Badal Kumar Datta

Tree species diversity and stand structure along major community types in lowland primary and secondary moist deciduous forests in Tripura, Northeast India

Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura. Overall 10,957 individual trees belonging to 46 family, 103 genera and 144 species were counted at ≥30 cm DBH (diameter at breast height) using 28 permanent belt transects with a size of 1 ha (10 m × 1000 m). Four different tree communities were identified. The primary forests was dominated by Shorea robusta (mean density 464.77 trees·ha−1, 105 species) and Schima wallichii (336.25 trees·ha−1, 82 species), while the secondary forests was dominated by Tectona grandis (333.88 trees·ha−1, 105 species) and Hevea brasiliensis (299.67 trees·ha−1, 82 species). Overall mean basal area in this study was 18.01m2·ha−1; the maximum value was recorded in primary Shorea forest (26.21 m2·ha−1). Mean density and diversity indices were differed significantly within four different communities. No significant differences were observed in number of species, genera, family and tree basal cover area. Significant relationships were found between the species richness and different tree population groups across the communities. Results revealed that species diversity and density were increased in those forests due to past disturbances which resulted in slow accumulation of native oligarchic small tree species. Seventeen species were recorded with <2 individuals of which Saraca asoka (Roxb.) de Wilde and Entada phaseoloides (L.) Merr. etc. extensively used in local ethno-medicinal formulations. The present S. robusta Gaertn dominated forest was recorded richer (105 species) than other reported studies. Moraceae was found more speciose family instead of Papilionaceae and Euphorbiaceae than other Indian moist deciduous forests. Seasonal phenological gap in such moist deciduous forests influenced the population of Trachypithecus pileatus and capped langur. The analysis of FIV suggested a slow trend of shifting the population of Lamiaceae group by Moraceae species in secondary T. grandis L. dominated community.

Trends in Tree Diversity and Stand Structure during Restoration: A Case Study in Fragmented Moist Deciduous Forest Ecosystems of Northeast India

Ecological implications for the conservation of fragmented forests to managed local plant diversity have recently drawn much attention of most conservationists. Present study investigates the importance of fragmented forests using different quantitative measures of species diversity and stand structure as indicators of natural restoration from past disturbances. Eleven independent 500 m × 10 m belt transects (5.5 ha) were established within fragmented low land moist deciduous forests of Tripura. All woody plants ≥10 cm girth at breast height (GBH) were measured. A total of 7,134 individuals with mean density of 648.55 stems ha−1 and 16.36 m2 ha−1 of basal area were recorded, which represented 134 species, 93 genera, and 43 families of woody plants. Diversity-dominance curve showed that maximum number of species were ranked >10 due to low abundance value. Maximum distributions of stems (>50%) were recorded at lowest girth class (10–30 cm) as an indication of advanced regeneration and significantly declined towards upper girth (; ) and height (; ) classes, which also indicated that some plants were adopted with ongoing disturbances through both seeded and nonseeded regeneration. Species richness (; ), dominance (; ), and density (; ) were significantly increased at different disturbance intensities. Disturbances strongly influenced typical community association and structure by increasing diversity and population at certain magnitude and thereby showed declining trend towards maturation. Fragmented moist deciduous forests seek immediate attention as they represent spatial habitat for many economical or ecological important species, thus sustaining local biodiversity for livelihoods.

Elemental analysis of some ethnomedicinaly important hydrophytes and marsh plants of India used in traditional medicine

Abstract Objective To study the elemental content of some ethnomedicinaly important hydrophytes and marsh plant of Tripura, India. Methods With the help of standardize d questionnaires, 10 informants were interviewed on the medicinal use of hydrophytes and marsh plants of Tripura, India during 2009-2010. The elemental content of those plants were determined using Atomic Absorption Spectrophotometer. Results A total of 8 plant species belonging to 8 different genera and 8 family were reported with their ethnomedicinaly uses. Among the different plant part used leaves and young tender shoots are most frequently used for the treatment of different disease. The hydrophytes and marsh plants are mostly used for the treatment of dysentery and other hepatic disorder. Different elemental constituents at trace levels of plants play an effective role in the medicines prepared. Elemental composition of eight ethno-medicinally important hydrophytes and marsh plants of Tripura, India have been determined using Atomic Absorption Spectrophotometer (AAS). A total of 11 elements K+, Mg+2, Ca+2, Na+, Fe+2, Mn+2, Cu+3, Mn+2, Cu+3, Cr+3, Zn+2, Pb+4 and Cd+2 have been measured. Their concentrations were found to vary in different samples. Toxic elements Cd and Pb were also found but at very low concentration. Medicinal properties of these plant samples and their elemental distribution have been correlated. These results can be used to set new standards for prescribing the dosage of the herbal drugs prepared from these plant materials in herbal remedies and in pharmaceutical companies. Conclusions The data obtained in the present work will be useful in synthesis of new herbal drugs with various combinations of plants, which can be used in the treatment of different diseases at global level.

