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| Endemic species found in Tama Abu and Long Banga, Sarawak, Heart of Borneo. A) Calanthe crenulata; B) Coelogyne endertii; C) Dendrochilum pubescens; D) Phalaenopsis modesta; E) Pteroceras fragrans; F) Robiquetia transversisaccata; G) Tainia scapigera; H) Trichotosia brevipedunculata; I) Tropidia saprophytica. in Besi, Nikong, Pungga & Go, 2020. Scale bars: A – 3 cm; B – 1 cm; C – 6 mm; D, E, F, H, I – 5 mm; G – 3 mm. |
Abstract
The Heart of Borneo (HoB) initiative facilitates conservation and environment protection while enhancing sustainable development that safeguards the welfare of natural resources and inhabitants of the island. The HoB research expeditions conducted in the Long Banga and Tama Abu were aimed to document the highland orchid species inhabited in one of the largest remaining transboundary rainforests in the world, which are racing dissolution from their habitat. Thus the resolution for their conservation in situ and ex situ could be drafted meritoriously. The research expeditions in the protected transboundary forest areas revealed a total of 206 species and 59 genera. A total of 118 species of 46 genera were recorded during the HoB Long Banga 2016 expedition, while 117 species in 46 genera were found from the HoB Tama Abu 2017 expedition. Roughly 70% of the species documented were epiphytes. A few of them were mycoheterotrophs, such as Aphyllorchis pallida, Cystorchis aphylla, and Tropidia saprophytica, and several «jewel» orchids, including Cystorchis stenoglossa and Macodes petola. Astonishingly, we discovered a number of endemic and newly recorded orchid species for Borneo. In Long Banga, the riverine forests are home to a higher number of orchids than the inland forests, owing to the presence of host trees with a spreading crown structure and moist bark texture suited epiphyte colonisation. In addition, the riverine forests are banked by a swampy alluvial vegetation that encourage the terrestrial species to grow in. Sites of the inland forests were seen disturbed with wide canopy gaps lacking of the emergent layer. Contrarily, in Tama Abu, the inland forest perceived as the more preferable habitats for orchids to thrive in as it was an undisturbed forested belt. In addition, they had a higher humidity essential for the orchid growth. It was not surprisingly, that a high abundance of orchid species was encountered in the undisturbed inland hill forest roofed with dense tree canopy cover. The hills transitioned into a montane vegetation with a lower number of species. This parameter peaked in a mossy forest, a distinct habitat harbouring endemic and rare species. In addition, ten endemic species are assessed as EN B2b(iii). Herewith, our discovery infers the need for a continuous biodiversity monitoring and conservation assessment to maintain orchid species survival and to reveal the accurate species richness within the highland habitats of Sarawak. Additionally, underlined herein is the need for establishment of an arboretum or a conservation centre for orchids to accommodate the botanical study.
Keywords: conservation assessment, endemism, inland forest, Northern Sarawak, Malaysia, Orchidaceae, riverine forest, species composition
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| Rare species found in Tama Abu and Long Banga, Sarawak, Heart of Borneo. A) Aphyllorchis pallida; B) Bromheadia rupestris; C) Cystorchis aphylla; D) Cystorchis javanica; E) Cystorchis stenoglossa (Plant); F) Cystorchis stenoglossa (Inflorescence); G) Cystorchis variegata; H) Cystorchis stenoglossa (Inflorescence); I) Dendrobium tetrachromum; J) Macodes petola; K) Nephelaphyllum tenuiflorum; L) Vanilla sp. Scale bars: A, B, F, I – 1 cm; C, H, K – 5 mm; D, E, J – 3 cm; G – 5 cm; L – 8 cm. |
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| Orchids species with new records for Borneo found in Tama Abu and Long Banga, Sarawak, Heart of Borneo. Dendrobium appendiculatum (A–B) and Phaius indigoferus (C–E): A) Flower; B) Plant, C) Flower, D) Plant, E) Flower with reddish brown pattern. Scale bars: A – 4 mm; B – 7 cm; C, E – 1 cm; D – 7 cm. |
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| Orchids of highland forests found in Tama Abu and Long Banga, Sarawak, Heart of Borneo. A) Agrostophyllum majus; B) Agrostophyllum stipulatum subsp. stipulatum; C) Appendicula anceps; D) Appendicula pendula; E) Arundina graminifolia; F) Bulbophyllum apodum; G) Bulbophyllum hirtulum; H) Bulbophyllum membranaceum; I) Bulbophyllum pileatum; J) Bulbophyllum sp(1); K) Bulbophyllum uniflorum; L) Bulbophyllum vaginatum; M) Cleisostoma discolor; N) Cleisostoma javanicum; O) Coelogyne incrassata; P) Coelogyne sp(5); Q) Dendrobium bancanum; R) Dendrobium derryi; S) Dendrobium rhodostele; T) Dendrobium rosellum; U) Dendrobium villosulum; V) Dipodium scandens; W) Liparis cespitosa; X) Liparis condylobulbon; Y) Mycaranthes obliqua; Z) Nephelaphyllum pulchrum; i) Oberonia brachystachys; ii) Phaius tankervilleae. Scale bars: A, B, S, Y – 2 mm; C, W – 4 mm; D, H, X – 3 mm; E, I, K, N, P, T, U, Z, i, iii – 1 cm; F, J, M, O, Q, R, iv – 5 mm; G – 6 mm; L – 3 cm; V – 1.5 cm; ii – 2 cm. |
Conclusions:
The generalised records obtained from the two
expeditions in the northeast region of Sarawak’s
Heart of Borneo strengthens the idea that the
Sarawak’s highland forest harbours a vast variety of
orchid species. A total of 206 species and 59 genera
were collected from the inland montane and riverine
forests, as well as non-trail sites in Long Banga and
Tama Abu forests. Bulbophyllum, Dendrobium, and
Coelogyne were the genera with the highest number
of species. Most of the documented species were
epiphytes, including ten endemics and threatened
species, as well as two species newly recorded for
Borneo. Here, we emphasise the importance and
influence of each vegetation type on the species
abundance, where the highest diversity was found
in the inland montane forests. In the inland montane
forests, undisturbed sites were dominated by emergent trees with dense and spreading crown structure
providing moisture that is suitable for both epiphyte
and terrestrial plant colonisation. However, an even
higher diversity of orchids could be expected, if all
found specimens were fertile. Therefore, further
cultivation of the living plants in an arboretum or an
ex situ conservation prior to species identification is
undoubtedly important.
Edward Entalai Besi, Dome Nikong, Runi Sylvester Pungga and Rusea Go. 2020. Wild Orchid Diversity of Highland Forest in the Heart of Borneo: Long Banga and Tama Abu, Sarawak. Nature Conservation Research. 5(Suppl.1): 125–135. DOI: 10.24189/ncr.2020.048
Electronic Supplement 1. Orchid species found in Tama Abu and Long Banga, Sarawak, Heart of Borneo
Electronic Supplement 2. List of orchid species found in the highland forests in Long Banga and Tama Abu, Heart of Borneo, including information on the growth habits and localities
