Western Ghats Biodiversity Hotspot Research Articles

Assessment of orchid diversity in the sacred groves of Kodagu, India’s Central Western Ghats Biodiversity Hotspot: implications for bio-cultural diversity management

Assessment of orchid diversity in the sacred groves of Kodagu, India’s Central Western Ghats Biodiversity Hotspot: implications for bio-cultural diversity management

A trait‐based understanding of the vulnerability of a Paleotropical moth community to predation by a sympatric bat with flexible foraging strategies

Abstract Prey vulnerability across seasons can be predicted by measuring their morphological traits and availability. Although conventional prey–predator dynamics focus on pairs of prey and predator species, the trait‐based approach allows us to draw inferences at the scale of the entire assemblage. Here, we coupled measurable prey traits with their availability in the study area, to identify the vulnerability of a diverse moth assemblage to predation by the lesser false vampire bat (Megaderma spasma) Chiroptera: Megadermatidae, Linneaus 1758, a bat with flexible foraging strategies, in the Western Ghats biodiversity hotspot of India. We analysed the discarded prey remains from several roosts, collected over 3 years, for seasonal patterns in the diet and selective hunting. Through light‐trapping, we collected moth specimens in different seasons and measured the morphological traits likely to affect their vulnerability to predation, such as body size and evasive flight capability. Our results showed that consumed moth prey diversity varies seasonally, with moths belonging to the Hepialidae family being preferred in the wet season. We found that the larger moth species with lower evasive capabilities are more vulnerable to predation. Sphingid and Hepialid moths, among the most abundant in the diet, have the lowest manoeuvrability and the maximum body size, respectively. By assessing vulnerability at the prey assemblage level, our study sets the stage for future research on moth–bat interactions from the diverse and less‐explored Paleotropical communities. In addition, the study reiterates the usefulness of trait‐based approaches to understanding prey–predator dynamics.

Demographics and reproductive characteristics of threatened Malabar pufferfish (Carinotetraodon travancoricus) from Western Ghats hotspot, India

Context Carinotetraodon travancoricus is a threatened ornamental aquarium fish endemic to Western Ghats (WG) biodiversity hotspot of India and indiscriminate collection of this species resulted in a severe population decline. Aims To understand the impacts of wild collection of C. travancoricus for aquarium-fish trade, information on their population status and reproductive characteristics is required. Methods Specimens for the present study were collected from the Chalakudy River of WG and growth, mortality, exploitation and reproductive characteristics of C. travancoricus were investigated. Key results The natural mortality of the species was higher than the fishing mortality. The peak spawning period of the species was from May to September. Length at first maturity (L50) for males and females was estimated to be 18.4 and 18.1 mm respectively. Conclusions The stock of C. travancoricus in the Chalakudy River may be in near full exploitation under current harvesting strategy. The lower value of length of first capture than size at first maturity indicated that C. travancoricus is likely to be captured before it matures and breeds, subsequently contributing to declining recruitment. Implications A combination of different strategies (closed fishing seasons, mesh-size regulation and no-fishing areas) will improve sustainable management and conservation of species.

Diversifying in the mountains: spatiotemporal diversification of frogs in the Western Ghats biodiversity hotspot.

Mountain ranges are hotspots of biodiversity. However, the mechanisms that generate biodiversity patterns in different mountainous regions and taxa are not apparent. The Western Ghats (WG) escarpment in India is a globally recognized biodiversity hotspot with high species richness and endemism. Most studies have either invoked paleoclimatic conditions or climatic stability in the southern WG refugium to explain this high diversity and endemism. However, the factors driving macroevolutionary change remain unexplored for most taxa. Here, we generated the most comprehensive dated phylogeny to date for ranoid frogs in the WG and tested the role of paleoclimatic events or climatic stability in influencing frog diversification. We found that the diversity of different ranoid frog clades in the WG either accumulated at a constant rate through time or underwent a decrease in speciation rates around 3-2.5 Ma during the Pleistocene glaciation cycles. We also find no significant difference in diversification rate estimates across elevational gradients and the three broad biogeographic zones in the WG (northern, central, and southern WG). However, time-for-speciation explained regional species richness within clades, wherein older lineages have more extant species diversity. Overall, we find that global paleoclimatic events have had little impact on WG frog diversification throughout most of its early history until the Quaternary and that the WG may have been climatically stable allowing lineages to accumulate and persist over evolutionary time.

