Biology subjects

Tshering, S.

Publications and source records attributed to Tshering, S..

4 recordsLinked to original sources

bioRxiv2026

The fate of a dynasty: Population genomics uncovers the demographic history of Ardea insignis, one of the rarest bird species in the world

The White-bellied Heron (Ardea insignis) is one of the worlds rarest birds, with fewer than 60 known individuals remaining in the wild. Whether this extreme rarity reflects a recent anthropogenic collapse or a long history of persistently small population size has remained unknown, limiting our understanding of the species evolutionary resilience and conservation needs. Here, we present the first high-quality reference genome for A. insignis, generated using Oxford Nanopore long-read sequencing and complemented with Illumina whole-genome data. Comparative mitochondrial and nuclear phylogenomic analyses consistently recover A. insignis as the sister species of Purple Heron (A. purpurea), while revealing moderate mitonuclear discordance among deeper ardeid lineages. Genome-wide analyses demonstrate exceptionally low heterozygosity and extensive runs of homozygosity relative to the widespread and closely related Great Blue Heron (A. herodias), indicating pronounced genomic erosion and long-term inbreeding. However, the predominance of short and intermediate-length homozygous tracts, together with robust Pairwise Sequentially Markovian Coalescent (PSMC) reconstructions across alternative parameterizations, indicates that A. insignis has persisted with comparatively small effective population sizes over much of its evolutionary history rather than experiencing only a recent demographic collapse. The two sampled individuals nevertheless differ in the abundance of longer homozygous tracts, indicating that inbreeding accumulated over the past few generations has not been uniform among the surviving birds, despite their shared history of chronic rarity. Our results indicate that the White-bellied Heron represents a lineage that has survived prolonged demographic adversity and that its greatest genetic challenge may be limited adaptive potential rather than recent genomic deterioration alone. Beyond providing the first genomic resource for this critically endangered species, our study establishes an evolutionary baseline for future monitoring and highlights the importance of integrating genomic and ecological data to guide conservation strategies for species persisting at the edge of extinction.

evolutionary biology↗

bioRxiv2025

Connections in the Dark: Social-Ecological Networks as a Promising Tool for Bat Conservation and One Health

Bats provide vital ecosystem services, including pest suppression and crop pollination. However, the increasing proximity of bats and humans is a growing conservation and public health concern with negative consequences for both sides. Mitigating these consequences requires integrative approaches like network science and the emerging field of social-ecological networks (SENs), which offer powerful tools to map and analyse complex social and ecological dynamics. Here, we synthesize how network approaches have been applied to bat research and conservation. Specifically, we: (i) assess the use of both ecological and social network analyses to study bats; (ii) identify network tools well-suited for SEN-based bat research; (iii) present a case study illustrating how SEN applications in bat research can inform conservation and One Health efforts; and, lastly, (iv) discuss key challenges and opportunities in using SENs to investigate the human-bat interface. Our review unveils a rise in network-based bat research from 2006 to 2020, followed by a post-pandemic decline. Nevertheless, across the 127 studies mapped by our review, only one applied an SEN lens. Finally, we suggest how applying some underexplored SEN tools to bat research could lead to novel perspectives, aiming to promote integrated strategies for the coexistence of bats and humans.

ecology↗

bioRxiv2021

Parallel adaptations to an altitudinal gradient persist in tetraploid snowtrout (Cyprinidae: Schizothorax), despite extensive genomic exchange within adjacent Himalayan rivers

The recurrence of similar evolutionary patterns within different habitats often reflects parallel selective pressures acting upon either standing or independently occurring genetic variation to produce a convergence of phenotypes. This interpretation (i.e. parallel divergences within adjacent streams) has been hypothesized for drainage-specific morphological ecotypes observed in polyploid snowtrout (Cyprinidae: Schizothorax). However, parallel patterns of differential introgression during secondary contact is a viable alternative hypothesis. Here, we utilized ddRADseq (N=35,319 de-novo and N=10,884 transcriptome-aligned SNPs), as derived from Nepali/Bhutanese samples (N=48 each), to test these competing hypotheses. We first employed genome-wide allelic depths to derive appropriate ploidy models, then a Bayesian approach to yield genotypes statistically consistent under the inferred expectations. Elevational ecotypes were consistent in geometric-morphometric space, but with phylogenetic relationships at the drainage-level, sustaining an hypothesis of independent emergence. However, partitioned analyses of phylogeny and admixture identified subsets of loci under selection that retained genealogical concordance with morphology, suggesting instead that apparent patterns of morphological/phylogenetic discordance are driven by widespread genomic homogenization. Here, admixture occurring in secondary contact effectively masks previous isolation. Our results underscore two salient factors:1) Morphological adaptations are retained despite hybridization; and 2) The degree of admixture varies across tributaries, presumably concomitant with underlying environmental or anthropogenic factors.

evolutionary biology↗

bioRxiv2020

Did the Himalayan Uplift Drive Evolution of Aquatic Biodiversity Across Asia? Snowtrout (Cyprinidae: Schizothorax) as a Test Case

The Himalayan uplift, a tectonic event of global importance, seemingly disseminated aquatic biodiversity broadly across Asia. But surprisingly, this hypothesis has yet to be tested. We do so herein by sequencing 1,140 base-pair of mtDNA cytochrome-b for 72 tetraploid Nepalese/Bhutanese Snowtrout (Schizothorax spp.), combining those data with 67 GENBANK(R) sequences (59 ingroup/8 outgroup), then reconstructing phylogenetic relationships using maximum likelihood/ Bayesian analyses. Results indicate Snowtrout originated in Central Asia, dispersed across the Qinghai-Tibetan Plateau (QTP), then into Bhutan via south-flowing tributaries of the east-flowing Yarlung-Tsangpo River (YLTR). The headwaters of five large Asian rivers provided dispersal corridors into southeast Asia. South of the Himalaya, the YLTR transitions into a westward-flowing Brahmaputra River that facilitated successive colonization of Himalayan drainages: First Bhutan, then Nepal, followed by far-western drainages subsequently captured by the Indus River. We found greater species-divergences across rather than within-basins, implicating vicariant evolution as a driver. The Himalaya is a component of the "third-pole" [Earths largest (but rapidly shrinking) glacial reservoir outside the Arctic/Antarctic]. Its unique aquatic biodiversity must not only be recognized (as herein) but also conserved through broad, trans-national collaborations. Our results effectively contrast phylogeography with taxonomy as a necessary first step in this process. The Himalaya is the most extensive and recently evolved mountain system on Earth (length=2400km; width=240km; elevation=75-8800m), with a global significance underscored by its large-scale lithospheric, cryospheric, and atmospheric interactions [1]. These have not only driven global climate, but also defined the cultural and biological endemism of the region [2]. Massive, tectonically derived mountain chains such as the Alps and the Himalaya are hypothesized as being fundamental to the formation of global biodiversity gradients via vicariance and local adaptation, with a significantly stronger signal in terrestrial rather than aquatic systems [3]. Here we test how orogeny (the deformation and folding of Earths crust by lateral compression) has contributed to the diversification of freshwater fishes broadly across Asia. We do so by evaluating the phylogeography of an endemic high-elevation fish, the Snowtrout (Schizothorax: Cyprinidae).

evolutionary biology↗