Browsing by Author "Santosh Kumar Pandey"

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Changes in plant traits and productivity of two functional types across a soil water content gradient in a tropical dry forest
(John Wiley and Sons Inc, 2025) R. K. Chaturvedi; Kyle Warwick Tomlinson; Santosh Kumar Pandey; Anshuman K. Tripathi; Akhilesh Singh Raghubanshi; Jamuna Sharan Singh
Specific differences in water use strategies may critically shift the structure and productivity of plant communities in monsoonal climates. Understanding the variation in functional traits in plant species across soil water content (SWC) gradients and their contributions to community productivity can help us understand the capacity of communities to cope with water stress and predict community change under climate variability. We conducted a study in 45 fragments of tropical dry forest distributed along a gradient of SWC within a radius of 50 km, to understand site-level changes in the means and ranges of community weighted traits of all trees with DBH ≥10 cm. Species were classified into two functional types representing different water use strategies, drought avoiders and drought tolerators, based on their leaf hydraulic behaviour (isohydric versus anisohydric). We compared how water safety traits, leaf carbon capture traits and canopy extent changed across the SWC gradient in the functional groups. We also measured site-level stem counts and growth rates for the two groups over a 5-year period across the SWC gradient, which we related to SWC and functional group trait means and ranges that were calculated from measurements taken annually over 5 years. Changes in trait means across the SWC gradient were markedly different between functional types, especially for water safety and leaf carbon capture traits, with larger differences towards the drier end of the SWC. Towards drier sites, drought tolerators showed increased wood and leaf density and reduced carbon capture capacity. On the contrary, drought avoiders had an increase in leaf-level carbon capture capacity towards drier sites. Drought avoiders had greater stem numbers and above-ground biomass at drier sites, but drought tolerators increased biomass nonlinearly across the SWC gradient and were dominant at wetter sites. Synthesis. We found nonlinear shifts in community biomass that appear to be related to trait-determined constraints on drought tolerators. We observed these patterns over a small spatial scale, indicating that landscape edaphic variability substantially alters the balance between drought tolerators and drought avoiders. The patterns further suggest that future climate changes will alter the spatial distribution of drought tolerators and drought avoiders. © 2025 The Author(s). Journal of Ecology © 2025 British Ecological Society.
Effect of Environmental Conditions on Decomposition in Eight Woody Species of a Dry Tropical Forest
(Taylor and Francis Ltd., 2014) Santosh Kumar Pandey; Hema Singh; J.S. Singh
Litter decay is a significant part of carbon budget. Due to strong environmental control, the changes in the environment may drastically influence the litter decay rates. Litter decomposition of eight dry tropical woody species, viz. Shorea robusta, Buchanania lanzan, Diospyros melanoxylon, Lagerstroemia parviflora, Lannea coromandelica, Terminalia tomentosa, Holarrhena antidysenterica and Lantana camara was studied to document the effect of intra-annual changes in the environment. Litter decomposition was monitored at monthly intervals at five sites using litter bag technique over an annual cycle in a dry tropical deciduous forest of Vindhyan highland, India. Weight loss differed among species and through months, and ranged from 15.38% in L. camara at Kotwa site in January to 30.72% in T. tomentosa at Hathinala site in August. Peak weight loss occurred in August and averaged 46.2% across species and sites. Nitrogen and phosphorus mineralization rates also varied significantly from species to species. T. tomentosa having higher nitrogen content and lower C/N ratio than other species exhibited faster weight loss. Nitrogen and phosphorus contents of litter showed significant positive correlation with weight loss. C/N ratio was negatively related to decay constant, and the weight loss was positively related to the soil surface temperature as well as soil moisture content. © 2013 Societá Botanica Italiana.
Leveraging Sponge Construction for Chaos-Driven Hash Function Generation
(IGI Global, 2025) Kavita Bhatia; Santosh Kumar Pandey; Vivek Kumar Singh; Deena Nath Gupta
Using hashes for user authentication allows systems to verify identity without storing or transmitting plaintext passwords, preventing theft or leakage. At the system level, access is granted if the hash matches and denied if it doesn't. A recent development in this area is chaos-based hashing, though it's not fully matured due to its complex and flawed design principles. This work proposes a novel chaos-based hash using a sponge construction. The design includes a four-state finite automaton to build the chaos structure, with a sponge mechanism for optimal bit mixing. Statistical evaluations show that the proposed hash offers strong diffusion, confusion, collision resistance, and balanced distribution. In addition to its provable security, it extends indifferentiability from random oracles in sponge-based constructions. Moreover, compared to existing chaos-based hashes, the proposed solution achieves superior performance. © 2025 IGI Global. All rights reserved.
Securing Ports of Web Applications Against Cross Site Port Attack (XSPA) by Using a Strong Session Identifier (Session ID)
(John Wiley and Sons Inc, 2025) Kavita Bhatia; Santosh Kumar Pandey; Vivek Kumar Singh; Deena Nath Gupta
XSPA vulnerability can be attacked by stealing the cookie's information. In this case, it becomes utmost necessary to secure the information written in a cookie. A cookie contains a session ID that is a unique number generated by the server. This session ID must be a large random number so that no one can guess a valid session ID in real-time. Numerous research studies have been accomplished on the same but the area still persist gaps in view of emerging threats, such as phishing, pharming, and DoS. This paper proposes a new random-number generator that produces unique numbers in bulk. This helps the server to match the high demand of unique session IDs from different clients. The proposed generator is suitable for all types of web applications, because it requires the smallest area of only 134 Gate Equivalent on the application specific integrated circuit (ASIC) for its execution. Additionally, the proposed generator passed all tests of EPCglobal. Total time delay of digital circuit and power analysis results presented in the subsequent sections are also in the favour of proposed generator. With the implementation of this proposed technique cookies are expected to be more secure as evident from try-out results. © 2025 The Author(s). IET Cyber-Physical Systems: Theory & Applications published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.
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.