Citation
Auyob, Nur Adilah
(2016)
Diversity of orchids in Gunung Jerai, Kedah, Malaysia.
Masters thesis, Universiti Putra Malaysia.
Abstract
As one of the isolated mountains in Malaysia, Gunung Jerai, Kedah served beautiful
scenery to visitors and potentially to be developed as an eco-tourism park in Kedah.
Activities such as amenity forests, camping sites and outdoor sports can cause
destruction to natural habitat. Geologically, the formation involved granites as the
core and quartzite covers the outer layer of the mountain. This indicates the
establishment of hill heath forest vegetation, mostly on the summit region and
lowland dipterocarp forest vegetation at lower region. The uniqueness of its
vegetation attracts botanists and collectors to do series of plant collection since 1845.
Orchid’s collection has started since 1924 by Ridley and continued by others until
today. Although it has been collected for almost 100 years, there is no intensive
study on the diversity of orchids in Gunung Jerai, Kedah. They just produced
checklists based on the species collected. Therefore, this study is needed to reveal
the current orchid diversity within this area towards a proper scientific
documentation apart from adding new information to the existing data. The
construction of taxonomic keys is essential as reference for future studies especially
in the similar type of habitats. Another objective is to propose a conservation plan
for the orchids through conservation assessments especially for rare and endemic
species. As to complete the sampling works, the whole mountain is divided into five
zones with fourteen accessible trails. Ten metres width belt-transects are plotted
along each trail. As a result, a total of 136 species are collected from five subfamilies
which represented by 65 genera in Orchidaceae. From the total collection, there are
57.0 % epiphytic orchids, 34.0 % terrestrial orchids, 7.0 % lithophytic orchids and
only 2.0 % are saprophytic orchids. The domination of Epidendroideae subfamily in
all zones shows that it has high adaptation ability in all different types of habitat.
Although sampling is done within only 0.3 % from the total area of 85.6 km2, 24
new records to Kedah are documented including three new records to Malaysia,
namely Coelogyne chrysotropis, Liparis geophila and Pteroceras teres. In addition,
two new species are listed and yet to be described from genera Corybas and Zeuxine.
Out of fives zones, Zone 3 harbours the most species richness (88 species) and
obtained the highest Simpson’s Index of Diversity (1- D = 0.890). Sorenson’s
Similarity Coefficient shows there is close relation between Zone 2 and 3 as they
have the highest value (Cs = 0.382) . Meanwhile, there is 67.0 % dissimilarity of species distribution between sunrise area and sunset area. As for conservation, there
are 21 species categorized as vulnerable species. Then, through Species Rarity Rank,
Zone 3 has the highest priority to be conserved (RT = 38). From the overall results,
obviously Gunung Jerai possesses majority of habitat-specific species with 71
species (52.0 %) are determined as unique species. Thus, status of the forest needs to
be changed from Rank 2 to Rank 1 to protect species and their natural habitat.
Besides that, strong enforcement from Department of Forestry also needed to
prohibit illegal poaching activities that can cause species extinction in wild.
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