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20204
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Subject: Natural Resources Management × End date: 2020 × Start date: 2020 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Floristic and edaphic attributes of a shola forest ecosystem in Mankulam forest division Kerala
    (Department of Natural Resource Management, College of Forestry, Vellanikkara, 2020) Abin M Thadathil; KAU; Gopakumar, S
    A study was undertaken in the shola forest ecosystem at Anakulam range of Mankulam forest division, Idukki, Kerala with a principal objective to understand the floristic composition, diversity and vegetation structure and also to investigate the physico-chemical properties of soil that supports this unique forest ecosystem. On this context the hypothesis examined was whether the shola forest exhibits high floristic diversity, structure and soil properties comparable to tropical evergreen forests. A total of 106 plant species was recorded from 0.5 ha. It included 50 species of trees, 20 shrubs, 12 herbs, 8 climbers and 16 fern species. The diversity indices of the shola forest ecosystem were Simpson’s index (0.97), Berger- Parker Dominance Index (0.05), Shannon – Wiener index (3.67), Pielou’s Equitability index (0.93) and Margaleaf Richness index (7.18) which are on par with similar published reports from the shola forests and tropical evergreen forests. A total number of 918 individuals were recorded from 0.5ha with a basal area of 22.46 m2 ha-1. Microtropis ramiflora, Vaccinium leschenaultia, Actinodaphne bourdillonii, Daphniphyllum neilgherrense, Schefflera racemosa, Syzygium lanceolatum, Syzygium densiflorum, Cinnamomum sulphuratum, Rhodomyrtus tomentosa and Symplocos obtuse are the dominant tree species in Mankulam shola. Lauraceae, Myrtaceae and Celastraceae are the tree dominant families. The diameter frequency as well as height frequency distribution of shola forest showed the “inverse J” shaped curve which reflects the existence of new recruits. The total number of plant species in the understory was 2353 belonging to 75 different species. The dominant understory plant species was Strobilanthes luridus, Ageratina adenophora, Strobilanthes lawsone and Strobilanthes neoasper. Profile diagram revealed that the trees are short boled and rarely exceed 15m. Soil was sandy clay loam (60.95%) followed by clay (24.35%) and silt (14.7%). Electrical conductivity was 0.52 dS/m, while bulk density was 0.82 g cm-3. Shola soil was moderate to slightly acidic (4.67 to 5.84), while SOC content was 7.99%. Total nitrogen content was 1.85 % and available phosphorus was 71.58 kg ha-1. The available potassium (K) was 562.42 kg ha-1 which are comparable to the published reports from the shola forests and tropical evergreen forests.
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    ThesisItemOpen Access
    Floristic and edaphic attributes of a shola forest ecosystem in Mankulam forest division Kerala
    (Department of Natural Resource Management, College of Forestry, Vellanikkara, 2020) Abin M, Thadathil; KAU; Gopakumar, S
    A study was undertaken in the shola forest ecosystem at Anakulam range of Mankulam forest division, Idukki, Kerala with a principal objective to understand the floristic composition, diversity and vegetation structure and also to investigate the physico-chemical properties of soil that supports this unique forest ecosystem. On this context the hypothesis examined was whether the shola forest exhibits high floristic diversity, structure and soil properties comparable to tropical evergreen forests. A total of 106 plant species was recorded from 0.5 ha. It included 50 species of trees, 20 shrubs, 12 herbs, 8 climbers and 16 fern species. The diversity indices of the shola forest ecosystem were Simpson’s index (0.97), Berger- Parker Dominance Index (0.05), Shannon – Wiener index (3.67), Pielou’s Equitability index (0.93) and Margaleaf Richness index (7.18) which are on par with similar published reports from the shola forests and tropical evergreen forests. A total number of 918 individuals were recorded from 0.5ha with a basal area of 22.46 m2 ha-1. Microtropis ramiflora, Vaccinium leschenaultia, Actinodaphne bourdillonii, Daphniphyllum neilgherrense, Schefflera racemosa, Syzygium lanceolatum, Syzygium densiflorum, Cinnamomum sulphuratum, Rhodomyrtus tomentosa and Symplocos obtuse are the dominant tree species in Mankulam shola. Lauraceae, Myrtaceae and Celastraceae are the tree dominant families. The diameter frequency as well as height frequency distribution of shola forest showed the “inverse J” shaped curve which reflects the existence of new recruits. The total number of plant species in the understory was 2353 belonging to 75 different species. The dominant understory plant species was Strobilanthes luridus, Ageratina adenophora, Strobilanthes lawsone and Strobilanthes neoasper. Profile diagram revealed that the trees are short boled and rarely exceed 15m. Soil was sandy clay loam (60.95%) followed by clay (24.35%) and silt (14.7%). Electrical conductivity was 0.52 dS/m, while bulk density was 0.82 g cm-3. Shola soil was moderate to slightly acidic (4.67 to 5.84), while SOC content was 7.99%. Total nitrogen content was 1.85 % and available phosphorus was 71.58 kg ha-1. The available potassium (K) was 562.42 kg ha-1 which are comparable to the published reports from the shola forests and tropical evergreen forests.
