International Research Journal of Biological Sciences ___________________________________ ISSN 2278-3202Vol. 3(1), 49-56, January (2014) Int. Res. J. Biological Sci. International Science Congress Association 49 Influence of Forest Fire on Floral Diversity of the Degraded Shola Forest EcosystemSaravanan V.*, Santhi R., Kumar P., Balasubramanian A. and Abhilash DamodaranDepartment of Tree Breeding, Forest College and Research Institute, Tamil Nadu Agricultural University, Mettupalayam - 641301, TN, INDIA Department of Soil Science and Agricultural Chemistry, Agricultural College and Research Institute, TN Agri. Uni., Coimbatore, TN, INDIA Dept. of Forest Ecology and Envi., Forest College & Research Institute, Tamil Nadu Agri. Uni., Mettupalayam - 641301, Tamil Nadu, INDIA Renuka Forest Division, Himachal Pradesh, INDIA Available online at: www.isca.in, www.isca.me Received 16th September 2013, revised 21st October 2013, accepted 19th November 2013Abstract Forest Fire is an important component in the development and sustainability of many forest ecosystems. With regard to the environmental aspect, the fire is known to alter the soil physical, chemical and biological properties besides influencing the vegetation pattern. However, information available on the nature and magnitude of changes brought out by forest fire on vegetation under degraded shola forest ecosystem is scanty. Keeping these points in view, the present investigation was carried out in the degraded shola forest ecosystem of the Nilgiris Eastern Slope Range situated in the Nilgiris North Division, Tamil Nadu, India to evaluate the effect of fire on the plant diversity of the area at two different periods (immediately after fire and after the monsoon). The effect of forest fire on the vegetation composition was studied using quadrate method by simple random sampling. The results were analyzed for various vegetational parameters and diversity indices. The study showed that the fire had severely affected the tree components in the vegetation when compared to herbs and shrubs. The research results also revealed that regeneration of herbs and shrubs occurred in the burned area after monsoon. The vegetation was already a degraded shola, regular occurrence of the fire is seriously damaging the vegetational composition enabling the further degradation of the vegetation. A good management plan for fire management will help to regain the vegetation through retrogression. Keywords: Forest fire, vegetation, degradation, burned and unburned area. Introduction Fires have influenced the character of the forest ecosystem throughout the world. In fact, many forest communities around the world persist only under the influence of periodic wildfires. Forest fires caused ecological, social and economical damages to a greater extent. In tropical regions, fires are common in seasonally dry environments and rare in perennially moist areas. Even the wettest tropical rain forests may burn at a time scale of thousands of years and the annual extent of fire may be greater in tropical and sub-tropical regions than in the rest of the world. On the basis of the place of their action, forest fires are classified into four types. They are creeping fire, ground fire, surface fire, and crown fire and among which, ground fire influences soil properties to the maximum. It burns the ground cover only, the carpet of herbaceous plants and low shrubs, which covers the soil. In other words, it refers to any fire that consumes the organic materials of the forest floor and also burns into the underlying soil itself. Repeated low-intensity fires may shape the forest by killing small trees, rejuvenating fire-tolerant grasses and accelerating the cycling of nutrients. High-intensity fires kill the majority of trees, oxidize large quantities of nutrients such as nitrogen and disturb soil - plant interactions for decades. This great pressure on forest fire has resulted in the loss of biodiversity disturbing the eco-system dynamics. In India, the inventories carried out by the Forest Survey