Extensive literature is available on the diversity and magnitude of impacts that alien species cause on recipient systems. Alien species may decrease or increase attributes of ecosystems (e.g. total biomass or species diversity), thus causing negative and positive environmental impacts. Alien species may also negatively or positively impact attributes linked to local human communities (e.g. the number of people involved in a given activity). Ethical and societal values contribute to define these environmental and socio-economic impacts as deleterious or beneficial. Whilst most of the literature focuses on the deleterious effects of alien taxa, some recognise their beneficial impacts on ecosystems and human activities. Impact assessment frameworks show a similar tendency to evaluate mainly deleterious impacts: only relatively few, and not widely applied, frameworks incorporate the beneficial impacts of alien species. Here, we provide a summary of the frameworks assessing beneficial impacts and briefly discuss why they might have been less frequently cited and applied than frameworks assessing exclusively deleterious impacts. Then, we review arguments that invoke a greater consideration of positive and beneficial impacts caused by alien species across the invasion science literature. We collate and describe arguments from a set of 47 papers, grouping them in two categories (value-free and value-laden), which span from a theoretical, basic science perspective to an applied science perspective. We also provide example cases associated with each argument. We advocate that the development of transparent and evidence-based frameworks assessing positive and beneficial impacts might advance our scientific understanding of impact dynamics and better inform management and prioritisation decisions. We also advise that this development should be achieved by recognising the underlying ethical and societal values of the frameworks and their intrinsic limitations. The evaluation of positive and beneficial impacts through impact assessment frameworks should not be seen as an attempt to outweigh or to discount deleterious impacts of alien taxa but rather as an opportunity to provide additional information for scientists, managers and policymakers.

中文翻译：

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评估外来物种的正面和有益影响的重要性

关于外来物种对受体系统的影响的多样性和严重性，已有大量文献可供参考。外来物种可能会减少或增加生态系统的属性（例如总生物量或物种多样性），从而造成负面和正面的环境影响。外来物种也可能对与当地人类社区有关的属性产生负面或正面影响（例如，参与特定活动的人数）。道德和社会价值有助于将这些环境和社会经济影响定义为有害或有益。尽管大多数文献关注外来生物分类群的有害影响，但一些文献认识到它们对生态系统和人类活动的有益影响。影响评估框架显示出一种类似的趋势来评估主要有害影响：只有相对较少，尽管没有得到广泛应用，但框架融合了外来物种的有益影响。在这里，我们提供了评估有益影响的框架的摘要，并简要讨论了为什么与专门评估有害影响的框架相比，为什么它们被较少引用和应用。然后，我们回顾了引起入侵科学文献中更多地考虑外来物种对正面和有益影响的论点。我们整理并描述了来自47篇论文的论点，将它们分为两类（无价值和有价值的），其范围从理论，基础科学的角度到应用科学的角度。我们还提供了与每个参数相关的示例案例。我们主张开发透明的，基于证据的评估积极和有益影响的框架可能会增进我们对影响动态的科学理解，并更好地为管理和优先级决策提供依据。我们还建议，应通过认识框架的潜在道德和社会价值及其固有局限性来实现这一发展。通过影响评估框架对积极和有益影响的评估不应被视为试图抵消或减轻外来生物群的有害影响，而应视为向科学家，管理人员和决策者提供更多信息的机会。我们还建议，应通过认识框架的潜在道德和社会价值及其固有局限性来实现这一发展。通过影响评估框架对积极和有益影响的评估不应被视为试图抵消或减轻外来生物群的有害影响，而应视为向科学家，管理人员和决策者提供更多信息的机会。我们还建议，应通过认识框架的潜在道德和社会价值及其固有局限性来实现这一发展。通过影响评估框架对积极和有益影响的评价不应被视为试图抵消或减轻外来生物群的有害影响，而应视为向科学家，管理人员和决策者提供更多信息的机会。