Paradox of nutrient removal: coupled socio-economic and ecological dynamics to control lake water pollution.
08/6/10, 13:30 at Room 3631 (6th floor of building 3 of the Faculty of Sciences)
We study the coupled socio-economical and ecological dynamics for the lake water pollution. Players choose between cooperative (but costly) option and economical option, and their decision is affected by the fraction of cooperators in the community (conformist tendency) and by the importance of the lake water pollution problem. The social dynamics of stochastic best response type are coupled with the dynamics of lake water pollution, the latter being affected by the fraction of cooperators. We analyzed the model mathematically when the preference is strong (i.e. people's choice is close to the best response type). First, oscillation of large amplitude may occur if people's cooperation level changes faster than the ecosystem responses. Second, the model can show "paradox of nutrient removal". If phosphorus is removed more effectively either from the influx by cooperative players or directly from the lake water, the pollution level may increase (rather than decrease) due to the decline of the people's willingness to cooperate. Third, we discuss the effectiveness of alternative methods of improving the water quality: decreasing the cost of cooperation by subsidy, the enhancement of people's concern on the water pollution problem, and the enhancement of the conformity among people by strengthening the local community.
|
| Back: Japanese / English |