Collaborative Research: Leaky Rivers: Nutrient Retention and Productivity in Rocky Mountain Streams Under Alternative Stable States

合作研究：渗漏河流：替代稳定状态下落基山脉溪流的养分保留和生产力

• 批准号: 1146283
• 负责人: Robert Hall
• 金额: $ 32.32万
• 依托单位: University of Wyoming
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1146283&HistoricalAwards=false
• 关键词: Collaborative; Research; Leaky; Rivers; Nutrient

Streams occupy a small part of Earth's surface, but are disproportionately important for transport and processing of nutrients and for maintaining global biodiversity. Logjams in streams increase retention of nutrients and fish production. Human removal of logjams is pervasive in forested ecosystems, creating "dam-impoverished" streams with limited capacity to store nutrients and produce fish. A prime example is streams of the southern Rocky Mountains, where a legacy of wood removal has greatly reduced logjams. This project asks: Does the loss of jams reduce the productive capacity of headwater streams? It is hypothesized that the loss of jams makes streams more leaky of nutrients, with subsequent decreased nutrient processing and fish production. This project will examine logjams and jam-associated processes across a gradient of streams, including streams in old-growth forests, unmanaged younger forests, and intensively managed forests. This work will provide the first landscape-scale assessment of the effects of jam removal on stream ecosystems. This research can transform current understanding of wood effects on stream ecosystems by combining estimates of logjam historical distribution with intensively measured geochemical and biological variables in contemporary jams, allowing extension of local-scale observations to entire steam networks. Understanding how the loss of jams affects streams will inform resource management of headwater streams in forested landscapes. The National Park Service and the US Forest Service oversee vast tracts of forested lands in the American West and are attempting to restore some of the inferred historical characteristics of the Rocky Mountain landscape. By enhancing understanding of changes in jams, as well as the biogeochemical and ecological influence of these structures, the proposed work will provide much-needed context for these management actions. This project will also provide training for one post-doctoral scholar and four graduate students. It will also provide research experiences for several undergraduate students.

溪流只占地球表面的一小部分，但对于养分的运输和加工以及维持全球生物多样性却异常重要。溪流堵塞会增加营养物质的保留和鱼类产量。在森林生态系统中，人类清除堵塞现象普遍存在，造成“水坝贫化”的溪流，储存养分和生产鱼类的能力有限。一个典型的例子是落基山脉南部的溪流，那里的伐木活动大大减少了堵塞。该项目提出的问题是：堵塞的消失是否会降低源头河流的生产能力？据推测，堵塞的消失会使溪流更多地流失营养物质，从而导致营养物质加工和鱼类产量减少。该项目将检查溪流梯度上的堵塞和堵塞相关过程，包括古老森林、未管理的年轻森林和集约化管理的森林中的溪流。 这项工作将对清除堵塞对溪流生态系统的影响进行首次景观尺度评估。这项研究可以通过将堵塞历史分布的估计与当代堵塞中密集测量的地球化学和生物变量相结合，改变目前对木材对河流生态系统影响的理解，从而将局部规模的观测扩展到整个蒸汽网络。了解堵塞的消失如何影响溪流将为森林景观中源头溪流的资源管理提供信息。国家公园管理局和美国林业局负责监管美国西部大片林地，并试图恢复落基山景观的一些推断历史特征。通过加深对堵塞变化以及这些结构的生物地球化学和生态影响的理解，拟议的工作将为这些管理行动提供急需的背景。 该项目还将培养一名博士后和四名研究生。它还将为几名本科生提供研究经验。