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Int.J.Curr.Microbiol.App.Sci (2020) 9(9): 2900-2912 International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 9 Number 9 (2020) Journal homepage: http://www.ijcmas.com Original Research Article https://doi.org/10.20546/ijcmas.2020.909.357 Impact of Mikania micrantha Kunth ex HBK Invasion on Micro-environment Component of Bherjan- Borajan–Podumoni Wild Life Sanctuary, Assam Kuntala Neog Barua*, Indrani P. Bora and Arundhati Baruah Rain Forest Research Institute, Sotai, Jorhat, India *Corresponding author ABSTRACT Keywords Microenvironment component, Impact, Mikania micrantha invasion, BherjanBorajan–Podumoni WLS, Assam Article Info Accepted: 20 August 2020 Available Online: 10 September 2020 The open sunny patches of the forest of upper Assam had been tremendously infested by the noxious alien vine Mikania micrantha and might be the prime factor for forest conversion. Present study was carried out in Bherjan-Borajan-Podumoni Wild Life Sanctuary situated in Tinsukia district of Assam. Extensive field surveys were conducted during the period 2014-2018 for evaluation of changes of microenvironment component viz. soil nutrient status, soil temperature, light interception and biomass production due to infestation of M. micrantha. Soil samples were and nutrient status were analyzed by standard analytical methods. Biomass study was done seasonally from M. micrantha infested forest sites by harvest method in sample plot of 1m x 1m. Seasonal structural changes of M. micrantha showed that the maximum dominancy of the weed was recorded in post monsoon season and highest infestation was found in Padumoni site of the WLS with IVI of 158.90 and biomass contribution of 2603.3 kg/ha. The average maximum temperature varies from 24ºC to 33.9ºC which supported the luxuriant growth of the weed. Soil was observed more acidic in natural forest than Mikania infested sites. Comparatively high value of moisture content, organic carbon, nitrogen content, potassium and phosphorus concentration were recorded in Mikania un-infested soil rather than infested soil. Correlation of environmental data, soil data and the biomass data revealed that Mikania biomass was highly significant with the interception of light by the canopy among the entire segment of Bherjan-Borjan-Padumoni WLS. Invasion of Mikania support the enrollment of light demanding deciduous species which facilitated the expansion of the weed and helped in degradation of the forest. Smothering effect of this fast growing vine triggered the deciduous species and displacing several indigenous species which may alter the forest scenario in near future. Maintaining close canopy coverage of the forest might be one of the precautionary measures against the rapid invasion of the weed. Introduction The stability and ecological function of natural wild lands depend on a diverse population of native plants. Native vegetation provided resilience against drought and flood, minimizes erosion, and promotes water infiltration and storage, along with providing wildlife and recreation values. Otherwise, the forest community was altered due to habitat 2900 Int.J.Curr.Microbiol.App.Sci (2020) 9(9): 2900-2912 fragmentation or invasion of foreign species (Pimm, 1986). Any biological species which establishes outside its native habitat and aggressively out-competes the