Urban ecosystem is a project of urban analysis, exploring the complex phenomena that immerge in the contemporary city. It introduces experimental techniques and methods of approaching the diverse character of the city along the axis of a balanced urban ecosystem. The main focus is in the area of Chueca which is characterized by this diversity which is the result of the coexistence of different levels of relationships among the organisms of the city. The project investigates in detail these relations and points out the possible threats that have the tendency to unbalance the urban equations. In the end a series of small-scale interventions is proposed in order to help the area keep and develop its diverse character. A specific intervention is developed further on the next project "i180".