Included here is Borneo (Kalimantan) and adjacent islands such the Bunguran (Natuna) Islands, Calamian Islands, Jolo Island, Laut Island, Palawan Island, Pangutaran Islands and the Tawitawi Islands.

Bornean Montane Forest

Being derived from both Asian and Australian elements, the montane forest of Borneo is one of the most diverse montane habitats in the world, and nowhere are these forests better developed than on Borneo’s highest mountain, Mount Kinabalu. Above about 1300 m Fagaceae becomes the main tree family with the lowland domination of the Dipterocarpaceae being replaced by oaks (Quercus and Lithocarpus) and chestnuts (Castanopsi). Among these are many endemic species like Lithocarpus luteus, Castanopsis clemensii and Quercus valdinervosa. These forests can be likened to montane islands in a sea of lowland dipterocarps. They experience high rainfall levels and are often bathed in clouds. Other important families include Araucariaceae, Clethraceae, Ericaceae, Lauraceae, Myrtaceae, Podocarpaceae, Symplocaceae and Theaceae. The canopy typically reaches heights of between 10 and 20 m, but larger emergent trees are absent, and there are very few trees with large buttresses.  Other endemic trees include Archidendron kinaballuense (Fabaceae), Horsfieldia androphora (Myristicaceae), Illicium kinabaluense (Illiciaceae), Knema hirtella (Myristicaeae), Polyscias borneensis (Araliaceae) and Xanthophyllum tenue (Xanthophyllaceae). Two particularly interesting trees are the curious celery pine Phyllocladus hypophyllus and the so-called trig-oak Trigonobalanus verticillata - both have been described as living fossils. The celery pine is thought to be the most primitive living conifer, while the trig-oak, which was only discovered in 1961, appears to be the missing link between beeches, southern beeches and oaks. It has the nuts of northern, temperate beeches (Fagus), but these are borne in acorn cups, and it has the timber and leaves of tropical oaks. Below the canopy various shrubs are usually present including many endemic species like Daphniphyllum borneense (Daphniphyllaceae), Diplycosia fimbriata (Ericaceae) and Symplocos tricoccata (Symplocaceae), while Vaccinium andersonii (Ericaceae) is one of several epiphytic endemic shrubs. Rhododendrons start to become more conspicuous with increasing altitude and are a major feature of the mossy forests of the upper montane zones. Lianas, climbers and vines are also plentiful. Adenia kinabaluensis (Passifloraceae), Bauhinia excelsa (Caesalpiniaceae) and Kudsura acsmithii (Schisandraceae) are a few of the endemic species. The forest floor, as you would expect, provides habitat for many bryophytes, ferns and flowering plants. The small mountain pitcher plant Nepenthes tentaculata found nestled in mounds of wet moss is one of the more interesting ground layer denizens with its distinctive tentacular bristles.

Bornean Montane Heath Forest

On the nutrient poor, acidic soils of Borneo a type of forest known as heath forest occurs (also known as Kerangas in Indonesia). The term ‘heath forest’ is slightly misleading since they are not particularly rich in heathland species, but are regarded as edaphic climax forest of poor soils where you would expect to find heathlands in other parts of the world. They have a low uniform single-layered canopy reaching no more than about 20 m in height, and are less species-rich than dipterocarp forests, but can extend well into the highlands where the trees become stunted and contorted. The tree species are dominated by members of the Casuarinaceae and Myrtaceae familes together with conifers such as Agathis, Dacrydium and Podocarpus, but dipterocarps may also be present especially in some of the less nutrient poor areas. Other, less favourable areas are dominated by species of Tristania (Myrtaceae). Some characteristic species, such as Casuarina nobilis, are able to fix nitrogen. Among the many endemic trees are Agathis borneensis (Araucariaceae), Castanopsis borneensis, Lithocarpus sericobalanus, Quercus kerangasensis (Fagaceae), Dactylocladus stenostachys (Crypteroniaceae), Hopea micrantha, Shorea coriacea, Vatica compressa (Dipterocarpaceae) and Horsfieldia carnosa (Myristicaceae). Shrubs such as the endemic Arthrophyllum crassum (Aristolochiaceae) and Diplycosia kalmiifolia (Ericaceae) may be present. The lack of available nutrients has fostered the developement of a rich assemblage of carnivorous plants including pitcher plants (Nepenthes), sundews (Drosera) and bladderworts (Utricularia), and these represent a characteristic feature of these forests. Some of the Nepenthes species are spectacular such N. veitchii with its red-streaked rims and N. reinwardtiana with its sensuous curvy shapes. The rich epiphytic flora is largely dominated by orchids, such as the endemic Bulbophyllum beccarii (Orchidaceae), and ferns like the endemic Selliguea setacea (Polypodiaceae). There are also many epiphytic shrubs, particularly of the Ericaceae such as the endemic Rhododendron nieuwenhuisii and Vaccinium monanthum, while among the endemic lianas and climbers are Bauhinia foraminifer (Caesalpiniaceae) and Costera cyclophylla (Ericaceae). The forest floor is typically dominated by bryophytes but may also include a number of herbaceous species such as the endemic ground orchid Entomophobia kinabaluensis (Orchidaceae) and the endemic sedge Tetraria borneensis (Cyperaceae). In other places, presumably because of low light levels and poor soil quality, the ground layer maybe completely devoid of species.