native species was called an invasive alien species (Tiwari, 2005). Convention on Biological Diversity (1992) emphasized on the invasion of alien species which was considered as the second worst threat for biodiversity. The invasive plants differ from native one, on their requirements and more consumption that may cause changes in soil structure, profile, decomposition rate, moisture and nutrient content, Singh (2001). Drake et al., (1989), Brown et al., (1998) also stated that exotic invasion in the natural ecosystem have undesirable impacts on economic and ecological sustainability. Wide-ranging infestations of weeds can permanently degrade natural forest ecosystem. Ehrenfeld (2003) declared that changes of vegetation composition due to exotic invasion are always connected with the changes of soil properties. Mikania micrantha Kunth. ex. H.B.K. is one of the world’s most aggressive tropical alien perennial vines of Asteraceae family native from South and Central America and placed amid the 10 worst exotic species in South and South East Asia (Lowe et al., 2000). Because of its vigorous and ramet growth habit, it successfully competes with trees and other crop plants for soil nutrients, water and reduces sunlight interception by covering the canopy. The open patches of the forest of upper Assam severely infested by this weed and might be the prime factor for forest conversion. Therefore, the present study was undertaken to evaluate the changes of microenvironment component of Bherjan- Borajan – Podumoni Wild Life Sanctuary, Assam due to infestation of M. micrantha. Materials and Methods Study site Bherjan, Borajan and Podumoni were the three tiny pockets of tropical forest on the flat plains of the Brahmputra Valley named Bherjan-Borjan-Padumoni Wild Life Sanctuary (WLS) situated in Tinsukia district of Assam in between the coordinates of 27°25'22.9˝ N to 27°32 '24˝ N and 95°18'40.5˝ E to 95°29'16.4˝ E (Figure 1). This was a small WLS which covered an area of 7.22 sq.km with altitude range of 119 – 122 m from MSL. The three small forest segments were disjuncted by tea gardens and human habitations. The natural vegetation is Tropical Wet Evergreen ‘rainforest’ type experiences a subtropical humid monsoon climate with an average annual rainfall of 2263 mm. Average maximum temperature varied from 24ºC to 33.9ºC and minimum temperature from 6.9ºC to 24.6º C. The relative humidity was highest at 88% in the month of June and January was the driest month having average relative humidity was 70.6 %. Soil was rich loamy with old alluvium deposition of Brahmaputra and acidic in nature with pH ranging from 4.07 to 4.7. Methodology Extensive field surveys were conducted during the period 2014-2018 for evaluation of impact of M. micrantha on microenvironment of native species in Bherjan-Borjan-Padumoni WLS. The forests were divided into two position i) M. micrantha un-infested, ii) M. micrantha infested site. To study the micro environmental characters, the parameters like soil nutrient status, soil temperature, light interception and biomass production were taken. Soil samples were collected from the forest with three different depths of 0-15 cm, 15-25 cm and 25-50 cm. 2901 Int.J.Curr.Microbiol.App.Sci (2020) 9(9): 2900-2912 Bulk density, pH and NPK were determined by the methods as described by Jackson (1973). Organic carbon percentage was estimated