The Dutch ecological network (EHS in Dutch) is a contiguous network of existing and planned nature reserves throughout the country that form the basis for environmental policy. The ecological network consists of core areas. The exchange of animals between different core areas occurs via an ecological connecting zone (EVZ). Creating an EVZ in the city provides an opportunity for the nature in the city to better adapt to climate change. All of the green and water elements in the city can improve the quality of the ecological connecting zone.
The presence of biotopes that are connected to each other is essential for exchange and dynamism. Urban biotopes may change completely with respect to their populations; this should be acceptable. A connection with a rural area is desirable for the dynamics and migration, for instance for large mammals and humans.
Obviously the nature reserves have a positive effect on water management and contribute to reducing flooding, desiccation and salinization.