Evaluating the ligninolytic potential of soil bacteria isolated from Western Ghats, India

Wind direction dominates the transport and deposition of fire proxies in tropical dry forest landscapes of the Western Ghats

Do human-modified landscapes influence composition and diversity of foraging guilds in mixed-species bird flocks in Wayanad, southern Western Ghats, India?

Background: Numerous degenerative diseases are brought on by inflammation and oxidative stress. Metabolites from plants contain anti-inflammatory and antioxidant properties. Indigenous and understudied, Thottea sivarajanii is a significant ethnobotanical herb. It is native to the Western Ghats and belongs to the Aristolochiaceae family. Objectives: The current study investigated the antioxidant and anti-inflammatory properties of T. sivarajanii leaf methanol extract (TSL) and the insights provided by phytochemical analysis. Methods: The HRLC–MS/MS (Q-TOF) study is used for the phytochemical analysis. The antioxidant efficacy is evaluated in terms of DPPH and ABTS radical scavenging, and reducing power (FRAP assay). In vitro anti-inflammatory efficacy was evaluated on RAW 264.7 cells challenged with lipopolysaccharide (LPS). Result: The HRLC–MS/MS (Q-TOF) study indicated the presence of bioactive molecules such as ursolic acid, Daidzein 4’,7-diglucoside, Calophyllin B, and Berbamine, etc. The results showed in vitro antioxidant capacity in DPPH, and ABTS, radical scavenging, and ferric-reducing activities with respective IC50 and EC50 values of 184.5 ± 2.4, 24.15 ± 0.13, and 4.94 ± 0.32 µg/mL, respectively. LPS significantly stimulated the production of IL-1β, IL-6, and TNF-α in RAW 264.7 cells (p < 0.001). Treatment with TSL reduced levels of IL-1β and IL-6 from 776.1 ± 11.4 and 1678.1 ± 12.4 to 195.4 ± 9.2 and 465.4 ± 11.8 pg/mg protein. It also reduced NO levels from 91.4 ± 1.3 to 30.8 ± 1.7 µM/mg protein while reducing TNF-α levels from 2041.2 ± 15.1 to 1037.5 ± 15.4 pg/mg protein. Conclusions: This work contributes to the growing evidence supporting the pharmacological importance of the underexplored Thottea sivarajanii, highlighting this species as a promising candidate for natural antioxidant and anti-inflammatory agents.

ABSTRACT Clouds significantly influence the Earth’s radiation budget and hydrological cycle, playing a key role in weather and climate. Different cloud types have unique radiative properties and often co-occur, complicating our understanding of weather dynamics. In the present study, we studied the radiative heating due to various cloud types over the Indian Summer Monsoon (ISM) region using observations from the CloudSat and CALIPSO satellite. The vertical distribution of radiative heating peaks at different altitudes for different cloud types. We quantified the cloud radiative heating rates for Cirrus (Ci), Stratocumulus (Sc), Nimbostratus (Ns), Cumulus (Cu), Altostratus (As), Altocumulus (Ac), and Deep Convective (DC) clouds. We found that the heating rates for longwave radiation peaked at 8 to 10 km in Ns and DC clouds, with maximum net heating of about 2 K/day at higher altitudes. Radiative heating rates peaked at 15 km in Central India and the Bay of Bengal, while they peaked at 12 to 13 km over the Western Ghats and Arabian Sea, and around 10 km in the Indo-Gangetic Plain. These differences are primarily attributed to the vertical development of DC clouds in these regions and are associated with varying background dynamics. Varying radiative heating at different altitudes affects the temperature gradient, alters atmospheric stability, and influences mesoscale circulation. The frequent occurrence of multi-layer clouds, associated with higher heating rates than single-layer clouds, was observed over the ISM region. Multi-layer clouds exhibited higher heating rates than single-layer clouds, particularly in Ci-Ac and Ci-Ac-Sc formations. This study analyzes the mean net cloud radiative heating due to various cloud types over the ISM for single-layer and multi-layer clouds. Our results can be applied to evaluate climate models for better understanding regional heterogeneity and provide new insights into the role of clouds in modifying the lower atmosphere’s thermal structure through radiative heating.