following modified Walkley and Black’s wet oxidation method (Jha, 2005). Soil temperature was recorded through soil thermometer at seasonal intervals. Biomass study was done seasonally from M. micrantha infested forest sites by harvest method with twenty five replications in sample plot of 1m x 1m. Samples were kept in the oven at 60700 C until constant weight will obtained. Total production was estimated by adding the biomass accumulation and standing dead material i.e. litter at seasonal intervals, by following Swamy and Ramakrishnan (1987 b). Population study of M. micrantha was carried out by randomly laid 125 quadrats of 1m x1m in each site. Quantitative analysis for density and Importance Value were calculated following Misra (1968) and Kershew (1973). Light intensity was recorded periodically from above the canopy and at ground level through lux meter and interception of light by the canopies was calculated by deduction method. Correlation of environmental data, soil data with the vegetation data recorded from infested forest sites was analyzed by using SPSS 16.0 software. Results and Discussion Rapid invasion of M. micrantha in natural ecosystems during recent years was correlated with the extinction of native species (Leeand Klasing, 2004). Vigorous vegetative and sexual reproductive ability of this invader species and its population dynamics was already described by Swamy and Ramakrishnan (1987a; 1987b) for north east India. It has now become a most troublesome in the Bherjan –Borjan-Padumonbi WLS of Assam.The forest was a mosaic of disturbed open canopy patches along with little closed canopy areas. Seasonal structural changes of M. micrantha showed that the weed was strongly invaded in the forest and the maximum dominancy was recorded in the monsoon and post monsoon season. Population density of Mikania declined in pre monsoon season and minimum density was found in the month of March to April (Figure 2). Puzari (2010) reported that the population of Mikania was positively correlated with temperature. Our present study revealed a similar observation in density and biomass production of Mikania correlated to atmospheric temperature. The average maximum temperature varied from 24ºC to 33.9ºC in the study sites which supported the luxuriant growth of the weed. The highest infestation was recorded in Padumoni segment of the WLS with IVI of 158.90. Aravind et al., 2010 reported that in Karnataka invasion of Lantana camara found higher in open forest areas. Study also found that the most preferred habitat for growth and development of Mikania was also in open sunny place with moist soil and cannot normally tolerate most impenetrable sites. Presently it was observed that the weed flourished mostly in canopy gap areas and the peripheral region of natural forests and absent in closed shaded areas. Frequent tree felling and lopping of trees created localized canopy gap patches in the WLS and acted as window for successful invasion of Mikania in the forest. Invasive weeds have tremendous potential to produce massive amount of biomass and Anonymous, 2007 reported that Parthenium produces 5-20 kg/m2, 9.3 kg/m2 in Chromolaena, 3 kg/m2 in Cassia, 1-1.5 kg/m2 in Lantana and 10-11.5 kg/m2 in Water hyacinth. Mikania also contributed a notable amount of biomass in the studied infested forest areas. Biomass accumulation was high in post monsoon