1. TREE SPECIES DIVERSITY IN PART OF WESTERN GHATS FORESTS IN INDIA V.K.Srivastava1, M.Niphadkar2, Neeti3, M.Kukreja4 1 = Land Resources Group, NRSA, HYDERABAD 50038, INDIA 2 = Dept. of Geography, California University, San Diego, California, U.S.A. 3 = Dept. of Geography, Clark University, Worcester, U.S.A. 4 = ROLTA India Ltd, Mumbai, INDIA and M.K.Janarthanam, Botany Department, Goa University, PANJIM, GOA, INDIA RESULTS AND DISCUSSION Forest in the region The geomorphology, bioclimatology and anthropogenic pressure are unique in each district of the study area. This affects the mode and magnitude of distribution of forest in the area. About 15.5 per cent of the total geographical area of the region is under forest covers. Table 1 gives the distribution and type of forests found in each district. Tropical dry deciduous, tropical moist deciduous, tropical semi evergreen and tropical broad leaf evergreen forests are found in these districts. The northern most district of the study area, Dhule district contained only tropical dry deciduous forest. The number of forest type increases in south wards districts. This may be due to the climatic conditions of each district (Srivastava et al, Loc cit). Evergreen forest was found in four districts of Maharashtra and both districts of Goa. The lowest value of Dd was recorded in Raigarh district (2.31), followed by Pune district (2.60). In the remaining districts, Dd was found to be more than 3.0. The highest Dd value was recorded in Ratnagiri (3.61). A minimum of 10 species per sample with a mean basal area of 33.46 m2 was observed in Raigarh district. The highest mean basal area of 67.4 m2 was recorded in South Goa where the average number of tree species was 15. ACKNOWLEDGEMENTS The authors are highly thankful to Dr. P.S.Roy, Deputy Director, RS & GIS-AA, NRSC, Hyderabad, for entrusting the job of carrying out biodiversity inventory in the study region. We are also highly indebted to the officials of the Maharashtra and Goa forest Departments for extending full support and co- operation in collection of field data. The financial support to participate in the13Th World Forestry Congress by the Organizing Committee, is highly acknowledged. For further details: Dr. V.K.Srivastava : vijayks52@gmail.com 13 th World Forestry Congress, Buenos Aires, Argentina, October 18-24, 2009 Table 4: Tree species diversity (Dd) in each forest type, in each district of the study area. Table 3: Important families and their contribution in species richness. INTRODUCTION Biodiversity is the very basis of human survival and economic well-being, encompassing all life forms, ecosystems and ecological processes, while acknowledging the hierarchy at genetic, taxon and ecosystem levels (Mc Neely, et al, 1990). The growing awareness of the benefits and anticipated rapid decline of biodiversity has necessitated speedy inventory and monitoring of biodiversity at all levels (Singh, 2002). Tropical ecosystems especially tropical forests are exceptionally rich in biodiversity, attracting much attention world wide (Whitmore, 1984). Forests are the largest store house of species found in any terrestrial ecosystems. It is widely recognized that assessments of forest biodiversity are essential if forests are to be effectively conserved and sustainably managed (Hunter, 1999). However, forests are more threatened today than in the past as a consequence of introduction of exotic species, deforestation, habitat destructions etc. As a result, there is a lot of spatial and temporal variation in reported values of species richness, composition and productivity (Bhat et al, 2000), leading to the need of continuous monitoring of forest stand. A meaningful conservation effort calls for inventorying the forest biodiversity at regular intervals, notwithstanding the growing volume of literature as there is paucity of concrete data, theories and methodologies on all aspects of biodiversity (Singh, Loc. cit.). The status of forest biodiversity is an indicator of forest condition. In India, about 45,000 plant species including 15,000 flowering plants are ascribed to forests (MOE&F, 1998). This diversity is attributed to the vast variety in physiographic and climatic conditions resulting in diverse habitats. As a result, India represents two major realms and three biomes which include 12 bio-geographical regions. India is one of the 12 mega-diversity centres having two of the 25 identified hotspots (Myers et al, 2000). These are: Eastern Himalayas and Western Ghats. Their floral wealth is particularly rich so is their endemism not only in flowering plants but also in reptiles, amphibians, butterflies and mammals. Though the tropical forests of the Western Ghats harbor a large variety of species, only a