Climate change is a vital driver of biodiversity patterns and species distributions, understanding how organisms respond to climate change will shed light on the conservation of endangered species. In this study, the MaxEnt model was used to predict the potential suitable area of 12 threatened medicinal plants in the QTP (Qinghai‐Tibet Plateau) under the current and future (2050s, 2070s) three climate scenarios (RCP2.6, RCP4.5, RCP8.5). The results showed that the climatically suitable habitats for the threatened medicinal plants were primarily found in the eastern, southeast, southern, and some parts of the central regions on the QTP. Moreover, 25% of the threatened medicinal plants would have reduced suitable habitat areas within the next 30–50 years in the different future global warming scenarios. Among these medicinal plants, RT (Rheum tanguticum) would miss the most habitat (98.97%), while the RAN (Rhododendron anthopogonoides) would miss the least habitat (10.15%). Nevertheless, 33.3% of the threatened medicinal plants showed an increase in their future habitat area because of their physiological characteristics which are more adaptable to a wide range of climates. The climatic suitable habitat for 50% of the threatened medicinal plants would migrate to higher altitudes or higher latitudes regions. This study provides a data foundation for the conservation of biodiversity and wild medicinal plants on the QTP.

As a species of considerable medicinal, ecological, and economic significance, the protection of C. songaricum and its host plants is of paramount importance. Biodiversity patterns and species distribution are profoundly influenced by climate change. Understanding the adaptive mechanisms of organisms in response to these changes is essential for effective species conservation. However, there is currently limited information available on simulating habitat suitability and assessing key environmental factors associated with parasite species using niche models. This study utilized environmental and species distribution data to analyze the shifts in the geographic range of C. songaricum and its host plants under current and projected future climate scenarios using the Biomod2 platform, which integrates multiple individual models into an ensemble framework. Additionally, the study quantified the environmental variables influencing the observed distribution patterns. The potential geographical distribution and overlapping areas of C. songaricum and its host plants are primarily concentrated in Asia and North America. Under all four scenarios within the two timeframes (2041–2060 and 2061–2080), the overall suitable habitat areas for C. songaricum, Nitraria tangutorum Bobr., N. sphaerocarpa Maxim., and Peganum multisectum (Maxim.) Bobrov are expected to decrease compared with current climatic conditions. Conversely, the total area of suitable habitat for Kalidium foliatum (Pall.) Moq., Nitraria sibirica Pall., and Zygophyllum xanthoxylum (Bunge) Maxim. is predicted to increase. All species except K. foliatum will experience greater reductions between 2041 and 2060 than between 2061 and 2080 under more severe climate change scenarios. There is significant ecological niche overlap among C. songaricum, N. sphaerocarpa, N. tangutorum, and P. multisectum. Key factors influencing the future distribution of C. songaricum include the mean ultraviolet-B light of the lowest month, altitude, and annual mean temperature. A comprehensive analysis demonstrated that the accuracy of predictions could be significantly enhanced and the distributional error for individual species could be minimized by employing the Biomod2 ensemble model to simulate the suitable habitats of parasitic species. The findings of this study can significantly inform both the management of C. songaricum plantations and the conservation of C. songaricum and its host plants.

Although the soils in the Tibetan Plateau shrublands store large amounts of total nitrogen (N), the estimated values remain uncertain because of spatial heterogeneity and a lack of field observations. In this study, we quantified the regional soil N storage, spatial and vertical density distributions, and related climatic controls using 183 soil profiles sampled from 61 sites across the Northeast Tibetan Plateau shrublands during the period of 2011–2013. Our analysis revealed a soil N storage value of 132.40 Tg at a depth of 100 cm, with an average density of 1.21 kg m⁻². Soil N density was distributed at greater levels in alpine shrublands, compared with desert shrublands. Spatially, soil N densities decreased from south to north and from east to west, and, vertically, the soil N in the upper 30 and 50 cm accounted for 42% and 64% of the total soil N stocks in the Tibetan Plateau. However, compared with desert shrublands, the surface layers in alpine shrublands exhibited a larger distribution of soil N stocks. Overall, the soil N density in the top 30 cm increased significantly with the mean annual precipitation (MAP) and tended to decrease with the mean annual temperature (MAT), although the dominant climatic controls differed among shrubland types. Specifically, MAP in alpine shrublands, and MAT in desert shrubland, had a weak effect on N density. Soil pH can significant affect soil N density in the Tibetan Plateau shrublands. In conclusion, changes in soil N density should be monitored over the long term to provide accurate information about the effects of climatic factors.