season for all the forest sites and it was found maximum in Padumoni 2902 Int.J.Curr.Microbiol.App.Sci (2020) 9(9): 2900-2912 segment (2603.3 kg/ha) during the full growing season. Seasonal Biomass and Litter Production (kg/ha) of Mikania and other species was given in Table 1. Average maximum soil temperature was observed in monsoon season of infested forest site of all three segments. The summer temperature of WLS was varied from 30.230C ±0.50 to 32.370C ±0.55 and Padumoni segment exhibited the highest one. In un– infested natural forest site the temperature goes up to 31.30C ±0.56 in monsoon season (Table 2). The exotic invader has a greater capacity to efficiently utilize light energy by producing more foliage that essential for growth and development (Feng et al., 2007).Comparative assessment of light interception percentage and Mikania biomass at different growth season revealed that the highest biomass was accumulated in the post monsoon season related to maximum light intercepted by the Mikania canopy. In pre monsoon season Mikania seedlings were in sprouting condition hence, intercepted minimum extent of light (Figure 3). In forest ecosystems the understory plants were highly sensitive to their micro environment governed by the light intensity, wind velocity, temperature, soil moisture, etc. Any change of these environmental parameters might be detrimental for the existence of some of the sensitive species as seen due to invasion of Mimosa diplotrica, in Kaziranga National Park of Assam or M. micrantha in Chitwan National Park of Nepal (Vasu, 2003; Ram, 2008). Infestation of M. micrantha was considered as of high risk as it smothered the vegetation causing tree death. Presence of the weed in the canopy gaps where light intensity is higher which indicated that an increase in light through disturbance in the forest canopy encourages invasion into the forest. The dense shade below canopies of the weed suppresses the growth of other plant species (Huang et al., 2000). Mikania caught up light intensity on ground surface of the forest and affected the regeneration of several tree seedlings. Invasion of the weed supported the enrollment of some light demanding deciduous species such as Alstonia scholaris, Balakata baccata, Bombax ceiba, Ficus hispida, Lagerstroemia speciosa, Premna latifolia, which facilitated the expansion of the weed and helped in degradation of the forest. Once the weed colonized the areas they increasingly penetrated the forest very tactfully. Through rapid proliferation and ramet formation, the weed entangled immediately the crown of the sapling and small seedlings. Sankaran et al., (2001) was reported similar problem in case of young plantation of Teak in Kerala. Barua and Hazarika (2016) also confirmed that Mikania encourage the alteration of evergreen species in Dilli reserve forest of Assam. Physico chemical properties of soil in different seasons in both infested and uninfested sites of Bherjan-Borjan-Padumoni WLS were given in Table 3–5. pH value ranges from 4.07 to 4.70 which indicate acidic nature of soil, this may be due to release of acidic compounds by the decomposition of organic residues from forest vegetation (Gogoi et al., 2011; Acharya and Shrestha, 2012 and Anup et al., 2013). The humification and leaching of basic ions were the two contributing factors along with rainfall and acidic parent