The environments of different plant species are diverse. The growth pattern and status of plant species and vegetation of various communities reflect natural substrate property and chemistry along with anthropogenic interactions. The present research work has focused on the biogeochemical link between vegetation (plant species) and landscape features. The output of this work will help adopt grass root level sustainable conservation approaches on the Gandhamardan hills as well as Eastern Ghats of this region. A schematic approach diagram having four main components viz. plant diversity, landscape ecology, pedology and edaphology, was developed to address biodiversity conservation of Gandhamardan hills. The components were simulated to get inference on vegetation, geography and soil relationship on the hills.

Literature survey suggests many plant taxonomic exploration studies, few quantitative floristics works and few geological surveys have been conducted on Eastern Ghats and Gandhamardan hills. Literature reveals hardly species specific domains, plant species population dynamics, profile based soil survey and chemistry, drainage basin morphometry and soil-vegetation link on the Eastern Ghats. Thorough analysis of literatures prompts to assess  six key areas i.e. plant taxonomic diversity, justification for taking abundance and dominance to calculate Importance Value Index (IVI) of plant species, species population status with their conservation priorities, geospatial landscape features, soil physico-chemical characterisation, and finally vegetation-geography-soil linkage.

Methods followed comprise three steps viz. preparation of maps, plant diversity assessment and biogeochemical analysis of soil, plant bark (roots in case of grasses) and leaf samples. Survey of India (SOI) toposheets F44W9, F44W10, F44W13, F44W14, F44WX1 and F44X2 on the 1:50000 scales were taken to prepare drainage network maps of 67 basins present over the hills. The morphometric parameters were calculated as per the formulae proposed by different workers and computed using Geomedia Professional software. Plant diversity assessment was done by quadrate method along the elevational gradient of BALCO road. The minimum size and number of quadrates were determined by species area curve method in the hill ecosystem. 42 sample quadrates of 20m×20m for tree community having >15cm GBH (Tree-1), 15m×15m for tree community having <15cm GBH (Tree-2), 10m×10m for shrubs, 10m×10m for liana, twinner and climber (LTC), 5m×5m for herb/grass as well as seedling community were laid down. Plant species were identified following flora of Orissa and National flora with reference to Herbarium of Council of Scientific and Industrial Research-Institute of Minerals and Materials Technology (CSIR-IMMT), Bhubaneswar. Tree species individuals were grouped into seven girth classes. They are Seedling (A), Sapling (B), Bole (C), Post bole (D), Mature bole (E), Tree (F) and Mature Tree (G). These represent Girth above Breast Height (GBH) classes of 0-10.5cm, 10.5-31.5cm, 31.5-55.5cm, 55.5-100cm, 100-135cm, 135-169cm and >169cm, respectively. Importance Value Index (IVI) was calculated taking relative values of frequency and density with both abundance and/or dominance of total 232 species enumerated as whole plant community. Also, IVI was calculated separately of each community viz. Tree-1 (86 species), Tree-2 (58 species), shrub (34 species), LTC (26 species), herb/grass (82 species) and seedling (101 species). Here Spearman’s rank correlation was applied to know how much Abundance guided IVI (A-IVI) is controlled by Abundance in comparison to Dominance guided IVI (D-IVI) controlled by Dominance. This model approach renders the justification whether abundance or dominance is more appropriate to calculate IVI of plant species. Distribution pattern of plant species was determined the ratio of Abundance to Frequency values (A/F). Based on A/F, three distribution patterns i.e. regular (< 0.025), random (0.025-0.050) and contiguous (> 0.050) were determined. Diversity indices were calculated using Shannon-Wiener and Simpson’s Index. Evenness Index was calculated to know spatial uniformity of the communities.

