Project description:Understanding the determinants of range location and size is fundamental to our understanding of spatial patterns in species richness. Here, we aimed to test the role of 'climatic stability' in determining latitudinal trends in range size and as a consequence on species richness of tropical woody plants. Using primary data from 156 (0.06 ha) plots comprising 20,400 occurrences of more than 400 species of tropical woody plants, we built a biome-wide species database that covers the entire latitudinal extent of the wet-evergreen forests of the Western Ghats (8o to 20o N), India. We consolidated this database using secondary data from other published species inventories. We then calculated the range sizes and climatic niche width of woody plants to test the predictions of the climatic stability hypothesis and examined the relationship between range position and climatic tolerance of species. Our results show a significant latitudinal gradient in species richness and turnover where local and regional species richness increase monotonically from higher latitudes to lower latitudes of the Western Ghats. We found strong support for Rapoport's Rule with an increase in range size from lower to higher latitudes; our results are consistent with the predictions of the climatic stability hypothesis, where species at higher latitudes exhibited greater tolerance to temperature and rainfall seasonality. Contrary to earlier work, our findings suggest that Rapoport's Rule and the climatic stability hypothesis can operate over regional scales, and even at lower latitudes. We suggest that latitude associated climatic seasonality through its influence on species ranges, can influence latitudinal patterns in species turnover as well as species richness.
Project description:Many groups of organisms show greater species richness in the tropics than in the temperate zone, particularly in tropical montane regions. Forty years ago, Janzen suggested that more limited temperature seasonality in the tropics leads to greater climatic zonation and more climatic barriers to organismal dispersal along elevational gradients in the tropics relative to temperate regions. These factors could lead to differences in how species arise in tropical versus temperate regions and possibly contribute to greater tropical diversity. However, no studies have compared the relationships among climate, elevational distribution and speciation in a group inhabiting both tropical and temperate regions. Here, we compare elevational and climatic divergence among 30 sister-species pairs (14 tropical, 16 temperate) within a single family of salamanders (Plethodontidae) that reaches its greatest species richness in montane Mesoamerica. In support of Janzen's hypothesis, we find that sister species are more elevationally and climatically divergent in the tropics than in the temperate zone. This pattern seemingly reflects regional variation in the role of climate in speciation, with niche conservatism predominating in the temperate zone and niche divergence in the tropics. Our study demonstrates how latitudinal differences in elevational climatic zonation may increase opportunities for geographical isolation, speciation and the associated build-up of species diversity in the tropics relative to the temperate zone.
Project description:Kyasanur forest disease virus (KFDV) is a rapidly expanding tick-borne zoonotic virus with natural foci in the forested region of the Western Ghats of South India. The Western Ghats is one of the world's most important biodiversity hotspots and, like many such areas of high biodiversity, is under significant pressure from anthropogenic landscape change. The current study sought to quantify mammalian species richness using ensemble models of the distributions of a sample of species extant in the Western Ghats and to explore its association with KFDV outbreaks, as well as the modifying effects of deforestation on this association. Species richness was quantified as a composite of individual species' distributions, as derived from ensembles of boosted regression tree, random forest, and generalised additive models. Species richness was further adjusted for the potential biotic constraints of sympatric species. Both species richness and forest loss demonstrated strong positive associations with KFDV outbreaks, however forest loss substantially modified the association between species richness and outbreaks. High species richness was associated with increased KFDV risk but only in areas of low forest loss. In contrast, lower species richness was associated with increased KFDV risk in areas of greater forest loss. This relationship persisted when species richness was adjusted for biotic constraints at the taluk-level. In addition, the taluk-level species abundances of three monkey species (Macaca radiata, Semnopithecus hypoleucus, and Semnopithecus priam) were also associated with outbreaks. These results suggest that increased monitoring of wildlife in areas of significant habitat fragmentation may add considerably to critical knowledge gaps in KFDV epidemiology and infection ecology and should be incorporated into novel One Health surveillance development for the region. In addition, the inclusion of some primate species as sentinels of KFDV circulation into general wildlife surveillance architecture may add further value.
Project description:A new species of Vigna Savi, subgenus Ceratotropis (Piper) Verdc., Vignayadavii S.P. Gaikwad, R.D. Gore, S.D. Randive & K.U. Garad, sp. nov. is described and illustrated here. It is morphologically close to Vignadalzelliana (Kuntze) Verdc. but differs in its underground obligate cleistogamous flowers on positively geotropic branches, hairy calyx, small corolla, linear style beak and dimorphic seeds with shiny seed coat.