materials. Comparatively high amount of litterfall in un infested natural forest contributed more organic matter to soil ultimately creating favourable environment to microbes responsible for production of organic acids into soil (Jha et al., 1979). Moisture Content of the soil was changeable according to the quantity of rainfall in the 2903 Int.J.Curr.Microbiol.App.Sci (2020) 9(9): 2900-2912 study sites. It was recorded more in uninfested forest site than the infested site and gradually increased with increasing depth. Maximum proliferation of surface absorbing roots of M. micrantha contributed to higher absorption of moisture in the surface layer. Highest moisture content was recorded in natural forest site of Bherjan segment (39.87 ± 0.03 due to high humid closed canopy cover of Dipterocarp-Mesua-–Artocarpus association. The percentage of moisture was higher in monsoon and post monsoon season (Table 3). Table.1 Biomass and Litter Production (kg/ha) in Infested sites of Bherjan-Borjan-Padumoni WLS Season Mikania Pre-monsoon Monsoon Post-monsoon Winter 428.6±0.39 960.3±0.48 1103.6±0.53 792.6±0.20 Pre-monsoon Monsoon Post-monsoon Winter 387.6 ±0.24 763.6±0.17 964.6±0.36 455.3±0.09 Pre-monsoon Monsoon Post-monsoon Winter 1154.6±0.52 2304.3±0.28 2603.3±7.45 1649.3±0.16 Other Bherjan 320±0.07 728±0.28 776.6±0.10 506.6±0.05 Borjan 303.6±0.08 624±0.22 711.3±0.53 345±0.76 Padumoni 452.3±0.32 596±0.93 578.6±0.31 550.3±0.32 Litter Total Production 909.3±0.72 183±0.20 170.6±0.29 846±0.04 1657.9±0.99 1871.3±0.59 2050.8±0.37 2145.2±0.25 684.6±0.35 214.3±0.20 264.3±0.07 805±0.34 1375.8±0.51 1601.9±0.22 1940.2±0.80 1605.3±0.99 653.6±0.11 196.3±0.35 248.6±0.13 404±0.59 2260.50±0.24 3096.6±0.89 3430.50±7.28 2603.6±0.64 Borjan Padumoni Trait Soil temperature(0C) Light interception (%) Soil temperature(0C) Light interception (%) Soil temperature(0C) Light interception (%) Bherjan Table.2 Seasonal variation of Light interception (%) and Soil Temperature of Bherjan-Borjan-Padumoni WLS Site I UI I UI I UI I UI I UI I UI Pre Monsoon 22.40±1.05 21.57±1.65 45.2±0.30 81.33±0.40 19.73±0.50 19.53±1.21 41.82±0.76 82.03±1.43 24.33±1.16 22.87±0.93 69.37±0.49 51.47±1.04 Monsoon 31.37±0.64 29.7±0.72 70.36±0.57 87.8±0.70 30.23±0.50 28.17±1.15 60.06±0.47 90.83±0.93 32.37±0.55 31.3±0.56 86.53±0.59 74.27±1.11 I: Infested UI: Un-infested 2904 Post Monsoon 27.50±1.57 26.00 ±0.92 79.75±0.06 87.8±0.90 26.93±1.46 26.370C±0.80 65.33±0.50 88.4±0.62 28.30±0.95 27.63±0.25 98.75±0.03 68.33±0.75 Winter 17.50±0.79 17.07±0.65 53.25±0.28 79.67±0.75 17.53±0.75 16.47±0.57 49.34±0.41 80.73±1.00 19.57±1.26 18.17±0.81 86.25±0.52 61.40±1.15 Int.J.Curr.Microbiol.App.Sci (2020) 9(9): 2900-2912 Table.3 pH and moisture content of soil in Bherjan-Borjan-Padumoni WLS Forest pH Pre-M Bherjan A Segment B C Borjan A Segment B C Padumoni A Segment B C Monsoon Post- M MOISTURE CONTENT Winter Pre-M Monsoon Post- M Winter IN UI IN UI IN UI IN UI IN UI IN UI IN UI IN UI 4.14 4.11 4.26 4.17 4.70 4.32 4.21 4.12 16.44 18.20 26.52 31.28 20.55 26.85 22.88 25.27 ±0.02 ±0.03 ±0.02 ±0.02 ±0.02 ±0.02 ±0.02 ±0.02 ±0.03 ±0.25 ±0.016 ±0.02 ±0.02 ±0.02 ±0.016 ±0.008 4.18 4.21 4.29 4.23 4.61 4.26 4.17 4.07 25.94 26.74 30.14 36.57 22.59 28.72 24.59 25.66 ±0.01 ±0.02 ±0.02 ±0.03 ±0.02 ±0.01 ±0.02 ±0.02 ±0.05 ±0.05 ±0.03 ±0.02 ±0.02 ±0.02 ±0.03 ±0.01 4.15 4.15 4.21 4.19 4.55 4.22 4.21 4.13 28.70 35.86 32.24 39.87 25.78 32.82 