few systematic studies (Sukumar et al, 1992 and Pelissier et al, 1998) are available describing the changes in vegetation and other related parameters of the forest stand. Daniels (2001) has reviewed the available literature and noted that nearly 38 per cent of all flowering plants and 63 per cent of evergreen woody plants are endemic to the Western Ghats. Rao (2006) have identified 3500 angiospermic flora, including 125 endemic species in the region. The importance of trees of different forest types and protected area in establishing biodiversity indicators is well recognized (Newton and Kapos, 2002) as species of several trophic levels are tied to tree species. Thus tree species extinctions are conspicuously disastrous. Estimates indicate that about 80per cent of the world’s 100,000 tree species are in the tropics and 10 per cent of all tree species are now threatened. As many as 77 tree species are already extinct and 976 tree species are critically endangered (Williams, 1998). In view of the above, Dept. of Biotechnology, Govt. of India, initiated a project in 1998 to characterization of Biodiversity at landscape level using remote sensing and GIS, in collaboration with the Dept. of Space, Govt. of India. The present study is a part of this project which attempts to understand tree species diversity in different forest types found in the Western Ghats districts of Maharashtra (10 revenue districts) and Goa states. STUDY AREA The Western Ghats, known locally as the Sayadhri Hills, is located in the southwestern part of India and formed by the Malabar plains and thechain of mountains, passing through the states of Maharashtra, Goa, Karnataka, Tamilnadu and Kerala. It runs parallel to India’s western coast, about 30 to 50 km inland and covers an area of about 160,000 km2 and stretch for 1,600 km from the country’s southern tip to Maharashtra in north, interrupted only by the 30 km Palghat Gap.The Western Ghats of Maharashtra, extending from the Satpura range to the north, travels south past Goa to Karnataka. The chief hill range of the segment is Sayadhri range, having two high peaks – one at 1646 m (Kalsubai) and the other 1567 m (Salher). The narrow coastal plain between the Western Ghats and the Arabian Sea is known as Konkan Coast in the north and Malabar Coast in the south. The lower partsof the Western Ghats record humid and tropical climate. The elevated regions (1500 m and above in the north and 2000 m in the south) have a more temperate climate. The mean temperature varies from 240 C in the north to 200 C in the south. The windward side (western part) receives an annual rainfall of about 3000 to 4000 mm and the leeward side i.e. eastern part records a meager average of 1000 mm. The drainage system of the Western Ghats constitutes the perennial rivers of peninsular India. The westward flowing rivers drain into theArabian Sea and that flows eastwards drain into the Bay of Bengal (Srivastava et al, 2005). Figure 1 show the part of Western Ghats, where present study was undertaken, in the states of Maharashtra and Goa. Ten revenue districts of Maharashtra (viz. Dhule, Nashik, Thane, Pune, Raigarh, Satara, Sangli, Ratnagiri, Kolhapur and Sidhudurg) and the state of Goa constituted the study area. These districts are located between 140 45’ and 220 05’ N latitude and between 720 45’ and 750 15’ E longitude. Dhule Nashik Thane Pune Raigarh Ratnagiri Sindhudurg Goa Satara Sangli Kolhapur Figure 1: Location map of the study area MATERIAL AND METHODS In order to estimate the diversity in the forests of the region, phytosociological survey was conducted in the forests of the region. Depending on the forest area in each district and the approachability, a total 299 samples were distributed randomly in the months of October, November, December, 1999; January, February, March and April, 2000 and April, May 2001. Each sample was square in shape, of the size 25m × 25 m and distributed randomly in the forest. Care was taken to distribute these samples in a manner that all forest types found in the districts could be sampled. All tree species falling within each sample were listed and their density / abundance were recorded. These trees were also enumerated for mensurational parameters like, girth at basal area, diameter at breast height, tree height, and canopy diameter. However, only number and density/ abundance of species in each sample were used for the present study. Shannon-Weiner Index of diversity (Dd) which incorporates both species richness and their abundance ( Odum, 1971 and William et al, 2005) was calculated for each sample, in each forest type in each district, using the following formula. s Dd = Σ (Pi/N) ln (Pi/N) I = 1 Where “Pi” is the decimal fraction of the total individuals