Effects of patch size, disturbances on diversity and structural traits of tropical semi-evergreen forest in the lowland Indo Burma hotspot: implication on conservation of the threatened tree species

Information on geographic distribution, population and threat status of most globally red listed species in the Indo Burma zone are inadequate. Given the increase in the prevalence of isolated forest patches in the part of this hotspot, evaluation is necessary on how size of the remnant forest patches and on-going disturbances affects structure and diversity of remaining habitats including the population of some globally threatened tree species. Quantitative vegetation inventory by 500 m long and 10 m wide (0.5 ha) line transects were randomly set in nine fragmented tropical semi-evergreen forest patches in Tripura, Northeast India. The studied forests patches grouped into small, medium and large based on their respected sizes. Spatial variability was analysed in woody species diversity and structure along the patch size gradients and their response to both patch size and anthropogenic disturbances. Out of 167 species, 13 identified as red-listed species by IUCN under the present inventory. Most of the diversity and structural parameters showed statistically significant positive response with the forest patch size, except for stand dominance, disturbance, sapling density and number of aggregated distribution pattern decreased when patch size increased. In addition, most of the diversity and structural attributes showed negative response with disturbances. Present baseline data would serve as an effective tool for management and protection of this important forest type. Future habitat restoration programme and strategies for relocation of additional population and re-introduction of those globally threatened trees are recommended.

Lower altitudinal variation in habitat associations, tree diversity and co-dominant population structures along moist deciduous forests dominated by sal (Shorea robusta) in Northeast India

We used line transects of 10 × 500 m size to analyze the patterns of sal associations, diversity and population structure at lower elevation (<100 meters above mean sea level) of moist deciduous forests dominated by sal (Shorea robusta) in Tripura, Northeast India. Overall 216 woody species with 898.56 ha−1 mean density and 33.21 m2 ha−1 mean basal area were recorded using 32 line transects of 0.5 ha size sampled by measuring sal forests at ≥10 cm girth at breast height. Five different sal associations were recognized by cluster analysis, where sal typically associated with Terminalia bellirica, Careya arborea and Schima wallichii in moist deciduous habitats. Rare associations of sal with Artocarpus chama and Dipterocarpus turbinatusa were also identified. Species diversity (p < 0.001) and dominance (p < 0.0001) was significantly different across the sal associations; species richness was recorded higher in S. robusta – S. wallichii association with 152 species than in S. robusta – T. bellirica association with 85 species. Existing habitat disturbances and intensity of sal effects on diversity and structure were significant (p ≤ 0.05), as observed by the changes in species richness and abundance of most abundant, least abundant and unique species along the associations. Population trends and regeneration potential of sal and its most associated trees were predicted using steepness and negative slope values in regression of size class distributions of tree density per hectare at 10 girth classes for each sal association. The present investigation helps in the understanding of broad ecological aspects in lowland sal habitats, particularly when this ecosystem is shifting to these regions in relatively wetter and plain areas due to climate change.

Ethno-medicinal plants used by Bengali communities in Tripura, northeast India

Northeastern India has high medicinal plant diversity due to variance in topography and physiognomy. We documented the uses of various medicinal plants by the Bengali people of West district and South district of Tripura state for their own health care as well as for domesticated animals. Based on semi structured interviews, group discussions and information from local informants, a total of 93 species of medicinal plants of 52 families and 83 genera were documented. These plants were used to treat more than 55 different human diseases and 6 diseases of livestock. Sixty-eight plant species were used singly and the rest were used in combination with other species for therapeutic formulations of various diseases. Leaves of plants were most often used for most of the ethnobotanical preparations. Maximum consensus value of 96% was recorded for Chromolaena odorata (L.) King & H. Rob., and the minimum was 15% for Bambusa balcooa Robx. Of the 93 plant species, 75 species showed pharmacological properties. Prospects for augmenting existing knowledge and enhancing the use of traditional medicinal plants are discussed.

