Rooted in environmental justice: phytogeography and ethnoecology of Serianthes

Abstract

Serianthes Benth. (Fabaceae) is one of the most endangered plant genera in the world, with 12 of the 18 species listed on the IUCN Red List of Threatened Species. Serianthes trees are culturally important to island communities of the Indo-Pacific region for canoes, boats, traditional houses, and medicine. Habitat loss and ecosystem degradation increased pressure on these trees, also threatening its Indigenous cosmology and traditional practices. This interdisciplinary study integrated genomic, biogeographic and ethnoecological approaches to develop appropriate policies that protect the Indigenous biocultural diversity of Serianthes. Phylogenomics of 401 nuclear exons and non-coding flanking regions using both a multi-species coalescent model and a partition gene tree analysis confirmed the monophyly of the genus and inferred the biogeography and phylogenetic relationships within Serianthes. The Guåhan (Guam) and Luta (Rota) endemic Serianthes nelsonii (known locally as Håyun lågu and Tronkon guåfi respectively) are closely related to South Pacific species. Serianthes kanehirae from Belau (Palau) and Wa'ab (Yap) are closely related to Malesian and Papuasian species. Phylogeographical patterns of Serianthes in Micronesia are discussed to inform conservation management. The ethnoecological study revealed interspecies relationships between people, animals, and plants remain strong. The traditional use of Ukall and Gumor (Serianthes kanehirae) on Belau and Wa'ab respectively remain part of Belau and Wa'ab's culture and are intertwined with rituals respecting the spiritual world. On Luta, Tronkon guåfi is an established flagship for endangered species conservation, while the last adult Håyun lågu tree on Guåhan became a rallying point for spiritual resistance when its habitat became threatened by military plans to construct a firing range. Despite its listing as critically endangered by the Endangered Species Act, its habitat is still at risk of being lost. The social movement guided by Prutehi Litekyan brought the community together to protect the Håyun lågu tree based on Indigenous belief systems. The social movement and policy research used a qualitative mixed-method approach to evaluate the dimensions of the Endangered Species Act in relation to environmental justice and biocultural rights. I concluded that a bottom-up co-management approach with polycentric networks best fits the social-cultural system of Guåhan. I propose Indigenous participation and the creation of an advisory council, comprising traditional and scientific knowledge holders, to advise on biocultural diversity preservation in the Mariana Islands.