Abstract Detail

Conservation Biology

Yong, Jean W. H.  [1], Maung, Win [2], Sheue, Chiou-Rong [3].

Further biogeographical and botanical examination of the rare and globally critically endangered mangrove Bruguiera hainesii (Rhizophoraceae) in Asia.

The rare mangrove Bruguiera hainesii C. G. Rogers is known from fragmented locations in Asia and therefore given the IUCN status of Critically Endangered. This category indicated that B. hainesii has the highest probability of extinction as determined by the IUCN Red Listing process and its scarcity (with less than 250 individuals) throughout its range was confirmed by past surveys. Ecologically, B. hainesii was reported to occur naturally on the landward side of the mangrove forest. However, recent surveys in Asia revealed that B. hainesii was able to grow in other zones within the mangroves, including the seaward zone. Such an anomaly in distribution may be attributed to the higher degree of anthropogenic disturbance experienced by mangrove trees and the dispersal of propagules within many mangrove forests. We postulated that the rarity of B. hainesii is due to the following: absence/rarity of pollinator, low level of propagule production, propagules having low viability, slow growth of propagules, low rates of photosynthesis, slow growth of adult trees, susceptible to herbivory, etc. Works are in progress and some interesting data are presented here. Most interestingly, our recent surveys in Western Myanmar (near Gwa Township) uncovered probably the largest population (over 1700 trees) of B. hainesii in the world! Previously misidentified as B. gymnorhiza by the locals, these B. hainesii trees were loosely managed by local communities as sources of fuelwood. One of the key and undiscovered attribute of B. hainesii trees, that ensure their survival in Western Myanmar despite facing very heavy pruning, was the inherent ability to reproduce vegetatively, i.e. to form “ramets of mangroves”. The unusual formation of new shoots from the pneumatophores of B. hainesii offers a novel and effective avenue to produce more trees vegetatively. Similar formation of new shoots arising from the pneumatophores was also observed in old trees located in Malaysia and Indonesia. This is also probably the first report of the formation of new mangrove trees directly from pneumatophores. Efforts to multiply this endangered species by rooting the “ramet” shoots through various means (e.g. auxin treatment, layering) had started. It is unclear whether this species can survive for the next 100 years as it natural habitat (usually the back mangrove) globally is under threat from land clearing. This implied that the protection of the remaining B. hainesii trees at the various current locations is very important and should therefore be accorded the highest conservation priority.

1 - Singapore University Of Technology and Design, Life Science, 20 Dover Drive, Singapore, Singapore, 138682, Singapore
2 - Myanmar Environment Rehabilitation-conservation Network (MERN), Yankin Township, Yangon, Myanmar
3 - National Chung Hsing University, Department of Life Sciences & Research Center for Global Change Biology, Taichung, 402, Taiwan

Keywords:
mangrove
Clonal growth
Conservation
Bruguiera
Rhizophoraceae
Biogeography.

Presentation Type: Oral Paper:Papers for Topics
Session: 16
Location: Firs North/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 9:30 AM
Number: 16007
Abstract ID:598
Candidate for Awards:None