Land managers decide how to allocate resources among multiple threats that can be addressed through multiple possible actions. Additionally, these actions vary in feasibility, effectiveness, and cost. We sought to provide a way to optimize resource allocation to address multiple threats when multiple management options are available, including mutually exclusive options. Formulating the decision as a combinatorial optimization problem, our framework takes as inputs the expected impact and cost of each threat for each action (including do nothing) and for each overall budget identifies the optimal action to take for each threat. We compared the optimal solution to an easy to calculate greedy algorithm approximation and a variety of plausible ranking schemes. We applied the framework to management of multiple introduced plant species in Australian alpine areas. We developed a model of invasion to predict the expected impact in 50 years for each species-action combination that accounted for each species’ current invasion state (absent, localized, widespread); arrival probability; spread rate; impact, if present, of each species; and management effectiveness of each species-action combination. We found that the recommended action for a threat changed with budget; there was no single optimal management action for each species; and considering more than one candidate action can substantially increase the management plan's overall efficiency. The approximate solution (solution ranked by marginal cost-effectiveness) performed well when the budget matched the cost of the prioritized actions, indicating that this approach would be effective if the budget was set as part of the prioritization process. The ranking schemes varied in performance, and achieving a close to optimal solution was not guaranteed. Global sensitivity analysis revealed a threat's expected impact and, to a lesser extent, management effectiveness were the most influential parameters, emphasizing the need to focus research and monitoring efforts on their quantification.

中文翻译：

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在多种威胁和行动之间分配保护资源的框架

土地管理者决定如何在多种威胁之间分配资源，这些威胁可以通过多种可能的行动加以解决。此外，这些行动的可行性、有效性和成本各不相同。我们试图提供一种优化资源分配的方法，以便在有多种管理选项（包括互斥选项）可用时应对多种威胁。将决策制定为组合优化问题，我们的框架将每个威胁对每个动作（包括什么都不做）的预期影响和成本作为输入，并为每个总体预算确定对每个威胁采取的最佳行动。我们将最佳解决方案与易于计算的贪婪算法近似和各种合理的排名方案进行了比较。我们将该框架应用于澳大利亚高山地区多种引进植物物种的管理。我们开发了一个入侵模型来预测每个物种-行动组合在 50 年内的预期影响，这些组合解释了每个物种当前的入侵状态（不存在、局部、广泛）；到达概率；传播率；对每个物种的影响（如果存在）；每个物种-行动组合的管理有效性。我们发现针对威胁的建议措施随预算而变化；每个物种没有单一的最佳管理措施；考虑多个候选行动可以显着提高管理计划的整体效率。当预算与优先行动的成本相匹配时，近似解决方案（按边际成本效益排序的解决方案）表现良好，表明如果将预算设置为优先排序过程的一部分，这种方法将是有效的。排名方案的性能各不相同，无法保证获得接近最优的解决方案。全球敏感性分析揭示了威胁的预期影响，在较小程度上，管理有效性是最具影响力的参数，强调需要将研究和监测工作重点放在其量化上。