A CASE STUDY OF FLOOD DISTURBANCE IMPACT ON HABITAT OF FRESH WATER MUSSELS

Abstract

 Excessive river improvements caused degradation of river ecosystems and loss of aquatic biodiversity. Mussels which are one of good indicator species of river environment are also decreasing their population and habitat drastically. The object of this study is to contribute to river restoration projects by revealing the factors that are limiting mussel's existence. We surveyed distribution of mussels, physical surroundings of their habitat and mussel defection experiment in the Matsuura River. Followings are indicated from the result. Floodplain, sand bar that causes burble flow, and focal projection such as woody debris function as shelters for mussels during flood event. Smaller mussels were easier to be effected by flush water than larger individuals.