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    ThesisItemOpen Access
    Ecological status of Nageia Wallichiana (C. PRESL.) kuntze an endangered conifier of western ghats in Mankulam forest division
    (Department of Natural Resource Management, College of Forestry, Vellanikkara, 2020) Abhirami, C; KAU; Vidyasagaran, K
    Nageia wallichiana (C.Presl.) Kuntze is a lesser-known rare arborescent, threatened evergreen conifer species of wet evergreen forests of Western Ghats. A study on the distributional status and ecology of this species was conducted in the natural habitats in Mankulam Forest Division. The study aimed at understanding the floristic composition and natural regeneration patterns in the natural habitats of Nageia wallichiana. The additional objective was to assess the physicochemical properties of the soil in the Nageia wallichiana growing areas. The purposive sampling of vegetation was done in 20 x 50 m main plots in Nageia wallichiana growing areas (NG) and control plots were taken in areas without Nageia wallichiana (WNG). The regeneration pattern of trees was studied by taking 5 m x 5 m subplots for saplings and 1 m x 1 m nested plots for seedlings inside the main plots of NG. From NG, a total of 188 individual trees belonging to 67 different species and 28 different families were identified from three different Nageia wallichiana growing patches, viz., Kannadipara, Idathattu, and Kallar. In WNG, 94 individual trees belonging to 46 species and 25 different families were identified. The altitudinal range of occurrence of Nageia wallichiana in the study area was found to be 934 –1463 m above MSL. The girth class distribution of the species showed an L-shaped curve with 90 percent of individuals below 50 cm girth. The floristic studies in the area showed that the natural habitats of Nageia wallichiana harbor a large number of trees in endemic and threatened categories. The typical evergreen species, Cullenia exarillata showed the maximum dominance in NG followed by Mesua ferrea and Bhesa indica. In WNG, the most dominant species were Dysoxylum malabaricum, Vateria indica and Polyalthia fragrans. The comparison of tree diversity between NG and WNG didn’t reveal any significant variations. The ecological distance analysis and clustering showed significant difference in species composition between NG and WNG. The ordination plots proved Bhesa indica as a strong species associate of Nageia wallichiana. The regeneration study showed a lower diversity of regenerating individuals in the study area than mature trees and a difference in species composition was also observed. The analysis of soil properties found that the soils from Nageia wallichiana habitats were higher in moisture content and organic carbon and lower in total nitrogen content. The study didn’t found any relation for soil pH and bulk density on the occurrence of N.wallichiana. The study identified the habitat specialist nature of Nageia wallichiana from the restricted distribution of the species in certain patches of the study area. The occurrence of this only conifer of the Western Ghats in the Mankulam forest Division indicates the importance of the area because Nageia wallichiana is considered as a better indicator of ecological conditions. The study also observed a higher rate of regeneration for this species in the study area indicating the presence of ideal ecological conditions. However, a more focused study considering the disturbance levels in the study area and some extra parameters such as soil depth, soil nutrient contents, frequency of fire occurrence etc. will give a better understanding of the restricted occurrence of this species in the study area and it may contribute in the development of specialized conservation strategies.