A new species of silverline butterfly, Cigaritis Donzel, 1847 (Lepidoptera: Lycaenidae), from the Western Ghats biodiversity hotspot, India.

A new species, Cigaritis conjuncta sp. nov. (Lepidoptera: Lycaenidae), is described based on five male and four female specimens from Honey Valley, Kodagu District, Karnataka, which is part of the Western Ghats biodiversity hotspot, India. Cigaritis conjuncta sp. nov. is distinguished from all other congeners in India and Sri Lanka based on the following combination of diagnostic characters in the male: (a) dorsal forewing outer half, costal margin and nearly upper half of the cell black without orange markings, the remaining wing shining deep blue, (b) dorsal hindwing tornus pale orange-red with two black spots, (c) ventral forewing bands at end of discal cell conjoined, and (e) ventral hindwing subbasal and discal bands composed of spots that are not separated but conjoined to form broad bands that have irregular outlines, leaving only a narrow background colour in between. Female is similar on the ventral side, but entirely dark brown above. Male and female genitalia are dissected and figured for two paratypes of each sex, and natural history notes on the species are provided.

Three new additions to the earthworm (Clitellata: Megadrili) fauna of Kerala state from the Western Ghats biodiversity hotspot, south-western India

Three new additions to the earthworm (Clitellata: Megadrili) fauna of Kerala state from the Western Ghats biodiversity hotspot, south-western India

Complete mitogenome of Lepidopygopsis typus, an evolutionarily-distinct, endangered cyprinid fish from the Western Ghats Biodiversity Hotspot: Phylogenetic relationships and implications for conservation

The mitogenome of Lepidopygopsis typus, an evolutionarily distinct, endangered, cyprinid fish from the Western Ghats Biodiversity Hotspot, was characterized. Total length of the mitogenome was 16,729 bp, and comprised of 13 protein coding, 22 tRNA and two rRNA genes. Thirteen protein coding genes contributed a total nucleotide length of 11,408 bp, which coded for a total of 3794 amino acids and accounting for 68.2 % of the mitogenome. A maximum likelihood phylogenetic tree based on mitogenomes of members of cyprinid subfamilies Torinae, Schizothoracinae and Schizopygopsinae, recovered L. typus in a well-resolved clade of Torinae with members of the Western Ghats endemic genus Hypselobarbus as sister taxa. Selection analysis suggested that the branch of L. typus and Hypselobarbus spp. was under intensified selection with reference to other members of Torinae. There were 19 codons under diversifying selection in L. typus, which could be the result of positive selection for adapting to high-altitude, upstream tributaries of Periyar River, where the species has a restricted distribution. With respect to Hypselobarbus spp., L. typus was under relaxed selection with about 68 % of codons experiencing neutral evolution. Restricted distribution, low population size and relaxation in selection can likely trigger extinction in L. typus, and therefore urgent conservation and monitoring plans are required to secure the future of this evolutionary distinct, and globally endangered species.

Civet latrines in three habitats of a coffee dominated landscape of the Western Ghats biodiversity hotspot

Civets are frugivorous animals in the Order Carnivora. They are relatively less shy towards people and anthropogenic habitats. It has been reported that the civets’ preference of defecating in open sites enable them to be important seed dispersers of degraded forests and urban ecosystems of Asia and Africa. We surveyed for scats of palm civet (Paradoxurus hermaphroditus) in forest fragments of sacred groves (closed), coffee plantations (partly closed) and home gardens (relatively open) during the fruit ripening period of Coffee and Caryota urens – the two preferred fruits of civet – to report the microhabitat characteristics and seed composition of civet latrines. The microhabitat of each scat position – whether on or off the ground and the shade type – was recorded. The scat analysis showed the presence of 4234 seeds belonging to coffee (90.2%), C. urens (9.7%), and an anonymous Rubiacea species (0.10%) in a total of 105 scats collected from coffee plantations (55), home gardens (5), and sacred groves (45). The number of scats sampled from the three habitats was different, but not the number of seeds per scat. Overall, the number of scats increased with the canopy cover, but the trend was different for different habitats. In home garden and coffee plantations, it decreased, but in sacred groves, it increased with the canopy cover. The number of scats sampled above the ground – on tree branches, logs and built-up structures– was more than that was on the ground. The findings contradict the general belief that the civet latrines occur more in open areas than the shaded areas. Because the civet latrines are seen more above ground than on the ground, their efficiency as seed dispersal agent may be examined critically in different contexts.

