Calamus manan Miquel (Rotan Manau)

Taxonomy
Calamus manan Miquel, J. Bot. Neerl. 1:23 (1861). SubTribe Calaminae, Tribe Calamae, SubFamily Calamoideae, Family Arecaceae.

Description
Calamus manan is a robust, single stemmed, high-climbing, dioecious rattan. Plants produce a strong durable cane up to 8 cm in diameter, with internodes to 40 cm in length, and with stems eventually reaching to over 100 m. Growth rates of over 7 m a year have been inferred from observation of plants in Sabah (Dransfield and Tan, pers. obs. 1989), but more usually 1-3 m or more a year. Leaves cirrate to 8 m long including the cirrus to 3 m long. Petiole short, leaflets irregular in juvenile leaves and regular in mature leaves, to 45 on each side of rachis, lanceolate. Inflorescences massive, the male much more finely branched than the female, 70 cm long. Ripe fruit rounded to ovoid, to 2.8 cm long by 2.0 cm wide and covered with 15 vertical rows of yellowish scales with blackish-brown margins. Seed ovoid, to 1.8 cm by 1.2 cm, with finely pitted surface.

Distribution and Ecology
Found naturally in Peninsular Malaysia, Sumatera and southern Borneo. Widespread, but usually confined to hill dipterocarp forests, rarely found in lowland dipterocarp forests, between 50-1000 m a.s.l. and most abundant between 600 - 1000 m a.s.l.

Uses
C. manan possesses a cane variable in size and coloration, durable and of great strength and flexibility. C. manan is the premier quality, most sought after rattan for large diameter cane used in the manufacture of furniture. Since 1975, some cultivation trials and small scale plantations have been developed in Sumatera, Java, Peninsular Malaysia, and Borneo.

Conservation Status
C. manan is vulnerable due to severe over exploitation leading to the depletion of populations. At a global level the threat status of the species is IUCN code '?' (No Information), however, in Borneo, Sumatera and Peninsular Malaysia the status is 'Vulnerable', ie. believed likely to move into the Endangered category in the near future if the causal factors continue operating.

Threats to Survival
The major threat to the survival of C. manan is the over-exploitation of wild populations for cane. The main aspect of C. manan biology which makes it vulnerable to overharvesting for cane is its solitary (single stemmed) growth which leads to the death of plants upon harvesting of the cane.

Description of Research
Joko Ridho Witono is involved in a collaborative project with Mr J.P. Mogea (coordinator) and Mr Wardi (both Herbarium Bogoriense), Mrs. Padmi Kramadibrata (Univ. of Indonesia), Mrs. Titi Kalima and Mr. Ipong Sarwetu (Dept. Forestry). The main emphases of the project are to research the cultivation and conservation of C. manan. The main objectives of the research are to:

1. Develop the cultivation technology of C. manan.
2. Provide seedlings of C. manan in large amounts.
3. Prevent the genetic erosion of C. manan in the wild.

Conservation Status of other Calamus species
14 other species of Calamus are listed by WCMC, July 1995, as threatened in the wild (refer to pg. 8 of this issue for defintions of codes):