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    ThesisItemOpen Access
    Zonation of woody vegetation and soil along an altitude gradient in Mankulam forest division Kerala
    (Department of Natural Resource Management, College of Forestry,, 2020) Honey, Bhatt; KAU; Gopakumar, S
    Altitudinal gradients are among the most powerful ‘natural experiments’ for testing ecological and evolutionary responses of biota and has strong influence on structure of vegetation.The present study was undertaken in a west coast tropical forest located along a gradient viz. Zone I (350-900m above msl) and Zone II (900-1450m above msl) in Mankulam Forest Division of Western Ghats region in Kerala, India. The aim of the study was to assess and compare the floristic composition, structure and diversity along this gradient. Additionally the changes in the physico-chemical properties of soil i.e.,Bulk density (BD) ,pH,Electrical conductivity (EC), total nitrogen (N), available phosphorus (P), available potassium (K), organic carbon (C) and available calcium (Ca) along this altitudinal gradient were also studied. Sampling of vegetation and soil was done using fifteen, 10 m x 10 m plots (covering 0.15ha in each altitudinal zone). Within each plot, all tree individuals (≥ 10cm GBH) were identified and their height was measured. In total, 200 individuals belonging to 88 tree species representing 34 families were recorded across the altitudinal gradient.In each sample plot, soil samples were analyzed at two depths viz. ‘upper’ (0–20 cm) and ‘lower’ (20–40 cm) along the altitudinal gradient. The diameter frequency distribution showed a “bell shaped pattern” in both altitudinal zones. The vegetation profile diagram at both altitudes showed a typical three layered structure which is a characteristic feature of evergreen forest with majority of individuals in lower storey (<10 m ) height classes in both zones. The maximum tree abundance (67.09) was recorded in Zone II. Tree density (713.33 trees ha-1) was also higher in zone II compared to zone I (613.33 trees ha- 1).Similarly highest tree percent frequency (546.6%) was recorded in zone II. Vateria indica (IVI= 24.09) was found as dominating tree species in zone II, while in zone I dominating tree species was Dysoxylum malabaricum (IVI= 34.85). However, the tree basal area (20.31 m2 ha-1) was estimated higher in zone I compared to zone II with basal area (12.31 m2 ha-1).Rank abundance curve indicated highest abundance for Gordonia obtusa in zone II, while in zone I Dysoxylum malabaricum recorded the highest abundance. Physico- chemical properties of soil viz. soil pH, C, N, P, K and Ca showed an increasing trend along the gradient. The highest values for soil pH (4.12-5.59), C (1.82-8.36%), TN (0.08-0.37 %), P (4.36- 1098.49 Kg ha-1), K (398.24- 1628.48 Kg ha-1) and Ca (320 - 1160 mg Kg-1) was recorded in zone II. BD (0.77-1.33g cm-3) and EC (0.30 – 1.82 dS m-1) values were higher in ‘upper’ (0–20 cm) layer of zone I. Canonical correspondence analysis (CCA) showed a complex interrelationship amongst species clustering, mountain ranges and soil properties. The study revealed that there is gradual increase in species abundance as the soil properties increases along the altitude, in both zones. Correlation analysis clearly indicated that in zone I AK is strongly and positively correlated with C because layer of organic matter significantly improves the retention of K in the soils. Whereas, N is negatively correlated with BD. Similarly, in zone II, TN was observed to be negatively correlated with BD while K was strongly and positively correlated with N. The floral diversity indices viz Simpson index, Shannon index and Pielou index of evenness showed marginal variation along the gradient. However, there was variation in species composition along altitude. Actinodaphne bourdillonii, Litsea keralana, Gordonia obtusa and Turpinia cochinchinensis were the characteristic species in zone II. In zone I Clausena anisata, Memecylon talbotianum and Madhuca neriifolia were observed to be prominent. Species abundance, diversity and vegetation structure and the physicochemical properties of soil showed a ‘‘humped’’ pattern along this altitudinal gradient at Mankulam. In Zone II, species diversity was marginally better with higher species richness and better floristic structure and species composition. Soil properties were also observed to be better in zone II. The possible reason for this could be attributed to several reasons including the presence of luxuriant and comparatively undisturbed vegetation which could have contributed to a higher soil organic matter content rich in humus.