Nepenthes Macrophylla - Ecology

Ecology

Nepenthes macrophylla is known with certainty only from the summit area of Mount Trus Madi in Sabah, Borneo, despite the presence of a number of nearby peaks (such as Mount Pinesowitan) that fall within its altitudinal range. However, there are unconfirmed reports that it also grows "on the summit of a neighbouring peak". Older sources list a number of different values for the altitudinal distribution of N. macrophylla, with some giving a narrow range of 2200–2400 m and others a much wider span of 2000–2600 m. It is now known that this species occurs between 2200 m and the summit at 2642 m.

The typical habitat of N. macrophylla is mossy montane forest along ridge tops, where the vegetation is dominated by Leptospermum and Rhododendron. Like most highland Nepenthes species, N. macrophylla experiences marked temperature fluctuations between day and night, from a noon maximum of around 30 °C to a nighttime minimum of 5 °C. Relative humidity is always high and in the late evening the summit of Mount Trus Madi is often shrouded in mist and clouds.

Nepenthes macrophylla occurs both terrestrially and as an epiphyte. The species is sympatric with N. lowii and N. tentaculata. A natural hybrid between N. lowii and N. macrophylla, described as N. × trusmadiensis, has been recorded.

Due to its restricted natural range and the fact that Mount Trus Madi does not receive the same high level of protection as Mount Kinabalu, N. macrophylla is classified as Critically Endangered on the 2006 IUCN Red List of Threatened Species. This differs slightly from an informal assessment made by botanist Charles Clarke in 1997, who classified the species as Endangered based on the IUCN criteria. Clarke wrote that the species "requires the highest level of protection if it is to persist in the wild into the next century". N. macrophylla is threatened by over-collection and damage caused to its habitat by visitors. These activities have already depleted populations of this species on the mountain and it is thought to be the most endangered highland Nepenthes of Borneo.