This study explores the ethnobotanical significance and conservation challenges of Scleria poiformis (locally known as wang), a traditional thatching material in northeastern Thailand. Despite its cultural importance and ecological value, the use of wang has drastically declined due to habitat loss, land-use changes, and the increasing preference for modern construction materials. Field surveys and participatory interviews conducted across 104 villages revealed that wang remains culturally significant in 71% of these communities, though only one village still reports its presence in the wild. Traditional knowledge about wang’s applications in thatching and medicinal practices persists but faces the risk of erosion alongside its declining habitat. The study highlights the need for conservation strategies that integrate traditional knowledge with ecological restoration, such as wetland habitat rehabilitation and sustainable harvesting practices. Additionally, wang presents opportunities for eco-friendly building materials and eco-tourism initiatives. The Belt and Road Initiative (BRI) framework could offer both opportunities and challenges in conserving wang by promoting biodiversity conservation while mitigating potential ecological impacts from infrastructure development. This work underscores the urgency of protecting Scleria poiformis as a vital cultural and ecological resource, ensuring its continued relevance for local communities and biodiversity conservation efforts.