Human pressure on the environment and climate change are two important factors contributing to species decline and overall loss of biodiversity. Orchids may be particularly vulnerable to human-induced losses of habitat and the pervasive impact of global climate change. In this study, we simulated the extent of the suitable habitat of three species of the terrestrial orchid genus Cypripedium in northeast China and assessed the impact of human pressure and climate change on the future distribution of these species. Cypripedium represents a genus of long-lived terrestrial orchids that contains several species with great ornamental value. Severe habitat destruction and overcollection have led to major population declines in recent decades. Our results showed that at present the most suitable habitats of the three species can be found in Da Xing’an Ling, Xiao Xing’an Ling and in the Changbai Mountains. Human activity was predicted to have the largest impact on species distributions in the Changbai Mountains. In addition, climate change was predicted to lead to a shift in distribution towards higher elevations and to an increased fragmentation of suitable habitats of the three investigated Cypripedium species in the study area. These results will be valuable for decision makers to identify areas that are likely to maintain viable Cypripedium populations in the future and to develop conservation strategies to protect the remaining populations of these enigmatic orchid species.

Young shoots of Aralia elata and young leaves of Eleutherococcus senticosus are two major non-timber forest products in northeastern China. However, human activities and climate change have resulted in serious threats to the habitats of two trees, which greatly limits resource conservation and exploitation of economic forest trees. We used the MaxEnt model to predict the suitable habitats of the two economic trees and analyzed the dominant factors affecting their distribution. The results showed that the suitable habitat areas of A. elata and E. senticosus in the current period were 159950 km² and 123449 km², respectively, and the suitable habitats of both economic forest trees were located in the eastern part of the northeast region. Climate factors (Annual precipitation, Precipitation Seasonality) and land use factors are important variables influencing changes in suitable habitat for both trees. With the change of climate and land use in the future, the overall trend of suitable habitat for both economic forest trees shows a northward and then a southward migration. These results may provide assistance in developing strategies for resource conservation and sustainable use of A. elata and E. senticosus, and we suggest that stable and suitable habitats should be selected as areas for in situ conservation and breeding of the two economic forest trees.

Climate change and land use/land cover (LULC) change have received widespread attention as the two main factors contributing to the shrinking of plant habitats. However, the different effects of these factors on understory economic tree species are not clear. This is not conducive to the conservation and exploitation of forest resources. Here, we used species distribution modeling to predict the extent to which climate change and LULC change will affect changes in suitable habitats for A. elata under different scenarios in the future. The results showed the suitable habitat to be located in the Changbai Mountain Range in northeast China. The current area is 110,962 km². The main variables that affect the suitable habitat are annual precipitation, LULC, slope, and mean diurnal range. The percentage contributions are 31.2%, 16.8%, 12.8%, and 12.3%, respectively. In the 2070s, the area of high-quality (moderately and highly) suitable habitat was reduced by an average of 6.05% when climate alone changed, and by an average of 10.21% when land use alone changed. When both factors changed together, there was an average decrease of 9.69%. When climate change and land use change acted together, the shrinking area of suitable habitat did not suddenly increase. These findings help to identify potentially suitable habitats for A. elata and to carry out conservation and exploitation efforts to ensure sustainability.

Cypripedium is renowned for its high morphological diversity and complex genetic and evolutionary characteristics. The chloroplast genome serves as a valuable tool for investigating phylogenetic relationships and evolutionary processes in plants. Currently, research on the evolution of the chloroplast genome within the Cypripedium genus is limited due to insufficient large-scale sampling and a lack of comprehensive understanding. Consequently, the mechanisms underlying the significant differences in chloroplast genome size among Cypripedium species remain poorly understood. In this study, we conducted a comprehensive comparative analysis of the chloroplast genomes of 29 Cypripedium species. The lengths of these genomes ranged from 162,092 to 246,177 base pairs (bp) and contained between 127 and 134 genes. Our results indicate that, while the overall structure of the chloroplast genomes in Cypripedium species is relatively conserved, significant differences were observed among the large single-copy (LSC), small single-copy (SSC), and inverted repeat (IR) regions. Several genes, including psaC, rpl32, ycf1, and psbK, exhibited higher levels of variability and may serve as molecular markers in taxonomic studies. The results of our correlation analysis suggest that the expansion of the LSC region, the increase in simple sequence repeats (SSRs), and tandem repeats (TRs) have significantly enlarged the size of the chloroplast genome in Cypripedium species. Phylogenetic signal testing supports the notion that genetic variation has driven species divergence within the genus. Overall, our findings provide insights into the substantial differences in chloroplast genome length observed among Cypripedium species. However, the relationship between diversification and the evolutionary mechanisms affecting Cypripedium, including ecological adaptive evolution, incomplete lineage sorting (ILS), hybridization, and reticulate events, requires further investigation.

Corydalis repens Mandl & Muhldorf is an early spring-blooming species within the genus Corydalis. In this study, we present the complete chloroplast genome of C. repens for the first time. The assembled genome is 188,101 base pairs (bp) long and is organized into a typical quadripartite structure consisting of a large single-copy (LSC) region of 89,844 bp, a small single-copy (SSC) region of 757 bp, and two inverted repeat (IR) regions totaling 48,750 bp. The overall GC content is 40.2%. The plastome encodes 141 genes, including 94 protein-coding genes, 38 transfer RNA genes, and eight ribosomal RNA genes, along with a single pseudogene (clpP). Phylogenetic reconstruction indicates that C. repens is nested within section Corydalis and shows the closest affinity to C. maculata. These findings provide an important genetic resource for future studies on the evolutionary history and conservation of the genus Corydalis.