To identify plant species specific domains, the elevational gradient of 620m (340m-960m a.m.s.l.) was classified into seven geographical bands i.e. Lower Elevation Range (LER), Middle Elevation Range (MER), Upper Elevation Range (UER), Lower and Middle Elevation Ranges (LMER), Lower and Upper Elevation Ranges (LUER), Middle and Upper Elevation Ranges (MUER) and All Elevation Ranges (AER). Soil survey, sample collection and determination of soil horizons were carried out according to National Bureau of Soil Survey and Land Use Planning (NBSS & LUP), Indian Council of Agricultural Research (ICAR). Seven soil sections (Sections-1 to 7) at different elevations from foot hill to plateau top having total 64 samples were taken. The base of these sections are at 331m, 367m, 404m, 489m, 507m, 677m and 960m a.m.s.l., respectively. Munsell Soil colour chart was used to determine soil matrix colour in dry and field condition. Soil moisture, Soil pH, conductivity, texture, water holding capacity, organic matter and organic carbon, available potassium, sodium, nitrate, sulphate, phosphate and elemental content were estimated following standard protocols. Pedological and Edaphological parameters i.e. Bio Accumulation Factor (BAF) or Bioconcentration factor (BCF), Enrichment Factor (EF), Geo-accumulation Index (Igeo), Contamination Factor (Cf) or Pollution Index (PI), Degree of Contamination (Cd), Modified Degree of Contamination (mCd), Pollution Load Index (PLI), Ecological Risk Index (ERI) or Ecological Risk Factor (ERF) and Potential Ecological risk Index (PERI) were measured using adopted formulae.

          The flora of Odisha shows that the enumerated 232 plant species represent 8.5% of total 2727 species found in Odisha. Tree, shrub, LTC (Lianas, Twinner and Climber) and herb represent 37.50%, 15.09%, 12.07% and 35.34% of the total species. The ten dominant plant families are Poaceae, Fabaceae, Rubiaceae, Euphorbiaceae, Acanthaceae, Lamiaceae, Cyperaceae, Moraceae, Rhamnaceae and Apocynaceae. The most dominant family of Tree-1 (GBH > 15cm), Tree-2 (GBH < 15cm), Shrub, LTC, Herb and seedling communities are Rubiaceae, Rubiaceae, Fabaceae, Fabaceae, Poaceae and Fabaceae, respectively. 232 plant species come under 189 genera and 66 families. Out of total 189 genera, 161 genera are represented by single species. In other words, 69% of total species occurrence spread over 85% of total genera which indicates the higher taxonomic diversity of the forest area. The availability of Embelia tsjeriam-cottam, Dioscorea bulbifera and Leptadenia reticulata only in seedling community shows the future threat of their sustenance in the surveyed part of Gandhamardan hills. Hence, these three species must be given highest priority of conservation.

The most common expression of an ecosystem is the species population. The population dynamics study on the hills is indispensable because of extraction of natural resources for food, fuel, housing materials, herbal medicine and other commercial purposes. Population dynamics of 87 tree species was done in this study. The total population of tree species is 3602. Out of this seedling, sapling, bole, post bole, mature bole, tree and mature tree represents 1979 (54.94%), 928 (25.76%), 343 (9.52%), 211 (5.86%), 81 (2.25%), 33 (0.92%) and 27 (0.75%) individuals, respectively. This forms the tree population pyramid on the hills to be upright at the tree community level. The tree species having highest population in whole tree community, seedling, sapling, bole, post bole, mature bole, tree and mature tree groups are Diospyros melanoxylon, Diospyros melanoxylon, Anogeissus latifolia, Cleistanthus collinus, Cleistanthus collinus, Diospyros melanoxylon, Pterocarpus marsupium and Pterocarpus marsupium, respectively. Only 6 tree species out of 87 are present in all the seven girth classes. Those six tree species are Anogeissus latifolia (Roxb.ex DC.) Wall.ex Guill. & Perr., Lagerstroemia parviflora Roxb., Mitragyna parviflora (Roxb.) Korth., Pterocarpus marsupium Roxb., Terminalia alata Heyne ex Roth and Terminalia bellirica (Gaertn.) Roxb. The population structures of these six species are not upright and they do not show consistent sustainable population structure. None of the tree species shows upright pyramid in population structure individually. Though it appears that trees are sustainable at community level, but there is no evidence found to be sustainable at species level.