Ecosystems worldwide are being influenced by climate change in complex ways, leading to profound impacts on biodiversity. While these shifts may constrain the adaptive capacity of some species, they may simultaneously promote the expansion of others, including certain rodents. The Funambulus pennantii (five-striped northern palm squirrel) and Funambulus palmarum (three-striped palm squirrel) demonstrate exceptional adaptability across diverse habitats from rural plantations to densely populated urban areas. Their close association with humans ranges from causing crop damage to becoming urban nuisances, leading to their broad classification as agricultural pests. Hence, this study utilizes ensemble species distribution models to identify the climatic niches of these two species and delineate overlapping suitable habitats within agricultural zones in current and different future climate scenarios. The ensemble model identified 215,748 km2 of suitable habitat for F. pennantii and 39,578 km2 for F. palmarum under current climatic conditions in India. The future projections indicate habitat increases of about 20.6% for F. pennantii and 48.1% for F. palmarum. The agricultural overlap is also projected to rise by up to 45% and 48%, respectively, compared with present overlaps of 215,595 km2 and 39,073 km2. The most substantial expansions are projected in the Gangetic Plains, Central Highlands, and parts of the Western and Eastern Ghats and Deccan Plateau. These findings suggest that both species possess high resilience to environmental change and may pose increasing risks to agriculture in a warming climate. The study underscores the need for proactive, ecologically sustainable management strategies to mitigate potential human–squirrel interactions and agricultural losses, offering a foundation for targeted regional interventions.

Soil microbial diversity represents one of the most complex and essential components of terrestrial ecosystems, playing crucial roles in nutrient cycling, organic matter decomposition, and ecosystem stability. This comprehensive review examines recent advances in understanding soil microbial communities and their functional significance in ecosystem processes. Through analysis of contemporary molecular techniques including high-throughput sequencing, metagenomics, and metabolomics, we explore how technological innovations have revolutionized our understanding of microbial diversity patterns across various soil types and environmental gradients. The review synthesizes findings on key microbial groups including bacteria, archaea, fungi, and protists, examining their interactions and contributions to critical ecosystem services such as carbon sequestration, nitrogen fixation, and phosphorus mobilization. We discuss the impacts of anthropogenic activities, climate change, and land-use practices on soil microbial communities and their functional resilience. Special attention is given to the Indian subcontinent's diverse soil ecosystems, from the Indo-Gangetic plains to the Western Ghats, highlighting region-specific microbial adaptations and their agricultural implications. The review identifies current knowledge gaps and proposes future research directions, emphasizing the need for integrated approaches combining traditional and cutting-edge methodologies. Understanding soil microbial diversity is paramount for developing sustainable land management strategies, enhancing agricultural productivity, and mitigating climate change impacts through improved soil health management.

Lagenandra pradeepiana, a new species of Araceae from Kerala, India is described and illustrated in photographs. It is closely allied to L. ovata, which shares characteristics such as scarce fibrous roots and a semi-circular petiole. However, it differs primarily in having a significantly long peduncle, distinct colour zones in the spathe, and a spadix with a well-developed, tapering appendix. The species also resembles L. toxicaria var. barnesii in its oblique leaf base and tapering spadix appendage but differs in having leaves with scalloped margins, a longer peduncle, and more ovules without placental hairs. A detailed morphological comparison with allied taxa and information on its distribution and conservation status are provided. The species has been classified as Critically Endangered according to the IUCN Red List, specifically under Criterion CR B1ab (ii, iii, iv, v) +2ab (ii, iii, iv, v).

The Cholanaikans, one of Kerala’s most secluded and diminutive scheduled tribes, inhabit the dense forests of the Nilambur Valley in Malappuram District. Known as ‘cave dwellers’ due to their traditional rock-shelter homes called “Alais”, they sustain a hunter-gatherer lifestyle deeply intertwined with the forest ecology. This study documents their history, social structure, subsistence patterns, cultural practices, and traditional medicinal knowledge, derived from field exploration and interviews with tribal elders. Their socio-political organization revolves around territorial kin groups led by hereditary chieftains, with a strict patrilineal and patrilocal family system. The Cholanaikans maintain distinctive ritual practices related to marriage, birth, and death, underscoring their unique cultural heritage. Despite increasing external influences, they continue to preserve their rich ethnobotanical knowledge and forest-based subsistence, marking them as vital guardians of the Southern Western Ghats' living heritage.

