Adaptively managing marine protected areas (MPAs) requires accurately assessing whether established MPAs are achieving their goals of protecting and conserving biomass, especially for harvested populations. Ecological MPA assessments commonly compare inside of the MPA to a reference point outside of and/or before implementation (i.e., calculating “response ratios”). Yet, MPAs are not simple ecological experiments; by design, protected populations interact with those outside, and population dynamic responses can be nonlinear. This complicates assessment interpretations. Here, we used a two‐patch population model to explore how MPA response ratios (outside–inside, before–after, and before–after‐control‐impact [BACI]) for fished populations behave under different conditions, like whether the population is receiving a sustainable larval supply or if it is declining despite protection from harvest. We then conducted a Bayesian evaluation of MPA effects on fish and invertebrate populations based on data collected from 82 published studies on 264 no‐take MPAs worldwide, using the results of an earlier global meta‐analysis as priors. We considered the effects of calculating different summary metrics on these results, drawing on the theoretical insights from our population model as a comparative framework. We demonstrate that not all response ratio comparison types provide the same information: For example, outside–inside and BACI comparisons can fail to detect population decline within MPAs, whereas before–after comparisons likely detect that pattern. Considering these limitations, we nonetheless found that MPAs globally are producing positive outcomes, with on average greater biomass, density, and organism size within their boundaries than reference sites. However, only a small portion of studies (18 of 82) provided the temporal data necessary to determine that protection, on average, has led to increased abundance of populations within MPAs over time. These findings demonstrate the importance of considering the underlying system dynamics when assessing MPA effects. Assuming that large outside–inside or BACI response ratios always reflect large and net positive conservation effects may lead to misleading conclusions, we recommend that: (1) when assessing specific MPA effects, empirical findings be considered alongside theoretical knowledge relevant to that MPA system, and (2) management should respond to the local conditions and outcomes, rather than a blanket expectation for positive MPA effects.

中文翻译：

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禁捕海洋保护区的生态成功：利用种群动力学理论为全球荟萃分析提供信息


适应性管理海洋保护区 （MPA） 需要准确评估已建立的 MPA 是否正在实现其保护和保存生物量的目标，尤其是对于收获的种群。生态 MPA 评估通常将 MPA 内部与实施外部和/或实施前的参考点进行比较（即计算“响应比率”）。然而，海洋保护区并不是简单的生态实验;根据设计，受保护的种群与外部种群相互作用，种群动态响应可以是非线性的。这使得评估解释复杂化。在这里，我们使用了双斑块种群模型来探索捕捞种群的 MPA 反应比（外-内、前-后和前后-控制-影响 [BACI]）在不同条件下的行为，例如种群是否正在获得可持续的幼虫供应，或者尽管受到保护免受捕捞，但它是否在下降。然后，我们根据从全球 264 个不服用 MPA 的 82 项已发表研究中收集的数据，使用早期全球荟萃分析的结果作为先验，对 MPA 对鱼类和无脊椎动物种群的影响进行了贝叶斯评估。我们考虑了计算不同汇总指标对这些结果的影响，借鉴了我们总体模型中的理论见解作为比较框架。我们证明，并非所有响应比率比较类型都提供相同的信息：例如，外部-内部和 BACI 比较可能无法检测到 MPA 内的种群下降，而前后比较可能会检测到这种模式。考虑到这些限制，我们发现全球 MPA 正在产生积极的结果，平均而言，其边界内的生物量、密度和生物体大小高于参考地点。 然而，只有一小部分研究（82 项研究中的 18 项）提供了必要的时间数据，以确定保护措施平均而言导致 MPA 内种群的丰度随着时间的推移而增加。这些发现证明了在评估 MPA 效应时考虑潜在系统动力学的重要性。假设较大的外-内响应比或 BACI 反应比总是反映较大的净正保护效应可能会导致误导性的结论，我们建议：（1） 在评估特定的 MPA 效应时，应将实证发现与该 MPA 系统相关的理论知识一起考虑，以及 （2） 管理层应响应当地条件和结果，而不是对积极的 MPA 效应一概而论。