Overview of the ant genus Vollenhovia (Hymenoptera, Formicidae) in India and Sri Lanka, with an illustrated key and the description of a new species

The ant genus Vollenhovia Mayr, 1865 (Myrmicinae, Crematogastrini) mostly occurs in the Australasian and Oriental regions. We revised its diversity in India and Sri Lanka based on qualitative and quantitative morphology, recognizing eleven taxa, including a new species which is described herewith: V. escherichi Forel, 1911, V. gastropunctata Bharti & Kumar, 2013, V. karimalaensis Dhadwal et al., 2023, V. keralensis Kripakaran & Sadasivan, 2022, V. mawrapensis Dhadwal et al., 2023, V. oblonga laevithorax Emery, 1889, V. penetrans (Smith, 1857), V. pfeifferi Bharti et al., 2023, V. taylori Rilta et al., 2023, V. terayamai Rilta et al., 2023, and V. yasmeenae sp. nov. The subspecies status of V. oblonga laevithorax and its relationship with V. penetrans, whose type series does not contain workers, still requires to be assessed in the context of a broader revision including the whole Oriental region. The known distribution of the genus in the Indian subcontinent appears to be fragmentary, still requiring extensive sampling efforts. Four species are from the Western Ghats biodiversity hotspot in the southern Indian state of Kerala, one is endemic to the biogeographically related Sri Lanka, three are known from Eastern India near the border with Bangladesh, two are reported from the Andaman and Nicobar Islands, and one is restricted to the Himachal Pradesh in northern India. A comprehensive key of the known Vollenhovia species from India and Sri Lanka is provided.

Local‐scale abiotic factors influence the organization of rock pool arthropod communities in a biodiversity hotspot

AbstractDetermining drivers of community assembly is central to ecology, and patchily distributed temporary habitats offer an ideal system to study the roles of ecological and evolutionary processes in structuring communities over different spatial scales. We studied functionally diverse arthropod communities in 32 freshwater rock pools on 3 plateaus in the Western Ghats biodiversity hotspot, sampling them throughout their hydroperiod (2–7 months). Using the Hierarchical Modeling of Species Communities approach, we assessed (a) the influence of local (water chemistry, habitat complexity at the pool level) and regional (seasonality in temperature and precipitation at the plateau level) scale abiotic covariates in shaping species' occurrence, (b) the influence of species traits (dispersal/reproductive mode, body size, feeding guild) and phylogenetic relationships on species response to abiotic covariates, and (c) the strength of biotic filtering in the communities. Environmental filtering was the dominant driver of community structure, where the pool‐level covariates (mainly hydroperiod and water chemistry), explained greater variation (56.3%) in species occurrences rather than plateau‐level covariates, that is, climatic seasonality (33.7%). Spatial factors explained only 11% of the variation in species occurrences. The selected traits explained 22% variation in species' responses, with body size responding to the abiotic covariates at both spatial scales. Closely related taxa exhibited shared responses to the abiotic covariates. Only a few residual associations were observed, all among passive dispersers, indicating a low contribution of biotic filtering to community structure. Our results highlight the importance of habitat‐level factors and the key role of evolutionary processes in shaping diversity in this vulnerable landscape characterized by its seasonality.

