Browsing by Author "Anshuman Tripathi"

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Assessment of habitat features modulated carbon sequestration strategies for drought management in tropical dry forest fragments
(Elsevier B.V., 2024) R.K. Chaturvedi; Anshuman Tripathi; Rajiv Pandey; A.S. Raghubanshi; J.S. Singh
Habitat features, such as species diversity, functional diversity, tree size, disturbances and fragment sizes have differential impacts on carbon (C) storage and C-sequestration in forest ecosystems. Present study attempted to understand the tree strategies for modulating C-sequestration capacity across tropical dry forest fragments with variable edge distances. We evaluated the differences between drought strategies (i.e., drought avoiding and drought tolerant) for variations in stem density, relative growth rate (RGR), C-storage and C-sequestration, species diversity, functional diversity, tree size and disturbance indicators along edge distance gradient, besides analyzed the differences between drought strategies for responses of C-storage and C-sequestration to variations in species diversity, functional diversity, tree size and disturbance indicators. Various traits and functional indices were analyzed using standard statistical techniques. For total trees and for the two drought strategies, generalized linear modeling results showed a significant decline in stem density, RGR, C-stock, C-sequestration, species diversity, functional diversity and tree size indicators, while a considerable increase in disturbance indicators, along decreasing edge distance across the fragments. The drought strategies exhibited a high degree of variation in the slope of associations for above variables with edge distance across fragments. For predicting C-sequestration, structural equation modeling results showed highly significant influence of functional diversity indicators for drought avoiding strategy, while species diversity indicators were strongly significant for drought tolerant strategy. Moreover, fire index and drought index were critical predictors for C-sequestration for drought avoiding and drought tolerant strategies, respectively. This study provide inputs to understand the largely ignored processes of C-storage and C-sequestration in fragmented forests, which are currently prevalent due to heavy anthropogenic pressures. Our findings are useful for forest managers to understand vegetation responses to interactions of species diversity, functional diversity, tree size and disturbance indicators, for predicting the stability of larger fragments and for planning restoration of smaller fragments. © 2024 Elsevier B.V.
Effect of disturbance, habitat fragmentation and alien invasive plants on floral diversity in dry tropical forests of Vindhyan highland: A review
(2009) A.S. Raghubanshi; Anshuman Tripathi
Effect of disturbance, habitat fragmentation and exotic plant species invasion on plant diversity is documented for the dry deciduous forests of India's Vindhyan highlands. Plant communities were identified with the help of satellite imagery and ground data, and community wise diversity was estimated. Analysis of landscape matrices using satellite images and GIS tools showed deforestation of smaller fragments, and fragmentation and degradation of larger ones. Fragments of smaller size had lesser number of plant communities compared to larger fragments. Generally large size fragments were species rich and more diverse as compared to smaller fragments. Lagestoemia-Acacia-Lannea community was richest for both tree and herb strata, whereas Shorea-Buchanania community was the richest when all vascular flora were considered. The study indicates that species rich communities of the dry tropical forests are not only being reduced in area but they are also becoming species poor and less diverse due to rapid deforestation and forest fragmentation. The communities most vulnerable to alien invasive plants were Acacia-Terminalia, Terminalia-Shorea and Hardwickia-Acacia. Ecological implications of plant invasion are discussed and conservation measures suggested. © International Society for Tropical Ecology.
Forest fragmentation and its impact on species diversity: An analysis using remote sensing and GIS
(2005) C.S. Jha; Laxmi Goparaju; Anshuman Tripathi; Biswadeep Gharai; A.S. Raghubanshi; J.S. Singh
The process of forest fragmentation, a common phenomenon occurring in tropical forests, not only results into continuously forest getting fragmented but also brings about several physical and biological changes in the environment of forests. Consequently, there is a loss of biodiversity due to change in habitat conditions. These remnant fragments provide the last hope for biodiversity conservation. The present study deals with the impact of decreasing patch size of a fragmented forest on the diversity of the tropical dry deciduous forests in Vindhyan highlands, India. There is considerable change in the vegetation cover of this region owing to rapid industrialization and urbanization, which has also contributed to forest fragmentation. In the present study, remotely sensed data has been used to describe the changes brought about in vegetated areas over a period of 10 years as a result of fragmentation and its impact on biodiversity was assessed. Further, in order to assess the loss of species with respect to the reduction in patch size, species area curves for various change areas were analysed. It was observed that the rate of decrease in the number of species is faster in the case of negative change areas as compared to the positive change areas of the region. Various diversity indices also support this observation. Such an analysis would help in formulating appropriate conservation measures for the region. © Springer 2005.
