Biological Diversity in Headwater Streams
Biological Diversity in Headwater Streams
复制标题
源头河流的生物多样性
作者：
J. Richardson
源头是所有河流网络的源头，提供了不同于其他淡水环境的独特栖息地，并被一个专门的水生物种子集所利用。提供特殊栖息地的源头特征包括无捕食者或无竞争者的空间;特定资源（特别是碎屑资源）;以及流量、温度和流量的适度变化。源头为几乎所有淡水门和部门的大量物种的所有或某些生命阶段提供了关键的栖息地。源头的一些特征，包括与世隔绝和种群规模小，使这些生境内外的许多生物群体能够进化辐射。作为小而容易工程化的物理空间，源头很容易因河岸开发、挖沟甚至掩埋而退化。源头河流是最敏感的淡水生态系统之一，因为它们与集水区有着密切的联系，而且很容易受到影响。作为一个拥有许多特殊物种的独特生态系统，源头河流应该得到更好的管理。
Headwaters, the sources of all stream networks, provide habitats that are unique from other freshwater environments and are used by a specialised subset of aquatic species. The features of headwaters that provide special habitats include predator-free or competitor-free spaces; specific resources (particularly detrital based); and moderate variations in flows, temperature and discharge. Headwaters provide key habitats for all or some life stages for a large number of species across just about all freshwater phyla and divisions. Some features of headwaters, including isolation and small population sizes, have allowed for the evolutionary radiation of many groups of organisms within and beyond those habitats. As small and easily engineered physical spaces, headwaters are easily degraded by streambank development, ditching and even burial. Headwater streams are among the most sensitive of freshwater ecosystems due to their intimate linkage with their catchments and how easily they are impacted. As a unique ecosystem with many specialist species, headwater streams deserve better stewardship.