Valuing coastal wetland restoration in Australia with discrete choice experiments

Coastal wetlands, including mangroves, tidal marshes, and seagrasses, are critical ecosystems that deliver ecological and socioeconomic benefits such as wildlife habitat, water filtration, coastal protection and carbon sequestration. This study employs a discrete choice experiment to estimate the value Australians place on the restoration of these ecosystems at a national scale. There are challenges in framing ecosystem restoration scenarios at a national scale compared to the more common local case study focus, as it is difficult to make national level scenarios relevant and consequential to respondents. To address the potential for bias through inflated responses, we employ two complementary approaches: a pre-experiment question gauging respondents' likelihood of supporting restoration improvements, and a post-experiment debrief probing their reasons for supporting particular options. In the study a representative sample of Australian households faced choices between hypothetical restoration programmes for mangroves, tidal marshes, and seagrasses, involving annual payments over a ten-year period. The model yields mean household willingness-to-pay (WTP) per 1000 ha: AUD 13.80 for mangrove restoration, AUD 11.96 for tidal marsh restoration and AUD 3.06 for seagrass restoration. Validity tests indicate potential hypothetical bias by over 40 % of respondents, although at least 80.5 % of respondents exhibited some positive WTP. Extrapolating to the national level, the proportion of inflated bidders has been excluded to generate total annual WTP estimates of AUD 79.4 million for mangroves, AUD 68.9 million for tidal marshes and AUD 17.6 million for seagrasses. These findings contribute one of the first economic valuations of coastal wetland restoration in Australia. • Coastal wetlands in Australia include mangroves, tidal marshes and seagrasses. • National values for restoration have been assessed with discrete choice experiments • Annual WTP for 1000 ha of restoration is highest for mangroves and lowest for seagrass • At least 80.5 % of respondents had some WTP for increased protection • Pre- and post-experiment debriefs have identified some over-bidding from respondents.