Urban ecological regulation based on information entropy at the town scale A case study on Tongzhou district, Beijing City

Based on dissipative structure theory and ecological cybernetics, an ecological regulation approach at the town scale was developed, which was aimed at increasing system order and maintaining a healthy system by reducing the entropy of the urban ecosystem. First, considering the characteristics of the urban nature-economy-society complex ecosystem and entropy theory, the entropy of the urban ecosystem was defined as a state parameter indicating system disorder, and it could be divided into entropy flow and entropy production. Second, an entropy evaluation indicator system for the urban ecosystem was constructed by associating ecosystem characteristics at the town scale. Then, using Tongzhou district of Beijing City as an example and future city development planning objects and policies about national environmental protection and energy-saving and emission-reduction, adjustable indicators were selected, and a system entropy regulation approach was established. These indicators were easy to obtain and regulate with the purpose of reducing system entropy. Finally, via quantitative model of computing information entropy, we analyzed the entropy change of the urban ecosystem, as well as the harmonious degree and developmental degree in Tongzhou district for both the evaluation time period (2000-2007) and the planning year (2020). Our results indicated that after the regulation approach was brought into effect, the entropy flow, entropy production and total entropy substantially would reduce compared with the same variable during the evaluation period. Thus, system order can be significantly enhanced, and the regulation approach was proven to be effective. This study provides a new regulation approach to solve complex eco-environmental problems during the urbanization process. (C) 2011 Published by Elsevier Ltd. Published by Elsevier B.V. Selection and/or peer-review under responsibility of School of Environment, Beijing Normal University.