Environmental drivers and spatial prediction of forest fires in the Western Ghats biodiversity hotspot, India: An ensemble machine learning approach

In ecologically sensitive areas like the Western Ghats, fire is largely considered to be the most significant management concern. Therefore, identifying and predicting the fire susceptible areas is crucial for managing protected area networks. In this study, we investigated the factors affecting forest fires and modelled the fire susceptibility in a human-dominated landscape in the central Western Ghats, India, by employing remote sensing, geographic information systems and machine learning techniques. We used six machine learning models (MLMs), including artificial neural network, random forest, generalized linear model, maximum entropy, multivariate adaptive regression splines, gradient boosting machine and the ensemble model, to relate the occurrence data of fires to 14 predictor variables categorized as climate, topography, vegetation, and anthropogenic disturbances to generate fire susceptibility maps. The area under the receiver operating characteristic (AUC-ROC), true skill statistic (TSS) curves, accuracy and continuous Boyce index (CBI) were used to assess the model's accuracy. We found that all models achieved acceptable performance while validating the independent test data. However, ensemble model had the best overall performance with an AUC-ROC = 0.93; TSS = 0.72; ACCURACY = 0.89; and CBI = 0.95. The land-use and land-cover, and the distance to the agricultural fields and settlements were the key determinants of fire occurrences in the study area based on the ensemble model. The results showed that the landscape has a high to very high fire risk for about 26.5% of the total area. Forest fires have mostly occurred in the northeastern regions of the landscape, which are dominated by deciduous forests and plantations, whereas western regions are less susceptible to fires. Finally, we developed an ensemble-based fire susceptibility map with a resolution of 10 m that may be used as a tool for the prevention of forest fires. Further, it aids the relevant authorities in mitigating the disastrous effects and safeguarding the environment. The results demonstrated that ensemble-based MLMs can be employed effectively for fire prediction in other regions.

Soil Carbon Dynamics Under Different Ecosystems of Ooty Region in the Western Ghats Biodiversity Hotspot of India

Soil Carbon Dynamics Under Different Ecosystems of Ooty Region in the Western Ghats Biodiversity Hotspot of India

Climate and forest loss interactively restructure trait composition across a human-modified landscape.

Traits determine species response to climate conditions and the match between phenotypes and climate mediates spatial variation in species composition.These trait-climate linkages can be disrupted in human-modified landscapes. Human land use creates forest fragments where dispersal limitation or edge effects exclude species that may otherwise suit a given macroclimate. Furthermore, stressful macroclimate can limit viable trait combinations such that only a subset of values of any given trait occurs with respect to another trait, resulting in stronger trait covariance. Because forest loss can compound climatic stress, trait covariance from benign to harsher climates is expected to be stronger in fragments compared to contiguous forests. In a wet tropical forest landscape in the Western Ghats Biodiversity Hotspot of peninsular India, I compared fragments with adjacent contiguous forests for signatures of trait-mediated assembly of tree communities. Using four key plant traits-seed size, specific leaf area (SLA), wood density, and maximum height-I evaluated trait-abundance associations and trait covariance across climate, soil, and elevation gradients. In the contiguous forest, smaller-seeded, shorter, thinner-leaved species became more abundant from low to high elevations. In fragments, species with higher SLA were more abundant at sites with more seasonal climates and lower precipitation, and larger seeded species were less abundant at warmer sites. However, traits only weakly predicted abundances in both habitats. Moreover, only contiguous forests exhibited significant compositional change via traits, driven by trait syndromes varying along a composite gradient defined by elevation, water deficit, and soil C:N ratio. Site-level trait covariance revealed that warmer, wetter conditions in fragments favored taller species for given seed size, as compared to similar conditions in contiguous forests. Overall, trait syndromes and trait covariance, rather than single traits, determined the phenotypes best suited to macroclimate conditions and should inform management or restoration goals in fragments.

Identity of cavity nesting honey bees of the Indian subcontinent with description of a new species (Hymenoptera: Apidae: Apinae: Apini: Apis)

A new species of cavity nesting honey bees, Apis karinjodian n. sp., endemic to the Western Ghats biodiversity hotspot is described and illustrated. Apis indica Fabricius, 1798 status restored is resurrected from synonymy with Apis cerana Fabricius, 1793. Key to distinguish the three native cavity nesting honey bee species occurring in the Indian subcontinent viz., Apis cerana Fabricius, 1793, Apis indica Fabricius, 1798 and Apis karinjodian n. sp. is provided. Distribution map is given for the native cavity nesting Apis species of the Indian subcontinent. The morphological description of the new species is supplemented with molecular and behavioral information. Radio-Medial Index (RMI), a new measure for species discrimination in Apis, is proposed. South India is proposed as the center of origin of the European honeybee, Apis mellifera Linnaeus, 1758.

