Floristic Richness and the Conservation Value of Tropical Montane Cloud Forests of Dothalugala Man and Biosphere Reserve, Sri Lanka
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- Figure 3.
Table 1. Number of nationally ‘Threatened’ and ‘Near Threatened’ plant species of Sri Lanka that were found at Dothalugala MAB Reserve area as per the National Red List of Flora and Fauna of Sri Lanka, 2012 (Species names are given in the Appendix I).
Number of plant species Trees
Shrubs Climbers Herbs Total
Critically Endangered 1 1 0 0 2 Endangered 7 6 2 0 15 Vulnerable 22
11 6 1 40 Total no. of Threatened species 30
18 8 1 57 No. of Near Threatened species 5 5 1 0 11 Table 2. Number of globally ‘Threatened’ plant species in Dothalugala MAB Reserve area as per the National Red List of Flora and Fauna of Sri Lanka, 2012 (Species names are given in the Appendix I).
Trees
Shrubs Climbers Herbs Total
Critically Endangered 1 0 0 0 1 Endangered 3 0 0 0 3 Vulnerable 10
3 0 0 13 Total no. of Threatened species 14
3 0 0 17
. Floristic Features of TMCFs at Dothalugala MAB Reserve, Sri Lanka 61
Figure 3. (a) Agrostistachys coriacea (E, VU-N), (b) Kendrickia walkeri (E), (c) Glochidium pachycarpum (E), (d) Stemonoporus affinis (E, CR-N, CR-G), (e) Symplocos cordifolia (E, VU-N, EN-G) and (f) Syzygium fergusonii (E, VU- N, EN-G) [E - Endemic; CR - Critically Endangered; EN - Endangered; VU - vulnerable; N - Nationally threatened; G - Globally threatened] (a)
(b) (c)
(d) (e)
(f) 62 Ekanayake et al. Table 3. Number of ‘Threatened’ and ‘Near Threatened’ endemic plant species of Sri Lanka that occur at Dothalugala MAB Reserve area according to the National Red List of Flora and Fauna of Sri Lanka, 2012 (Species names are given in the Appendix I).
Number of endemic plant species Trees
Shrubs Climbers Herbs Total
Critically Endangered 1 0 0 0 1 Endangered 5 5 1 0 11 Vulnerable 14
10 3 1 28 Total Threatened species 20 15
4 1 40 Near Threatened species 1 4 0 0 5 Impacts of disturbances on endemic and threatened flora in the area The floristic features of abandoned cardamom cultivation lands were compared with those of adjacent relatively less disturbed sites in the dry parts of the mountain range as given in the Table 4. Floristic richness (number of plant families, genera, total species and species of endemic and threatened taxa) in secondary forests grown after the abandonment of cardamom cultivation was lower than that in adjacent, relatively less disturbed forests in the drier slopes of the mountain (Table 4). Nearly one third of the plant families and genera and half of the natural forest species have disappeared from the land as a consequence of cardamom cultivation. A fewer number of tree and shrub species were present in secondary forests that have emerged after the abandonment of cardamom cultivation (Table 4).
the dry-face of the mountain range
North-eastern slope of the mountain range Floristic feature Relatively less disturbed natural forests (n=8) Abandoned cardamom cultivation sites (n=4) Plant families 47
30 Plant genera 82 50
Plant species 104
61 Life form Shrub species Climber species
56 31 17
32
17 12
Nationally Threatened species Endangered Vulnerable
1
29
0 3 16
Near Threatened (nationally) species 9 7 Globally Threatened species
3 11
2 5 Endemic species 55 30
Nationally Threatened endemic species Endangered Vulnerable
6 22
2 13 Near Threatened (nationally) endemic species 5 3
Floristic Features of TMCFs at Dothalugala MAB Reserve, Sri Lanka 63
However, it was evident that many pioneer or exotic species such as Macaranga indica and Clidemia hirta thrive well in these disturbed sites. Although the number of experimental plots established in the two forest categories were different, this would not much affect the pattern explained and any ecologist who visits the two sites can easily detect this by visual observation.
Only 30 endemic plant species were found in abandoned cardamom cultivation sites and almost all of these were widely occurring species in the study area. Some other endemic plant species, most of which may need specific micro- habitats, did not occur in the site even 15-20 years after the abandonment of cardamom cultivation. ‘Critically Endangered’ Memecylon
secondary forests though the species was frequently found in relatively undisturbed natural forests.
The results of the current study are comparable with a similar study carried out at Kaelaebokka, towards Rangala of the Knuckles massif. There, approximately a 50% reduction of species was noticed in abandoned cardamom cultivated sites compared with the adjacent relatively less disturbed areas, while the endemicity of trees was as low as 22%. Some nationally endangered plant species such as Elaeocarpus montanus and Gordonia zeylanica, globally vulnerable
plant species of the country including Lasianthus oliganthus and Syzygium micranthum were absent in cardamom cultivation lands (Adikaram and Perera, 2005).