Forest fragmentation impacts on phytodiversity - An analysis using remote sensing and GIS
(2005) Laxmi Goparaju; Anshuman Tripathi; C.S. Jha
The present study deals with the forest fragmentation of Vindhyan highlands in the Indian dry tropical forests. The fragmentation scenario has been quantified using remote sensing data and GIS techniques. The remotely sensed data-derived vegetation map was an input to the fragmentation analysis. Transects were laid to inventory along different forest patch sizes of various communities to study the biodiversity levels. It was observed that with changing fragment, there is change in biodiversity levels. Hence, patch size might play an important role in the regulation of biodiversity levels. This information may provide an insight into the conservation strategy formulation for the fragmented dry tropical area. The analysis has brought out that biodiversity levels are different in various fragments of different sizes. Small fragments are similar to each other in terms of species composition; similar is the case with large fragments in general. It was also found that the small and large fragments are dissimilar in terms of species composition. The diversity levels among the fragments of similar size class varied across the anthropogenic gradient. Analysis of species richness, diversity indices has helped in studying the patterns/levels of biodiversity in different fragment size classes along different levels of anthropogenic pressure. The merits of conserving the small and large fragments have been discussed.
Functional traits indicate a continuum of tree drought strategies across a soil water availability gradient in a tropical dry forest
(Elsevier B.V., 2021) R.K. Chaturvedi; Anshuman Tripathi; A.S. Raghubanshi; J.S. Singh
This study evaluates drought survival mechanisms of tropical dry forest (TDF) trees based on their functional traits (FTs). We addressed the following questions: (i) What are the dominant functional guilds (FGs) of tree species across a soil water availability gradient in TDF? (ii) What are the important FTs influencing tree species assemblage in different FGs? (iii) What is the functional composition of different FGs in the study sites, and how are they influencing biomass accumulation capacity (BAC) across the soil water availability gradient? We selected 12 FTs associated with plant water use strategies, viz., canopy cover intensity (CC), wood specific gravity (WSG), saturated stem water content (QWsat), leaf size or leaf area (LA), specific leaf area (SLA), relative water content (RWC), leaf dry matter content (LDMC), leaf nitrogen content (LNC), leaf phosphorus content (LPC), maximum saturated stomatal conductance (Gsmax), maximum saturated photosynthetic rate (Amax), and intrinsic water use efficiency (WUEi). By using these FTs, we classified 47 tree species by HCPC (hierarchical clustering on principal components) into three FGs, viz, drought avoiding (DAFG), drought resistant (DRFG), and drought tolerant (DTFG). For species grouping, QWsat was the most significant for DAFG, impacts of Amax, LPC, Gsmax and LNC were significant for DRFG, while LDMC and CC were significant for DTFG. Across the five forest fragments, along a soil moisture content (SMC) gradient, the three FGs exhibited significant differences in species richness, stem density, aboveground biomass, and biomass accumulation capacity (BAC). We observed increasing dominance of DAFG towards drier sites, while the abundance of DRFG and DTFG was higher towards moister sites. Among the three FGs, DTFG showed highest biomass and BAC in our study region. Strategies of DAFG were more associated with savanna habitats, while DRFG and DTFG exhibited strategies important for TDFs. Our findings could help forest managers in restoration and conservation of TDFs. © 2020 Elsevier B.V.