Project description:The importance of patch quality for amphibians is frequently overlooked in distribution models. Here we demonstrate that it is highly important for the persistence of endemic and endangered amphibians found in the threatened and fragile ecosystems that are the rocky plateaus in Western Maharashtra, India. These plateaus are ferricretes of laterite and characterise the northern section of the Western Ghats/Sri Lanka Biodiversity Hotspot, the eighth most important global hotspot and one of the three most threatened by population growth. We present statistically supported habitat associations for endangered and data-deficient Indian amphibians, demonstrating significant relationships between individual species and their microhabitats. Data were collected during early monsoon across two seasons. Twenty-one amphibian taxa were identified from 14 lateritic plateaus between 67 and 1179m above sea level. Twelve of the study taxa had significant associations with microhabitats using a stepwise analysis of the AICc subroutine (distLM, Primer-e, v7). Generalist taxa were associated with increased numbers of microhabitat types. Non-significant associations are reported for the remaining 9 taxa. Microhabitat distribution was spatially structured and driven by climate and human activity. Woody plants were associated with 44% of high-elevation taxa. Of the 8 low-elevation taxa 63% related to water bodies and 60% of those were associated with pools. Rock size and abundance were important for 33% of high elevation specialists. Three of the 4 caecilians were associated with rocks in addition to soil and stream presence. We conclude the plateaus are individualistic patches whose habitat quality is defined by their microhabitats within climatic zones.
Project description:A new species of Amomum Roxb. from Western Ghats of Kerala is illustrated and described. Amomum nilgiricum VP.Thomas & M.Sabu, sp. nov. shows similarity with Amomum masticatorium Thwaites in having long drying ligule with an acuminate apex, pubescent anther and echinate capsules, but differs in clump forming habit with non-stoloniferous rhizomes, tomentose lamina beneath, long corolla tube, obovate to rhomboid labellum with clefted apex and without any colour design, emarginate anther crest and reduced staminodes. Detailed description, illustration, photographs, conservation status, and distributional details are provided.
Project description:BackgroundVigna subg. Ceratotropis (Piper) Verdc. represents a homogenous and distinct group of species with highly specialized complex floral characters. It is most diverse in Asia. India, with 24 species, represents a secondary center of species diversity of the subgenus.New informationA new species, Vignapandeyana RD Gore, SP Gaikwad & SD Randive, is described from hill slopes of the northern Western Ghats of India. It resembles Vignayadavii Gaikwad et al. and Vignadalzelliana (Kuntze) Verdc. but differs from the latter in its dimorphic shoots (some subterranean, with cleistogamous flowers) and densely hairy pods, from the former by its curved style, flattened style beak, foveolate seed coat and absence of standard protuberance and horn-like keel pocket in cleistogamous flowers.
Project description:The frogs of genus Nyctibatrachus from the Western Ghats are endemic, with some taxa showing a narrow distribution range. Nyctibatrachus jog was known only from the type locality, Jog falls from Sharavathi river basin suggesting a restricted distribution. In this study, using DNA barcoding, we studied the distribution patterns of N. jog by sampling multiple river basins. 16S rRNA and Cytochrome b genes were used to distinguish N. jog from its congeners as well as to infer intra-species relationships. The results from the 16S rRNA gene showed 99% similarity of the collected individuals with the type specimen from Jog Falls confirming the identity of N. jog. The results indicate that N. jog has wide distribution extending its range in multiple river basins in the Western Ghats, India. This study also provides the Area of Occurrence and Extent of Occurrence of N. jog which could help in developing strategies for its conservation.
Project description:This project mainly aims to characterize the complex toxic components present in the venom of Indian cobra (Naja naja) from the Western Ghats of India. Naja naja (NN) is native to the Indian subcontinent and is also found in Pakistan, Sri Lanka, Bangladesh and Southern Nepal. It is a highly venomous snake species of genus Naja of the Elapidae family. They are seen in wide habitats like plains, dense or open forests, rocky terrains, wetlands, agricultural lands, and outskirts of villages and even in highly populated urban areas. This species has been included in the ‘Big 4’ category of venomous snake species that accounts for majority of morbidity and mortality cases in India. Therefore, exploring the venom proteome of Naja naja is decisive to develop and design new antivenom and therapeutics against its envenomation. The venom proteome of Naja naja was characterized through various orthogonal separation strategies and identification strategies. In order to achieve this the crude venom components were resolved on a 12% SDS page. Also, the venom was decomplexed through reversed-phase HPLC followed by SDS analysis. Further each of the bands were subjected to in-gel digestion using trypsin, chymotrypsin and V8 proteases. All the digested peptides were then subjected to Q-TOF LC-MS/MS analysis.
Project description:Many marine and terrestrial clades show similar latitudinal gradients in species richness, but opposite gradients in range size-on land, ranges are the smallest in the tropics, whereas in the sea, ranges are the largest in the tropics. Therefore, richness gradients in marine and terrestrial systems do not arise from a shared latitudinal arrangement of species range sizes. Comparing terrestrial birds and marine bivalves, we find that gradients in range size are concordant at the level of genera. Here, both groups show a nested pattern in which narrow-ranging genera are confined to the tropics and broad-ranging genera extend across much of the gradient. We find that (i) genus range size and its variation with latitude is closely associated with per-genus species richness and (ii) broad-ranging genera contain more species both within and outside of the tropics when compared with tropical- or temperate-only genera. Within-genus species diversification thus promotes genus expansion to novel latitudes. Despite underlying differences in the species range-size gradients, species-rich genera are more likely to produce a descendant that extends its range relative to the ancestor's range. These results unify species richness gradients with those of genera, implying that birds and bivalves share similar latitudinal dynamics in net species diversification.