Assessment of Level of Human Disturbance in Village-adjacent Natural Forest Plots in the Kerala Part of Nilgiri Biosphere Reserve

U.M. Chandrashekara

Abstract


The structure and composition of tree community was analysed in ten forest plots, adjacent to villages, in the Kerala part of Nilgiri Biosphere Reserve (NBR), and the level of disturbance in each plot was determined. These plots represent secondary forest, generally dominated by evergreen light demanding, late and early successional species and deciduous species such as Xylia xylocarpa, Terminalia paniculata, Macaranga peltata, Aglaia malabarica, Alseodaphne semecarpifolia, Bischofia javanica, Wrightia tinctoria etc. In all the plots, a distorted girth class distribution, with a drastic decline in the number of individuals of girth ranging from 20 cm to 60 cm, was noticed. The litter removal from the forest floor depicted a three-fold adverse effect on species richness; by way of physical removal of tree propagules along with other litter materials, run-off of tree propagules in the absence of litter layer and seedling mortality consequent to soil dryness and desiccation. However, in the forest plots adjacent to villages  Kadasseri and Manikunnmala, the species number increased due to invasion of exotic species from the adjoining landuse systems. In order to assess the level of disturbance in these plots, three forest quality indicators namely Ramakrishnan Index of Stand Quality (RISQ), Index of Ecological Quality (IEQ) and Index of Human disturbance (IHD) were measured. The high value for RISQ (more than 3) is an indicative of the fact that majority of the forest plots are under different stages of succession and need more time for their recovery from the anthropogenic disturbances. A positive correlation between any two forest quality indicators suggested that they are complementary to each other and helpful to accurately assess ecological and human factors responsible for the status of the forest stand and identify site-specific suitable conservation and management strategies.

Keywords


Chronic Disturbance; Disturbance Variables; Biomass Harvest; Tree Community; Tree Girth Class Distribution; Successional Status; Forest Quality Indicators

References


Ayyappan, N. and Parthasarathy, N. 1999. Biodiversity inventory of trees in a large-scale permanent plot of tropical evergreen forest at Varagalaiar, Anamalais, Western Ghats, India. Biodiversity Conservation 8:1533-1554.

Baithalu, S.; Anbarashan, M. and Parthasarathy, N. 2012. Changes in tree diversity and stand structure of two tropical dry evergreen forests on the Coromandel coast of peninsular India over a decade (2001-2011). International Journal of Ecology and Environmental Sciences 38:87-96.

Chandrashekara, U.M. and Jayaraman, K. 2002. Stand Structural Diversity and Dynamics in Natural Forests of Kerala. KFRI Research Report No. 232. Kerala Forest Research Institute, Peechi, Kerala.131 pages.

Coates, K.D. 2002. Tree recruitment in gaps of various size, clearcuts and undisturbed mixed forest of interior British Columbia, Canada. Forest Ecology and Management 155: 387-398.

Collins, N.M.; Sayer, J. A. and Whitmore, T. C. 1991. The Conservation atlas of tropical rainforests: Asia and the Pacific. Macmillan, London. 335 pages.

Denslow, J.S. 1980. Patterns of plant species diversity during succession under different disturbance regimes. Oecologia 46: 18-21.

Fashing, P.J.; Forrestel. A.; Scully, C. and Cords, M. 2004. Long-term tree population dynamics and their implications for the conservation of the Kakamega Forest, Kenya. Biodiversity Conservation 13:753-771.

Hubbell, S.P. and Foster, P.B. 1992. Short-term dynamics of a neotropical forest: why ecological research matters to tropical conservation and management. Oikos 63:48-61.

Kershaw, K.A. 1973. Quantitative and dynamic plant ecology. Edward Arnold, London. 308 pages.

Kohyama, T.; Ohyama, T.; Suzuki, E.; Partomiharjo, T.; Artomiharjo, T.; Yamad, T. And Kobo, T. 2003. Tree species differentiation in growth, recruitment and allometry in relation to maximum height of Bornean mixed dipterocarp forest. Journal of Ecology 91: 797-806.

Korning,J. And Balslev, H. 1994. Growth rates and mortality patterns of tropical lowland tree species and the relation to forest structure in Amazonian Ecuador. Journal of Tropical Ecology 10:151-166.

Lang, G.L. and Knight, D.H. 1983. Tree growth, mortality, recruitment and canopy gap formation during a 10-year period in a tropical moist forest. Ecology 64: 1075-1080.

