Vegetation and Selected Environmental Factors of Bukit Charas Limestone
The Limestone flora of Peninsular Malaysia is exceptionally rich in diversity and endemism but is under extreme threat. Moreover, the ecology of limestone plants is little understood. Bukit Charas stands out as one of the last sanctuaries for the flora of the Panching Limestone Formation. Therefo...
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| 格式: | Thesis |
| 语言: | English English |
| 出版: |
2002
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| 主题: | |
| 在线阅读: | http://psasir.upm.edu.my/id/eprint/9483/1/FSAS_2002_29_A.pdf |
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| 总结: | The Limestone flora of Peninsular Malaysia is exceptionally rich in diversity and
endemism but is under extreme threat. Moreover, the ecology of limestone plants is
little understood. Bukit Charas stands out as one of the last sanctuaries for the flora
of the Panching Limestone Formation. Therefore a floristic and ecological study
were undertaken to document and conserve the hill. The flora in this study stood at
249 species in 175 genera and 82 families. The largest family is the Euphorbiaceae
(19) followed by the Rubiaceae (18), Araceae (13), Annonaceae (10) and Lauraceae
(7). Six rare species; (Suregada multiflora var lamellata, Ardisia sujJrutieosa,
Teetaria eherasiea, Emarhendia bettiana, Monophyl/aea hendersonii and Polyalthia
sp.) are recognised from Bukit Charas. Cluster analysis has identified four types of
vegetation groups at the base of the hill (BASE), at the slope of the hill (SLOPE), at
the talus slope (TALUS) and at the cave (CAVE). Plants, characteristic to the
limestone habitat are found in the TALUS and CAVE groups. Twelve environmental
variables have been used for ordination. Unrotated principal component analysis has
reduced these variables to two components, i.e. calcium and magnesium; and kalium
and carbonate. Two primary environmental gradients were identified with the Varimax-rotated principal component .analysis of environmental data:
topographic situation and soil fertility. The TALUS and CAVE groups were
significantly associated with high level of soil exchangeable calcium and
magnesium. The TALUS group is also associated with high organic matter and the
CAVE group with high carbonate content. The results of the species and quadrat
ordination of the detrended correspondence analysis were similar to the principal
component analysis. Three hypotheses are proposed: Firstly, the plant endemism in
limestone habitat is greatly driven by edaphic factor and not by the need to avoid
competition. Secondly, the high level of exchangeable calcium and magnesium, and
high soil pH in the limestone soil act as important limiting factors for limestone
endemics. These conditions are important requirements for limestone habitats.
Thirdly, there exist limiting factors within a limestone habitat that create a niche
partition among the limestone endemic species. The current threat to Bukit Charas
flora is agricultural activities at the surrounding base of the hill. A buffer zone that
stretched 50 m from the forest margin is proposed as a strategy to conserve Bukit
Charas. Future study should be expanded to other hills for comparison and green
house experiment should be undertaken to test the hypotheses. |
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