Estimation of Aquatic Animals' Potential Habitats based on Geographical Information System.

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Prior to analyzing the potential habitat of aquatic and wetland animals in Hyogo Prefecture, we gathering a numerous number of assessment reports, local papers and scientific publications. The data base sample of the fresh water animals reach up to fifteen thousands. Then, we analyzed the multiple-regression between these aquatic animals distribution and the existing geological, geographical, meteorological and plant sociological database on the base of given scale grid in Geographical Information System (GIS ; ESRI soft). These analysis revealed that the area of the drainage, the gradient of given point and the area of vertical section following downstream, decides time of creek water replacement frequency. The low value of creek water replacement surely related to sedimentation rate of suspended substances such as mud and sand. This deposit layer provides the suitable habitat for freshwater bivalves, and then these bivalves provide the suitable spawning substances of endangered cypri … More nid fish such as small bitterling. In Hyogo Prefecture, the stream reach embedded by mud and sand is now quite scarce habitats. These habitats are already invaded by alien fish of largemouth bass and blue gill. The endangered freshwater fish is double punched situation. Actions depressing these alien species population by the prefectural government is urgently needed now.The same method is employed about Japanese countryside salamander, Kasumi. In this case, the lack of the gradual slope created by paddy field construction located mountain slope, provides the leak point of ground water, it making temporal pool for spawning point for this aquatic animal. The set of two variables of temporal pool and gradual slope with vegetation strongly correlated to potential habitat of this salamander. In this case, the distance from nearest another suitable habitat is also important factor.In addition, we investigated the fish communities differences between prior to and after stream channel improvement at muddy and sandy reach, where inhabited by endangered cyprinid fishes. Before improvement stream structure were characterized by, complicated shore-line, existence of deep point, and embedded by muddy substrate. After improvement these characters changed to plain shape, shallow area and sandy substrate. According to this dramatic change of the habitat factors, fish community structure strictly responses immediately. We judge this change will be temporal phenomenon. The monitoring research both habitats structure and fish communities are continued. Less