belonging to the “ith” species. Table 1: Distribution of forest types in different districts of the study area. Tropical deciduous forest constitutes about 10.8 per cent of the total forest area found in the ten Western Ghats districts of Maharashtra. More than half of this forest type is found in the northern most district of the study area i.e. Dhule and a little less than half in Nashik district and the remaining in Pune district.The tropical broad leaved evergreen forest constitute about 8 per cent of the total forest area and are found in Pune, Raigarh, Ratnagiri and Sindhudurg districts.The major part of the forest in the region belongs to moist deciduous (56 per cent) and semi evergreen forest (25 per cent). It is generally believed that dry deciduous forest is found in the drier condition and the evergreen forest in the wetter condition. The moist deciduous and semi evergreen forest are theintermediate type between the two extremes (Champion and Seth 1969). In the state of Goa, only moist and wet forests i.e. moist deciduous, semi evergreen and evergreen forests are found. Here again, the bulk is the forest is made up of moist deciduous forest, followed by semi evergreen and evergreen forest respectively. Listing of species A comprehensive list of vegetation present in an area, community or stand is an essential characteristic in vegetation analysis as various species makea community and each species has its own ecological amplitude. Each species has a particular relationship with the environment and to other species. Therefore, a list of tree species in each forest type found in the study area was prepared. The comprehensive list of tree species found in the region was published elsewhere (Anonymous, 2002). 59 species were recorded from dry deciduous forest; 194 in moist deciduous forest; 329 in semi evergreen forest and 124 in evergreen forest. The total number of species, total number of genera and average number of species found in each forest type in each district is given in Table 2. The minimum number of trees per sample was found in the dry deciduous forest in Pune district; and the maximum number of trees per sample was found in semi evergreen forest in Kolhapur district. In general 5 to 7 tree species per sample was found in dry deciduous forest (Pune, Nashik and Dhule). Moist deciduous forest was distributed in nine districts and the average number of tree species per sample varied from 11 (Nashik, Pune, Sindhudurg and South Goa to 18 in Satara district. The distribution of tree species per sample varied from 13 in Sangli district to 28 in Kolhapur district. However in evergreen forest, the average tree species per sample varied from 10 in Raigard to 23 in North Goa. Taxonomic diversity The taxonomic diversity in each of the forest type in each district of the study area is given in Table 3. All the tree species found in the dry deciduous forest belonged to 28 families. Amongst the families, Papilionaceae was most common family represented by six species belonging to six genera. The contribution of species of this family in Dhule district was about 17 per cent to the total species, having a density of about 28 per cent. However, this family’s contribution to total species decreased to about 10 per cent in Nashik district and with 2 per cent density and to 6 per cent in Pune districtwith a density of 19 per cent. Rubiaceae was the next common family in this type of forest, represented by 5 species belonging to 5 genera. Combretaceaewas represented by 8 species belonging to 5 genera as three species namely Terminalia arjuna, Terminalia chebula and Terminalia tomentosa belonged to the same genus. Most of the other families were represented by single species or genus. 195 species belonging to 72 families were found to be distributed in the oist eciduous forest. However, the intensity of distribution varied from district to district. For example, Euphorbiaceae was most abundant in both the district of Goa. 10 pecies in south Goa and 6 species in North Goa represented this family. In the districts of Maharashtra, 5 species of this family was recorded in Sindhudurg and Raigarh districts, where this family was co dominant. The dominant family in indhudurg district was Apocynaceae with six ciesHowever, Combretaceae with six species dominated Raigarh district. ut of all the families found in this type of forest, Euphorbiaceae, Anacardiaceae, Combretaceae, Rubiaceae, Papilionaceae and Apocynaceae were the most common families. However, the per cent ontribution of species belonging to these families to total species and density varied from district to istrict,Ebenaceae, Apocynaceae, Flacourtiaceae, Rubiaceae, Papilionaceae, Combretaceae and Mimosaceae were most common families. The