Physical Events, Environments, and Geological—Ecological Interactions at Mount St. Helens: March 1980–2004
Physical Events, Environments, and Geological—Ecological Interactions at Mount St. Helens: March 1980–2004
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圣海伦斯火山的物理事件、环境和地质生态相互作用：1980 年 3 月至 2004 年
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
J. Major
中科院分区：
文献类型：
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作者：
F. Swanson;J. Major
1980年圣海伦斯火山爆发期间火山活动的多样性和强度影响了广大地区的各种生态系统，为研究动态景观中地球物理和生态过程的相互作用创造了难得的机会。在1980年5月18日早晨的几个小时内，圣海伦斯火山爆发，释放出大量的碎片雪崩、侧向火山爆发、泥石流、火山碎屑流和大面积火山灰（见图1.1;图3.1、3.2;表3.1），影响了数千平方公里的地区。这些主要的物理事件杀死了生物体，移走或掩埋了有机物质和土壤，并创造了新的陆地和水生生境。尽管发生了这些深刻的环境变化，但扰动前生态系统的重要遗产，包括活的生物体、繁殖体以及有机和物理结构，在许多受影响的景观中仍然存在。火山过程的物理特征（高温、冲击力、磨损、侵蚀和掩埋深度）部分决定了死亡率的程度以及后破坏景观中生物遗产的类型和意义。1980年5月18日的主要火山事件引发了圣海伦斯火山地区一连串相互作用的生物、地质、水文和人为变化（见图1.2）。最初的事件改变了地貌、流域水文、沉积物的供应和输送，以及植被和动物在调节物理和生物过程中的作用。同时，水文和地貌过程改变了路径和生态反应的速度，不断修改栖息地，从而有利于一些物种和生态过程，而阻碍他人。了解地质和生态过程之间的相互作用是解释生态变化的后破坏景观的关键。为研究植物、动物、真菌、微生物和生态过程对1980年大爆发的反应奠定基础，我们总结了火山爆发前的火山事件、与大爆发和随后爆发相关的火山事件以及后火山景观的特征。我们还强调生态条件在几周内导致的主要喷发，因为在这个近距离的时间尺度的一些条件强烈影响posteruption生态反应。此外，我们讨论了新的环境所造成的喷发，气候和水文的变化，影响二次扰动和潜在的生态反应，和二次扰动对生态过程的性质和变化的步伐，通过第一季度世纪后爆发。我们探讨的概念，连接生态演替的地貌过程发生在大规模的，严重的干扰的继承。斯旺森等人（本卷第二章）描述了直到1980年的地质学和生态学方面的广泛地理和历史背景。在这里，我们总结了最近的火山喷发活动在圣海伦斯在其相关的生态反应。关于1980年喷发活动的更全面的技术讨论可以在其他地方找到（Lipman和Mullineaux 1981; Foxworthy和Hill 1982; Major et al. 2005）。
The diversity and intensity of volcanic processes during the 1980 eruption of Mount St. Helens affected a variety of ecosystems over a broad area and created an exceptional opportunity to study interactions of geophysical and ecological processes in dynamic landscapes. Within a few hours on the morning of May 18, 1980, a major explosive eruption of Mount St. Helens affected thousands of square kilometers by releasing a massive debris avalanche, a laterally directed volcanic blast, mudflows, pyroclastic flows, and widespread tephra fall (see Figure 1.1; Figures 3.1, 3.2; Table 3.1). These primary physical events killed organisms, removed or buried organic material and soil, and created new terrestrial and aquatic habitats. Despite these profound environmental changes, important legacies of predisturbance ecosystems, including live organisms, propagules, and organic and physical structures, persisted across much of the affected landscape. The physical characteristics of the volcanic processes (elevated temperature, impact force, abrasion, and depth of erosion and burial) in part determined the extent of mortality and the types and significance of biotic legacies in the posteruption landscape. The primary volcanic events of May 18, 1980 triggered a succession of interacting biological, geological, hydrologic, and anthropogenic changes in the Mount St. Helens area (see Figure 1.2). The initial events altered landforms, watershed hydrology, sediment availability and delivery, and the roles of vegetation and animals in regulating physical and biological processes. Concurrently, hydrologic and geomorphic processes altered the paths and rates of ecological responses by persistently modifying habitats, thereby favoring some species and ecological processes while impeding others. Understanding the interactions between geological and ecological processes is critical for interpreting ecological change in the posteruption landscape. To set the stage for examining the responses of plants, animals, fungi, microbes, and ecological processes to the major 1980 eruption, we summarize volcanic events immediately preceding the eruption, those associated with that major eruption and subsequent eruptions, and characteristics of the posteruption landscape. We also highlight ecological conditions in the weeks leading up to the major eruption because some conditions at this proximal time scale strongly influenced posteruption ecological responses. In addition, we discuss new environments created by the eruption, variations in climate and hydrology that affected both secondary disturbances and the potential for ecological responses, and the nature and pace of change imposed by secondary disturbances on ecological processes through the first quarter century after the eruption. We explore concepts linking ecological succession to the succession of geomorphic processes that occur in response to large-scale, severe disturbances. Broad geographical and historical contexts in geological and ecological terms leading up to 1980 are described by Swanson et al. (Chapter 2, this volume). Here, we summarize the recent eruptive activity at Mount St. Helens in terms of its relevance to ecological responses. More comprehensive technical discussions of the 1980 eruptive activity can be found elsewhere (Lipman and Mullineaux 1981; Foxworthy and Hill 1982; Major et al. 2005).