In the present study, IVI of each plant species has been calculated taking both Abundance and Dominance separately with frequency and density and examine whether Abundance or Dominance is more justified to calculate IVI applying Spearman’s correlation index. The Spearman’s rank correlation (?) values for Tree-1 (GBH > 15cm), Tree-2 (GBH < 15cm), Shrub, LTC, Herb/Grass, Seedling and Whole plant communities guided by D-IVI are higher than the Spearman’s rank correlation (?) values guided by A-IVI. The debate of usefulness of the relative abundance and relative dominance in IVI calculation has been examined in the present study. Further investigation shows the higher Spearman’s rank correlation values between D-IVI and Dominance compared to that of A-IVI and Abundance in case of all the studied vegetation communities. This suggests that Dominance is more justified compared to abundance in IVI calculation. This supersedes the inference that dominance and abundance are appropriate for the calculation of IVI in case of tree and other communities, respectively. Hence, Importance Value Index (IVI) of plant species should be calculated most preferably taking only dominance in addition to frequency and density.

            Geographical distribution of plant species with respect to elevation was analysed in seven elevational bands to find their specific domains of occurrence at species, genera and family level on the Gandhamardan hills. The trend of species prevalence is decreasing from lower to upper elevation on the hills and this obeys Rapoport's elevation rule. Plant species are more pronounced in the LER, LMER and AER. Trees are more conspicuous in LER and AER than other elevation ranges at species, genera and family level. Shrub taxa are dominant in LER, LMER and AER but no shrub taxa are observed in the MUER. LTC genera and families become prominent in elevational bands of LER, LMER and AER. Herb species and genera are highly adapted in the LER and LMER and at family level; the community is relatively well adapted in LER, LMER, LUER and AER. Grass species are well acclimatised in UER and LUER. Majority of grass species occurrence in the UER can be linked as geobotanical indicator species of heavily weathered rocks and lateritised plateau top of Gandhamardan hill range. Eight grass species on UER such as Arthraxon lancifolius, Chrysopogon verticillatus, Dimeria ornithopoda, Heteropogon contortus, Pennisetum pedicellatum, Sorghum nitidum, Themeda quadrivalvis and Themeda triandra can be evaluated in terms of tolerance indicator of Iron and Aluminium oxide enriched soil profiles. This will pave the path for bio-prospecting of plant diversity in modern era of environmental concerns.

            The area of protected and reserved forest on the hills is 192.1Km2 out of total 301Km2 area of all 67 drainage basins. Landscape features like substrate material, vegetation, infiltration, permeability, erodibility potential, perennial stream development and basin water storage were analysed. The studied terrain of the Gandhamardan has highest and lowest elevation of 1002m and 219m, respectively. The drainage attains a maximum of fifth order and the drainage characteristics confirm Horton’s first law of drainage numbers. The stream length characteristics also follow and confirm Horton’s second law of stream length. Sixty seven drainage basins with 1477 drainage channels including 1098 first order, 274 second order, 81 third order, 22 fourth order and 2 fifth order were measured. The hill can generate high runoff due to average drainage density of 3.42Km/Km2. Coarse drainage texture is observed inferring widely spaced channels, presence of massive, resistive rocks and well protected basins by vegetation. Form factor, circularity ratio, elongation ratio, constant channel maintenance, length of over land flow and infiltration number indicate most of the basins to be with good infiltration capacity and permeable substrate material favouring vegetation growth and wider spatial spread on the hills. Relief ratio and Ruggedness number show gentle slope and mild erosion process operating on the hills leading to slow run off and more percolation of water into the substrate material. Form factor indicates 80.20% of the total geographical area of sixty seven basins is with efficient percolation favouring luxuriant growth of vegetation. Constant channel maintenance shows sixty three basins accounting 298.7Km2 (99.24%) have value above 0.2 reflecting effective permeability and infiltration through the substrate material. Sixty three basins constituting 298.7Km2 (99.24%) area show Length of Overland Flow (Lof) value above 0.10 and reflects effective permeability and infiltration through the substrate material. This may be the reason for many perennial stream developments around the hill slopes of Gandhamardan hills. Ruggedness index also indicates the drainage basins to be mildly rough. Dissection index shows that 48.24% geographical area of sixty seven drainage basins is less dissected. Average slope of the watershed shows that 90.90% geographical area is under least erodibility class supporting intact substrate soil material which will help growing vegetation in adverse water scarce seasons. The time of concentration validates the presence of perennial streams like Nrusinghanath and Harishankar on the Gandhamardan hills. Therefore, drainage morphometry is one of the important tools to assess landscape dynamics operating in a region and characterize landscapes with reference to substrate material, vegetation, infiltration, permeability, erodibility potential, perennial stream development and underground water storage. This, in turn, will help biodiversity characterization at landscape level.

