River-ice ecology. II: Biological aspects

River ice is an integral and important component of the flow regime in cold-regions environments. As demonstrated in a companion paper, it can significantly affect many of the hydrologic, geomorphic. and chemical characteristics of a river. Building on such a physical template. this paper reviews the related biological effects at all stages of winter ice cover, including the period of autumn cooling, initial freeze-up. main winter, and breakup. Special focus is placed on the role of ice in seasonal movements and avoidance behavior of fish and benthic organisms. the creation of unique in-channel and riparian habitats, the modification of aquatic and floodplain vegetation, and some river-ecology theories, including disturbance ecology and flood-pulse theory. Included is a comprehensive reference list, the most complete ever assembled on this subject.