Biodiversity Surveys conducted in 2003, 2012 and 2014 have identified around 566 plant species from various habitus; 11 mammal species originating from 7 families; and 94 species of birds. The unique natural heritage in Belitong Island is The Belitong Tarsiers (Cephalopachus bancanus satator) and the Asian Arowana (Scleropages formosus).
The Belitong Tarsiers
The Belitong Tarsiers are an endemic tarsier in Belitung Island recognized as one of sub-species of Cephalopachusbancanus genus. The Belitong Tarsiers can be characterised based on the morphology and molecular investigations. The morphology of Belitong Tarsiers highlights the non massive dense hair, gray colour background, and no vocal duets in the morning (Shekell, 2008; Groves and Shekelle, 2010; Fodgen, 1974; Yustian, 2007). The molecular analysis proved that they were classified as the Cephalopachus genera. This has changed from the previous authors which categorized them into Tarsius genera.
The Belitong Tarsiers inhabit the dry and shrub land and the secondary dry land. Those areas are the habitat for the insects which are food for the Belitong Tarsiers (Fitriana et al, 2016). Trees in the dry and shrub land and the secondary dry land have been well developed in the poor nutrients soil which was mainly composed by the transported weathering of the rich silica material from the granite rock (Whitmore 1984; Whitten et al. 1984; MacKinnon et al, 1996). This rock is commonly found in the northwest of the Belitung Island..
The Asian Arowana
The Asian Arowana is a premium ornamental fish which can be distinguished from other sub-species of Scleropages based on physical appearance such as dark green dorsal colour, ventral side silver colour and shining laterraly (Weber and De Beaufort, 1913). This has existed since the Early Cretaceous period (112 – 146 mya) during the Gondwanaland divergence. One of the separated continents moved towards north across the Paleo Indian Ocean at Tethys Sea on the Indian subcontinent carrying the Arowana.
Then, another divergence between Asian and Australasian occured 138 ± 18 mya when the Indian sub-continent separated from the Gondwana land. The India subcontinent merged into the Eurasia which was consistent with the Asian Arowana fossil ages in central Sumatra (Sanders, 1934); indicating that the Asian Arowana came from the Indian subcontinent (Kumazawa and Nishida, 2000).
The Asian Arowana distribution in Belitung occurred during the last glacial maximum period which can be traced to the Paleo Sunda rivers. The ancient East Sunda rivers flowed crossing from the present-day Java Sea to Bali. This river branched to north coast of Java, and south coast of Kalimantan (Solihuddin, 2014). This river is responsible to the Asian Arowana distribution in Belitung Island which can originally be found in the Lenggang River, East Belitung (Yunita, 2004).
The Heath Forest
The heath forest, one example of a desert ecosystem, is commonly found in the island. The forests have a layer of podzol soil, high levels of silica, acidic (ph less than 5.5), low oxygen content and an iron layer in the soil. The iron and tannin layers make the waters in the heath habitat brown.
Rarely, there are trees with large stem diameters and relatively flat canopy layers. The function of this forest along with other forests as a source of natural medicine was very prominent in the past, and is still now in several places.
There are 224 plant species and 72 families found in the heath forests obtained from various habitus and growth rates (Oktavia, 2012). Oktavia (2012) further stated that the most cured disease group with the use of medicinal plants is fever and heartburn.
Nepenthes sp. is one of the typical plants of shellfish found in heath forest. There are four types of Nepenthes including Nepenthes ampullaria (Munawaroh, 2012).