ABSTRACT Convective storms CS frequently occur in Kerala during the premonsoon period, particularly in the month of May, presenting numerous hazards such as intense rainfall, lightning, and wind gusts, which cause significant damage to life, property, infrastructure, livelihoods, and various societal sectors. The current study explored the triple-threat nature of convective storms in the month of May over Kerala. This study revealed that CS is accompanied by excessive rainfall in northern regions and exhibits greater intensity than in southern areas. The coastal areas are emerging as the most vulnerable to extreme rainfall hotspots, exhibiting increased intensity from Ernakulam to Kasargod. The topographical characteristics of these regions, encompassing the Kottayam–Idukki border and the eastern sections of Malapuram, also influence rainfall intensity. The districts of Kottayam, Ernakulam, Idukki, and Pathanamthitta are particularly vulnerable to lightning strikes. Over Kerala, CS clouds with brightness temperatures below 240 K and gust winds above 30 kt are particularly hazardous since they pose the triple threat of heavy rainfall, lightning, and strong winds. The study revealed that CS occurs more frequently in regions adjacent to western Ghats WG with northern Kerala exhibiting the highest intensity and southern Kerala displaying a greater frequency of CS.

An experimental study was conducted to analyze the impact of fertigation with nitrogen (N), phosphorus (P) and potassium (K) fertilizers on soil nutrients and microbial communities in a cocoa (Theobroma cacao L.) plantation in the Western Ghats of Pollachi. The experiment followed a randomized block design with seven Fertigation treatments. Treatments included soil application (control) and twice-weekly applications of conventional fertilizers at 75 %, 100 % and 125 % of the recommended doses, along with equivalent water-soluble fertilizers (WSF). The experiment was replicated three times. With 125 % recommended dose of fertilizer (RDF) applied as a water-soluble fertilizer by fertigation, the soil provided the highest levels of N, P and K throughout the year. Applying water-soluble fertilizer and conventional fertilizers through the drip system at lower levels (75 %) resulted in much higher values of soil microbial activity. Plants receiving 100 % RDF as water-soluble fertilizer through drip fertigation recorded the highest pod counts (31.74 and 25.97 in the first year; 32.41 and 26.18 in the second year) and maximum dry bean yields (1931.69 and 1501.84 g per tree) during the respective seasons. Compared with ring basin irrigation, drip irrigation reduced N, P and K fertilizers requirements for cocoa by up to 25 % of the recommended dose.

Abstract Chytridiomycosis is caused by Batrachochytrium dendrobatidis ( Bd ) and contributes significantly to amphibian declines globally. It has affected more than 500 amphibian species on five continents. In South Asia, the Western Ghats is an amphibian biodiversity hotspot; however, the population status of anurans and their burden of chytridiomycosis are not well understood. Our aim was to understand pathogen prevalence, load, and its persistence in a stream anuran community in the Western Ghats. We carried out a capture–mark–recapture (CMR) program in five ephemeral streams of the Tillari Conservation Reserve (TCR), Western Ghats, India, from 2018 to 2020 during the early (wet) and late (dry) recovery periods. We used quantitative polymerase chain reaction (qPCR) to assign disease states: no (N), low (L), and high (H) level to every anuran, based on the Bd loads detected. We constructed population models using CMR data from skittering frogs, with Program MARK and estimated transition probability, apparent survival probability, and capture probability in each disease state. We found that the overall Bd prevalence was 74.6% in the community with an average infection load of 49–700 zoospores/swab. Many anurans cleared infections between early (wet) and late (dry) recovery periods, while some maintained high infection loads. In skittering frogs, the infection states did not influence capture probabilities and apparent survival probabilities. The transition probability between infection states was random and transitions from any disease state to low were more probable than transitions from any disease state to high or no disease states. The maintenance of a substantial burden of Bd in the anuran community with no apparent impact on their survival or capture probabilities suggests an effective pathogen transmission mechanism. As anurans continue to show a declining trend in the Asian tropics, investigation of the impacts of sub‐clinical Bd infections in anurans needs impetus.

Kyasanur Forest disease: an emerging arboviral threat.

Physical characterization and hygroscopicity of ambient aerosols and their role in CCN closure over Western Ghats, India

Seasonal dynamics of suspended sediment transport and controlling factors from monthly water-sediment hysteresis relationship in the tropical rivers of the Western Ghat

First global report of pathogens causing anthracnose in threatened seedlings of Hopea erosa and Cynometra beddomei: A molecular and pathological study from the Southern Western Ghats, India

This study investigates health risks associated with radon (222Rn) in groundwater from Vamanapuram River Basin (VRB), Southern Western Ghats, Kerala, India. The annual effective dose (AED) attributable to 222Rn in groundwater (n = 40) was quantified for different age groups - infants, children and adults, yielding ranges of 1.95-243.74µSv a-1, 1.74-217.01µSv a-1 and 1.78-221.87µSv a-1 respectively. The mean AED is found to be within the recommended limit proposed by WHO (100µSv a-1). The analysis of Health Risk Factor (HRF) indicates that infants exhibit the highest vulnerability to radiation exposure. The estimated excess lifetime cancer risk (ELCR), ranged from 0.01 to 0.78 × 10-3, reveals that 17.5% of groundwater samples surpass the threshold limit set by the USEPA. As no prior data on 222Rn related dose exposure exists for the study area, this investigation constitutes a novel contribution, offering essential baseline information for future radiological assessments. By integrating both deterministic and probabilistic methods for dose estimation, this study not only enhances the reliability of risk evaluation but also emphasizes the importance of establishing regulatory frameworks to safeguard groundwater resources and public health.