of Indiashowed that on an average 54.7 per cent of the forest is affected by the fire, 77.6 per cent area has grazing incidence and 72.1 per cent forest area has no regeneration. It is also estimated that the proportion of forest area prone to forest fires annually ranges from 33 to 90 per cent. About 90 per cent forest fires in India are man-made. Out of 3,53,782 km forest area in the country, 47.17 per cent (1,40,818 km) is annually affected by fire. A characteristic feature of the Nilgiri Biosphere Reserve is the occurrence of ‘sholas’ (Montane forests) above 1,500 m. They are found in patches, in hollows and sheltered folds surrounded by rolling downs in the Anamalais, Nilgiri and Palani hills and the high ranges of Kerala and Karnataka. Montane evergreen forests have thick undergrowth; the trees are short bolded and attain a low height of 15-20 m. The shola forest community had wider distribution in the past which has been established through pollen analytical investigations. Forest fire occurs in one or the other part of Nilgiri Biosphere (approximately 1,000 ha area annually under heavy intentional fires), which not only retards the growth of existing vegetation but also not allowing new recruits to emerge out on the forest floor. In the process, many endemic species of the area disappeared from their native habitat. Exotics such as Wattle, Eucalyptus, Eupatorium, Cestrum, Eulex species which were introduced long back in the Nilgiri plateau are invading the burnt areas very fast. The ill effects of this are well known and spread of alien weeds can be International Research Journal of Biological Sciences ________________________________________________ ISSN 2278-3202 Vol. 3(1), 49-56, January (2014) Int. Res. J. Biological Sci. International Science Congress Association 50 destructive to native species. More importantly, species like Lantana camara and recently Eupatorium odoratum, Mikania cordata, Parthenium hysterophorus, Eulex europeans, Cestrum nigrum, Cassia tora have invaded the Nilgiri Biosphere Reserve and tend to smother the natural vegetation. Wattle, introduced long back, has now become a weed. Srivastva found that the major cause for the depletion and loss of biodiversity in the Nilgiris is the fire originating from human causes. The recurrent fire set by grazers during the summer dealt a severe blow to the floristic composition. Though the incidence of forest fire is not a frequent phenomenon in the shola forest ecosystem which is known for its rich floristic diversity, it is frequent in the degraded sholas due to severe biotic interference. Hence, systematic experimental studies are needed to understand the effect of fire on the vegetation during different seasons. Keeping the above points in view, the present investigation was undertaken in the degraded shola forest ecosystem of Nilgiris Eastern Slope Range, Nilgiris North Division, Tamil Nadu, India with the following objective to study the effect of forest fire on the diversity status of vegetation. Material and Methods The present study was carried out to investigate the effect of forest fire on the vegetation status of the fire affected area. The details of the field studies conducted and the methods followed are presented in this chapter. Location: The Niligiris North Forest Division is located between the latitudes 11 14’ North and 11 36’ North and the longitudes 76 31’ East and 77 1’ East. The geographical area of this division is situated in Udhagamandalam, Coonoor, Gudalur and Kotagiri taluks of Nilgiris revenue district. Nilgiris North Forest Division falls under the Coimbatore Circle. The headquarters of this division is Udhagamandalam. The total forest area of this division is 54,722.806 ha with forest boundary of 138 kilometers. The present study area is located between the latitudes 11 26.272’ North and 11 26.516’ North and the longitudes 76 55.073’ East and 76 55.112’ East of Kotagiri taluk in the Paravakkadavu Reserve Forest (271.387 ha) of the Kengarai beat which comes under the administration of Sholur Mattam section