Background: Subtribe Swertiinae, a medicinally significant and highly speciose Subtribe of family Gentianaceae. Despite previous extensive studies based on both morphology and molecular data, intergeneric and infrageneric relationships within subtribe Swertiinae remain controversial. Methods: Here, we employed four newly generated Swertia chloroplast genomes with thirty other published genomes to elucidate their genomic characteristics. Results: The 34 chloroplast genomes were small and ranged in size from 149,036 to 154,365 bp, each comprising two inverted repeat regions (size range 25,069–26,126 bp) that separated large single-copy (80,432–84,153 bp) and small single-copy (17,887–18,47 bp) regions, and all the chloroplast genomes showed similar gene orders, contents, and structures. These chloroplast genomes contained 129–134 genes each, including 84–89 protein-coding genes, 37 tRNAs, and 8 rRNAs. The chloroplast genomes of subtribe Swertiinae appeared to have lost some genes, such as rpl33, rpl2 and ycf15 genes. Comparative analyses revealed that two mutation hotspot regions (accD-psaI and ycf1) could serve as effective molecular markers for further phylogenetic analyses and species identification in subtribe Swertiinae. Positive selection analyses showed that two genes (ccsA and psbB) had high Ka/Ks ratios, indicating that chloroplast genes may have undergone positive selection in their evolutionary history. Phylogenetic analysis showed that the 34 subtribe Swertiinae species formed a monophyletic clade, with Veratrilla, Gentianopsis and Pterygocalyx located at the base of the phylogenetic tree. Some genera of this subtribe, however, were not monophyletic, including Swertia, Gentianopsis, Lomatogonium, Halenia, Veratrilla and Gentianopsis. In addition, our molecular phylogeny was consistent with taxonomic classification of subtribe Swertiinae in the Roate group and Tubular group. The results of molecular dating showed that the divergence between subtrib Gentianinae and subtrib Swertiinae was estimated to occur in 33.68 Ma. Roate group and Tubular group in subtribe Swertiinae approximately diverged in 25.17 Ma. Conclusion: Overall, our study highlighted the taxonomic utility of chloroplast genomes in subtribe Swertiinae, and the genetic markers identified here will facilitate future studies on the evolution, conservation, population genetics, and phylogeography of subtribe Swertiinae species.

Intercropping is a sustainable method for cultivating medicinal herbs since it requires lower dependence on chemical fertilizers than a sole cropping system. In this study, we compared the effects of sole cropping and intercropping on early bolting, yield, and the chemical composition of Angelica sinensis (Oliv.) Diels. Field experiments were conducted, in 2018 and in 2019, using different cropping systems including sole cropping of A. sinensis (AS), sole cropping of Vicia faba (VF), and intercropping (without fertilization) at three ratios: one row of A. sinensis + three rows of V. faba, AS/VF (1:3), two rows of A. sinensis + two rows V. faba, AS/VF (2:2), three rows of A. sinensis + one row V. faba, AS/VF (3:1). The effect of each cropping system was evaluated by measuring the dry biomass of V. faba and the dry biomass, ferulic acid content, and essential oil content and composition of A. sinensis. The early bolting rate of A. sinensis was significantly lower in the intercropping system as compared with that in a sole cropping system. The AS/VF (3:1) intercropping pattern resulted in an optimal yield and the highest ferulic acid content of A. sinensis, highest dry biomass of V. faba, and highest land equivalent ratio (LER). Additionally, the A. sinensis was more aggressive (the aggressivity value of A. sinensis was positive, and its competitive ratio was >1) under AS/VF (3:1) intercropping pattern, and it dominated over V. faba (which had negative aggressivity values and a competitive ratio of <1) under AS/VF (3:1) intercropping pattern. Ligustilide was the most dominant component of the essential oil of A. sinensis, regardless of the cropping system; however, the chemical component of essential oil was not influenced by intercropping patterns. Overall, the AS/VF (3:1) intercropping pattern without fertilization was the most productive, with the highest LER and ferulic acid content. These data indicate that intercropping can serve as an alternative for reducing the use of chemical fertilizers and intercropping also decreases the early bolting rate of A. sinensis, thus, enabling its sustainable production.