All the soil sections on the hills fall under eastern plateau of peninsular region. They contain gneissic granite and khondalite rock materials. These are excessively drained and are under the effect of dry deciduous forest system. All soil profiles fall under either sand or loamy sand or sandy loam texture. Eighteen Munsell soil colours were identified while investigating on the 64 soil horizons in seven soil sections. They are Dark gray, Light yellow brown, Light brown, Reddish yellow, Strong brown, Yellowish brown, Reddish gray, Reddish brown, Light reddish brown, Yellowish red, Gray, Brown, Brownish yellow, Pink, Weak red, Dark red, Red and Dark reddish brown. There are no mottles or redoximorphic features observed in the horizons of seven sections. All 64 soil samples show no effervescence with 10% HCl and H2O2. Maximum average clay of 10.32% was found in the soil section-1 followed by 6.59% (section-5), 5.39% (section-6), 4.67% (section-2), 3.67% (section-3), 2.91% (section-4), and 2.38% (section-7). This reflects that clay is decreased with increasing elevation on the hills. This may be one of the several factors behind absence of deep rooted tree communities and presence of dominating seasonal grass communities on plateau top of the upper elevation range where soil section-7 has been sampled. As tree community is not sustainable in the upper elevation range, it may be fatal for understorey vegetation like herbs, shrubs and lianas to survive in water deficit winter and summer seasons. For this reason, these communities are less prominent in upper elevation range rendering decrease in plant diversity from lower to upper elevations.

            The value of pH varies from 5.67 to 7.47 in seven soil sections. The pH gradually decreases along the elevational gradient from foot hill to plateau top. This may be the mechanistic reason for first of the two patterns of species occurrence in a hill ecosystem i.e. (i) many investigations have established a declining tendency in the richness of species with increase in elevation and (ii) a hump shaped relationship with a peak in the richness of species at mid elevations. pH of forty three soil samples within 6 to 7 indicates the suitability for growth of luxuriant vegetation on the hills when within pH 6 to 7, there is maximum availability of nutrients. At stronger acidic or basic pH conditions, nutrients unite to form insoluble chemical compound structures reducing their utilization by plants. Maximum soil horizons showing pH 6 to 7 are prevalent in mid elevational ranges. This supplements the theory of mid-domain effect with hard boundary concept of more plant species distribution in and around mid elevation of major mountain ecosystem.    

Conductivity decreases from lower to upper elevation. Conductivity is also positively correlated with Sodium and Potassium concentrations. Also, Sodium and Potassium concentrations decrease from lower to upper elevation range. Therefore, decrease in conductivity, pH, Sodium and Potassium concentrations from lower to upper elevation may be correlated and interpreted with the decrease in plant species prevalence from foot hill to upper plateau top of Gandhamardan hills. Temperature, measure of moisture content and water holding capacity (WHC) of soil samples increase from lower foot hill to upper plateau top. These factors may be helpful for establishment, growth, reproduction process, survival and dominance of maximum grass species in the upper elevation ranges. The time of concentration (Tc) of water on the drainage basins 1 and 60, where the soil sections have been sampled, are 179.344minutes (2.98hrs) and 118.051minutes (1.96hrs), respectively. The mean time of concentration of water on the hills is 80.751 minutes (1.34hrs). These Tc values show how rain water is percolated down to water table enriching soil moisture which supports vegetation growth and sustenance. These factors may be the cause behind deep rooted plants on the hills as evident from 1.05m, 0.75m, 1.5m, 2.25m, 2.55m, 0.75m and 1.05m deep root growths in soil sections-1, 2, 3, 4, 5, 6 and 7, respectively.

