impacts, as revealed by retrospective counterfactual-based evaluations. To address this, a prospective counterfactual-based approach can be used to estimate potential benefits and design conservation interventions to maximize outcomes. We developed a framework for estimating the expected benefit of retaining natural regeneration of forest and woodland ecosystems (hereafter regrowth). First, we considered the additionality of retaining regrowth, by developing a model of deforestation risk. Second, we considered the potential habitat value that the regrowth provides to 29 threatened species, based on expert-elicited estimates for each species that account for regrowth age. Then, we combined this information to identify where retention of regrowth would yield the greatest additional benefits. Applying this framework to a case study in Queensland, Australia, which contains globally significant deforestation rates and exceptional biodiversity, we found that areas with the greatest expected benefit from retaining regrowth differ greatly when both averted loss of regrowth clearing and threatened species habitat are considered together, versus when these factors are considered individually. We also found that most (56%) of the highest expected benefit areas (i.e., above the 90th percentile) were consistently identified regardless of whether species were treated equally or weighted based on their threatened status or proportion of habitat occurring in regrowth. Our results can help guide conservation investment in the region, and we recommend a similar approach be used more broadly when designing conservation interventions to maximize benefits.