Doctoral Dissertation Research: The Impact of Historical Logging Activities on the Ecology and Geomorphology of Mountain Streams

这个博士论文研究改进项目是关于历史性的河流通道干扰和生态系统功能的相关影响。 以往的研究表明，流地貌和生态系统过程，如流代谢之间的密切关系，但鲜为人知的是，过去的流通道干扰如何影响这些关系或流恢复这些历史性的干扰。 了解地貌过程和生态系统功能之间的联系，以及这些关系是如何受到干扰的影响，对溪流的环境管理，特别是溪流恢复的做法有影响。 生态系统代谢是指藻类和水生植物群落的总初级生产力（GPP）与生态系统呼吸（ER）之间的平衡，它占系统中所有水生群落对有机碳的总消耗。 光、温度、水流和通道复杂性都相互作用并影响GPP和ER的速率。 这项研究将解决在何种程度上过去的流通道干扰和最近的恢复工作影响这些控制。 该项目的研究问题是：（1）结构和功能地貌特征在扰动、未扰动和恢复的河道条件下如何变化？2）GPP和ER如何应对这些变化？ 在过去，山区溪流受到一种被称为“枕木驱动”的森林采伐策略的影响，在此期间，有系统地清理和疏导溪流，以帮助铁路枕木的运输。 这种做法在怀俄明州和科罗拉多非常普遍，这种做法的遗产在今天的景观上仍然很明显。 我们假设：1）与非干扰流相比，由于较薄的河岸覆盖和较低的河道河岸，增加了光的可用性，因此，与非干扰流相比，联系驱动流中的GPP将更高，2）与非干扰流相比，由于有机物现存量减少和河道复杂性降低，联系驱动流中的ER将最低，以及3）在所有流中ER的速率将大于GPP的速率，这表明社区依赖于源自信道外部的能量补贴。 这项研究的结果将解决与河流地貌，河岸组成，及生态系统代谢，并将发展一个综合的基础，以了解河流恢复工程的生态结果。本项目的结果将有助于通过在干扰的背景下综合调查河流地貌和生态系统功能，为未来的河流恢复和管理工作提供信息政权 改善这些学科的联系将导致更有效率和更有效的河流恢复项目和更有效地利用联邦和州恢复投资。 在该项目的过程中，研究结果和相关数据将直接与美国农业部林务局和美国鱼类和野生动物管理局等当地机构共享，确保研究结果将快速有效地纳入机构管理工作。 作为博士论文研究改进奖，该项目将提供支持，使有前途的研究生建立一个独立的研究生涯。

This Doctoral Dissertation Research Improvement project is about historic stream channel disturbances and associated implications for ecosystem functioning. Previous research has demonstrated strong relationships between stream geomorphology and ecosystem processes such as stream metabolism, but little is known about how past stream channel disturbances influence these relationships or how streams recover from these historic disturbances. Understanding the link between geomorphic processes and ecosystem function as well as how these relationships are affected by disturbance has implications for the environmental management of streams, particularly the practice of stream restoration. Ecosystem metabolism refers to the balance between the processes of gross primary production (GPP) by algal and aquatic plant communities and ecosystem respiration (ER), which accounts for the total consumption of organic carbon by all aquatic communities in the system. Light, temperature, stream flow, and channel complexity all interact and influence rates of GPP and ER. This research will address the degree to which past stream channel disturbances and recent restoration efforts affect these controls. The project's research questions are 1) how do structural and functional geomorphic characteristics vary between disturbed, non-disturbed, and restored channel conditions?; and 2) how do GPP and ER respond to these changes? In the past mountain streams were impacted by a forest harvesting strategy known as 'tie-driving,' during which there was systematic clearing and channelizing of streams to aid in the transport of railroad ties. This practice was very common in Wyoming and Colorado and the legacy of this practice is still evident on the landscape today. We hypothesize that 1) GPP will be higher in tie-driven streams as compared to non-disturbed streams because of increased light availability as a result of thinner riparian cover and lower channel banks, 2) ER will be lowest in tie-driven streams compared to non-disturbed streams because of decreased organic matter standing stocks and decreased channel complexity, and 3) rates of ER will be greater than rates of GPP in all streams indicating that communities are reliant on energy subsidies originating from outside the channel. Results from this study will address knowledge gaps related to the interactions between stream geomorphology, riparian composition, and ecosystem metabolism and will develop an integrative foundation for understanding ecological outcomes of stream restoration projects.Results of this project will help to inform future stream restoration and management efforts through the integrative investigation of stream geomorphology and ecosystem function within the context of a disturbance regime. Improving these disciplinary links will result in more efficient and effective stream restoration projects and more efficient use of federal and state restoration investments. Over the course of this project, results and associated data will be shared directly with local agencies such as the USDA Forest Service and the U.S. Fish and Wildlife Service, ensuring that research findings will be incorporated in agency management efforts quickly and efficiently. As a Doctoral Dissertation Research Improvement award, the project will provide support to enable a promising graduate student to establish an independent research career.