Lessons from other disciplines for setting management thresholds for biodiversity conservation.

Successful, state-dependent management, where the goal of management is to maintain a system within a desired state, involves defining the boundaries between different states. Once these boundaries have been defined, managers require a strategic action plan, with thresholds that will initiate management interventions to either maintain or return the system to a desired state. This approach to management is widely used across diverse industries from agriculture to medicine to information technology, but has only been adopted in conservation management relatively recently. Conservation practitioners have expressed a willingness to integrate this structured approach into their management systems, but have also voiced concerns, including the lack of a robust process for doing so. Given the widespread use of state-dependent management in other fields, we conducted an extensive review of the literature on threshold-based management, to gain insight into how and where it is applied, and identify potential lessons for conservation management. We identified 22 industries using 75 different methods for setting management thresholds, spanning six broad analytical approaches, including expert driven, statistical, predictive, optimisation, experiments and artificial intelligence methods. We found that the objectives of each study influenced the approaches used, including the methods for setting thresholds and selecting actions, and the number of thresholds set. The role of value judgements in setting thresholds was clear, as studies across all industries frequently involved experts in setting thresholds, often accompanied by computational tools to simulate the consequences of proposed thresholds under different conditions. Of the 30 conservation studies identified, two thirds used expert-driven methods, consistent with prior evidence that experience-based information often drives conservation management decisions. The methods we identified from other disciplines could support conservation decision-makers with setting thresholds for management interventions in different contexts, linking monitoring to management actions and ensuring that conservation interventions are timely and effective. This article is protected by copyright. All rights reserved.