Author(s): Mitsukuni Tsuchiya; Keiji Morota
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Keywords: Flood disturbance; Benthic organisms; Probability of exceedence; Simpson index
Abstract: In the study of river hydrology, particularly fluctuations in run-off, the relationship between the diversity of benthic organisms and that has rarely been demonstrated. Here we report the findings of a 20-year study of the diversity in the benthic fauna of the Aki, Hirai and Kita-asakawa rivers in Tama-river system that has been undertaken by the Tokyo Metropolitan Government from 1980 era. Differences between natural and artificial impacts were assessed by comparing faunal diversity data for dates on which disturbances occurred against data obtained on days when samples were taken. Statistical analysis revealed a strong relationship between flood disturbance and the diversity benthic organisms. Consequently, it was found that flood disturbances of moderate scale could be explained using a probability of exceedence flow regime curve (Q95) and the Simpson index, and that these could be described using a parabolic function over protruding
Year: 2005