Forest management guidelines are designed to protect water quality from unintended effects of land use changes such as timber harvest, mining, or forest road construction. Although streams that periodically cease to flow (nonperennial) drain the majority of forested areas, these streams are not consistently included in forest management guidelines. This paper reviews management guidelines for nonperennial (intermittent and ephemeral) streams draining temperate forests in the continental U.S., evaluates potential impacts of land use activities on ecosystem services provided by these streams, and identifies information needed to incorporate nonperennial streams into water quality protection practices. For federally administered lands, national management guidance is deliberately nonprescriptive, deferring to regional and forest-level recommendations for both perennial and nonperennial streams. Most state guidelines recommend riparian management zone (RMZ) protection for perennial streams (48/50 states) and intermittent streams (45/50 states), but only Alaska and West Virginia require RMZs around ephemeral streams. Based on the National Hydrography Dataset, an average of 58% of forested land area in the U.S. drains to nonperennial headwater streams, making these stream types the most common connectors between forested lands and the aquatic system. Land uses that modify flow regimes in these streams can affect sediment and organic matter transport and distribution, stream temperature dynamics, and biogeochemical processing. Nonperennial streams also provide material subsidies to downstream waters and serve as temporary habitats for some aquatic species. However, limited research has examined how forest land uses affect ecosystem services and biota in these streams. Therefore we highlight a set of key questions about nonperennial streams in forests, not the least of which is simply understanding where headwater stream channels are located and associated patterns of flow duration. Although many questions remain, we also note where recent advances in data collection, modeling and process-level research provide opportunties to resolve uncertainties around nonperennial streams in forested landscapes of the continental U.S.

森林管理指南旨在保护水质免受土地利用变化（如木材采伐、采矿或林道建设）的意外影响。尽管定期停止流动（非多年生）的溪流耗尽了大部分森林地区，但这些溪流并未始终包括在森林管理指南中。本文回顾了美国大陆温带森林排水的非多年生（间歇性和短暂性）溪流的管理指南，评估了土地利用活动对这些溪流提供的生态系统服务的潜在影响，并确定了将非多年生溪流纳入水质保护实践所需的信息。对于联邦管理的土地，国家管理指南是故意非规定性的，对多年生和非多年生溪流遵循区域和森林层面的建议。大多数州指南建议对常年溪流（48/50 州）和间歇性溪流（45/50 州）进行河岸管理区 (RMZ) 保护，但只有阿拉斯加和西弗吉尼亚州需要在短暂溪流周围设置 RMZ。根据国家水文数据集，美国平均 58% 的林地面积排入非多年生源头溪流，使这些溪流类型成为林地和水生系统之间最常见的连接器。改变这些河流流态的土地利用会影响沉积物和有机物质的运输和分布、河流温度动态和生物地球化学处理。非多年生河流还为下游水域提供物质补贴，并作为一些水生物种的临时栖息地。然而，有限的研究研究了林地使用如何影响这些河流中的生态系统服务和生物群。因此，我们强调了一系列关于森林中非多年生溪流的关键问题，其中最重要的是简单地了解源头溪流通道的位置和相关的流动持续时间模式。尽管仍有许多问题，但我们也注意到数据收集、建模和过程级研究的最新进展为解决美国大陆森林景观中非多年生溪流的不确定性提供了机会 因此，我们强调了一系列关于森林中非多年生溪流的关键问题，其中最重要的是简单地了解源头溪流通道的位置和相关的流动持续时间模式。尽管仍有许多问题，但我们也注意到数据收集、建模和过程级研究的最新进展为解决美国大陆森林景观中非多年生溪流的不确定性提供了机会 因此，我们强调了一系列关于森林中非多年生溪流的关键问题，其中最重要的是简单地了解源头溪流通道的位置和相关的流动持续时间模式。尽管仍有许多问题，但我们也注意到数据收集、建模和过程级研究的最新进展为解决美国大陆森林景观中非多年生溪流的不确定性提供了机会