There is also a trend of increase in the organic carbon content of soil samples with respect to elevational gradient from lower to upper elevation. Potassium plays important role in cell metabolism, photosynthesis, transport, storage of food, cell wall development and disease resistance. Other cations like Sodium in excess prevent plants from taking up Potassium. At high concentrations in the cytoplasm, Na+ renders in detrimental consequences on the cell metabolism and photosynthesis. Further, low pH of soil reduces the Potassium availability. In this context, the Sodium-Potassium ratio of 61 soil samples remain below 0.5 except 3 samples having ratio 1.1 being the indicator of sustaining healthy forest growth. With decrease in pH (7.5-5.5) from lower to upper elevations, it is presumed to have decreased availability of Potassium to plants in upper elevations which may be correlated with very less or stunted growth of herb, liana, shrub and tree except grass communities on the hill plateau top or otherwise decreasing trend of plant species occurrence from foot hill to plateau top.

Plants readily take up nitrate. Sixty three soil samples except horizon ‘A’ of section-6 (31.44mg/Kg) are having nitrate below 15mg/Kg. This unusual phenomenon may be due to the existence of only three plant species on section-6 out of which Bauhinia vahlii and Millettia extensa are leguminous type lianas and their surficial root networks are spread on the forest floor indicating leguminous lianas to be conserved, managed and propagated in forest ecosystems to enrich soil nitrate. Phosphorous is a significant nutrient, but its plant-available form i.e. phosphate is always small within natural forest ecosystems. This may be probable reason behind phosphate concentration below detection limit of 37 samples out of total 64. Major quantities of adsorbed sulphate are available only in clay and sesquioxide enriched soil horizons with pH less than 5, which is far below pH range observed in Gandhamardan composite samples of soil and rocks. In the present work, the SO42- concentrations vary from lowest 49.92g/Kg of section-7 to highest 84.48g/Kg of section-4. It indicates that the parent materials on Gandhamardan hills provide enough sulphate which is utilized by plant species from different soil horizons. Secondly, effective pH range for sulphur availability to plants is 5.5 to 7.5. Further, free sulphate availability increases as pH goes on increasing from 5.5 (moderately acidic) to 7.5 (slightly alkaline) that adsorption of sulphate in the soil systems is favoured by strong acidic conditions and this becomes insignificant at pH values greater than 6. Analysis indicates decreasing pH and increasing Al and Fe from foot hill to plateau top which may be the reason behind decreasing plant species prevalence along the elevational gradient from foot hill towards plateau top.

The present work demonstrates that As, Cd, Cr, Al and Fe are less available and the other five elements Co, Cu, Mn, Zn and Ni are more available as the pH of soil samples vary from acidic to alkaline nature. Hence, the availability of As, Cd, Cr, Al and Fe increases and that of Co, Cu, Mn, Zn and Ni decreases along the elevational gradient from base to summit of Gandhamardan hills because of decreasing trend in pH from alkaline to acidic nature. The background concentrations of As, Cd, Co, Cu, Mn, Zn, Ni, Cr, Al and Fe in the Shale are used in the present work to calculate soil quality indices. The shale concentration value of elements was preferred over the earth’s crustal average because heterogenous assemblages of minerals are existent in earth’s crust. Six elements viz. Cd, Co, Cu, Mn, Cr and Al except As, Zn, Ni and Fe show Igeo values less than zero in soil section-1. Seven elements viz. As, Cd, Co, Cu, Mn, Ni, Cr and Al except Cu, Zn and Fe show Igeo values less than zero in soil section-5. Five elements viz. Cd, Co, Cu, Mn and Ni except As, Zn, Cr, Al and Fe show Igeo values less than zero in soil section-7. Therefore, the soil is practically not contaminated with Cd, Co and Mn on Gandhamardan hills. Only two elements Co and Mn show low contamination in all the three soil sections. Soil sections 1 and 5 show low contamination and section-7 show moderate contamination with As, Cd, Cr and Al. Cu moderately contaminates sections 1 and 5 but contaminates with lower degree in section-7. Ni moderately contaminates section-1 but contaminates with low degree in sections-5 and 7. Fe shows considerable contamination in section-5 but moderate in the sections 1 and 7. Zn is the exceptional element which shows very high contamination in all the three sections. The moderate contamination of four elements As, Cd, Cr and Al in the plateau top soil section–7 only may be attributed to extreme weathering event there.

