Wild Orchids of the Highland Forests in the Heart of Borneo, Sarawak

Abstract

The Heart of Borneo (HoB) Scientific Expeditions in the Long Banga and Tama Abu was aimed to identify and document the highland orchid species inhabited in one of the largest remaining transboundary rainforests in the world, which are racing dissolution from their habitat, consequently the resolution for their conservation in-situ and ex-situ could be drafted meritoriously. The 10 days’ expeditions had revealed orchids are abundant in the montane and riverine forests. A total of 118 species in 46 genera were recorded during the HoB Long Banga 2016 expedition, while 117 species in 46 genera from the HoB Tama Abu 2017 expedition. About 70% of the species documented were epiphytes, a few were mycoheterophytes, namely Aphyllorchis montana, Cystorchis aphylla, Gastrodia javanica and Tropidia saprophytica, and several jewel orchids, including Crepidium lowii and Cystorchis stenoglossa. Several endemic and newly recorded species for Sarawak and Borneo were also discovered. Dimorphorchis lowii, an endemic orchid species to Borneo was documented during these two expeditions indicating its occurrence in this part of the country. As for distribution and abundance, the riverine forests in Long Banga perceived as the more preferable habitat for orchids to thrive as it was an undisturbed forested belt, and also had higher humidity essential for orchid growth. In Tama Abu, a high abundance of orchid species was collected in the undisturbed hill and montane forests with dense tree canopy cover. The high diversity and density of orchids discovered from the undisturbed forests in Tama Abu indicate that rescue operations from active logging concessionaires should be initiated to safeguard orchid species survival and to reveal the accurate species richness within the highland habitat of Sarawak.