Plant diversity and ecology of ultramafic outcrops in Sabah (Malaysia)

Abstract

Ultramafic outcrops occupy less than 1% of the land surface of the Earth and are renowned as hotspots of plant diversity and endemism. With over 3500 km2 of ultramafic outcrops in Sabah (4.6% of the total landmass of the state) on the island of Borneo and a total of 4252 plant species recorded occurring on this substrate, Malaysia has one of the most species-rich floras occupying these outcrops globally. Over 2542 plant species have been documented on ultramafic outcrops in Kinabalu Park alone, of which a large percentage is endemic to either Kinabalu Park or Borneo. Despite the existence of this species rich flora, the full plant diversity and ecology remains largely unknown because of a lack of focussed research. Furthermore, plant diversity in many areas of Sabah is severely threatened by land-use conversion and, because many plant species occur only in a single or a few ultramafic sites, impacts on the ecosystems that support them could eventually result in their extinction.