Geomorphic influence of beaver on fluvial systems in the greater Yellowstone ecosystem

海狸对大黄石生态系统河流系统的地貌影响

• 批准号: 0844293
• 负责人: Grant Meyer
• 金额: $ 18.5万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0844293&HistoricalAwards=false
• 关键词: Geomorphic; influence; beaver; fluvial; systems

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).It has been assumed that when beavers build their dams across small stream systems it causes long-term filling of valleys with sediment and creates broad, flat "beaver meadows". Thus beaver activity is thought to promote both a persistent reduction in sediment flux and greater groundwater storage capacity in the accumulated deposits. By reducing flow velocities, individual beaver ponds clearly trap sediment, but the depth and spatial distribution of sediment deposition caused by beaver dams have never been quantified over timescales longer than the lifetime of a single beaver pond. The goal of this project is to document the effects of beaver dams in floodplains of small streams in the greater Yellowstone area, in deposits dating from the present back to the end of the last glaciation about 12,000 years ago (the Holocene epoch). By detailing the texture, mineral and organic composition, chemistry, and sedimentary structures of modern beaver-pond deposits and their associated landforms, this work will define diagnostic characteristics essential to identifying these deposits in older floodplain sequences and abandoned channels. Radiocarbon dating will put the timing of beaver-pond deposits in the context of long-term environmental change in the Yellowstone region. Knowledge gained in this study about the long-term effects of beaver damming is of significance in understanding the long-term evolution of stream valleys. It also has relevance to improving the overall health of small stream systems, such as those where a decline in beaver populations has caused a notable increase in channel incision. It will thus help to focus available resources for restoring and protecting stream habitat and water quality on those waterways that are most in need. Such information is particularly relevant to management in northern Yellowstone National Park, where a lack of beaver damming is thought to have caused downcutting of many streams, with consequent lowering of water tables and reduction of wetlands habitat. The study will involve independent research projects and advanced scientific training for two graduate students. In addition, undergraduate students from the predominantly Native American population at the UNM-Gallup campus will be involved in both field and laboratory research that will assist in movement of these students into scientific degree programs and careers.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。人们认为，当海狸在小溪系统上建造水坝时，会导致沉积物长期填充山谷，并创造出宽阔平坦的“海狸草地”。 因此，海狸活动被认为是促进沉积物通量的持续减少和积累的沉积物中更大的地下水储存能力。 通过降低流速，单个海狸池塘明显地捕获沉积物，但是海狸水坝引起的沉积物沉积的深度和空间分布在比单个海狸池塘的寿命更长的时间尺度上从未被量化。 该项目的目标是记录大黄石地区小溪流洪泛区海狸坝的影响，其沉积物可追溯到大约12，000年前的最后一次冰川作用结束（全新世）。 通过详细描述现代海狸池塘沉积物及其相关地貌的纹理、矿物和有机成分、化学和沉积结构，这项工作将定义诊断特征，这些特征对于在较老的洪泛平原序列和废弃通道中识别这些沉积物至关重要。 放射性碳测年将把海狸池塘沉积的时间放在黄石地区长期环境变化的背景下。 河狸筑坝的长期影响，在这项研究中获得的知识是有意义的，在理解长期演变的河流流域。 它也有相关性，以改善整体健康的小河流系统，如海狸种群的下降，导致了显着增加的渠道切口。 因此，这将有助于把恢复和保护溪流生境和水质的现有资源集中用于最需要的水道。 这些信息与北方黄石国家公园的管理特别相关，人们认为，在那里，由于没有河狸筑坝，许多溪流被切断，从而降低了地下水位，减少了湿地生境。 这项研究将涉及独立的研究项目和两名研究生的高级科学培训。 此外，来自联合国大学盖洛普校区的主要美洲原住民人口的本科生将参与实地和实验室研究，这将有助于这些学生进入科学学位课程和职业生涯。