of the Nilgiris Eastern Slopes Range. Its headquarters is located at Sholur Mattam. Vegetation: The forest types occurring in the Nilgiris North Forest Division generally falls within the following groups as shown in table 1. These broad groups exhibit certain distinct types of vegetation along with its seral and transitional stages as well as their edaphic variations. The line of distinction between two types is not very clear in few cases, one type merge almost imperceptibly into another. The extensive artificial plantations of Eucalyptusglobules, E. grandis, Acacia mearnsii and Pinus species have transformed the vegetational map of the division greatly. Champion and Seth have classified two more forest types under the sub group 11A (Southern montane wet temperate forest). They are i. Degraded stage of sholas (i.e. Southern montane wet scrub-type 11A/DS1) and ii. Degraded stage of grasslands (i.e. Southern Montane wet grasslands-type 11A/DS2). Table-1 Forest types of the Nilgiris North Forest Division Sl. No. Forest type Sub group 1 Southern montane wet temperate forest 11A 2 Southern tropical broad leaved hill forest 8A 3 Southern moist deciduous forest 3B 4 Southern tropical dry deciduous forest 5A 5 Southern tropical thorn forest 6A Since the present study area comes under the degraded stage of sholas, it is classified into the forest type of Southern montane wet scrub-type (11A/DS1). Methods: The present study involves the vegetation analysis in the forest fire affected and unaffected areas of degraded shola forest ecosystem of the Nilgiris Eastern Slope Range, Nilgiris North Division, Tamil Nadu, India. Assessment of floral diversity: The vegetation analysis was carried out twice (i.e.) immediately after fire and after monsoon period in the unburnt and burnt areas of degraded shola forest ecosystem. The following parameters were assessed. A variety of approaches exists to aid in the inventory and analysis of vegetation. All the methods of data analysis can be regarded as explicit forms of mathematical modeling. The most familiar models are equations, which specify the functional relationship between one or more controlling factors10,11. Floral diversity assessment was done using standard method established by Daniels et al12. In the study site simple random sampling method was followed in laying the sample plots. The trees diversity was measured in 10 m x 10 m sample plot, smaller plots of 5 m x 5 m for shrubs and 1 m x 1 m for herbs were demarcated. In order to determine the quantitative relationship between the plant species, the following parameters were determined. Density: Density is defined as the number of plants per unit area. Total absolute density of species is commonly measured per hectare. Total number of all individuals of all species Density = Total number of quadrates sampled Relative density: Relative density is used to express the contribution of individuals of one species in relation to the total number of individuals of all species and is determined as follows: Total number of individuals of a species Relative density = x 100 Total number of individuals of all species International Research Journal of Biological Sciences ________________________________________________ ISSN 2278-3202 Vol. 3(1), 49-56, January (2014) Int. Res. J. Biological Sci. International Science Congress Association 51 Abundance Total no. of individuals of the species Abundance = No. of quadrates of occurrence Frequency: It is the measure of commonness and distribution of a species within a study area. Frequency is defined as the change of finding a species in a particular trial sample and expressed as a percentage of sample plots in which a species occurs13. Number of sample plots in which a species occurs Frequency of a species = x 100 Total number of sample plots Relative frequency: Frequency can also be expressed in relative terms. Frequency of a species Relative frequency = -------------------------------------------- x 100 Sum of frequencies of all species Dominance: Dominance is a measure of the