Conservation genetics of endangered Trillium govanianum Wall. ex D. Don - A pharmaceutically prized medicinal plant from the Himalaya and implications for species recovery.

Understanding the genetic diversity and population structure of pharmaceutically important endangered plant species is crucial for their conservation and sustainable use. Despite the continuous population decline in Trillium govanianum Wall. ex D. Don, a highly prized medicinal plant endemic to the Himalaya, information regarding its conservation genetics has been lacking. Here, we employed a conservation genetics approach to investigate how drastically declining populations in natural habitats impact population genetic diversity and structure of this endangered species across the Kashmir Himalaya. We used Start codon targeted (SCoT) and Simple sequence repeat (SSR) markers to assess the intra- and inter-population genetic variation in seven sites across the study region. Based on these markers, we found a very low genetic diversity in T. govanianum populations. Very low levels of observed heterozygosity (Ho = 0.000) and that expected (He = 0.064) in the populations indicate high heterozygote deficiency and high levels of inbreeding depression (FIS = 1.000). A high genetic differentiation was observed among the populations for both SCoT (Gst = 0.719) and SSR (Fst = 0.707) markers. Both the markers showed low gene flow, SCoT (Nm = 0.195) and SSR (Nm = 0.119), depicting high among-population variation than within-population variation. Analysis of molecular variance also indicated a higher genetic variation between the populations than within populations. We also observed a significant positive correlation between genetic divergence and geographical distance, indicating that genetic differentiation in T. govanianum follows a pattern of isolation by distance. Bayesian structure and cluster analysis grouped the populations according to their geographical proximity. Further, redundancy analysis (RDA) revealed the presence of one polymorphic locus for each marker with high discriminatory power. Overall, our findings reveal a very low genetic diversity, high levels of inbreeding, and high genetic differentiation among the populations; likely resulting from habitat fragmentation, population isolation, bottleneck effect, low gene flow, and predominantly asexual reproduction currently operative in the species. Finally, based on the insights gained, we discuss the potential implications of our findings in guiding species recovery and habitat rehabilitation of T. govanianum in the Himalaya with conservation lessons for elsewhere in the world.

Habitat suitability, range dynamics, and threat assessment of Swertia petiolata D. Don: a Himalayan endemic medicinally important plant under climate change.

In the current era of the anthropocene, climate change is one of the main determinants of species redistribution and biodiversity loss. Worryingly, the situation is alarming for endemic and medicinally important plant species with a narrow distributional range. Therefore, it is pivotal to inspect the influence of accelerated climate change on medicinally important threatened and endemic plant species. Using an ensemble approach, the current study aims at modelling the present distribution and predicting the future potential distribution coupled with the threat assessment of Swertia petiolata-a medicinally important endemic plant species in the Himalayan biodiversity hotspot. Our study revealed that under current climatic scenarios, the suitable habitats for the species occur across the western Himalayan region which includes the north-western Indian states (Jammu and Kashmir, Himachal Pradesh, and southern Uttarakhand), northern Pakistan, and north-western Nepal. Also, temperature seasonality (BIO4) and precipitation seasonality (BIO15) are the most significant bioclimatic variables determining the distribution of S. petiolata. Furthermore, the study projected a reduction in the suitable habitats for the species under future changing climatic scenarios with a reduction ranging from - 40.298% under RCP4.5 2050 to - 83.421% under RCP8.5 2070. Most of the habitat reduction will occur in the western Himalayan region. In contrast, some of the currently unsuitable Himalayan regions like northern Uttarakhand will show increasing suitability under climate change scenarios. The current study also revealed that S. petiolata is classified as Near Threatened (NT) following the IUCN criterion B. Hopefully, the present study will provide a robust tool for predicting the cultivation hotspots and devising scientifically effective conservation strategies for this medicinally important plant species in the Himalaya and similar environments elsewhere in the world.