As an attempt to examine the causes of forest disturbance and degradation of the
orchid community, a comparative study on diversity and ecology in eight
undisturbed (Padang 7, Bukit Rongkit, Taman Rimba Komanwel, Bukit Batu Kapal,
Lata Kekabu, Lata Lawin, Lata Tanjung Kala, Bukit Pedu) and ten disturbed (Bukit
Sekayu, Gunung Perlis, Bukit Batu Kapal, Tanah Merah, Hulu Setiu, Kuala Koh,
Logging Bukit Batu Kapal, Bintang Hijau, Gawi, Petuang) forests in Peninsular
Malaysia was conducted. The study reported 239 orchid species belonging to 65
genera, inclusive of not just the rare and endemic species, but also five new record
species. Species richness, abundance, density and diversity of orchids varied across
the localities. A higher density of orchids (2.433 plants/km2) occurred exclusively in
the undisturbed forests than in the disturbed forests (0.228 plants/km2). As with the
character of undisturbed forests, the temperature was between 27.8±0.3 oC and
31.2±0.2 oC, humid (77.1±1.2 %–89.6±0.9 %) and low light intensity (23.8±3.3
μmol m-2s-1–171.7±18.8 μmol m-2s-1) thus supporting the high density of the plants.
Disturbed forests harboured higher diversity (H=4.934 and 1-D=0.990) and
abundance (183 species of 57 genera) that determined to be highly influenced by the
higher abundance of epiphytic orchids on the fallen trees and ease of accessibility in
the logged forests. The lower diversity of orchids in the undisturbed forests
supported by the higher dominance (D=0.015) of most abundant species. However,
terrestrial and mycoheterotroph orchids were lower in density and abundance in the
disturbed habitat indicating a gradual reduction in their niche availability following
the disturbance. Also, the ecology data shows the microclimate conditions of the
canopy-covered forest influenced by proximity to the logged area. Furthermore, the
results show the composition of orchid communities in the undisturbed and disturbed
forests associated with the host plant characteristics. Host types and bark texture
preference were apparent for the epiphytic orchid species with certain types and
textures hosting more orchid species than others. To further obtain
an accurate estimate of the orchid floristic composition, integrative methods of macromorphology, micromorphology and molecular genetics are necessary to solve
the taxonomic uncertainty and resolve species complexes at the infrageneric level.
Floral micromorphology of three critically endangered Paphiopedilum were
analysed concerning either infrageneric taxonomy or physioecological demands.
Using scanning electron microscopy (SEM), surface of the dorsal sepal, synsepal,
lateral petals, pouch or labellum, and staminode were investigated. Amongst the
investigated features were epicuticular waxes, epicuticular ornamentation, trichome
distribution and type, pustular glands, and papillae. The finding supports the
distinction of P. barbatum from P. callosum var. sublaeve, which belong to subgenus
Paphiopedilum, and from P. niveum, a species belonging to subgenus
Brachypetalum, a separated monophyletic clade. From the physioecological view,
the absence of glandular trichomes, and the low occurrence of papillae and stomata
on the floral parts explain the unscented flowers of P. barbatum and P. callosum var.
sublaeve. In this study, other than morphology, efficacy of the nuclear and
chloroplast regions in discriminating the uncertain taxa of Dendrobium Sect.
Calcarifera species were examined. For barcoding, nrITS, rbcL, matK, and psbAtrnH
regions of 60 samples, including six samples of unknown identity, were
sequenced except for D. corydaliflorum where only rbcL was reproducible.
Amongst the single barcode regions, nrITS showed a high sequence quality (100%),
high discriminatory power (99.7%), clear resolution of species in Maximum-
Likelihood phylogenetic tree, and high congruence with the morphology data.
Combined markers showed a high species resolution with the conspecific individuals
all grouped together, especially any combinations with nrITS, due to the added
sequence variation. Eighteen species were assessed using the internationally
accepted IUCN criteria and categories. Of the 18 species, eight are classified as
threatened (Endangered, Critically Endangered, or Vulnerable). Furthermore, 30
species are included in a poster on Endangered, Threatened and Rare Wild Orchids
of Malaysia (Part 1 and 2) in collaboration with the Forestry Department of
Peninsular Malaysia as an effort to increase awareness on the importance of orchid
conservation between the public and the effectiveness of the current monitoring on
illegal trade. The monitoring effort is now supported by DNA barcoding work which
has so far included 74 entries for four barcode markers belonging to 43 endemic and
rare species