size, bulk or weight of the vegetation. Three characteristics of the vegetation are commonly evaluated as a measure of dominance; they are weight or biomass, basal cover or basal area and canopy cover or canopy area. Total absolute dominance is equal to the total of all dominance values for all species divided by the total number of samples. Total basal area of a species Dominance = Area sampled Relative dominance: Dominance is a measure of the size, bulk or weight of the vegetation. Three characteristics of the vegetation are commonly evaluated as a measure of dominance; weight or biomass, basal cover or basal area and canopy cover or canopy area. Canopy or basal cover of a species expressed as a percentage of canopy or basal cover for all species, gives the relative dominance. Dominance of a species Relative dominance = x 100 Dominance of all species Important value index: Girth, height and canopy cover of all the trees were measured. Girth class distribution of trees and Important Value Index (IVI) was calculated as IVI = Relative dominance + Relative density + Relative frequency14. Relative Important Value Index: RIVI = IVI / 3 Study of Diversity indices: Species richness: The species richness was calculated using Margalef‘s and Menhinick’s Index. Margalef‘s Index15 D Mg = (S-1) / LnN Menhinick’s Index : D Mn = S / N Where N = Total number of individual, S = Total number of species in this plot Biodiversity indices: Measure of diversity is frequently seen as indicators of the well being of any ecosystem. They also serve as a measure of the species diversity in the ecosystem. The following indices were worked out to assess and compare the diversity and distribution of plant species in different types of forests and at different altitudes. The species diversity was calculated using Shannon-Wiener Index and Simpson’s Index12,16,17. Shannon-Wienner Index (1963) H’ = - (Pi x Ln Pi) where, H’ - the measure of diversity, Pi - the proportion of the th species in the landscape element, Ln Pi - natural logarithm of the proportion of each species. Modified Simpson’s Index (Simpson, 1949) 1 S = PiWhere, S - the measure of diversity, Pi - the proportion of ithspecies sampled. The above diversity indices take into account not only the number of species but also their relative abundance. Evenness using Shannon – Wiener Index: The evenness of the species was calculated using Shannon-Wiener Index. It was worked out as follows: E=H’ / Ln S Where, H = Shannon index, S = Total number of species Diversity: Diversity estimates the species turnover. Jaccard’s index of similarity assesses comparative species turnover. j = -------------- (a+b-j) Where, j = number of species common to both plots, a = number of species in plot A, b = number of species in plot B Results and Discussion Effect of fire on diversity status of vegetation: The overall density of plants in the unburnt area was 3,55,610 plants ha-1prior to monsoon. Of this there were 3,370 trees ha-1 (0.96 %), 10,240 shrubs ha-1 (2.86 %) and 3,42,000 herbs ha-1 (96.18 %). Among the trees T. asiatica had highest density of 2,600 stems ha-1, among shrubs Pteridium aquilinium had highest density of 5,200 plants ha-1 and among the herbs Cyonotis sp. had highest density of 2,30,000 plants ha-1. The result revealed that, among the different plant communities, trees were heavily affected by fire because it accounted only at 66 stems ha-1, which is very low compared to the unburnt study area. The total plant density of fire affected area was 2,27,620 plants ha-1 which is lower than the unburnt site. The trees contribute a very meager, i.e. International Research Journal of Biological Sciences ________________________________________________ ISSN 2278-3202 Vol. 3(1), 49-56, January (2014) Int. Res. J. Biological Sci. International Science Congress Association 52 0.026 per cent to the total density compared to 0.095 per cent in the unburnt plot. Shrubs had a density of 23,560 plants ha-1(Relative density 10.35), while herbs contributed 89.64 per cent (Relative density) with a