The decline of the floristic richness and the conservation value of the secondary forests investigated may be an artifact of past disturbances due to cardamom cultivation. During cardamom cultivation, the understory and ground layers are cleared (Gunawardana, 2003) and as a result, many tree, climber and herbaceous flora in the ground and understory layers are removed. Tree canopy is also damaged during cardamom cultivation so as to allow more light to penetrate to the ground layer (Gunawardana, 2003;
Ranawana et al., 2004). Gunawardana (2003) pointed out that these cardamom cultivation lands were also frequently found on the slopes of 30-70% steep terrain and on stream banks which were highly environmentally sensitive areas situated over an elevation of 1000 m. THESE Cardamom cultivation lands are frequently been cleaned and as a result, the soil erosion takes place (Gunawardana, 2003). Prolonged cardamom cultivation therefore, proved to remove many native plant species from the sites and the remaining plants could be a choice of the cardamom growers. At present, there is an increasing trend to grow plant species alien to the region (e.g. Alstonia scholaris, Artocarpus
canopy gaps that have occurred due to the death of native canopy trees. This salient change of species composition in cardamom cultivation lands would potentially hasten the complete devastation of this fragile ecosystem. It is true that cardamom cultivation is a profitable industry. However, in the Knuckles region, the majority of those engaged in cardamom cultivation is represented by the elites from different parts of the country whereas only a few local rural villagers may be involved in cardamom cultivation at small-scale. In addition, a vast majority of the local villagers serve as labourers in the cardamom industry and thus, this venture would not much support the rural development in the region.
The current study revealed the high plant species richness and high conservation value of TMCFs of Dothalugala while reiterating the irreparable consequences and effects of cardamom cultivation on this globally valued ecosystem. This situation is more or less the same for other parts of the Knuckles massif too. Therefore, measures should be taken to reassess the possible options for this incomparable land. Could we afford to achieve sustainable development at the cost of the biodiversity of our country? Would cardamom cultivation in this environmentally sensitive area be a sensible option for this region? Would not the development of ecotourism industry in the Knuckles region with the participation of local people be a better alternative for the sustainable development of the country? Therefore, we firmly propose strict protection of this fragile and invaluable resource through change of existing policies and strengthening of relevant institutes.
ACKNOWLEDGEMENTS Financial assistance provided by the National Science Foundation, Sri Lanka (Grant No.: RG/2003/FR/02) and the kind permission granted by the Forest Department of Sri Lanka for conducting this study at Dothalugala MAB Reserve are gratefully acknowledged. Authors
64 Ekanayake et al. also wish to extent their sincere gratitude to Mr. B. K. B. Waththegama and Mr. B. D. C. G. Priyantha of the Forest Department for providing facilities during field activities, Mr. Milinda Bandara and Mr. Palitha Chandrasiri for helping in the field, Ms. Ranjani Edirisinghe of the National Herbarium, Peradeniya for assisting in the identification of plant species and Mr. Rusiru Hemage for assisting in preparing the map of Sri Lanka in the Figure 1.
Abeywickrama, B. A. (1986). The Threatened Plants of Sri Lanka. UNESCO and MAB National committee for Sri Lanka. Publication No 16. NARESA, Colombo, Sri Lanka. Adikaram, N. W. A. M. M. D. and Perera, G. A. D. (2005). Impacts of Cardamom cultivation on the floristic diversity of the montane forests of the Knuckles Range. Proceedings of
Lanka.
Aubad, J., Arago´n, P., Olalla-Ta´rraga, M. A. and Rodríguez, M. A. (2008). Illegal logging, landscape structure and the variation of tree species richness across North Andean forest remnants. Forest Ecology and Management
Balasubramaniam, S. (1988). The major forest formation of the Knuckles region. Proceedings of the Preliminary workshop for the preparation of a conservation plan for the Knuckles range of forest, Forest Department, Colombo, Sri Lanka. Bharathie, K. P. S. (1989). Impacts on the Knuckles Range of Forest in Sri Lanka. Forest Department. Colombo, Sri Lanka. Brooks, T. M., Mittermeier, R. A., da Fonseca, G. A. B., Gerlach, J., Hoffmann, M., Lamoreux, J. F., Mittermeier, C. G., Pilgrim, J. D. and Rodrigues, A. S. L. (2006). Global biodiversity conservation priorities. Science
Broun, A. F. (1900). On the forest and waste land of Ceylon. In: The flora of Ceylon, Hand
Peradeniya, Sri Lanka, Volume 5: 355-363. Bruijnzeel, L. A. and Veneklaas, E. J. (1998). Climatic conditions and tropical montane forest productivity: The fog has not lifted yet.
Cooray, P. G. (1998). The Knuckles Massif - A Portfolio. Forest Department, Sri Lanka. de Rosayro, R. A. (1958). The climate and vegetation of the Knuckles region of Ceylon.