Bornean Montane Limestone Forest

In the lowlands these forests are often dominated by large emergent tree reaching heights of 40 m or so. Dipterocarps, such as the endemic Hopea andersonii, H. dasyrachis and Shorea patoiensis (Dipterocarpaceae) are common together with nondipterocarps like Brownlowia glabrata and Palaquium sericeum. Many of these large trees are heavily buttressed. Other trees include various endemics such as Aglaia ramotricha (Meliaceae), Chisocheton ruber (Meliaceae), Daphniphyllum dichotomum (Daphniphyllaceae), Osmoxylon kostermansii (Araliaceae), Tristiropsis ferruginea (Sapindaceae) together with the two endemic palms Livistona exigua and Pinanya yassinii (Arecaceae). The shrub layer is sparse but several epiphytic shrubs may be present like the endemic Vaccinium lobbii (Ericaceae). Large woody climbers are also less common than in the dipterocarp forests but may, for example, include species of Derris and Phanera.  Surprisingly, the epiphytic flora is also comparatively poor especially in the more shady areas, but may include the endemic fern Pyrrosia platiphylla (Polypodiaceae). Moving into the montane zones, dipterocarps decrease in number although Hopea argentea often persists well into the uplands. More typical here are species such as Casuarina nobilis while in the upper zones above 1200 m the conifers Dacrydium beccarii and Phyllocladus hypophyllus come to dominate. Knema sericea (Myristicaeae) is one of many endemic trees, and there are many shrubby species including a number of endemic rhododendrons, and several endemic ferns such as Ctenitis muluensis (Tectariaceae). In fact, these limestone forests have extremely high levels of endemism.

Bornean Montane Mossy Forest

Above about 1800 m and extending to about 3200 m is the so-called mossy forest. At this height the mountain is frequently enveloped in mist, and mosses and other epiphytes cling to virtually every available tree trunk and branch. The trees are rich in endemic species such as Agathis kinabaluensis (Araucariaceae), Arthrophyllum ashtonii (Araliaceae), Dacrydium ericoides (Podocarpaceae), Diplycosia punctata (Ericaceae), Horsfieldia endertii (Myristicaceae), Knema muscosa (Myristicaeae), Lithocarpus turbinatus (Fagaceae), Podocarpus laubenfelsii (Podocarpaceae), Prunus oocarpa (Rosaceae), Quercus chrysotricha (Fagaceae) and include many endemic members of the Ericaceae like Rhododendron lowii, R. polyanthemum, Vaccinium claoxylon, V. moultonii, V. pachydermum, V. retivenium, V. stapfianum and V. stenanthum. Many of the tree are stunted allowing more light to reach the forest floor which results in a profusion of plant growth including a great variety of colourful rhododendron shrubs many of which, like Rhododendron acuminatum, R. durionifolium, R. ericoides, R. fallacinum, R. fortunans, R. maxwellii, R. moultonii and R. salicifolium (Ericaceae) are endemic. Other endemic shrubs include Diplycosia acuminata, D. ciliolata, D. cinnamomifolia, D. kostermansii, D. orophila, D. sphenophylla (Ericaceae), Rhus borneensis (Anacardiaceae), Vaccinium cercidifolium, V. kemulense, and V. tenerellum (Ericaceae). Members of the Ericaceae often dominate the shrub flora and some of these upland forests are sometimes referred to as ericaceous forests. There is also a wealth of ericaceous epiphytic and climbing shrubs - Diplycosia caudatifolia, Rhododendron crassifolium and Costera tetramera (Ericaceae) are just a few of the many endemic ones.  Ferns, including spectacular tree ferns like the endemic Cyathea megalosora (Cyatheaceae) are plentiful, and there are literally hundreds of endemic orchids. Pitcher plants, like the endemic Nepenthes edwardsiana, N. lowii and N. villosa (Nepenthaceae), are also well represented. Above about 2,600 m the gnarled and stunted trees of the endemic conifer Dacrydium gibbaiae (Podocarpaceae) and Leptospermum recurvum form the curious elfin forest. At altitudes above about 3,400 m a treeless zone occurs where herbs and stunted shrubs predominate. Borneo’s only buttercup, the endemic Ranunculus lowii (Ranunculaceae), is found here together with shrubs of Gentiana, Potentilla and Rubus.


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