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The influence of major FLOOD disturbance on River EcoSystem Evolution Trajectories in recently deglaciated terrain (FLOODRESET)

主要洪水扰动对最近冰川消融地区河流生态系统演化轨迹的影响（FLOODRESET）

基本信息

批准号：
NE/E004148/1
负责人：
Alexander Milner
金额：
$ 1.39万
依托单位：
University of Roehampton
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2006
资助国家：
英国
起止时间：
2006 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FE004148%2F1
关键词：
influence major FLOOD disturbance River

项目摘要

One of the major factors influencing river ecosystems is disturbance, particularly that related to flooding. Floods maintain ecosystem diversity and redistribute energy, nutrients, sediment and biota in rivers. The biota of rivers (e.g. invertebrates and fish) may survive floods either by withstanding the disturbance (resistance) or recovering rapidly (resilience). Although disturbance to river ecosystems due to severe flooding have been relatively well studied, many studies have a restricted pre-disturbance series of data against which to evaluate flood effects and rarely in terms of their successional development. This in part reflects minimal continuous, year-on-year monitoring of stream communities against which to measure any disturbance effects. Between November 21 and 26 of 2005, a strong winter storm with high winds and record rainfall caused widespread flooding, landslides, and wind damage in southeast Alaska. The cities of Juneau, Haines, and Sitka made local disaster declarations and requested state and public assistance for response and recovery. Continuous heavy rainfall (over 650mm in less than 72 hours) occurred over a region called Glacier Bay in southeast Alaska, leading to large scale flooding and extreme disturbance to many rivers. The size of this event is evident when compared against an average annual rainfall of 920mm. In Glacier Bay, we hold long-term continuous data sets (up to 29 years for some streams) detailing stream community evolution following glacial retreat. This data set has provided unique insights into primary succession (change over time) of stream invertebrates and fish. For one stream (Wolf Point Creek; WPC) a highly detailed trajectory of community change has been assembled since 1977, showing how the stream has evolved from one dominated by a few species of Chironomidae to one more recently (2005) containing a diverse community of invertebrates (insects/non-insects) and juvenile salmonids. However, during a brief visit to Glacier Bay at the beginning of June 2006 we observed that many of the streams (including WPC) had been severely affected by floods with major changes in channel morphology evident. This disturbance is likely to have had a major effect on the biological communities of these streams. Four major avenues of research will be followed: (1) the effect of the flooding on the stream habitat and morphology across streams of different ages, (2) an investigation of the effect of the flooding on the primary successional framework (invertebrates, fish) in Wolf Point Creek, (3) an investigation into the effects of the flooding on streams of different ages to provide information on how streams at different stages of successional development respond to flooding, and; (4) a stream side channel experiment to examine if resistant/resilient invertebrates modify the subsequent successional trajectory of stream biota. This study will assess the effects of these major flood disturbances on the primary succession trajectories of stream invertebrates and fish and identify persistent taxa. It is critical that we investigate as soon as possible the effect of the flood on the biotic communities because recolonisation and succession will potentially occur throughout this summer as communities recover. We aim to assess the recovery trajectory over the next 13 months to determine if full recovery occurs. It is probable that some invertebrate species have been lost from streams due to the flood, and these may take a long time to return due to the presence of dispersal barriers such as mountains and large icefields. The results will be in interpreted in terms of community persistence (constancy of presence/absence) and compositional stability (constancy of relative abundance of taxa) traits of the taxa that confer resistance and resilience and of habitat complexity providing the potential for more refugia.

影响河流生态系统的主要因素之一是干扰，特别是与洪水相关的干扰。洪水维持了生态系统的多样性，并重新分配河流中的能量、养分、沉积物和生物群。河流生物群（例如无脊椎动物和鱼类）可以通过承受干扰（抵抗力）或快速恢复（恢复力）而在洪水中幸存下来。尽管严重洪水对河流生态系统的干扰已经得到了相对充分的研究，但许多研究只有有限的干扰前数据系列来评估洪水影响，而很少涉及其连续发展。这在一定程度上反映了对溪流群落进行最低程度的连续、逐年监测，以衡量任何干扰影响。 2005 年 11 月 21 日至 26 日期间，一场强冬季风暴伴随着大风和创纪录的降雨量，在阿拉斯加东南部造成大范围的洪水、山体滑坡和风灾。朱诺、海恩斯和锡特卡等市发布了当地灾难声明，并请求州和公共援助以应对和恢复。阿拉斯加东南部冰川湾地区连续强降雨（不到72小时降雨量超过650毫米），导致大面积洪水泛滥，多条河流受到严重扰动。与年平均降雨量 920 毫米相比，这一事件的规模显而易见。在冰川湾，我们拥有长期连续数据集（某些溪流长达 29 年），详细描述了冰川退缩后溪流群落的演变。该数据集为河流无脊椎动物和鱼类的初级演替（随时间的变化）提供了独特的见解。对于一条溪流（Wolf Point Creek；WPC），自 1977 年以来就已经收集了非常详细的群落变化轨迹，显示了该溪流如何从以少数摇蚊科物种为主的溪流演变为最近（2005 年）包含多种无脊椎动物（昆虫/非昆虫）和幼鱼群落的溪流。然而，在2006年6月初对冰川湾的短暂访问中，我们观察到许多溪流（包括WPC）受到洪水的严重影响，河道形态发生了明显的重大变化。这种干扰可能对这些溪流的生物群落产生了重大影响。将遵循四个主要研究途径：（1）洪水对不同年龄溪流栖息地和形态的影响，（2）调查洪水对沃尔夫角溪主要演替框架（无脊椎动物、鱼类）的影响，（3）调查洪水对不同年龄溪流的影响，以提供不同演替发展阶段的溪流如何应对洪水的信息，以及； (4) 河边水道实验，以检查抗性/弹性无脊椎动物是否改变了河流生物群的后续演替轨迹。这项研究将评估这些主要洪水扰动对河流无脊椎动物和鱼类主要演替轨迹的影响，并确定持久性类群。我们必须尽快调查洪水对生物群落的影响，这一点至关重要，因为随着群落的恢复，今年夏天可能会发生重新殖民和演替。我们的目标是评估未来 13 个月的恢复轨迹，以确定是否会完全恢复。一些无脊椎动物物种可能因洪水而从溪流中消失，并且由于山脉和大冰原等扩散障碍的存在，这些物种可能需要很长时间才能恢复。结果将根据类群的群落持久性（存在/不存在的恒定性）和组成稳定性（类群相对丰度的恒定性）特征进行解释，这些特征赋予类群抵抗力和恢复力，以及提供更多避难所潜力的栖息地复杂性。