The Short-Term Carbon Sequestration Potential of New Zealand Indigenous Plant Species in Riparian Zones of Ephemeral Wetlands

Ephemeral wetlands and their riparian zones provide a number of critical ecosystemservices, however the potential carbon sequestration of these areas is poorly understood. Greater understanding of the short term (10 year) carbon sequestration potential of these wetlands may provide a profit incentive for businesses to invest additional resources into ecological restoration.

The Stage 3 area of the Wairio Wetland provides an excellent testing ground for assessing this. Historically a Kahikatea swamp forest, the Wairio Wetland has been extensivelymodified due to the Lower Wairarapa Development Scheme, which permanently changed the hydrology of the Wairio Wetland by draining it. The Wairio Wetland was used as a farm post-drainage, until before a bund wall was erected in 2005 that partially restored the hydrology of the site, with on-going restoration up until present day.

Riparian replanting of the site has been completed in stages, with the Stage 3 areaestablished in 2011 to run a cost - benefit analysis on different planting schemes. 9 yearslater, this study utilized allometric equations to predict the carbon sequestered in individual planting combinations.

The harsh ephemeral riparian environmental stressors likely severely limited indigenous plant growth within the Wairio Stage 3, with the largest plants often half the size of theirexpected growth rates in more ideal climates. Ultimately, the environmental conditions of ephemeral wetland riparian zones target prevented any of the species of interest fromreaching the 5 m height requirement necessary to apply for carbon credits from forests.