Iron shows second highest average contamination factor which may have resulted from parent materials. Exceptional very high Zn contamination may be due to the site specific analysis of soil composite samples including rock fragments on Gandhamardan hills. Degree of Contamination (Cd) values indicate the very high degree of contamination of all three soil sections in the area with escalated values due to high Contamination factor (Cf) of Zn only. Leaving Zn, the Cd shows moderate degree of contamination. Modified degree of contamination values also indicates very high degree of contamination of all the three soil sections. In this case, apart from inclusion of Zn, the soil sections show nil to very low degree of contamination. Therefore, the influence of Zn on the Cd and mCd needs special attention. The Pollution Load Index (PLI) of soil sections 1, 5 and 7 are 7.36, 1.41 and 6.29, respectively, taking escalated Cf values of Zn. This indicates the deterioration of site qualities. On the other hand, leaving Cf values of Zn, the PLI of soil sections 1, 5 and 7 would have been 0.62, 0.12 and 0.64, respectively. This indicates no pollution existing at the sites.

The Potential Ecological Risk Index (PERI) is calculated taking the summation of single element Ecological Risk Index (ERI). Elements like As, Cd, Co, Cu, Mn, Ni and Cr show low potential ecological risk having ERI values less than 40 in each of the three soil sections 1, 5 and 7. Zn is the only element showing moderate potential ecological risk with ERI values 139.84, 133.80 and 98.04 in soil sections 1, 5 and 7, respectively. PERI of three soil sections 1, 5 and 7 were calculated to be 188.53, 165.59 and 166.86 taking the sum of ERI of eight elements. Based on this PERI values, there is moderate ecological risk on Gandhamardan hills. These PERI values on section 1, 5 and 7 would be 48.69, 31.79 and 68.82 respectively, excluding ERI values of Zn, reflecting low ecological risk on Gandhamardan hills. With this background, it is inferred that excessive Zn concentration may have been inherited from the rock materials which have been crushed and powdered along with the soil samples of each profiles in each soil sections to make soil composite samples.                    

The edaphological impact analysis can be done with respect to variation of plant species occurrence on the seven soil sections having different soil characteristics. Maximum twelve and minimum three plant species are found on soil section 3 and 6, respectively. Maximum 10 families are found on each of the sections 2, 3 and 4. Only 3 families are found on section 6. The species to family ratio of plants on sections 1, 2, 3, 4, 5, 6 and 7 are 1.3, 1.1, 1.2, 1.1, 1.1, 1.0 and 2.5, respectively. Again, species to genera ratio of plants on those sections are 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 and 1.1, respectively. Further, genera to family ratio of plants on those sections are 1.3, 1.1, 1.2, 1.1, 1.1, 1.0 and 2.3, respectively. The ratio of lower to higher taxa shows the richness of the flora, i.e. the less the value the richer the community. Comparing the above three types of ratios of plant community over the all soil sections, it is revealed that least diverse flora is prevalent over the soil section-7. On the other hand, it also indicates the dominance of single family i.e. poaceae of six plant species out of total ten species found there. This trend shows that the environment in particular the soil or pedological environment does not provide opportunistic niches for sustenance of plant diversity there due to severely weathered rocks and soil profiles. This changing environment favours more towards seasonal flora than existence of perennial flora like tree, shrub and liana species. The exclusive tolerance and dominance of grass species belonging to poaceae family on the hill plateau top may be correlated with positive Igeo values of Al only in the section-7. Corroborating this inference, it is found that among three species Lagerstroemia parviflora, Homalium nepalense and Chrysopogon verticillatus analysed for Fe and Al on the soil section-7, the grass species C. verticillatus belonging to poaceae family accumulates maximum Fe and Al in its tissues than other two tree species. As the severe weathering process progresses from top to down of the hill, it is expected to have logically a negative impact producing unfavourable environment for the ecosystem. This trend of ecosystem degradation, in long run impact of diurnal and seasonal weather changes, rainfall pattern, temperture variation and climate related effect, may have affected plant species occurrence along the elevational gradient.