26.37 28.26 ±0.01 ±0.01 ±0.02 ±0.02 ±0.03 ±0.01 ±0.02 ±0.01 ±0.04 ±0.02 ±0.03 ±0.03 ±0.01 ±0.02 ±0.01 ±0.01 4.37 4.28 4.32 4.28 4.41 4.30 4.22 4.18 14.55 15.81 24.75 29.46 16.22 27.66 22.41 24.37 ±0.02 ±0.01 ±0.02 ±0.02 ±0.04 ±0.02 ±0.02 ±0.03 ±0.03 ±0.02 ±0.03 ±0.04 ±0.05 ±0.03 ±0.01 ±0.03 4.32 4.24 4.28 4.14 4.30 4.26 4.22 4.15 16.55 20.62 28.68 32.56 21.45 28.74 26.39 26.88 ±0.02 ±0.02 ±0.02 ±0.02 ±0.04 ±0.02 ±0.03 ±0.03 ±0.02 ±0.03 ±0.02 ±0.04 ±0.02 ±0.04 ±0.03 ±0.04 4.30 4.19 4.24 4.19 4.26 4.13 4.18 4.12 20.62 31.57 30.76 34.55 21.86 30.54 28.88 29.76 ±0.04 ±0.06 ±0.02 ±0.02 ±0.02 ±0.02 ±0.03 ±0.04 ±0.02 ±0.04 ±0.03 ±0.03 ±0.04 ±0.04 ±0.04 ±0.03 4.24 4.12 4.30 4.22 4.28 4.22 4.18 4.17 12.99 21.31 24.57 30.48 22.56 25.76 12.87 17.76 ±0.02 ±0.05 ±0.17 ±0.04 ±0.03 ±0.04 ±0.03 ±0.03 ±0.06 ±0.03 ±0.03 ±0.02 ±0.03 ±0.05 ±0.04 ±0.02 4.22 4.11 4.27 4.20 4.25 4.16 4.11 4.07 18.76 22.24 29.42 34.58 24.59 25.77 13.55 18.88 ±0.02 ±0.03 0.04 ±0.03 ±0.02 ±0.02 ±0.03 ±0.02 ±0.04 ±0.04 ±0.03 ±0.02 ±0.03 ±0.03 ±0.03 ±0.03 4.19 4.05 4.25 4.19 4.19 4.12 4.07 4.08 19.61 29.87 33.48 38.46 26.48 28.84 19.87 21.84 ±0.05 ±0.03 0.02 ±0.02 ±0.03 ±0.03 ±0.04 ±0.03 ±0.02 ±0.02 ±0.03 ±0.04 ±0.05 ±0.04 ±0.05 ±0.05 I= infested, UI= un- infested, A: 0-15 cm, B: 5-25 cm, C: 25-50 cm 2905 Int.J.Curr.Microbiol.App.Sci (2020) 9(9): 2900-2912 Table.4 Organic carbon and Available Nitrogen content of soil in Bherjan-Borjan-Padumoni WLS Forest Bherjan Segment A B C Borjan Segment A B C Padumoni Segment A B C Pre-M IN 1.56 ±0.02 1.24 ±0.02 1.16 ±0.03 1.29 ±0.04 1.22 ±0.03 1.14 ±0.02 1.06 ±0.03 1.02 ±0.03 0.91 ±0.04 UI 1.83 ±0.03 1.64 ±0.02 1.38 ±0.02 1.58 ±0.05 1.35 ±0.04 1.21 ±0.03 1.13 ±0.03 1.09 ±0.02 1.05 ±0.024 Organic Carbon (%) Monsoon Post- M IN UI IN UI 1.45 1.65 1.95 2.71 ±0.02 ±0.04 ±0.02 ±0.02 1.18 1.32 1.68 2.38 ±0.03 ±0.02 ±0.03 ±0.04 1.12 1.24 1.36 1.96 ±0.03 ±0.02 ±0.02 ±0.02 1.24 1.36 1.48 2.08 ±0.02 ±0.03 ±0.04 ±0.02 1.17 1.24 1.36 1.86 ±0.03 ±0.04 ±0.03 ±0.03 1.08 1.16 1.19 1.61 ±0.03 ±0.04 ±0.038 ±0.020 1.02 1.24 1.42 1.76 ±0.03 ±0.02 ±0.03 ±0.03 0.98 1.12 1.34 1.58 ±0.04 ±0.03 ±0.04 ±0.05 0.85 1.08 1.18 1.23 ±0.04 ±0.03 ±0.04 ±0.04 Winter IN 1.26 ±0.01 1.06 ±0.03 1.02 ±0.004 1.15 ±0.03 1.08 ±0.04 1.02 ±0.033 0.96 ±0.03 0.92 ±0.03 0.82 ±0.02 UI 1.58 ±0.02 1.24 ±0.01 1.14 ±0.02 1.29 ±0.04 1.22 ±0.02 1.08 ±0.032 1.11 ±0.04 1.06 ±0.03 1.05 ±0.02 I= infested, UI= un- infested, A: 0-15 cm, B: 5-25 cm, C: 25-50 cm 2906 Pre-M IN 147.39 ±0.47 141.12 ±0.02 112.89 ±0.05 238.3 ±0.32 213.25 ±0.30 200.7 ±0.73 106.62 ±2.1 103.48 ±2.28 100.35 ±0.98 UI 232.06 ±0.06 206.97 ±0.02 197.56 ±0.03 263.42 ±0.14 225.79 ±0.32 219.52 ±0.10 200.7 ±2.0 169.34 ±3.10 131.71 ±2.69 Available Nitrogen (Kg ha-1) Monsoon Post- M IN UI IN UI 123.53 225.5 257.5 285.3 ±0.03 ±0.24 ±0.65 ±0.57 119.36 200.88 246.8 256.2 ±0.02 ±0.09 ±0.16 ±0.24 110.68 158.76 204.4 178.5 ±0.06 ±0.18 ±0.48 ±0.42 216.83 254.86 251.5 266.4 ±0.15 ±0.13 ±0.38 ±0.34 208.35 237.65 238.6 248.2 ±0.36 ±0.13 ±0.32 ±0.15 195.45 208.46 224.5 241.4 ±0.04 ±0.28 ±0.28 ±0.48 101.62 196.55 259.0 268.2 ±2.36 ±1.46 ±2.5 ±2.6 100.78 174.72 241.8 241.6 ±2.32 ±1.56 ±2.60 ±1.50 100.08 126.64 232.2 234.6 ±1.55 ±0.93 ±2.50 ±2.60 Winter IN 107.6 ±0.28 100.4 ±0.41 186.5 ±0.20 135.8 ±0.65 116.5 ±0.02 108.5 ±0.24 101.6 ±1.26 101.5 ±1.20 98.6 ±1.50 UI 98.5 ±0.44 135.5 ±0.21 108.4 ±0.36 174.6 ±0.16 129.7 ±0.20 113.8 ±0.17 187.5 ±1.80 158.4 ±1.30 