stribution of species in each of these families varied widely between different tricts.Similarly, 129 species belonging to 56 families were recorded in evergreen forest which occurred only in five districts. lusiaceae,Ebenaceae, Euphorbiaceae, Anacardiaceae, Apocynaceae, Mimosaceae, Rubiaceae, Lauraceae, Rutaceae and Papilionaceae are the dominant families in the districts. However, the species composition of each family varied from district to district. For xample,Clusiaceae and Ebenaceae were dominant families in South oa;Euphorbiaceae was dominant in Sindhudurg, Ratnagiri and Pune districts. The above results indicates that the maximum number of tree species was found in semi evergreen forest followed by moist deciduous and evergreen forest respectively. Minimum number of tree species was recorded in dry deciduous forest. Thus, taxonomically, semi evergreen forest was found to contain highest diversity followed by moist deciduous and evergreen species respectively. Tree diversity was found to be lowest in the dry deciduous forest in caparison with other three types of forest found in the study area.. Ecological diversity (Evaluation of Shannon-Weiner index of diversity) Among the various types of ecological diversity, species diversity is easily understood owing to its ease in measurement. Species diversity measures the species variety and their variability in distribution. Shannon-Weiner index uses the proportional distribution of species in a sample. Hence, it is considered to be a good measure of diversity. This index assumes that the abundant a species is, it is more important to the community. In communities embracing organisms possessing wide range of sizes, the importance of fewer but lager individuals may be underestimated and more common species are weighted heavily than such species (Srivastava et al, Loc. cit.). Still this index of diversity (Dd) being commonly used, was calculated using the variety and abundance of each species in a sample, using the formula quoted above. The average Dd value in each forest type, in each district along with average number of species and average basal area is given in Table 4. A cursory glance of Table 4 indicated that the minimum value of Shannon-Weiner index of diversity (Dd) was observed in dry deciduous forest. This forest type was found in three districts of the study area (Dhule, Nashik and Pune). The lowest value of Dd was observed in Pune district, having lowest number of species per sample. Dd value and number of species per sample though alike in Dhule and Nashik districts, were higher than Pune district. However, the average basal area was found to be higher in Pune district as compared to the other two districts. Strong positive correlation within the samples in each district was observed between Dd values and the number of species found in each sample. A negative relationship between Dd and basal area was observed in the samples in each district. This suggests that though with increasing number of species, diversity increases but the niche loci of each species overlaps leading perhaps to the resource competition affecting the growth performance of the species as reflected in the basal area. Moist deciduous forest, present in nine districts, showed consistently higher Dd values as compared to the dry deciduous forest (Table 4). The highest value of Dd was recorded in Satara district followed by Thane and South Goa districts respectively. In these districts, the value of Dd was more than 3.0. The average n umber of species was highest in Satara district, followed by Thane and south Goa districts respectively. The mean basal area was very low in Satara district as compared to Thane or South Goa. In the remaining six districts Dd was found to be lowest in Pune district being 2.45. The value of Dd ranged between 2.6 and 2.8 in the remaining five districts. 15 tree species per sample was recorded in North Goa and 14 in Ratnagiri district. In the remaining districts, 11 tree species per sample was recorded with an exception of 12 species in Raigarh district. Thus, in general, with increasing number of species, the diversity (Dd) increases as evident from the value of coefficient of correlation ( r = 0.73). A negative correlation between mean basal area and number of species per sample or diversity index was observed, indicating that with increase in diversity, basal area reduces. This may per haps due to the overlap of niche loci of each species, leading to competition for resources resulting in poor growth of trees. Semi evergreen forest like moist deciduous forest was found in nine districts. The value of Dd varied from 3.02 (Sindhudurg) and 3.72 (Kolhapur). A maximum of 28 tree species per sample was recorded in Kolhapur district with low