Integration of Ecology, Larval Phenotypes, and Mate-Recognition Signals with Molecular and Morphological Data Indicate Taxonomic Inflation in Nyctibatrachus (Anura: Nyctibatrachidae)

Taxonomic studies over the past decade of the endemic Night Frog genus Nyctibatrachus (originally described in 1882) from Peninsular India have more than tripled, from 11 at the turn of this century to 36 by 2017. Despite these revisionary contributions, it is still challenging for field biologists to identify night frog species reliably, due to a near-complete absence of diagnostic, discrete character states or trait values. Worse, many questionably diagnosed night frog species' status has ostensibly been “supported” by phylogenies derived from sparsely sampled gene-trees that are based on a single locus or a handful of markers—with topology and arbitrary genetic distance thresholds of 3–6% used to support new species descriptions. We sought to re-evaluate and validate the species boundaries of six currently nominated species of Nyctibatrachus of the aliciae group (N. aliciae, N. periyar, N. deveni, N. pillaii), N. vasanthi, and N. poocha clade using a comprehensive integrative taxonomic approach that integrates classical taxonomy, molecular species delimitation analysis, statistical analysis of morphological characters of adults and larvae, analyses of bioacoustics, and natural history information. Our results indicate that recent descriptions of Nyctibatrachus deveni, N. periyar, and N. pillaii represent cases of taxonomic inflation (over-splitting), because the evidence cited in support of their recognition is irreproducible, subjective, and devoid of strong statistical support. We demonstrate the need for multidimensional species delimitation approaches in the celebrated Western Ghats biodiversity hotspot paleo-endemic genus Nyctibatrachus and suspect that this concerning trend of over-splitting amphibian species based on limited data and untenable support may be applicable to other amphibian groups.

Shedding light on taxonomic chaos: Diversity and distribution of South Asian skipper frogs (Anura, Dicroglossidae, Euphlyctis)

A known haven of amphibian diversity, South Asia is also a hotspot of taxonomic confusions. Vastly distributed from Saudi Arabia to Myanmar, the dicroglossid genus Euphlyctis (“skittering” or “skipper” frogs) is a representative example. Combining phylogenetic analyses with 16S barcoding and genome size variation of 403 frogs from 136 localities, we examined genetic diversity and distributions across the whole range of Euphlyctis, with a particular focus on taxonomic and nomenclatural issues. We recovered two deeply divergent mitochondrial clades totalling ten lineages that we considered as species, and eight could be attributed valid taxonomic names and junior synonyms. The first clade (subgenus Phrynoderma) is confirmed in South India, Bangladesh and Sri Lanka, and comprises six species: E. karaavali, E. hexadactyla, E. aloysii, E. kerala and two undescribed taxa. Five are endemic to the Western Ghats biodiversity hotspot and four of them form the E. aloysii species complex. The second clade (subgenus Euphlyctis) extends across South Asia and neighbouring regions, and comprises four species: E. ehrenbergii, E. jaladhara, and two widespread lineages erroneously called “E. mudigere” and “E. kalasgramensis” in recent literature, while their oldest valid names appear to be E. cyanophlyctis and E. adolfi, respectively. Additional analyses on this pair of taxa highlighted strong phenotypic resemblance, notable intraspecific phylogeographic structure, and an extensive contact zone along the southern slopes of the Himalaya, with putative signs of genetic introgression. Through an independent investigation of the historical literature, we identified overlooked issues and misconceptions regarding the status of many old and recent taxa, and proposed solutions, such as transferring “E. ghoshi” to the genus Limnonectes. Our study illustrates how range-wide genetic barcoding can clarify taxonomic confusions, and we call to solve remaining issues prior to the description of new taxa.

Identifying priority areas for bat conservation in the Western Ghats mountain range, peninsular India

AbstractUnderstanding patterns of species distribution and diversity plays a vital role in biodiversity conservation. Such documentation is frequently lacking for bats, which are relatively little studied and often threatened. The Western Ghats biodiversity hotspot in peninsular India is a bat hotspot with 63 species. We conducted a comprehensive bat survey across the southern Western Ghats and used maximum entropy modeling (MaxEnt) to model the potential distribution of 37 bat species for which sufficient data were available. We generated binary maps of each species using species-specific thresholds to estimate suitable habitat areas and overlaid binary maps of species to produce bat hotspots (we use the term “bat hotspot” for regions that were suitable for more than 25 bat species). We also estimated species richness across protected area networks in the southern Western Ghats to assess the level of protection. The highest levels of species richness were found mainly along the southmost Periyar–Agastyamalai landscape. The study also identified a 1,683 km2 area of potential bat hotspot and 726 km2 (43%) of the total bat hotspots are currently within the protected area network. However, more than 50% of suitable habitats for each of the 37 species remain unprotected. Therefore, conservation decisions are needed to take into account both bat hotspots and species with restricted distributions.

