Longitudinal patterns in stream channel geomorphology and aquatic habitat in the Luquillo Mountains of Puerto Rico
Longitudinal patterns in stream channel geomorphology and aquatic habitat in the Luquillo Mountains of Puerto Rico
复制标题
波多黎各卢基约山脉河道地貌和水生栖息地的纵向模式
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发表时间：
2008
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通讯作者：
A. Pike
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作者：
A. Pike
波多黎各卢基略山区河道地貌和水生生境的纵向格局。派克·弗雷德里克·N与许多温带和/或冲积河流相比，热带山地河流的水文、地貌和生态动力学知之甚少。然而，随着对热带淡水环境威胁的增加，关于相对原始河流动态的信息对于了解景观演变、管理和保护自然资源以及实施河流恢复非常重要。本文描述了波多黎各东北部卢基略实验森林（LEF）的五个相邻流域的地貌和水文特征，并讨论了对水生生境的影响。我进行了几项相互关联的研究，包括：1）制定地理信息系统（GIS）框架，根据地形信息和水文记录估计水文参数，2）开发确定活动河道边界的方法（“满岸”级），其允许基于流动频率比较通道几何形状，3）通过广泛的实地河流调查和对河流剖面、河道几何形状和沉积动力学的分析，消除岩性和水力控制对河道形态的相对影响，4）通过地貌调查和水生动物取样相结合的协作分析，将网络和池规模的地质河流动力学与洄游鱼类和IV虾的丰度联系起来。这项研究表明，这些溪流有一些性质类似于温带山区和冲积河流。类似的低梯度河流，洪泛平原标志着渠道边界，在这些溪流的活跃渠道阶段是由木本植被和土壤发育的初期存在。系统的盆地规模的地貌模式是发达的，尽管明显的非河流和岩性控制当地的通道形态。这意味着强大的河流力足以覆盖河道边界阻力;这是自形成“门槛”冲积河道的常见特征。迁徙水生动物丰度受到屏障瀑布和合适的源头栖息地等多种地貌因素的影响，因此变化很大且呈斑块状。这些结果与水生群落反映系统地貌梯度的概念相反，而是承认多尺度地貌过程的影响。最终，这项研究提供了相对不变的热带溪流的物理和生物过程的基线信息，并可用于进一步研究，记录人类与溪流网络的相互作用。
LONGITUDINAL PATTERNS IN STREAM CHANNEL GEOMORPHOLOGY AND AQUATIC HABITAT IN THE LUQUILLO MOUNTAINS OF PUERTO RICO Andrew S. Pike Frederick N. Scatena The hydrologic, geomorphic, and ecological dynamics of tropical montane streams are poorly understood in comparison to many temperate and/or alluvial rivers. Yet as the threat to tropical freshwater environments increases, information on the dynamics of relatively pristine streams is important for understanding landscape evolution, managing and conserving natural resources, and implementing stream restoration. This dissertation characterizes the geomorphology and hydrology of five adjacent watersheds draining the Luquillo Experimental Forest (LEF) in northeastern Puerto Rico, and discusses implications on aquatic habitat. I performed several interrelated studies, including: 1) formulating a geographic information systems (GIS) framework to estimate hydrologic parameters from topographic information and hydrologic records, 2) developing a method to determine active stream channel boundaries (“bankfull” stage) that allows for comparison of channel geometry on the basis of flow-frequency, 3) decoupling the relative influences of lithologic and hydraulic controls on channel morphology using an extensive field-based stream survey and analysis of stream profiles, channel geometry, and sediment dynamics, 4) linking networkand pool-scale geofluvial dynamics to the abundance of migratory fish and iv shrimp through a collaborative analysis combining geomorphic surveys and aquatic faunal sampling. This research indicates that these streams have some properties resembling both temperate montane and alluvial rivers. Similar to low-gradient rivers where floodplains mark channel boundaries, the active channel stage in these streams is defined by the incipient presence of woody vegetation and soil development. Systematic basin-scale geomorphic patterns are well-developed despite apparent non-fluvial and lithologic control on local channel morphology. This implies that strong fluvial forces are sufficient to override channel boundary resistance; a feature common in self-forming “threshold” alluvial channels. Migratory aquatic fauna abundances are influenced by a variety of geomorphic factors such as barrier waterfalls and suitable headwater habitat, and are consequently highly variable and patchy. These results stand in contrast to the notion that aquatic communities mirror systematic geomorphic gradients, but rather acknowledges the influences of multiscale geomorphic processes. Ultimately, this research provides baseline information on physical and biological processes in relatively unaltered tropical streams and can be used to inform further studies that document human interactions with stream networks.