The steppe-desert is much older than previously thought, but has evolved substantially from the Paleogene to the present.

As one of the global biodiversity hotspots, the mountains of Central Asia are home to a large number of wild fruit species. Although the hotspots are constantly being seriously affected by climate and land-use changes, effective assessments of the impacts of these changes for the dominant species of wild fruit forests, wild apple (Malus sieversii), have been limited. We compiled 8344 occurrence records for wild apple across its whole distribution ranges from field surveys and herbarium and literature records. After data thinning to reduce sampling bias, we used ensemble niche models to project current and future suitable habitats, examined the importance of environmental factors, and assessed whether current national protected areas (PAs) are effective in protecting the suitable habitats. We found that the distribution of wild apple is currently fragmented. Under future scenarios, it would shift 118–227 km towards high latitudes and ~200 m towards high elevations, losing nearly 27–56% of suitable habitats in the south, and gaining some habitats in the north. The increased temperature and expansion of cropland contributed to these shifts. Nevertheless, about 13% of the suitable habitats are covered by existing PAs and less than 25% of suitable habitats will be protected in the future. The cold spots for protecting intact wild fruit forests are located in Xinjiang, China and Kyrgyzstan. Overall, we provide a detailed evaluation of the impacts of climate and land-use changes on current and future distributions of wild apple in Central Asia. Considering that this species faces a greater risk of habitat loss in the south of Central Asia, we advocate developing effective in situ conservation strategies with long-term monitoring that will provide deep insights into the fate of wild fruit forests.

Extensive range of deserts and gobis (rocks) had promoted habitat fragmentation of species in arid northwestern China. Distribution of endangered Gymnocarpos przewalskii Maxim. covers most of gobis (rocks) and desert terrain across arid regions of northwestern China. In the present study, we had employed genomic phylogeographical analysis to investigate population structure of G. przewalskii and test the effect of environmental conditions on spatial pattern of genetic diversity. Results showed four groups were identified from east to west: Edge of the Alxa Desert, Hexi Corridor, Hami Basin, and North edge of the Tarim Basin. Genetic diversity was at an equal level among four groups. General linear model (GLM) analysis showed spatial pattern of genetic diversity was significant correlated with three habitat variables including habitat suitability at present (N_pre) and last glacial maximum (LGM) (N_LGM) periods, and locality habitat stability (N_Stab). It concluded that habitat fragmentation had triggered lineage divergences of G. przewalskii in response to long-term aridification. Genome-wide single nucleotide polymorphisms (SNPs) could increase the ability of clarifying population structures in comparison with traditional molecular markers. Spatial pattern of genetic diversity was determined by fragmented habitats with high habitat suitability (N_pre and N_LGM) and stability (N_Stab). At last, we propose to establish four conservation units which are in consistent with the population grouping to maintain the genetic integrity of this endangered species.

As a Tertiary Tethyan relict, Capparis spinosa is a typical wind-preventing and sand-fixing deciduous subshrub in arid central Asia. Due to its medicinal and energy value, this species is at risk of potential threat from human overexploitation, habitat destruction and resource depletion. In this study, our purpose was to evaluate the conservation strategies of C. spinosa according to its genetic structure characteristics and genetic diversity pattern among 37 natural distributional populations. Based on genomic SNP data generated from dd-RAD sequencing, genetic diversity analysis, principal component analysis, maximum likelihood phylogenetic trees and ADMIXTURE clustering, the significant population structure and differentiation were explored. The results showed the following: (1) Six distinct lineages were identified corresponding to geographic locations, and various levels of genetic diversity existed among the lineages for the natural habitat heterogeneity or human interferences; (2) The lineage divergences were influenced by isolation by distances, vicariance and restricted gene flow under complex topographic and climatic conditions. Finally, for the preservation of the genetic integrity of C. spinosa, we suggest that conservation units should be established corresponding to different geographic groups, and that attention should be paid to isolated and peripheral populations that are experiencing biodiversity loss. Simultaneously, monitoring and reducing anthropogenic disturbances in addition to rationally and sustainably utilizing wild resources would be beneficial to guarantee population resilience and evolutionary potential of this xerophyte in response to future environmental changes.