These cooler and moister slopes rise above the carpet of thick rainforest that covers the warmer lowlands below, and as well as additional rainfall also derive moisture from low clouds.

Carnivorous plants, including species of Nepenthes, Drosera, and Utricularia, are most abundant in areas with high rainfall and a stunted, open tree canopy.

[4] This ecoregion also contains important areas of forest on limestone upland, especially Mount Api which has clear elevational zones of differing vegetation.

Endemic and near-endemic bird species include the crimson-headed partridge (Haematortyx sanguiniceps), fruithunter (Chlamydochaera jefferyi), pygmy white-eye (Heleia squamifrons), Rajah scops owl (Otus brookii), Kinabalu serpent eagle (Spilornis kinabaluensis), Whitehead's trogon (Harpactes whiteheadi), Bornean barbet (Psilopogon eximius), golden-naped barbet (Psilopogon pulcherrimus), Whitehead's spiderhunter (Arachnothera juliae), Hose's broadbill (Calyptomena hosii), Whitehead's broadbill (Calyptomena whiteheadi), black-sided flowerpecker (Dicaeum monticolum), black oriole (Oriolus hosii), Bornean whistler (Pachycephala hypoxantha) friendly bush warbler (Locustella accentor), eyebrowed jungle flycatcher (Vauriella gularis), blue-wattled bulbul (Pycnonotus nieuwenhuisii), Bornean stubtail (Urosphena whiteheadi), bare-headed babbler (Melanocichla calva), chestnut-crested yuhina (Staphida everetti), mountain wren-babbler (Gypsophila crassa), Sunda laughingthrush (Garrulax palliatus), Everett's thrush (Zoothera everetti), black-capped white-eye (Zosterops atricapilla), and mountain blackeye (Zosterops emiliae).

[3] Protected areas include a very large block in Kayan Mentarang National Park, which is home to communities of indigenous people but is threatened by commercial logging and road building.