Abstract
Relationship between diversity of aquatic animals and environmental factors were evaluated. In this study, a field investigation was carried out in a paddy-field area in the eastern part of Shimane Prefecture. Parameters of this study were water qualities, fishes, aquatic insects, and physical environmental factors (breadth of canal, water depth, flow velocity, vegetation coverage, and soil coverage of undersurface) in drainage canals. Eleven species of fishes and fourteen species or family of aquatic insects were observed in the investigation sites and diversity indexes were calculated by Shannon-Wiener method. Multiple linear regression analysis was conducted between the diversity indexes and environmental factors that would affect inhabitation of these aquatic animals. By this analysis, statistical results suggested that the important factors for fish habitation were total nitrogen (T-N), dissolved oxygen (DO), chemical oxygen demand (COD), suspended soils (SS), vegetation coverage, and soil coverage of undersurface. On the other hand, the factors for aquatic insect habitation were DO, nitrite nitrogen (NO2-N), breadth of canal, vegetation coverage, and soil coverage of undersurface.