mean basal area (1.08 m2). Minimum number of tree species per sample (13) was recorded in Sangli district. For the remaining districts, it varied from 14 to 18 tree species per sample. Mean basal area of less than 2 m2 was recorded Satara, Sangli and Kolhapur districts. The forest in these districts were regenerating ones, hence most of the individuals of each species were at sapling stage. In the remaining districts, the mean basal area varied from 19.5 m2 (Raigarh) to 46.4 m2 (South Goa). In Maharashtra, it was highest in Pune (38.5 m2) and in Sindhudurg district (33.2 m2). The high mean basal area in Goa and in the southern districts of Maharashtra may perhaps be due to low biotic pressure, orography, better environmental conditions and better differentiation of niche loci. As one moves southwards in the study area, towards Goa, the climate becomes more humid. This coupled with difficult orography may perhaps be acting as deterrent to biotic pressure, leading to the existence of suitable habitat as reflected in the mean basal area. Interpretation of results with respect to forest ypesonly, independent of the district of occurrence, showed a different pattern. For this type of analysis, all samples within a forest type were clubbed together to derive various measures. Semi evergreen forest contained highest diversity (Dd = 4.08), followed by moist deciduous (Dd = 3. 89) and evergreen (Dd = 3.48) respectively. Minimum value of Dd was observed in dry deciduous forest (Dd = 1.30). The average number of tree species per sample was 15 in semi evergreen and evergreen forest while it was 12 in moist deciduous and only 7 in dry deciduous forest. The average basal area per sample was highest in evergreen forest (22.16 m2), closely followed by semi evergreen (21.38 m2). Minimum basal area per sample was recorded in dry deciduous forest (0.98 m2). It was 5.28 m2 in moist deciduous forest. It is of interest to note that all the three measures are positively related with each other ( Figure 2). The highest correlation was observed between average number of species and average basal area per sample i.e. with increasing number of species, the total average basal area also increased. This may perhaps be true as dry deciduous forest in under high degree of climatic and biotic stress. But as climate becomes moister and wetter, the stress decreases and the habitat become more suitable to afford more species and better growth. This may be interpreted in terms of climatic stability theory (Smith, 1980) wherein with stability in climate diversity increases, as evident from these results. The relationship between Dd and number of species was also high as the number of species is an input to the calculation of Dd. The high basal area in semi evergreen and evergreen forest may be explained by the productivity theory wherein level of diversity in a community is determined by the amount of energy flow through the food web. The rate of energy flow is influenced by the limitation of the ecosystem and by the degree of stability of the environment. This may also explain the reason of low total basal area in moist and dry deciduous forest. Figure 2: Relationship between diversity index (Dd), average number of species (Av. Sps.) and average basal area (ABA) in the four types of forest found in the study area. CONCLUSIONS The study described above revealed that the study area i.e. part of Western Ghats (i.e. coastal districts of Maharashtra and Goa states) contained about 600 tree species. These species were distributed in the four types of tropical forests (dry deciduous, moist deciduous, semi evergreen and evergreen forests) found in the region. The forest area in the region covered about 15.5 per cent of the geographical area. The average number of species varied from 7 in dry deciduous to 11 in moist deciduous; 15 in semi evergreen and evergreen forests. The dry deciduous forest was found in the northern districts of the study area. The other types of forest were found in the southern districts. Moist deciduous forest dominated in the region which was followed by semi evergreen, evergreen and dry deciduous forest respectively. However, highest tree species diversity in terms of Shannon-Weiner index (Dd) was observed in semi evergreen forest followed by moist deciduous and evergreen forest respectively. The lowest value of Dd was observed in dry deciduous forest. REFERENCES Anonymous, 2002. Biodivrsity characterization at landscape level in Western Ghats, India, using remote sensing and geographic information system, DOS-DBT Project, IIRS (NRSA), Dehra dun, pp 244. Bhat,D.M.,Naik, M.B.,Patagar,S.G., Hegde,G.T.,Kanade,Y.G., Hegde,G.N., Shastri,C.M., Shetti, D.M. and Furtado, R.M. 2000. Forest dynamics in tropical rain forests of Uttar Kannada districts in Western Ghats, India. Curr. Science, vol. 79 (7), 975-985. Champion, H.J. and Seth, S.K. 1969. Revised Forest Types of India, Govt. of India Press, New Delhi. Daniels, R.J. 2001. Biodiversity of the Western Ghats – An Overview. http://www.wii.gov.in/envis/rain_forest/chapter2.htm.http://www.wii.gov.in/envis/rain_forest/chapter2.htm Hunter, M.L (ed). 