Growing evidence shows that carbon sequestration in world’s natural ecosystems is necessary to address the associated impacts of global climate change on earth. This project studies urban wetlands and their ability to sequester atmospheric carbon and will analyse ways through which their carbon storage capacity be optimised for long-term duration through spatial design approaches. Wetlands regulate biogeochemical cycles with their complex ecosystem structure and are closely connected to climate change, as they are both carbon sinks and sources of methane. Long-term carbon storage occurs in their ecosystems due to unique reduced conditions and high plant-productivity. However, their role in moderating carbon fluxes in global carbon cycle is poorly estimated and understood due to lack of information from different wetland types belonging to different regions in the world. This Ph.D. project investigates the relation between plant-diversity and carbon sequestration in wetland ecosystems of Christchurch, to establish the dynamics that causes spatial design of plant communities to optimise carbon storage capacity of these ecosystems. It is a design-oriented research thesis and an interdisciplinary attempt to combine theory from wetland science and ecology, carbon sequestration, plant-ecology and planting design with an aim to improve ways through which we design urban-wetlands in landscape architecture. A combination of deductive and inductive strategies are being used and data collection is limited to specific locations in Christchurch only. The project is in the initial phases of development with preliminary results expected in early November 2020. Research implications will be applicable across created and restored wetlands in Christchurch, that would minimize methane fluxes and simultaneously improve carbon-stock within its ecosystem, along with providing habitats for avian species in their vegetation structure.