Isolation of potentially pathogenic Escherichia coli O157:H7 from the Ganges River
(2007) Steve Hamner; Susan C. Broadaway; Veer Bhadra Mishra; Anshuman Tripathi; Rajesh Kumar Mishra; Elinor Pulcini; Barry H. Pyle; Timothy E. Ford
Escherichia coli serotype O157:H7 was detected among bacteria collected from the Ganges River. O157:H7 isolates tested positive for stx1, stx2, and eae gene sequences. Identification of potentially pathogenic isolates from extensively used source water indicates that O157:H7 may be a significant but as yet underacknowledged public health concern in India. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
The role of water use patterns and sewage pollution in incidence of water-borne/enteric diseases along the Ganges River in Varanasi, India
(2006) Steve Hamner; Anshuman Tripathi; Rajesh Kumar Mishra; Nik Bouskill; Susan C. Broadaway; Barry H. Pyle; Timothy E. Ford
In Varanasi, India, an estimated 200 million liters daily or more of untreated human sewage is discharged into the Ganges River. River water monitoring over the past 12 years has demonstrated faecal coliform counts up to 108 MPN (most probable number) per 100 ml and biological oxygen demand levels averaging over 40 mg/l in the most polluted part of the river in Varanasi. A questionnaire-based survey was used to estimate water-borne and enteric disease incidence and study river use among resident users of the Ganges River in Varanasi. The overall rate of water-borne/enteric disease incidence, including acute gastrointestinal disease, cholera, dysentery, hepatitis-A, and typhoid, was estimated to be about 66% during the one-year period prior to the survey. Logistic regression analysis revealed significant associations between water-borne/enteric disease occurrence and the use of the river for bathing, laundry, washing eating utensils, and brushing teeth. Thirty-three cases of cholera were identified among families exposed to washing clothing or bathing in the Ganges while no cholera cases occurred in unexposed families. Other exposure factors such as lack of sewerage and toilets at residence, children defecating outdoors, poor sanitation, low income and low education levels also showed significant associations with enteric disease outcome. This study provides an estimate of water-borne/enteric disease incidence and identifies possible risk factors for residents who live by and use the Ganges River in Varanasi. © 2006 Taylor & Francis.
Variations in the plasticity of functional traits indicate the differential impacts of abiotic and biotic factors on the structure and growth of trees in tropical dry forest fragments
(Frontiers Media SA, 2023) Ravi Kant Chaturvedi; Santosh Kumar Pandey; Anshuman Tripathi; Laxmi Goparaju; Akhilesh Singh Raghubanshi; J.S. Singh
Abiotic and biotic factors have considerable impact on the plasticity of plant functional traits, which influences forest structure and productivity; however, their inter-relationships have not been quantified for fragmented tropical dry forest (TDF) ecosystems. We asked the following questions: (1) what are the variations in the plasticity of functional traits due to soil moisture availability in TDF fragments? (2) what are the roles of soil nutrients and forest disturbances in influencing variations in the plasticity of functional traits in the TDF fragments? and (3) how do the variations in the plasticity of functional traits influence the structure and productivity of TDF fragments? Based on linear mixed-effects results, we observed significant variations among tree species for soil moisture content (SMC) under the canopy and selected functional traits across forest fragments. We categorized tree species across fragments by principal component analysis (PCA) and hierarchical clustering on principal components (HCPC) analyses into three functional types, viz., low wood density high deciduous (LWHD), high wood density medium deciduous (HWMD), and high wood density low deciduous (HWLD). Assemblage of functional traits suggested that the LWHD functional type exhibits a drought-avoiding strategy, whereas HWMD and HWLD adopt a drought-tolerant strategy. Our study showed that the variations in functional trait plasticity and the structural attributes of trees in the three functional types exhibit contrasting affinity with SMC, soil nutrients, and disturbances, although the LWHD functional type was comparatively more influenced by soil resources and disturbances compared to HWMD and HWLD along the declining SMC and edge distance gradients. Plasticity in functional traits for the LWHD functional type exhibited greater variations in traits associated with the conservation of water and resources, whereas for HWMD and HWLD, the traits exhibiting greater plasticity were linked with higher productivity and water transport. The cumulative influence of SMC, disturbances, and functional trait variations was also visible in the relative abundance of functional types in large and small sized fragments. Our analysis further revealed the critical differences in the responses of functional trait plasticity of the coexisting tree species in TDF, which suggests that important deciduous endemic species with drought-avoiding strategies might be prone to strategic exclusion under expected rises in anthropogenic disturbances, habitat fragmentation, and resource limitations. Copyright © 2024 Chaturvedi, Pandey, Tripathi, Goparaju, Raghubanshi and Singh.