density of 20,400 plants ha-1. Though, fire decreased the density of trees and overall plant density, it increased the density of shrubs and herbs. These results help to conclude that the forest fire in the study area was primarily the crown fire, which totally consumed the crown cover and the trees were worst affected compared to shrubs and herbs. After monsoon, overall density of vegetation in unburnt and burnt sites increased drastically. This is primarily due to the regeneration of herbs and shrubs favoured by fire and rain. Vegetational study: The vegetational analysis of the present study includes assessment of density, relative density, dominance, relative dominance, frequency, relative frequency, important value index, species richness indices and the diversity indices using Shannon-Wiener index and Simpson’s index (table 3, 4, 5 and 6). The evenness was assessed using Shannon’s-Wiener index and the diversity was assessed using Jaccard’s index of similarity. In the present study, the estimation of the above parameters in the unburnt area revealed that the shrubs and herbs dominated more in the vegetational composition. The results also explained that number of trees was very less and they were scantly and unevenly distributed. This result clearly confirms that the study area is a degraded forest and also it invites regular fire. It is also interesting to note that the vegetation composition study of the unburnt area immediately after fire as well as in the monsoon seasons revealed that there was no significant difference in the vegetational composition. Hence, this also helps to conclude that this forest is a degraded shola forest which has been regularly affected by fire and their retrogression is being deeply promoted. The study of the burnt area revealed that immediately after fire, trees are the worst affected component in the vegetational community which is observed interms of their lower density, frequency, dominance and abundance values compared to the unburnt area. The result also revealed that herbs and shrubs were comparatively less affected than trees. The vegetational analysis after fire showed comparatively higher vegetation value for shrubs and herbs. However, the study revealed that there was no significant change in the vegetational composition value for trees. The increase in composition of herbs and shrubs in the burnt area after monsoon favoured for their high regeneration with added advantage of increased N and K availability. This situation might have also favoured the regeneration of the tree species Todalia asiatica, Rhodomyrtus tomentosa, Symplocos spicata and syzygium cumini. Similar increase in herbaceous population after fire was also reported by Srivastava18 in shola-grass land ecotone of Nilgiri Biosphere Reserve. Calvo et al.19also observed increase in herbaceous population after fire under Pinus pinaster and Quercus pyrenaica dominated forest. The observations drive to conclude that increase in herb and shrub population is helpful for protection of regenerated tree species and to tide over the ensuing summer season. Since the fire is the regular phenomenon in the study area and was seriously affecting the regeneration of tree species this study assuming importance on a larger perspective. Diversity indices: The diversity indices of burnt and unburnt areas were analyzed and the results were presented in the table 2. The Simpson’s index and Shannon-Wienner index, Simpson dominance index showed that high diversity was accounted in unburnt areas in both the seasons of study. It is important to note that high diversity status in terms of all the above indices was reflected in the burnt area after monsoon. This clearly shows that though the site is continuously disturbed, it is having the potential to recover its original vegetation. Unless the regular occurrence of fire is not stopped, the forest may develop into pre-climax vegetation and the vegetation composition may also end with fire hardy species alone. The evenness indices showed very low evenness in the burnt area