Purpose of Review

Forests play an essential role in conserving pollinating insects and supporting pollination services in mixed-use landscapes and are particularly important to species that require resources restricted to forests. However, some forests provide higher quality habitat for these organisms than others. The primary objectives of this article are to 1) review how pollinator communities are influenced by changes in forest structure, composition, and age, 2) explore how these patterns differ between conifer and broadleaf forests, and 3) provide recommendations for managers interested in optimizing forest conditions for pollinating insects.

Recent Findings

Although biodiversity generally increases as forests mature and become more structurally and compositionally complex, patterns exhibited by pollinating insects vary depending on forest type and prevailing disturbance regimes. For example, conifer forests can either sustain pollinator diversity comparable to open habitats or experience reduced pollinator diversity depending on the openness of the canopy. In broadleaf forests, pollinator diversity often increases with age (following the stem exclusion stage) and increasing tree diversity, and diversity in these areas can exceed what is observed in open habitats even under closed-canopy conditions. Such patterns likely reflect the importance of flowering broadleaf trees to pollinators, including many forest-dependent species, and suggest that optimal management practices for conserving pollinators differ between conifer and broadleaf forests.

Summary

We conclude that: 1) the quality of forests to pollinating insects is a function of forest structure and composition as mediated by forest age and disturbance history and 2) best management practices need to be developed separately for conserving pollinators in conifer and broadleaf forests. Research aimed at better understanding the value of different broadleaf tree taxa to pollinators, especially forest-dependent species, is needed.

中文翻译：

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森林对昆虫授粉的价值因森林结构、组成和年龄而异

 审查目的

森林在保护授粉昆虫和支持混合用途景观中的授粉服务方面发挥着重要作用，对于需要森林资源的物种尤其重要。然而，一些森林比其他森林为这些生物提供了更高质量的栖息地。本文的主要目标是 1) 回顾森林结构、组成和年龄变化如何影响授粉媒介群落，2) 探索针叶林和阔叶林之间这些模式的差异，以及 3) 为有兴趣优化的管理者提供建议授粉昆虫的森林条件。

 最近的发现

尽管生物多样性通常随着森林的成熟而增加，并且在结构和组成上变得更加复杂，但传粉昆虫表现出的模式会根据森林类型和普遍的干扰状况而有所不同。例如，针叶林要么可以维持与开放栖息地相当的传粉媒介多样性，要么根据树冠的开放程度而减少传粉媒介多样性。在阔叶林中，传粉媒介多样性通常随着年龄（在茎排除阶段之后）和树木多样性的增加而增加，并且这些地区的多样性甚至可以超过在开放栖息地中观察到的多样性，即使在封闭的树冠条件下也是如此。这种模式可能反映了开花阔叶树对授粉媒介（包括许多依赖森林的物种）的重要性，并表明保护授粉媒介的最佳管理实践在针叶林和阔叶林之间有所不同。

 概括

我们的结论是：1）森林对传粉昆虫的质量是森林结构和组成的函数，由森林年龄和干扰历史介导；2）需要单独制定最佳管理实践，以保护针叶林和阔叶林的传粉媒介。需要开展旨在更好地了解不同阔叶树类群对传粉昆虫、特别是依赖森林的物种的价值的研究。