Rapid climate change has significantly impacted species distribution patterns, necessitating a comprehensive understanding of dominant tree dynamics for effective forest resource management and utilization. The Camellia subgenus Camellia, a widely distributed taxon in subtropical China, represents an ecologically and economically important group of woody plants valued for both oil production and ornamental purposes. In this study, we employed the BIOMOD2 ensemble modeling framework to investigate the spatial distribution patterns and range dynamics of the subgenus Camellia under projected climate change scenarios. Our analysis incorporated 1455 georeferenced occurrence records from 15 species, following the filtering of duplicate points, along with seven bioclimatic variables selected after highly correlated factors were eliminated. The ensemble model, which integrates six single species distribution models, demonstrated robust predictive performance, with mean true skil l statistic (TSS) and area under curve (AUC) values exceeding 0.8. Our results identified precipitation of the coldest quarter (Bio19) and temperature seasonality (Bio4) as the primary determinants influencing species distribution patterns. The center of species richness for the subgenus Camellia was located in the Nanling Mountains and eastern Guangxi Zhuang Autonomous Region. The projections indicate an overall expansion of suitable habitats for the subgenus under future climate conditions, with notable scenario-dependent variations: distribution hotspots are predicted to increase by 8.86% under the SSP126 scenario but experience a 2.53% reduction under the SSP585 scenario. Furthermore, a westward shift in the distribution centroid is anticipated. To ensure long-term conservation of Camellia genetic resources, we recommend establishing a germplasm conservation center in the Nanling Mountains region, which represents a critical biodiversity hotspot for this taxon.

Background: Fritillaria karelinii is an endangered medicinal herb mainly distributed in Central Asia, extending to northwestern China. Due to habitat fragmentation, overharvesting, and poor natural regeneration, this species has been designated as a Grade II national key protected species in China. Methods: To inform effective conservation strategies, we assessed the genetic diversity and population structure of F. karelinii using single nucleotide polymorphism (SNP) loci obtained via genotype-by-sequencing (GBS). A total of 87 individuals from 11 sampling sites across the Tacheng region in northern Xinjiang were genotyped, representing the species’ known extant distribution in China. Results: A relatively high level of genetic diversity (mean H_E = 0.1461) was detected in the species, and Bayesian assignment divided the sampled populations into two subtle but detectable genetic clusters. Conclusions: The relatively high diversity may be attributed to the edge-population effect and long-lived life-history traits, while the weak differentiation between the two groups may reflect restricted gene flow and genetic drift resulting from habitat isolation. Based on these findings, we propose conservation actions including immediate fencing of habitats to exclude livestock, ex situ germplasm collection separately from the two genetic groups as distinct management units, and cautious evaluation of potential germplasm introduction from Central Asia to broaden the genetic base while preserving local adaptation.