and very high evenness in the unburnt area reflecting that the species composition of the vegetation is totally affected between unburnt and burnt area. These indices help to predict that the vegetation composition is under serious threat of degradation. The Margalef’s, Menhinick’s and Jaccard’s indices also revealed the similar trend like that of evenness index. The present findings are in accordance with the results of Swarupanandan et al.20and Thomas21. The vegetation analysis and diversity indices estimation repeatedly emphasized that the forest fire is totally changing the vegetation composition in the study site. They also indicated that forest fire is seriously promoting the retrogression, as the result the present state of the forest in the study site has developed into secondary and degraded forest. Serious efforts are needed to prevent fire occurrence in the study site to help the retrogression to be stopped, so as to enable the vegetation to regain its original status. Table-2 Diversity indices for the unburnt and burnt areas Diversity indices Immediately after fire After monsoon Unburnt area Burnt area Unburnt area Burnt area Simpson’s Index 0.831 0.530 0.863 0.86 Simpson’s dominance Index 0.169 0.470 0.136 0.14 Shannon –Wiener Index 3.195 1.637 3.715 3.617 H max 4.755 3.907 5.209 5.426 Evenness Index 0.672 0.419 0.713 0.667 Maralef’s Index 4.456 2.633 5.115 3.383 Menhinicks Index 1.465 1.050 1.096 0.075 Jaccard’s Index 0.315 0.315 0.455 0.455 International Research Journal of Biological Sciences ________________________________________________ ISSN 2278-3202 Vol. 3(1), 49-56, January (2014) Int. Res. J. Biological Sci. International Science Congress Association 53 Table-3 Density and relative density for the unburnt and burnt areas Species Immediately after fire After monsoon Unburnt area Burnt area Unburnt area Burnt area D RD D RD D RD D RD TREES Todalia asiatica 2600.00 0.73 10.00 0.004 2410.00 0.400 20.00 0.002 Rhodomyrtus tomentosa 630.00 0.18 30.00 0.010 720.00 0.120 30.00 0.003 Symplocos spicata 70.00 0.02 10.00 0.004 60.00 0.010 10.00 0.001 Syzygium cumini 30.00 0.01 0.00 0.000 30.00 0.005 0.00 0.000 Acacia sp.20.00 0.01 10.00 0.004 10.00 0.002 20.00 0.002 Glochidion malabaricum 20.00 0.01 0.00 0.000 20.00 0.003 0.00 0.000 Trees total 3370.00 0.96 60.00 0.02 3250.00 0.54 80.00 0.01 SHRUBS Dodonea viscosa 1040.00 0.29 600.00 0.260 560.00 0.090 520.00 0.050 Osbeckia sp.1280.00 0.36 0.00 0.000 280.00 0.050 160.00 0.020 Berberis tinctorea 120.00 0.03 1040.00 0.460 160.00 0.030 1120.00 0.110 Desmodium rufescens 160.00 0.04 1120.00 0.490 480.00 0.080 760.00 0.070 Smilax zeylanica 160.00 0.04 0.00 0.000 200.00 0.030 0.00 0.000 Pteridium aquilinum 5200.00 1.46 20800.00 9.140 2600.00 0.440 15000.00 1.440 Myrsine sp.80.00 0.02 0.00 0.000 120.00 0.020 0.00 0.000 Brachylepis nervosa 120.00 0.03 0.00 0.000 280.00 0.050 0.00 0.000 Rosa leschenaultii 200.00 0.06 0.00 0.000 200.00 0.030 0.00 0.000 Eupatorium glandulosa 1520.00 0.43 0.00 0.000 2480.00 0.420 1400.00 0.130 sclepiadaceae climber 160.00 0.04 0.00 0.000 840.00 0.140 0.00 0.000 Lantana camara 200.00 0.06 0.00 0.000 960.00 0.160 0.00 0.000 Shrubs total 10240.00 2.86 23560.00 10.350 8200.00 1.540 18960.00 1.820 HERBS Eragrostis nigra 22000.00 6.19 177000.00 77.760 34000.00 5.690 210000.00 20.110 Rubus racemosus 0.00 0.00 5000.00 2.200 0.00 0.000 5000.00 0.480 Vernonia cineraria 0.00 0.00 5000.00 2.200 0.00 0.000 15000.00 1.440 Cyperus angulatus 34000.00 9.56 0.00 0.000 41000.00 6.860 0.00 0.000 Mimosa sp.0.00 0.00 7000.00 3.080 0.00 0.000 14000.00 1.340 Anaphalis sp.0.00 0.00 0.00 0.000 5000.00 0.840 5000.00 0.480 Cyanotis sp.230000.00 64.68 0.00 0.000 310000.00 51.890 217000.00 20.780 Blumea hieracifolia 5000.00 1.41 0.00 0.000 6000.00 1.004 3000.00 0.290 Emilia sonchifolia 3000.00 0.84 0.00 0.000 3000.00 0.500 7000.00 0.670 Cyperus rotundus 0.00 0.00 0.00 0.000 31000.00 5.190 48000.00 4.600 Solanum sp.1000.00 0.28 4000.00 1.760 0.00 0.000 4000.00 0.380 Commelina sp.0.00 0.00 0.00 0.000 12000.00 2.010 0.00 0.000 Centella asiatica 0.00 0.00 