Kumanoa periyarensis, a new species of freshwater red algae (Batrachospermales, Rhodophyta) from the Western Ghats, India

ABSTRACT We describe a new species of the freshwater red algal genus Kumanoa, K. periyarensis, from the Western Ghats, southern peninsular India, based on morphology, and rbcL and COI-5P DNA sequence data. The new species is distinguished from other species of Kumanoa by having the following combination of characters: reduced obconical or elongate-obconical whorls, carpogonial branches with compact helices bearing long, sessile ellipsoidal, elliptical, or elongate cylindrical trichogynes, monosporangia, and exerted carposporophytes. These morphological characters are shared with other species, but the combination is unique to K. periyarensis. The new species is genetically distinct and sister to K. tabagatenensis in the phylogenetic analyses. Kumanoa periyarensis was discovered in stagnant water bodies as well as shallow streams in the midlands and hilly regions of the southern part of the Western Ghats Biodiversity Hotspot.

Burmagomphus chaukulensis, a new species of dragonfly (Odonata: Anisoptera: Gomphidae) from the Western Ghats, Maharashtra, India.

We describe a new species of dragonfly, Burmagomphus chaukulensis sp. nov., based on four males and two females from Chaukul, Sindhudurg, Maharashtra located in the Western Ghats biodiversity hotspot of India. The newly described species is diagnosed from its congeners by a combination of following characters: the shape of male caudal appendages (prominent lateral spines on cerci) and the lateral thoracic markings (stripe on mesepisternum reduced and pointed anteriorly). Additionally, B. chaukulensis is unique in terms of the shape of hamuli, strongly angulated with spines at both sides. An updated identification key to Indian Burmagomphus spp. is also provided.

A natural outbreak of infectious spleen and kidney necrosis virus threatens wild pearlspot, Etroplus suratensis in Peechi Dam in the Western Ghats biodiversity hotspot, India.

A large-scale mortality of pearlspot, Etroplus suratensis was reported from Peechi Dam, an artificial tropical lake made for irrigation and drinking water supply in Kerala, India during 2018. This dam is located in the premises of Western Ghats, recognized as one of the biodiversity hotspots of the world. The objective of this study was to identify the aetiological agent of this large-scale mortality of E. suratensis by systematic diagnostic investigation and identification of the pathogen. Virus isolation was carried out on a species-specific pearlspot fin (PSF) cell line. Infected PSF cells showed cytopathic effects (CPEs) like cell shrinkage, rounding, enlargement, clustering, and subsequent detachment of cells with a high viral titre of 106⋅95 TCID50 ml-1 at 8 days post-inoculation (dpi). Histopathological examination of the fish showed the presence of numerous abnormal enlarged basophilic cells and intracytoplasmic eosinophilic inclusions in the liver. Moreover, transmission electron microscopy (TEM) analysis revealed the presence of large numbers of 125-132nm viral particles in the spleen tissues. PCR amplification and phylogenetic analysis of the major capsid protein (MCP) gene sequence confirmed that the causative agent was infectious spleen and kidney necrosis virus (ISKNV) of the genus Megalocytivirus. The experimental infection recorded 86.7 ± 2.7% mortality in the E. suratensis (body weight 11.01 ± 2.7g; body length 8.01 ± 2.23cm) injected with 1×104⋅25 TCID50 ml-1 ISKNV per fish. Our detailed investigation provided definitive diagnosis of ISKNV in the severe mass mortality event in wild E. suratensis in Peechi Dam, India, adding one more species to expanding host range of ISKNV infection. The high mortality rate of ISKNV infection in pearlspot suggests the perilous nature of this disease, particularly among the wild fish population.