Application of Population Dynamics Modeling to Habitat Evaluation – Growth of Some Species of Attached Algae and Its Detachment by Transported Sediment –

¹ Professor, Dept. of Civil Engineering, Nagoya University. Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
² Post doctoral fellow, Aqua Restoration Research Center, Public Works Research Institute. Kasada-cho, Kawashima-cho, Hashima-gun, Gifu pref. 501-6021, Japan.

Abstract

Mathematical population dynamics modelling has been employed to simulate and predict habitat situation of living species. It is introduced to description of botanical growth in aquatic ecosystem by setting the growth and decay rate. Although the PHABSIM technique also can discuss habitat situation, it cannot evaluate the habitat with dynamical changes efficiently. Population dynamics is applied for developing habitat evaluation method in the paper. By investigating the algal habitat in the middle reach of the Yahagi River, the net growth rate is changed spatially corresponding to velocity and water-depth. According to the field observation and conventional hydraulic modeling, the growth rate and the detachment rate of attached algae is estimated. By applying the simulation, population dynamics modeling can be identified as one of the necessary angles for habitat evaluation.