Community ecology and spatial distribution of trees in a tropical wet evergreen forest in Kaptai national park in Chittagong Hill Tracts, Bangladesh

Abstract

We investigated the floristic composition, woody species diversity and spatial distribution of trees in a tropical wet evergreen forest in Kaptai national park in Chittagong Hill Tracks, Bangladesh. We recorded 25 families, 37 genera, 40 species and 1771 woody individuals in a 0.09 ha plot. Euphorbiaceae and Moraceae were the most speciesrich families, and Castanopsis, Ficus and Terminalia were the most species-rich genera. Bursera serrata Wall. ex Colebr. was the dominant species in terms of highest importance value (13%). Trema orientalis (L.) Bl was typically a light demanding species as it appeared in the top canopy with only one individual having the seventh highest IV, but had no regeneration. The expected maximum number of species (S _max) was 140, indicating that many species may invade the forest as the S _max is greater than the recorded total number of species. The nature of the disappearance and appearance of species in the present forest reflects instability of floristic composition. The values of Shannon’s index H′ and Pielou’s index J′ (evenness) were 3.36 bit and 0.63, respectively. These values show moderately high species diversity as compared to other subtropical forests in the tropics. In addition, a sample area of 200 m² in this forest would be sufficient for measuring the diversity indices H′ and J′, whereas the trend of J′ may indicate the rate of equality of individuals among the different species decreased with increasing area. The distribution pattern for the total stand was completely random. However, the dominant species showed aggregate distribution for small areas, but random distribution for large areas. The spatial association between species showed that the strongest positive interspecific association occurred between Streblus asper Lour. and Castanea indica Roxb. (ω = 0.51). As a whole, most species were weakly associated with each other, of which 58% species associations were completely negative. The result of cluster analysis showed that species pairs were spatially independent at all or most small clusters; stands of species from all clusters are mosaics of complete habitat and pioneer habitat. All patches in this forest community have similar habitat and regeneration niches, which could be a phenomenon for a young growth forest. Thus, the existence of habitat and regeneration niches may be an important factor in the maintenance of diversity in this forest.

References

[1] Anonymous. 1960. Working plan of the Chittagong Hill Tracts North and South Forest Division for the period from 1953–54 to 1972–73, vol. 2. Working Plan Division, Forest Department, the Government of East Pakistan, pp. 1–89.

[2] Bunyavejchewin S, LaFrankie JV, Baker PJ, Kanzaki M, Ashton PS, Yamakura T. Spatial distribution patterns of the dominant canopy dipterocarp species in a seasonal dry evergreen forest in western Thailand. Forest Ecology Management, 2003, 175: 87-101.

[3] Das DK, Alam MK. Trees of Bangladesh. 2001, Chittagong, Bangladesh: BFRI

[4] Feroz SM, Hagihara A, Yokota M. Stand structure and woody species diversity in relation to the stand stratification in a subtropical evergreen broadleaf forest, Okinawa Island. Journal of Plant Research, 2006, 119: 293-301.

[5] Feroz SM, Yoshimura K, Hagihara A. Stand stratification and woody species diversity of a subtropical forest in limestone habitat in the northern part of Okinawa Island. Journal of Plant Research, 2008, 121: 329-337.

[6] Goldman S. Information theory. 2005, New York: Dover Publications, 400.

[7] Hagihara A. The Size-Dependence curve as a generalized Competition-Density curve. Japanese Journal of Forest Planning, 1995, 24: 15-23.

[8] Hall JB, Swaine MD. Classification and ecology of closed-canopy forest in Ghana. Journal of Ecology, 1976, 64: 913-951.

[9] Huang W, Pohjonen V, Johansson S, Nashanda M, Katigula MIL, Luukkanen O. Species diversity, forest structure and species composition in Tanzanian tropical forests. Forest Ecology and Management, 2003, 173: 11-24.

[10] Hurlbert SH. The nonconcept of species diversity: a critique and alternative parameters. Ecology, 1971, 133: 125-133.

[11] Huston MA. Biological Diversity. 1994, Cambridge: Cambridge University Press, 681.

[12] Hozumi K. Studies on the frequency distribution of the weight of individual trees in a forest stand. V. The M-w diagram for various types of forest stands. Jpn J Ecol, 1975, 25: 123-131.

[13] Itô Y. Diversity of forest tree species in Yanbaru, the northern part of Okinawa Island. Plant Ecology, 1997, 133: 125-133.

[14] Iwao S. Application of the *m-m method to the analysis of spatial patterns by changing the quadrat size. Researches on Population Ecology, 1972, 14: 97-128.

[15] Iwao S. Analysis of spatial association between two species based on the interspecies mean crowding. Researches on Population Ecology, 1977, 18: 243-260.

[16] Lloyd M. Mean crowding. Journal of Animal Ecology, 1967, 36: 1-30.

[17] MacArthur RH, MacArthur JW. On bird species diversity. Ecology, 1961, 42: 594-598.

[18] Miyawaki A. Vegetation of Japan Vol. 10. 1989, Okinawa & Ogasawara. Tokyo: Shibundo Co. Ltd., 676.

[19] Mountford MD. Murphy PW. An index of similarity and its application to classificatory problems. Progress in Soil Zoology. 1962, London: Butterworths, 43 50

[20] Niiro Y. An outline of vegetations found on Mt. Omoto and its vicinity (in Japanese). Science Report on Biota on Mt. Omoto and its Neighboring Areas, a Candidate Site for Nature Conservation Areas of Okinawa Prefecture. 1981, Naha: Okinawa Prefectural Government, 55 114

[21] Niiro Y, Miyagi Y, Shinjo K, Shimabukuro H. Ikehara S. Vegetation of the Yaeyama Islands. Ecological Studies of Conservation of the Ryukyu Islands (1). 1974, Naha: University of the Ryukyus, 5 36

[22] Ogawa H. Structure and Function of Populations. 1980, Tokyo: Asakurashoten, 221.

[23] Pielou EC. An Introduction to Mathematical Ecology. 1969, New York: John Wiley & Sons, Inc

[24] Shinozaki K. Note on the species-area curve (in Japanese). Proceedings of Annual Meeting for the Ecological Society of Japan, Tokyo, 1963 5.

[25] Sneath PHA, Sokal RR. Numerical Taxonomy. 1973, San Francisco: W. H. Freeman and Company, 572.

[26] Sterner RW. Testing for life historical changes in spatial patterns of four tropical tree species. Journal of Ecology, 1986, 74: 621-623.

[27] Suzuki K. Vegetation der Ryukyu-Inseln, Japan — Pflanzensoziologische Studien der Ryukyu-Inseln VI. Bulletin of the Institute of Environmental Science and Technology, Yokohama National University, 1979, 5: 87-160.

[28] Uddin SN, Hassan MA. Angiosperm flora of Rampahar reserve forest under Rangamati district in Bangladesh. L. Liliopsida (Monocots). Bangladesh J Plant Taxon, 2012, 19: 37-44.

[29] Whitmore TC. An Introduction to Tropical Rain Forests. 1998, London: Oxford University Press, 282.

[30] Wilson EO. Biodiversity. 1988, Washington, D.C.: National Academy Press

[31] Wilson EO. The Diversity of Life. 1992, Cambridge: Harvard University Press

[32] Wu M, Feroz SM, Hagihara A, Xue L, Huang ZL. Vertical stratification, floristic composition and woody species diversity in a subtropical evergreen broadleaf forest (Dinghushan Nature Reserve, South China). Tropics, 2010, 19: 9-20.