Beyond Blue Carbon: Estimating the Value of Ecosystem Services Provided by Coastal Wetlands in Aotearoa New Zealand

Abstract

Blue carbon ecosystems (BCE), including mangroves, saltmarshes, and seagrasses, provide essential functions and services globally but are increasingly challenged by climate change and other anthropogenic activities. In Aotearoa New Zealand (Aotearoa NZ), there is mounting interest in blue carbon as a nature‐based solution to climate change. Quantifying the monetary co‐benefits of BCE, in addition to carbon sequestration, can help illustrate the relative contribution of ecosystem services provided by existing habitats, as well as the potential additional value associated with restoration. Here, we estimated the value of provisioning, regulating, and cultural ecosystem services provided by BCE in Aotearoa NZ. We found that the most valuable ecosystem service provided by mangroves was carbon sequestration, while in saltmarsh and seagrass, the most valuable ecosystem services were waste treatment and existence, bequest values, respectively. Unit monetary valuations of ecosystem services range from NZD 3 ha −1 yr −1 (water flow regulation) to NZD 32,590 ha −1 yr −1 (climate regulation) for mangroves, NZD 8 ha −1 yr −1 (spiritual experience) to NZD 23,045 ha −1 yr −1 (waste treatment) for saltmarshes, and NZD 3 ha −1 yr −1 (water regulation) to NZD 14,512 ha −1 yr −1 (existence, bequest values) for seagrasses. The estimated national potential monetary value of ecosystem services provided by current habitats ranges from NZD 0.8–995 million yr −1 for mangroves (30,533 ha nationally), NZD 0.2–482 million yr −1 for saltmarshes (20,932 ha nationally), and NZD 0.2–216 million yr −1 for seagrasses (61,340 ha nationally). If drained areas were restored from drained agricultural use, values would increase accordingly. These results apply the benefit transfer approach (applying monetary values from analogous temperate ecosystems globally to estimate values in Aotearoa NZ) to generate indicative monetary benchmarks, which can help inform discussions around investment in BCE and long‐term coastal climate change adaptation decision‐making in Aotearoa NZ.

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