Previous attempts to elucidate the drivers of speciation mechanisms and spatial distribution patterns of biodiversity in mountain regions have treated different floras within a single geological region as one flora, ignoring the potential contributions of high habitat/ecosystem heterogeneity. Furthermore, current conservation strategies largely focus on forest ecosystems and/or specific flagship species, ignoring marginal ecosystems, leaving species in these ecosystems at risk. Here, we compared the spatial patterns of biodiversity and the potential drivers of these patterns in the river valley and subnival ecosystems of the Hengduan Mountains region (HDM) in southwestern China. Specifically, we compared spatial patterns of diversity, endemism, and threatened species in these ecosystems based on both traditional measurements and recent phylogenetic approaches. We then examined how those patterns were related to environmental factors and human activity in these same regions. We found that the middle-southern HDM supports the highest diversity and endemism for the river valley and subnival ecosystems; however, the distribution patterns of neo- and paleo-endemism in these two ecosystems differ. Regression models indicate that habitat diversity and paleo-climatic fluctuation are important drivers of diversity and endemism for these two ecosystems. Temperature and precipitation, however, showed different influences on the spatial patterns in different ecosystems. Categorical analysis of neo- and paleo-endemism (CANAPE) indicated that most endemism centers are not covered by current nature reserves. Moreover, the intensity of human activity is highest in the southern and southeastern HDM, which coincides with the distribution patterns of diversity, mixed-endemism and high-priority (and threatened) species. These findings suggest that different floras within a single geographic/floristic region respond differently to environmental factors and show different spatial phylogenetic patterns. We, therefore, recommend that future research into the drivers of biodiversity consider the contributions of various ecosystem types within a single geological region. This study also provides a theoretical basis for protecting habitat diversity. Our work confirms that current conservation efforts are insufficient to protect ecosystem diversity in the river valley and subnival ecosystems of the Hengduan Mountains. Therefore, we recommend the establishment of nature reserves in the regions identified in this study; furthermore, we strongly recommend improving current and establishing new management policies for biodiversity conservation in this region.

The Qinghai-Tibet Plateau (QTP) is an important cushion plant hotspot. However, the distribution of cushion plants on the QTP is unknown, as are the factors that drive cushion plant distribution, limiting our understanding of the evolution of cushion species in the region. In this study, we assessed spatial patterns of total cushion plant diversity (including taxonomic and phylogenetic) over the entire QTP and compared patterns of diversity of cushion plants with different typologies (i.e., compact vs. loose). We also examined how these patterns were related to climatic features. Our results indicate that the southern QTP hosts the highest total cushion plant richness, especially in the south-central Hengduan Mountains subregion. The total number of cushion species declines from south to north and from southeast to northwest. Compact cushion plants exhibit similar patterns as the total cushion plant richness, whereas loose cushion plants show random distribution. Cushion plant phylogenetic diversity showed a similar pattern as that of the total cushion plant richness. In addition, cushion plant phylogenetic community structure was clustered in the eastern and southwestern QTP, whereas random or overdispersed in other areas. Climatic features represented by annual energy and water trends, seasonality and extreme environmental factors, had significant effects on cushion plant diversity patterns but limited effects on the phylogenetic community structure, suggesting that climatic features indeed promote the formation of cushion plants. Because cushion plants play vital roles in alpine ecosystems, our findings not only promote our understanding of the evolution and formation of alpine cushion plant diversity but also provide an indispensable foundation for future studies on cushion plant functions and thus alpine ecosystem sustainability in the entire QTP region.

The successful launch of the GF-4 satellite has greatly enhanced wide-swath and high-frequency imaging capabilities, both of which are urgently needed in the fields of ship detection and monitoring. In this letter, the applicability of GF-4 satellite data for ship recognition and maritime traffic surveillance was investigated. It is concluded that the movement of ships, the velocity and direction, for instance, can be detected by using either a single GF-4 image that has short time lags between bands, or time-series GF-4 images that have a short interval between their acquisition times, implying that GF-4 satellite images have the potentiality for the monitoring of moving ships.

A large number of studies have attempted to determine the mechanisms driving plant diversity and distribution on a global scale, but the diverse and endemic alpine herbs found in harsh environments, showing adaptive evolution, require more studies. Here, we selected 466 species from the genus Saussurea, one of the northern hemisphere’s highest-altitude plant genera with high species richness and striking morphological traits, to explore the mechanisms driving speciation and adaptative evolution. We conducted phylogenetic signals analysis and ancestral character estimation to explore the phylogenetic significance of ecological factors. Moreover, we used spatial simultaneous autoregressive (SAR) error models, modified t-tests and partial regression models to quantify the relative effects of ecological factors and morphological diversity upon diversity and endemism of Saussurea. Phylogenetic analyses reveal that geological influences and climate stability exhibit significant phylogenetic signals and that Saussurea originated at a relatively high elevation. Regression models indicate that geological influences and climatic stability significantly affect the diversity and endemism patterns of Saussurea and its morphological innovations. Moreover, morphological innovations in an area show significant contributions to the local diversity and endemism of Saussurea. We conclude that geological influences (mean altitude and topographic heterogeneity), glacial–interglacial climate stability and phylogenetic conservatism have together promoted the speciation and adaptive evolution of the genus Saussurea. In addition, adaptively morphological innovations of alpine species also promote diversification in local regions. Our findings improve the understanding of the distribution pattern of diversity/endemism and adaptive evolution of alpine specie in the whole northern hemisphere.