Saraca asoca, commonly known as ‘Asoka’ or 'Ashoka,' holds significant medicinal value in India. However, due to the escalating demand in the herbal market, the species has suffered a severe decline in naturally occurring populations, primarily caused by the unregulated extraction of its wood. Particularly within the Western Ghats, a global biodiversity hotspot, the species faces critically low population sizes. The study addresses a highly relevant conservation concern, focusing on an ecologically and culturally important species within a global biodiversity hotspot. Twelve populations in the Western Ghats were analyzed using five highly polymorphic and newly developed microsatellite markers. The results revealed a total of 78 alleles, with an average of 15.6 alleles per locus across the twelve populations. The AMOVA analysis indicated that the species exhibits higher diversity within populations (91.38% variation) compared to the variation observed among populations (8.62%). Further analysis employing Bayesian clustering identified six distinct genetic clusters within Saraca asoca. Based on these genetic findings, strategies for the development of an in-situ conservation plan for the species have been formulated. Overall, this study sheds light on the genetic characteristics of Saraca asoca populations in the Western Ghats and provides valuable insights for the implementation of effective conservation measures.

The gut microbiome of honey bees plays a crucial role in regulating key physiological traits and metabolic processes, including digestion, detoxification, nutrient assimilation, development and immunity. However, information on the gut bacterial diversity of Apis cerana indica bee populations in India remains limited. This study aims to address this critical knowledge gap in Western Ghats, India with outcomes that may provide valuable insights for improving beekeeping practices in the region. To fill this gap, we investigated and characterized the gut bacteriome of A. cerana indica collected from two ecologically distinct regions within the Western Ghats. We employed a combination of next-generation sequencing (NGS) using the Oxford Nanopore platform and traditional culture-based methods targeting the 16S rRNA gene to analyze the microbial communities. Our results revealed that the gut bacterial communities of foraging A. cerana indica bees from both locations displayed unique and overlapping microbiome profiles. A total of 225 bacterial species across 30 bacterial orders were identified via 16S rRNA amplicon sequencing, with 92 species shared between the two sites. Prominent symbiotic bacterial groups included Gammaproteobacteria, Betaproteobacteria, Flavobacteria, Actinobacteria, Firmicutes, Proteobacteria, and Actinomycetota. Notably, core bee-associated symbionts exhibited a negative correlation with pathogenic bacterial taxa. These findings offer valuable insights into the ecological and functional roles of the gut microbiome in A. cerana indica, a native honeybee species of the Western Ghats. The presence of shared bacterial species across regions suggests their potential significance in formulating conservation strategies for indigenous bee populations.

The importance of integrating climate resilience into conservation efforts to safeguard the Western Ghats, one of the hottest hotspots in the world, is underscored by our findings. The research was designed to provide an integrated approach to help preserve the ecological productivity in a biodiversity sensitive area. The study investigates the dynamics of terrestrial productivity, examining its trends over time (2001–2023) and identifying the various factors that influence it, a topic that has been understudied in this biodiversity hotspot. In 2019, Net Primary Productivity (NPP) results experienced significant declines across all land cover types, with the decline starting in 2015 when forest NPP dropped by 0.24 and cropland by 0.1 kg C m^{-2} year^{-1}. The NPP steadily recovered the following year, especially in the croplands. The factor detector q value indicated the degree of influence of each factor as vegetation parameters (58.96%), climatic indicators (21.97%), anthropogenic factor (17.39%), and topographic condition (1.68%). Results from the innovative approach to assess spatial heterogeneity emphasize the influence of the combinations of Land Use Land Cover (LULC) with Fraction of Photosynthetically Active Radiation (FPAR), Leaf Area Index (LAI), Normalized Difference Vegetation Index (NDVI), Land Surface Temperature (LST), and Enhanced Vegetation Index (EVI), followed by LST interacting with FPAR, and NDVI with LAI, had the greatest impact on NPP. The study employs multiple regression to evaluate the effects of variables, the Mann–Kendall method for trend analysis, and Geo-detector for spatial variation.