Marginal populations are those at the geographical edge of a species’ distribution. Appropriate evaluation of genetic diversity in marginal populations is of crucial significance for understanding the impacts of climate changes on species expansion or contraction in the post Quaternary glaciations, conservation of genetic resources and exploitation, and peripatric speciation. Here, we discuss the evolutionary mechanisms for maintaining genetic diversity in marginal populations, analyze the role of plant mating system in shaping a plant species’ range and the genetic diversity in marginal populations, assess the difference or similarity in genetic diversity between central and marginal populations and the underlying ecological and evolutionary processes, and discuss the species genetic diversity correlation (SGDC) and the theory underlying such correlations. We proposed that future research includes the use of genome-wide sequences or transcriptome data to study the adaptive differential between leading- and rear-edge populations or between central and marginal populations and the molecular mechanisms of the interactions between the genetic diversity in marginal populations and the species diversity in the resident community of a focal species. This may help to understand the adaptability of marginal populations to local habitats and the ecological and evolutionary processes for SGDC at species’ edges.

Bryophyte participate in karstification is an important part of biokarst process. Numerous studies on bryophyte karstification provide theoretical and technical foundation for restoration and comprehensive management of bare rock in the rocky desertification area. This article systematically reviewed the process (dissolution and sedimentation), mechanism and interaction relationship between bryophyte karstification and habitats. Bryophyte and its biological crusts emerge physical forces such as expansion, curling, freezing and thawing when they are under alternating wet or dry conditions can destroy rock. In addition, their metabolic secretions and H₂CO₃ formed by respiration, which react with minerals resulting in destruction of the crystal structure, pyrolysis the minerals, further the rock surface disintegrated and the surface morphology changed, the karst landform and the original soil formed. The driving force of bryophyte karstification closely related to plant functional traits, rock properties and habitat. Studies on biokarst need long-term monitoring and long research period. It is recommended to establish a long-term monitoring sites for strengthening examinations on process, internal mechanisms, and interaction relationship with habitat of bryophyte karstification. At the same time, physiological metabolic processes of bryophytes and the relationship with bryophyte karstification should be emphasized. The environmental adaptability of bryophyte and the maintenance mechanism of biodiversity in karst areas need research attention as well.