Middle- and Large-sized Aquatic Animal Assemblages Associated with Submerged Riparian Plants in the Kamo River, Kyoto

Abstract

Middle- and large-sized aquatic animal assemblages associated with the submersed leaves, stems and roots of the reed Phragmites japonica and other riparian plants were studied in the Kamo River, Kyoto, with a focus on the faunal differences in both longitudinal and seasonal distribution. At the upper and middle sites, mayfly larvae inhabiting slow riffles and shallow pools were dominant in winter and spring.
Several lentic hemipteran insect species such as water scorpions and back swimmers associated chiefly with hydrophytes in ponds and marshes were also found in summer or autumn within the stands of monocotyledonous plants on the wide gravel bar of the middle site. At the lower site, within the Kyoto city limits, water slaters, leeches and snails were abundant from spring through autumn. In addition, many larvae of calopterygid and coenagrionid dragonflies were collected in spring and summer, respectively. Juvenile fishes of dark chub and lizard goby were abundant in summer and autumn at all three sites. Riparian plants were thus suggested to increase species diversity of lotic fauna, providing habitats not only for lotic invertebrates but also for lentic insects and juvenile fishes.