1999. Maintaining biodiversity in forest ecosystems. Cambridge University Press, Cambridge. McNeely, G.A., Miller, K.R., Reid, W.V., Mittermeier, R.A. and Werner, T.R. 1990. Conserving the World’s Biological Diversity, IUCN, Gland. Ministry of Environment and Forest (MOE & F), 1998. Implementation of article -6 of the convention on Biological Diversity in India – National Report, Ministry of Environment & Forests, New Delhi, pp 60. Myers,N.,Mittermeier,R.A., Mittermeier, C.G.,da Fonseca,G.A.B. and Kent, J. 2000. Biodivrsity hotspots for conservation priorities. Nature, vol. 403, 853 – 858. Newton, A.C. and Kapos, V. 2002. Biodiversity indicators in national forest inventories. (Back ground paper) Expert Consultation on Global Forest Resources Assessments – Linking national and International efforts, Kotka, Finland, 1-5 July, 2002. Odum, E.P. 1971. Fundamentals of Ecology, W.M. Sanders and Company, Phyladelphia. Pelissier, R., Pascal, J.P., Houllier, F and Laborde, H. 1998. Impact of selective logging on the dynamics of a low elevation dense moist evergreen forest in the Western Ghats (South India). For. Ecol. Mang., vol 105(1), 107 – 119. Rao, P.S.N. 2006. A comparative floristic analysis of WesternGhats (Maharashtra) and Andaman & Nicobar Islands of India for opting suitable conservation strategies and educational needs. http://www.bgci.org/educationcongress/Proceedings/Posters/rao%20PSN%20-%20RP.pdfhttp://www.bgci.org/educationcongress/Proceedings/Posters/rao%20PSN%20-%20RP.pdf Singh, J.S. 2002. The biodiversity crisis: A multifaceted review. Curr. Science, vol 82(6), 628 – 647. Smith, R.L. 1980. Ecology and Field Biology, Harper and Row Publishers, New York. Srivastava, V.K., Niphadkar, M, Neeti, Kukreja, M.K., Ravana, S.A., Janarthanam, M.K., Joshi, V.C. and Rajkumar, S. 2005. Biodiversity in the Western Ghats districts of Maharashtra and Goa. SAC/RESIPA/FLPG/FED/DOS-DBT/R/02/2004, pp 259. Sukumar, R., Duttaraj, H.S., Suresh, H.S., Radhakrishnan, J., Vasudeva, R., Nirmala, S. and Joshi, N.V. 1992. Long-term monitoring of vegetation in a tropical deciduous forest in Mudumalai, Southern India. Curr. Science, vol 62 (99), 608 – 618. Whitmore, T.C. 1984. Tropical rain Forests of the Far East, Claredon Press, London. Williams, N. 1998. Study Finds 10% of Tree Species Under Threat, Science, vol. 281(5382), 1426. Williams, V.L., Witkowski, E.T.F. and Balkwill, K. 2005. Application of diversity indices to appraise plant availability in the traditional medicinal markets of Johannesburg, South Africa. Biodiversity and Conservation, vol. 14; 2971 – 3001. Table 2: Total number of species, total number of genera and average number of species found in each forest type in each district of the study area. SUMMARY Western Ghats of India is one among the major “Biodiversity Hotspots” of the world. Its rich floral wealth is considered a store house of endemism not only for flora bt also for fauna. In order to boost the conservation efforts,esessential to characterize tree diversity of the region.Western Ghats stretches to about 1600 km through the Indian states of Maharahtra, Goa, Karnatak, Kerala and Tamil Nadu, running parallel to the West coast nearly 40 Km away from the shoreline. The study reported here confines itself to the Western Ghats region of Maharashtra and Goa. The region covers a wide variety of forest typranging from tropical broad leaf evergreen to tropical southern mixed dry deciduous forest. About 15.5 per cent of the region’s geographical area is under forest cover. More than 600 tree species were recorded from about 300 quadrates of the size 25 X 25 m distributed randomly in the forests of the region. Average number of tree species varied from as low as 6 per sample in dry deciduous forest to a high of 21 in semi evergreen forest. 28 families were represented in dry deciduous forest; 72 families in moist deciduous forest; 63 families in semi evergreen forest and 56 families in evergreen forest.Shannon-Weiner index (Dd) of diversity, which incorporates both species richness and evenness, was calculated for each forest type. Dry deciduous forest had least value of Dd (1.62), followed by moist deciduous forest (2.72), evergreen forest (3.0) and semi evergreen forest (3.26) respectively. Semi evergreen forest, being a transient type between evergreen and moist deciduous forest, contained highest diversity.