Wetlands in The Netherlands and New Zealand: Optimising biodiversity and carbon sequestration during urbanisation

The halting of biodiversity decline of wetlands necessitates ecosystem protection, restoration and re-creation of all wetland types preferably in all suitable landscapes. As peat wetlands (bogs and fens) are superior as carbon stores, and because of their rarity they have a higher biodiversity value relative to other wetland types, they need to be prioritised for protection and restoration. The hydrological, pH, and nutrient conditions essential to each type of wetland that need to be understood and provided for during development are discussed for The Netherlands’ and New Zealand. Case studies describe freshwater wetland management and challenges during urbanisation in the Stad van de Zon and Blauwestad in The Netherlands, and in the Styx valley and Pegasus in Christchurch, New Zealand. A summary of the history of urbanisation and wetland destruction, and of biodiversity management for each country provides a context for the case studies. These case studies demonstrate the degree to which the relative values of bogs, fens and swamps, with respect to biodiversity and carbon sequestration, are understood and managed using diverse protection measures, within the boundaries of new urban developments and in adjacent ecological corridors.

► Four residential developments are examined for wetland restoration and re-creation. ► Changes in nutrients, pH and hydrology limit these wetlands. ► Limited biodiversity and carbon sequestration gains are evident. ► Peat wetlands in ecological corridors optimise rare biodiversity and carbon sequestration.