0.00 0.000 21000.00 2.520 0.00 0.000 Isachne sp.0.00 0.00 0.00 0.000 19000.00 3.180 26000.00 2.490 Viola serpens 5000.00 1.41 0.00 0.000 2000.00 0.330 10000.00 0.960 Impatiens sp.32000.00 9.00 0.00 0.000 56000.00 9.370 0.00 0.000 Impatiens tomentosa 0.00 0.00 0.00 0.000 0.00 0.000 4000.00 0.380 Polygala crotolaria 0.00 0.00 0.00 0.000 3000.00 0.500 7000.00 0.670 Oldenlandia heyni 10000.00 2.81 0.00 0.000 7000.00 1.170 34000.00 3.260 Impatiens crenata 0.00 0.00 0.00 0.000 3000.00 0.500 7000.00 0.670 Justicia simplex 0.00 0.00 0.00 0.000 14000.00 2.340 15000.00 1.440 Fimbriostylis sp.0.00 0.00 0.00 0.000 4000.00 0.670 7000.00 0.670 Oxalis corniculata 0.00 0.00 0.00 0.000 0.00 0.000 265000.00 25.380 Rubus ellipticus 0.00 0.00 5000.00 2.200 0.00 0.000 6000.00 0.570 Rosa leschenaultii 0.00 0.00 1000.00 0.440 0.00 0.000 4000.00 0.380 Kyllinga sp.0.00 0.00 0.00 0.000 0.00 0.000 17000.00 1.630 Tripogon 0.00 0.00 0.00 0.000 0.00 0.000 3000.00 0.290 Pennisetum grandestimum 0.00 0.00 0.00 0.000 0.00 0.000 7000.00 0.670 Themeda sp.0.00 0.00 0.00 0.000 0.00 0.000 3000.00 0.290 Ulex europaeus 0.00 0.00 0.00 0.000 0.00 0.000 1000.00 0.095 Isachne kunthiana 0.00 0.00 0.00 0.000 0.00 0.000 6000.00 0.570 Setaria glauca 0.00 0.00 0.00 0.000 0.00 0.000 12000.00 1.150 Leucas aspera 0.00 0.00 0.00 0.000 13000.00 2.180 42000.00 4.020 Conyza ambigua 0.00 0.00 0.00 0.000 0.00 0.000 1000.00 0.095 Digitaria sp.0.00 0.00 0.00 0.000 0.00 0.000 12000.00 1.150 Amaranthus sp.0.00 0.00 0.00 0.000 0.00 0.000 5000.00 0.480 Anotis sp.0.00 0.00 0.00 0.000 1000.00 0.170 3000.00 0.290 Herbs total 342000.00 96.18 204000.00 89.64 585000.00 96.91 1025000.00 98.17 Overall total 355610.00 100.00 227620.00 100.00 596450.00 100.00 1044040.00 100.00 International Research Journal of Biological Sciences ________________________________________________ ISSN 2278-3202 Vol. 3(1), 49-56, January (2014) Int. Res. J. Biological Sci. International Science Congress Association 54 Table-4 Abundance, frequency and relative frequency for unburnt and burnt areas Species Immediately after fire After monsoon Unburnt area Burnt area Unburnt area Burnt area Ab F RF Ab F RF Ab F RF Ab F RF TREES Todalia asiatica 26.00 100 8.13 1.00 10 1.47 24.10 100 5.41 2.00 10 0.52 Rhodomyrtus tomentosa 6.30 100 8.13 1.00 30 4.41 7.20 100 5.41 1.00 30 1.57 Symplocos spicata 1.75 40 3.25 1.00 10 1.47 1.50 40 2.16 1.00 10 0.52 Syzygium cumini 1.50 20 1.63 0.00 0 0.00 1.50 20 1.08 0.00 0 0.00 Acacia sp. 1.00 20 1.63 1.00 10 1.47 1.00 10 0.54 2.00 10 0.52 Glochidion malabaricum 2.00 10 0.81 0.00 0 0.00 2.00 10 0.54 0.00 0 0.00 Trees total 38.55 280 23.58 4.00 60 8.82 37.30 280 15.14 6.00 60 3.13 SHRUBS Dodonea viscosa 3.25 80 6.50 2.14 70 10.29 2.00 70 3.78 1.86 70 3.66 Osbeckia sp.4.57 70 5.69 0.00 0 0.00 1.17 60 3.24 1.33 30 1.57 Berberis tinctorea 1.50 20 1.63 4.33 60 8.82 1.00 40 2.16 4.67 60 3.14 Desmodium rufescens 1.00 40 3.25 4.00 70 10.29 2.40 50 2.70 2.71 70 3.66 Smilax zeylanica 1.33 30 2.44 0.00 0 0.00 1.67 30 1.62 0.00 0 0.00 Pteridium aquilinum 13.00 100 8.13 52.00 100 14.71 6.50 100 5.41 37.50 100 5.24 Myrsine sp.2.00 10 0.81 0.00 0 0.00 1.00 30 1.62 0.00 0 0.00 Brachylepis nervosa 1.00 30 2.44 0.00 0 0.00 1.40 50 2.70 0.00 0 0.00 Rosa leschenaultii 1.00 50 4.07 0.00 0 0.00 1.00 50 2.70 0.00 0 0.00 Eupatorium glandulosa 5.43 70 5.69 0.00 0 0.00 6.89 90 4.86 8.75 40 2.09 Asclepiadaceae climber 1.33 30 2.44 0.00 0 0.00 3.00 70 3.78 0.00 0 0.00 Lantana camara 2.50 20 1.63 0.00 0 0.00 4.80 50 2.70 0.00 0 0.00 Shrubs total 37.92 550 44.72 62.47 300 44.11 32.83 690 37.27 56.82 370 19.36 HERBS Eragrostis nigra 7.33 30 2.44 17.70 100 14.71 3.78 90 4.86 21.00 100 5.24 Rubus racemosus 0.00 0 0.00 1.00 50 7.35 0.00 0 0.00 1.25 40 2.09 Vernonia cineraria 0.00 0 0.00 1.25 40 5.88 0.00 0 0.00 1.88 80 4.19 Cyperus angulatus 6.80 50 4.07 0.00 0 0.00 4.10 100 5.41 0.00 0 0.00 Mimosa sp.0.00 0 0.00 1.00 70 10.29 0.00 0 0.00 2.00 70 3.66 Anaphalis sp.0.00 0 0.00 0.00 0 0.00 1.66 30 1.62 2.50 20 1.05 Cyanotis sp.28.75 80 6.50 0.00 0 0.00 44.29 70 3.78 27.13 80 4.19 Blumea hieracifolia 1.00 