142.7 ±0.65 Int.J.Curr.Microbiol.App.Sci (2020) 9(9): 2900-2912 Table.5 Available Phosphorus and Potassiun content of soil in Bherjan-Borjan-Padumoni WLS Padumoni Segment Borjan Segment Bherjan Segment Forest Available Phosphorus (Kg ha-1) Pre-M Available Potassium (Kg ha-1) Monsoon Post- M UI IN UI IN UI IN UI IN UI IN UI IN UI IN UI A 28.98 31.89 28.64 30.58 16.35 25.63 15.86 23.76 254.72 288.44 188.99 236.67 214.62 258.1 157.5 205.8 ±0.02 ±0.03 ±0.05 ±0.02 ±0.01 ±0.04 ±0.06 ±0.04 ±0.06 ±0.0 6 ±0.77 ±0.06 ±0.02 ±0.06 ±0.44 ±0.77 B 28.78 22.67 25.57 26.86 15.96 22.77 13.64 19.62 223.9 231.75 188.95 212.57 208.55 229.6 142.8 188.4 ±0.04 ±0.03 ±0.03 ±0.03 ±0.05 ±0.02 ±0.04 ±0.02 ±0.11 ±0.64 ±0.06 ±0.06 ±0.77 ±0.28 ±0.20 ±0.69 C 26.56 19.98 21.68 24.76 14.77 20.85 12.49 15.44 169.87 196.59 174.6 192.66 158.4 208.5 128.4 164.5 ±0.03 ±0.05 ±0.03 ±0.03 ±0.04 ±0.02 ±0.04 ±0.04 ±0.09 ±0.57 ±0.16 ±0.02 ±0.36 ±0.41 ±0.41 ±0.36 A 34.44 36.67 27.85 29.88 15.28 27.25 12.89 24.56 234.72 259.44 208.44 224.58 164.4 173.2 138.5 156.8 ±0.04 ±0.06 ±0.04 ±0.05 ±0.02 ±0.05 ±0.03 ±0.04 ±0.06 ±0.06 ±0.04 ±0.14 ±0.02 ±0.32 ±0.32 ±0.16 B 29.30 26.77 26.75 24.56 14.66 25.66 10.48 18.54 218.50 227.75 195.80 208.43 152.8 164.8 124.7 144.5 ±0.04 ±0.03 ±0.03 ±0.03 ±0.02 ±0.04 ±0.04 ±0.06 ±0.20 ±0.13 ±0.03 ±0.20 ±0.16 ±0.16 ±0.20 ±0.57 C 22.34 20.11 18.68 20.69 13.59 24.72 10.08 12.52 156.87 185.54 185.25 189.57 136.4 156.8 118.4 132.5 ±0.05 ±0.07 ±0.07 ±0.04 ±0.07 ±0.05 ±0.03 ±0.06 ±0.06 ±0.04 ±0.03 ±0.80 ±0.20 ±0.16 ±0.40 ±0.24 A 28.55 28.59 27.58 26.67 21.87 26.64 12.55 14.69 248.79 268.44 207.64 237.3 213.55 254.6 132.6 168.6 ±0.04 ±0.06 ±0.05 ±0.06 ±0.07 ±0.06 ±0.07 ±0.04 ±1.69 ±0.06 ±0.05 ±0.05 ±0.10 ±0.23 ±0.25 ±0.33 B 24.56 22.64 22.49 23.88 21.56 26.46 10.24 13.46 211.14 239.98 190.85 196.54 228.5 225.8 118.8 149.8 ±0.05 ±0.04 ±0.06 ±0.05 ±0.09 ±0.04 ±0.03 ±0.04 ±0.08 ±0.03 ±0.09 ±0.04 ±0.19 ±0.72 ±0.82 ±0.40 C 19.89 16.99 18.47 22.55 20.78 23.77 9.76 10.54 153.23 178.49 148.48 158.65 140.6 168.6 108.6 134.4 ±0.04 ±0.04 ±0.04 ±0.06 ±0.02 ±0.04 ±0.05 ±0.05 ±0.24 ±0.11 ±0.11 ±0.07 ±0.24 ±0.28 ±0.24 ±0.56 IN Winter Pre-M I= infested, UI= un- infested, A: 0-15 cm, B: 5-25 cm, C: 25-50 cm 2907 Monsoon Post- M Winter Int.J.Curr.Microbiol.App.Sci (2020) 9(9): 2900-2912 Table.6 Correlation of different parameters relevant to Mikania infestation A: Bherjan B: Borjan C: Podumoni Season ST ST LI BM SM 0.7262 0.5362 0.4248 ST LI BM SM 0.8102 0.8275 0.2908 ST LI BM SM 0.2855 0.6466 0.4166 LI BM Bherjan 0.7262 0.5362 0.9471** ** 0.9471 0.4905 0.6443 Borjan 0.8102 0.8275 0.9772** 0.9772** 0.2678 0.0751 Padumoni 0.2855 0.6466 0.9156** ** 0.9156 0.6438 0.8966* SM 0.4248 0.4905 0.6443 0.2908 0.2678 0.0751 0.4166 0.6438 0.8966* - ST: soil temperature LI: light interception BM: biomass SM: soil moisture Fig.1 Map of Bherjan-Borjan-Padumoni WLS Fig.2 Structural changes of Mikania micrantha in different season 2908 Int.J.Curr.Microbiol.App.Sci (2020) 9(9): 2900-2912 Fig.3 Comparative assessment of light interception % and Mikania biomass at different growth season in Bherjan-Borjan-Padumoni WLS Plate.1 Glimpses of Bherjan- Borajan–Podumoni Wild Life Sanctuary A& B: Fragmentation by road and Infestation of Mikania in Bherjan segment C: Amomum maximum- an important spice species in forest floor of Borjan segment D: Mikania Converted Padumoni segment -a degraded forest A B C D 2909