Abstract

Reintroducing the Oriental Pied Hornbill (Anthracoceros albirostris) on Koh Kut, Thailand:
A Case Study in Species-Based Biodiversity Crediting

Nantida SUTUMMAWONG^1*, Vijak CHIMCHOM², Siriwan NAKKHUNTOD², Chinarong PUNKONG³, Somying THUNHIKORN⁴, Nukool PUNKONG³, Sittichia JINAMOY², Sarinya WIANGWONG², Peerawut RINKUM¹,
and Pilai POONSWAD²

¹Department of Forest Biology, Faculty of Forestry, Kasetsart University, ffornis@ku.ac.th
²Hornbill Research Foundation, Faculty of Science, Mahidol University
³Khao Kheow Open Zoo, the Zoological Park Organization
⁴Wildlife Research Division, Wildlife Conservation Office, Department of National Parks, Wildlife and Plant Conservation

 A nature-positive economy requires reliable ecological indicators that clearly show the outcomes of restoration efforts. This study examines the reintroduction of the Oriental Pied Hornbill on Koh Kut Island, as a species-based indicator relevant to the development of biodiversity credits. Given that hornbill-dispersed plants make up about 68% of the island's native flora, the return of this keystone frugivore could restore seed dispersal processes necessary for forest regeneration after nearly 40 years of local extinction.

 Data from 2021–2025 show positive early signals of recovery, most notably the documentation of a wild-born chick in 2024 Yet, the population remains short of reaching demographic stability. In 2025, the stoppage of Anchor Partner funding (Soneva Foundation) poses a substantial threat to project continuity, as no future releases are being made.

 This study is compared with four biodiversity crediting frameworks, Savimbo, Wallacea Trust, Plan Vivo, and Verra, to analyze how indicator species credits could bridge financial gaps to meet additional species releases for population establishment. Despite the lack of establishment of populations, it has been made clear that species reintroduction could act as an ecologically practical and informative indicator for monitoring restoration to ensure biodiversity credit mechanisms.