Laurance, W.F. and Bierregaard, R.O. 1997. Tropical forest remnants: ecology, managements and conservation of fragmented communities. University of Chicago Press, Chicago. 616 pages.

.

Lieberman, D.; Hartshorn, G.S.; Lieberman, M. and Peralta, R.1990. Forest dynamics at La Selva biological station (1969-1985). Pages 509-521, In: Gentry, A.H. (Editor) Four neotropical rainforests. Yale University Press, New Haven.

Margalef, R. 1968. Perspective in ecological theory. University of Chicago Press, Chicago.111 pages.

Miura, M.; Manabe, E, T.; Nishimura, N. and Yamamoto, S. 2001. Forest canopy and community dynamics in a temperate old-growth evergreen broad-leaved forest, south-western Japan: a 7-year study of a 4-ha plot. Journal of Ecology 89: 841-849.

Mori, S.A.; Boom, B.M.; De Carvalho, A.M. and Dos Santos, T.S. 1983. Southern Bahaian moist forests. Botanical Review 49: 155-232.

Myers, N. 1988. Tropical forests and their species: going, going ------- ? Pages 28-35. In: Wilson E.O. (Editor) Biodiversity. National Academy Press, Washington.

Nebel, G.; Kvist, L.P.; Vanclay, J.K. and Vidaurre, H. 2001. Forest dynamics in flood plain forests in the Peruvian Amazon; effects of disturbance and implication for management. Forest Ecology and Management 150: 79-92.

Oliveira-Filho, A.T.; Mello, J.M. and Scolford, J.R.S.1997. Effects of past disturbance and edges on tree community structure and dynamics within a fragment of tropical semi-deciduous forest in south-eastern Brazil over a five-year period (1987-1992). Plant Ecology 131:45-66.

Parsons, R.F. and Cameron, D.S. 1974. Maximum plant species diversity in terrestrial communities. Biotropica 6: 202-203.

Pascal, J.P. 1988. Wet evergreen forests of the Western Ghats of India: ecology, structure, floristic composition and succession. French Institute of Pondicherry, Pondicherry, India. 345 pages.

Pascal, J.P. and Pelissier, R. 1996. Structure and floristic composition of a tropical evergreen forest in the south-west India. Journal of Tropical Ecology12: 191-214.

Phillips, O.L. 1996. Long-term environmental change in tropical forest: increasing tree turnover. Environmental Conservation 23: 235-248.

Phillips, O.L and Gentry, A.H. 1994. Increasing turnover through time in tropical forests. Science 263: 954-958.

Rai, S.N. 1981. Floristic composition and survival of rainforest tree species of Western Ghats, India. My Forest 2: 101-110.

Richards, P.W. 1996. The tropical rainforest. Cambridge University Press, Cambridge. 600 pages.

Runkle, J.R. 2000. Canopy tree turnover in old-growth mesic forests of eastern North America. Ecology 81: 554-567.

Sheil, D.; Jennings, S. and Savill, P. 2000. Long-term permanent plot observations of vegetation dynamics in Budongo, a Ugandan rainforest. Journal of Tropical Ecology16:765-800.

Sheil, D. and May, R.M. 1996. Mortality and recruitment rate evaluations in heterogenous tropical forests. Journal of Ecology 84: 91-100.

Simpson, E.H. 1949. Measurement of diversity. Nature 163:688.

Singh, J.S.; Singh, S.P.; Saxena, A.K. and Rawat, Y.S. 1981. The Silent valley forest ecosystem and possible impact of proposed hydroelectric project: reports on the Silent valley study. Ecological Research Circle, Kumaun University, Nainital, India. 86 pages.

Stork, N.E. 2010. Reassessing extinctive rates. Biodiversity and Conservation19: 357-371.

Sukumar, R.; Suresh, H.S.; Dattaraja, H.S. and Joshi, N.V. 1998. Dynamics of tropical deciduous forest: population changes (1988 through 1993) in a 50-ha plot at Mudumalai, Southern India. Pages 529-540. In: Dallmeier, F. and Comiskey, J.A. (Editors). Forest biodiversity research, monitoring and modelling: conceptual background and old world case studies. Parthenon Publishing, Paris.

Swaine, M.D.; Lieberman, D. and Putz, F.E. 1987. The dynamics of tree populations in tropical forest: a review. Journal of Tropical Ecology 3: 359-366.

Whitmore, T.C. 1984. Tropical rainforests of the Far East (2nd edition). Oxford University Press, Oxford. 352 pages.


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