The eighteen tree species viz. Alangium salvifolium, Alstonia scholaris, Antidesma acidum, Antidesma acuminatum, Ardisia solanacea, Azadirachta indica, Cipadessa baccifera, Ficus arnottiana, Ficus benghalensis, Ficus microcarpa, Ficus religiosa, Ficus virens, Glochidion zeylanicum, Murraya paniculata, Pterospermum acerifolium, Streblus asper, Trema orientalis and Ziziphus mauritiana present in only one girth class and thirteen tree species viz. Alangium salvifolium, Alstonia scholaris, Antidesma acidum, Ardisia solanacea, Ficus arnottiana, Ficus benghalensis, Ficus microcarpa, Ficus religiosa, Ficus virens, Glochidion zeylanicum, Pterospermum acerifolium, Streblus asper and Trema orientalis having population of only one must be given highest priority in conservation measures on the hills.

Soil nitrate analysis in seven soil sections reveals the usefulness and positive impact of two leguminous lianas i.e. Bauhinia vahlii and Millettia extensa must be propagated and conserved to maintain soil nitrate and water conservation in the ecosystem. Eight grass species dominant and sustainable in upper elevation range of Gandhamardan hills can be evaluated as abiotic stress tolerant species in the Iron and Aluminium oxide enriched, deeply weathered and lateritised plateau top for soil pollution abatement, mine reclamation and mineral exploration. Among three species Lagerstroemia parviflora, Homalium nepalense and Chrysopogon verticillatus analysed for Fe and Al content in their tissues on the soil section-7, the grass species C. verticillatus of poaceae family accumulates 5 to 47 times more Fe and Al in its tissues than other two tree species. This approach will pave the path for geobotanical and bio-prospecting of plant diversity in modern era of environmental concerns.

Present study indicates some future research on germination studies of soil seed bank of all tree species to determine their regeneration potential and understand population structure. Plant species surviving and growing luxuriantly on the weathered lateritised plateau top should be screened for their abiotic tolerance to find out potential species for bioprospecting. Phosphate and Zinc concentrations need to be thoroughly examined both in the rocks and soil parts compared to their composite samples. All leguminous plants should be evaluated in terms of their nitrogen fixing ability. Biodiversity conservation policy and planning must be based on multisectoral approaches including afforestation programmes giving emphasis not only on vegetation coverage and commercial timber production but also on plant species important for non-timber forest products (NTFP), herbal and pharmaceutical drugs, wildlives, soil conservation, water conservation and underground water percolation, articrafts, handicrafts and cottage industries. Plant exploration studies must accompany Geographical Information Studies to make a holistic strong framework on the geobotanical database for long term monitoring of natural resources. Looking at the numerous perennial streams on the hills, it provides the scope for hydrogeological studies exploring scientific mechanisms of water storage and ground recharge in bauxite rich hill ecosystems. As the present vegetation and soil sampling are done in the drainage basins 1 and 60 of North-Western part of the Gandhamardan hills, there is lot more scope to explore other 65 drainage basins to develop a complete database on vegetation and soil resources of the hills. To adopt biodiversity conservation rules, regulations and protocols, there is urgent need of quantitative estimation of timbers, fuel woods, bamboo, NTFP, medicinal plants, economic grasses and other bio-resources being extracted from the Gandhamardan hills.