Foster, P. (2001). The potential negative impacts of global climate change on tropical montane cloud forests. Earth-Science Reviews 55 (1- 2): 73–106. Gärdenfors, U., Hilton-Taylor, C., Mace, G. M. and Rodríguez, J. P. (2001). The Application of IUCN Red List Criteria at Regional Levels. Conservation Biology 15(5): 1206–1212. DOI: 10.1111/j.1523-1739.2001.00112.x Gaussen, H., Legris, P., Viart, M. and Labroue, L. (1968). Explanatory Notes on the Vegetation Map of Ceylon. Govt. Press, Colombo. 14. Gentry, A. H. (1992). Tropical forest biodiversity: distributional patterns and their
conservational significance. Journal of Oikos 63: 19-28. Gentry, A. H. (1993). Patterns of and floristic composition in neotropical montane forests.
Green, M. and Jayasooriya, M. (1996). Lost and found. Sri Lanka’s rare and endemic plant revealed. Plant Talk 18-21. Greller, A. M., Gunatilleke, I. A. U. N., Jayasuriya, A. H. M., Gunatilleke, C. V. S., Balasubramaniam, S. and Dassanayake, M. D. (1987). Stemonoporus dominated montane forests in the Adam’s Peak Wilderness, Sri Lanka. Journal of Tropical Ecology 3 (1): 243-253. Greller, A. M. and Balasubramaniam, S. (1980). A preliminary floristic-climatic classification of the forest of Sri Lanka. The Sri Lanka Forester 14: 163-170. Grubb, P. J. (1971). Letter on interpretation of the 'Massenerhebung' effect on tropical mountains. Journal of Nature 229: 44-45. Grubb, P. J. and Whitmore, J. (1965). A comparison of montane and lowland rain forest in Ecudor II. The climate and its effects on the distribution and physiognomy of the forest. Journal of Ecology 53: 422-463. Grubb, P. J. and Whitmore, T. C. (1966). A comparison of montane and lowland rain forest in Ecuador. II The climate and its effects on the distribution and physiognomy of the forest. Journal of Ecology 54: 303-333. Gunawardana, H. G. (2003). Ecological Implication of Cardamom Cultivation in the high altitudes of Knuckles Forest Reserve, Sri Lanka. The Sri Lanka Forester 26: 1-9. Hamilton, L. S., Juvik, J. O. and Scatena, F. N. (1995). Tropical montane cloud forests. Ecological Studies (Germany), Vol. 110. Springer-Verlag, New York.
Floristic Features of TMCFs at Dothalugala MAB Reserve, Sri Lanka 65
Hurlbert, S. H. (1971). The non-concept of species diversity: a critique and alternative parameters. Ecology 52: 577-586. IUCN (2007). The 2007 Red List of Threatened Fauna and Flora of Sri Lanka. IUCN, Sri Lanka. Jacobs, M. (1988). The tropical rain forest: A first encounter. Springer-Verlag, Berlin, 295pp. Jarvis, A. J. (2001). Terrain controls on the distribution of tree Species diversity and structure in tropical Lowland and tropical montane forest. A thesis submitted to the University of London for the Degree of Doctor of Philosophy, King’s College, London, U.K. Jayasuriya, A. H. M., Balasubramaniam, S., Greller, A. M. and Dasanayake, M. D. (1988). Botany of the Knuckles Mountain Range (Unpublished). Jesús, I. (1998) Types of rarity of plant communities. Journal of Vegetation Science 9(5): 641–646. Kapos, V., Rhind, J., Edwards, M., Ravilious, C. and Price, M. (2000). Developing a map of the world’s mountain forests. In: Price, M. F. & Butts, N. (Eds.) Forests in Sustainable
International, Wallingford, UK. Koelmeyer, K. O. (1957). Climatic classification and the distribution of vegetation in Ceylon. The Ceylon Forester 3 (2): 144-163. Kumaran, S. Perumal, B., Davison, G., Ainuddin, A. N., Lee, M. S. and Bruijnzeel, L. A. (2011). Tropical montane cloud forests in Malaysia, Current status of knowledge. In:
Hydrology Series. L. A. Bruijnzeel, F. N. Scatena, L. S. Hamilton (Eds.), Cambridge University Press, U.K. Lamoreux, J. F., Morrison, J. C., Ricketts, T. H., Olson, D. M., Dinerstein, E., McKnight, M. W. and Shugart H. H. (2006). Global tests of biodiversity concordance and the importance of endemism. Nature 440: 212–214. Ledo, A., Montes, F. and Condes, S. (2009). Species dynamics in a montane cloud forest: identifying factors involved in changes in tree diversity and functional characteristics.
584.
Legg, C. (1995). A Geographic information system for planning and managing the Conservation of tropical forest in the Knuckles Range. The Sri Lanka Forester, Special issue: 25 - 36. Loope, L. L. and Giambelluca, T. W. (1998). Vulnerability of island Tropical Montane Cloud Forests to climate change, with special reference to East Maui, Hawaii.
Margules, C. and Usher, M. B. (1981). Criteria used in assessing wildlife conservation potential: a review. Biological Conservation Yüklə 1,16 Mb. Dostları ilə paylaş:
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