50 4.07 0.00 0 0.00 1.20 50 2.70 1.00 30 1.57 Emilia sonchifolia 1.50 20 1.63 0.00 0 0.00 1.00 30 1.62 1.40 50 2.62 Cyperus rotundus 0.00 0 0.00 0.00 0 0.00 4.43 70 3.78 12.00 40 2.09 Solanum sp.1.00 10 0.81 1.33 30 4.41 0.00 0 0.00 1.00 40 2.09 Commelina sp.0.00 0 0.00 0.00 0 0.00 1.50 80 4.32 0.00 0 0.00 Centella asiatica 0.00 0 0.00 0.00 0 0.00 5.25 40 2.16 0.00 0 0.00 Isachne sp.0.00 0 0.00 0.00 0 0.00 3.17 60 3.24 3.71 70 3.66 Viola serpens 1.25 40 3.25 0.00 0 0.00 2.00 10 0.54 1.67 60 3.14 Impatiens sp.4.57 70 5.69 0.00 0 0.00 9.33 60 3.24 3.71 70 3.66 Impatiens tomentosa 0.00 0 0.00 0.00 0 0.00 1.00 30 1.62 1.33 30 1.57 Polygala crotolaria 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 1.75 40 2.09 Oldenlandia heyni 2.50 40 3.25 0.00 0 0.00 2.33 30 1.62 4.86 70 3.67 Impatiens crenata 0.00 0 0.00 0.00 0 0.00 1.50 20 1.08 1.75 40 2.09 Justicia simplex 0.00 0 0.00 0.00 0 0.00 2.00 70 3.78 3.00 50 2.62 Fimbriostylis sp.0.00 0 0.00 0.00 0 0.00 4.00 10 0.54 1.75 40 2.09 Oxalis corniculata 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 33.13 80 4.19 Rubus ellipticus 0.00 0 0.00 2.50 20 2.94 0.00 0 0.00 1.20 50 2.62 Rosa leschenaultii 0.00 0 0.00 1.00 10 1.47 0.00 0 0.00 1.00 40 2.09 Kyllinga sp.0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 4.25 40 2.09 Tripogon 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 3.00 10 0.52 Pennisetum grandestimum 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 2.33 30 1.57 Themeda sp.0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 3.00 10 0.52 Ulex europaeus 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 1.00 10 0.52 Isachne kunthiana 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 3.00 20 1.05 Setaria glauca 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 1.71 70 3.66 Leucas aspera 0.00 0 0.00 0.00 0 0.00 6.50 20 1.08 8.40 50 2.62 Conyza ambigua 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 1.00 10 0.52 Digitaria sp.0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 2.40 50 2.62 Amaranthus sp.0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 1.25 40 2.09 Anotis sp.0.00 0 0.00 0.00 0 0.00 1.00 10 0.54 1.50 20 1.05 Herbs total 54.70 390 31.71 25.78 320 47.05 100.04 880 47.53 162.86 1550 81.11 Overall total 131.17 1230 100.00 92.25 680 100.00 170.17 1850 100.00 225.68 1980 100.00 International Research Journal of Biological Sciences ________________________________________________ ISSN 2278-3202 Vol. 3(1), 49-56, January (2014) Int. Res. J. Biological Sci. International Science Congress Association 55 Table-5 Dominance and relative dominance for the trees of unburnt and burnt areas Species Immediately after fire After monsoon Unburnt area Burnt area Unburnt area Burnt area D (m/ha) RD (%) D (m/ha) RD (%) D (m/ha) RD (%) D (m/ha) RD (%) Todalia asiatica 0.00806 72.48 0.00003 17.65 0.00844 69.81 0.00006 24 Rhodomyrtus tomentosa 0.00239 21.49 0.00008 47.06 0.00302 24.98 0.00010 40 Symplcos spicata 0.00018 1.62 0.00004 23.53 0.00015 1.24 0.00003 12 Syzygium cumini 0.00040 3.60 - - 0.00040 3.31 - - Acacia sp.0.00004 0.36 0.00002 11.76 0.00002 0.17 0.00006 24 Glochidion malabaricum 0.00005 0.45 - - 0.00006 0.50 - - Total 0.01112 100 0.00017 100 0.01209 100 0.00025 100 Table-6 Importance value index for trees in burnt and unburnt areas Species Immediately after fire After monsoon Unburnt area Burnt area Unburnt area Burnt area IVI RIVI IVI RIVI IVI RIVI IVI RIVI Todalia asiatica 123.170 41.055 56.780 18.926 123.468 41.156 65.749 21.916 Rhodomyrtus tomentosus 67.130 22.377 126.122 42.041 73.918 24.639 16.920 38.973 Symplcos spicatus 25.211 8.404 65.244 21.748 25.681 8.560 58.586 19.529 Syzygium cumini 56.247 18.749 0.000 0.000 55.129 18.376 0.000 0.000 Acacia sp.14.870 4.957 51.857 17.286 11.138 3.713 58.745 19.582 Glochidion neiloghirensis 13.382 4.461 0.000 0.000 14.369 4.790 0.000 0.000 Total 300.01 100.00 300.00 100.00 300.00 100.00 300.00 100.00 Conclusion The effect of forest fire has heavily influenced the vegetation composition of the study site. 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