A quantitative checklist of woody angiosperm diversity,population structure and habitat grouping in Trishna Wildlife Sanctuary of Tripura, northeast India

A quantitative vegetation inventory was conducted in Trishna Wildlife Sanctuary of Tripura, Northeast India. Twenty five 500×10 m belt transects were used to record diversity and population structure of woody angiosperms. Overall 289 species belonging to 158 genera and 64 families were recorded at ≥10 cm GBH (Girth at Breast Height). Moraceae (25 spp.), Phyllanthaceae (21 spp.), Leguminosae (21 spp.), Euphorbiaceae (15 spp.), and Rubiaceae (14 spp.) were the top five families with highest species diversity. Habit wise, 226 species were trees, 25 woody shrubs, 23 woody climbers, 6 bamboos, 6 rattan and 3 palm species. Shannon–Wiener diversity index values ranged between 1.42–4.25, and Simpson dominance index ranged between 0.02–0.42. Mean species richness index was 2.83 and species evenness index was 0.78. The present quantitative checklist indicates the potential plant resources of the sanctuary which can be used for future biodiversity inventories and species conservation.

Tree Species Richness and Carbon Stock in Tripura University Campus, NortheastIndia

Trees are the prevalent component of a terrestrial ecosystem. They provide benefiting function by accumulating atmospheric Carbon. Instead of forest area, trees are generally found sporadically in every urban area within the boundaries of cities, towns along the road side or even in the periphery of settlement and institutional confinement. In the present study, we explored the potential of tree species richness in an institutional campus. The study constitutes an assessment of tree species richness, standing biomass and carbon stock of trees in Tripura University campus. A total of 66 tree species with 1301 individuals (40.69 individual ha-1) belonging to 56 genera from 32 families were identified. The dominant family was Mimosaceae and species was Acacia auriculiformis (n=524), followed by Cassia siamea (n=31) and Cassia fistula (n=25). The compositional pattern shows that number of individual with the lower DBH was higher and only 47 individuals were found in > 45 cm DBH class. The total biomass (AGB and BGB) was 377.76 T in the entire area, with 11.82 Tha-1 and carbon as 5.91 Tha-1. Acacia auriculiformis emerged as the highest biomass contributor due to its higher number of individuals. The study shows that the tree species found in the campus make an important contribution in conserving diversity and helps to maintain the carbon stock in the University Campus.

Carbon Sequestration Potential and Edaphic Properties Along the Plantation Age of Rubber in Tripura, Northeastern India

India is voluntarily committed towards reducing carbon emission. Rubber plantation could be an important means for carbon sequestration at state and national level. Tripura holds second position as rubber grower state in India, spreading over a 72273 hectare areas. Present study designed to estimate the carbon storage potential, sequestration rate and some selected edaphic properties under four different aged rubber plantations viz. HB05, HB10, HB15 and HB20, following stratified random sampling methodology. Total, 40; 100×10 m transects were laid for estimation of biomass carbon stock and transects were further subdivided into five equal quadrates 20×10 m sized for sampling soil. The stand structural variables like mean girth size, height, basal area, tree carbon and overall carbon stock significantly varied among the different aged rubber plantations. The periodic annual increment in terms of carbon sequestration was estimated at the rate of 2.97, 3.30, 3.14 and 2.82 (Mg C ha-1 yr-1). The result indicated that total carbon stock in rubber plantation was 202.48 Mg ha-1, out of which tree carbon shared 41.85 and Soil Organic Carbon (SOC) 160.71 Mg ha-1 respectively. SOC did not show any significant variation along the plantation ages. The study suggested that the potentiality of carbon sequestration of rubber plantation in Tripura has immense scope for future carbon credit and incentives.

Effects of anthropogenic disturbances on vegetation diversity and structure:a case study in the remnant forests surrounding the village ecosystems of Tripura,Northeast India

The types, frequency, and intensity of human interference with forests markedly affect the vegetation dynamics. Assessment of the impact of anthropogenic disturbances on forest diversity and structure is one of the central issues related to human behaviour and forest ecosystems and management. Both species diversity and density are very sensitive to local anthropogenic disturbance, which can be reduced depending on land-use systems. We used 10 line transects of 500 × 10 m to record and measure all plants ≥10 cm girth in some of the remaining forests surrounding villages in Tripura, Northeast India. To predict the effects of anthropogenic pressure on species richness and forest structure, we recorded and scored all ongoing disturbances in all transects of the forests. Although our study did not show any significant effects on the mean number of species, all diversity indices were significantly affected by disturbance. Total stem density (F = 128.60, p < 0.0001) and basal area (F = 65.30, p < 0.0001) of the forest stands were significantly affected by disturbance. Disturbance significantly (F = 84.81, p < 0.0001) impacts the abundance of mature voluminous trees removed by extensive illegal logging. Further, stem density at the middle (F = 10.01, p < 0.05) and upper (F = 131.70, p < 0.0001) canopy stories was also reduced by high disturbance intensity. The present analysis will be useful to policy-makers and planners for implementation of sustainable forest management at both the local and regional scale.