Identifying drivers behind biodiversity recovery is critical to promote efficient ecological restoration. Yet to date, for secondary forests in China there is a considerable uncertainty concerning the ecological drivers that affect plant diversity recovery. Following up on a previous published meta-analysis on the patterns of species recovery across the country, here we further incorporate data on the logging history, climate, forest landscape and forest attribute to conduct a nationwide analysis of the main drivers influencing the recovery of woody plant species richness in secondary forests. Results showed that regional species pool exerted a positive effect on the recovery ratio of species richness and this effect was stronger in selective cutting forests than that in clear cutting forests. We also found that temperature had a negative effect, and the shape complexity of forest patches as well as the percentage of forest cover in the landscape had positive effects on the recovery ratio of species richness. Our study provides basic information on recovery and resilience analyses of secondary forests in China.

Previous studies on large-scale patterns in plant richness and underlying mechanisms have mostly focused on forests and mountains, while drylands covering most of the world's grasslands and deserts are more poorly investigated for lack of data. Here, we aim to 1) evaluate the plant richness patterns in Inner Asian drylands; 2) compare the relative importance of contemporary environment, historical climate, vegetation changes, and mid-domain effect (MDE); and 3) explore whether the dominant drivers of species richness differ across growth forms (woody vs herbaceous) and range sizes (common vs rare). Distribution data and growth forms of 13 248 seed plants were compiled from literature and species range sizes were estimated. Generalized linear models and hierarchical partitioning were used to evaluate the relative contribution of different factors. We found that habitat heterogeneity strongly affected both woody and herbaceous species. Precipitation, climate change since the mid-Holocene and climate seasonality dominated herbaceous richness patterns, while climate change since the Last Glacial Maximum dominated woody richness patterns. Rare species richness was strongly correlated with precipitation, habitat heterogeneity and historical climatic changes, while common species richness was strongly correlated with MDE (woody) or climate seasonality (herbaceous). Temperature had little effects on the species richness patterns of all groups. This study represents the first evaluation of the large-scale patterns of plant species richness in the Inner Asian drylands. Our results suggest that increasing water deficit due to anthropogenic activities combined with future global warming may increase the extinction risk of many grassland species. Rare species (both herbaceous and woody) may face severe challenges in the future due to increased habitat destruction caused by urbanization and resource exploitation. Overall, our findings indicate that the hypotheses on species richness patterns based on woody plants alone can be insufficient to explain the richness patterns of herbaceous species.

Abstract Identifying hotspots of species richness/rarity is the most commonly used approach worldwide for defining areas of high conservation importance. However, the use of the hotspot method limits one's ability to protect or exclude particular species as all species are treated equally. Particularly, range-restricted species require high conservation attention because they are more vulnerable than common species. However, the efficiency of the hotspot method in capturing range-restricted species is yet to be explored, although it is known that this method provides low species coverage. Here, using a comprehensive database of Chinese woody plants, we mapped the diversity pattern of 11,405 species at the spatial resolution of 50 × 50 km2 and identified hotspot areas using 1, 2.5, 5, 10, 25, and 50% thresholds. We then evaluated the proportion of range-restricted versus common species captured/missed by each hotspot threshold. We found that the commonly used hotspot thresholds (5 and 10%) failed to capture 41–45% of range-restricted species, which indicates that using the hotspot method for conservation prioritization exposes range-restricted species to high extinction risk. Relying entirely on the hotspot method to prioritize conservation areas, therefore, can be risky not only because it provides low species coverage but also because the missed species are mostly range-restricted species. We advocate adopting more efficient methods, such as systematic conservation planning, rather than the hotspot method, to increase the coverage of range-restricted species in designated priority areas and balance the needs of biodiversity conservation and economic development.

Abstract Plant pathogens are increasingly considered as important agents in promoting plant coexistence, while plant symbionts like ectomycorrhizal fungi (EMF) can facilitate plant dominance by helping conspecific individuals to defend against plant pathogens. However, we know little about their relationships with plants at large scales. Here, using soil fungal data collected from 28 forest reserves across China, we explored the latitudinal diversity gradients of overall fungi and different fungal functional guilds, including putative plant pathogens, EMF and saprotrophic fungi. We further linked the spatial patterns of alpha diversities of putative plant pathogens and EMF to the variation of plant species richness. We found that the relationships between latitude and alpha diversities of putative plant pathogens and EMF were region-dependent with sharp diversity shifts around the mid-latitude (~ 35 oN), which differed from the unimodal diversity distributions of the overall and saprotrophic fungi. The variations in the diversities of putative plant pathogens and EMF were largely explained by the spatial regions (south Vs north / subtropical zone Vs temperate zone). Additionally, the alpha diversities of these two fungal guilds exhibited opposing trends across latitude. EMF could alter the relationship between diversities of putative plant pathogens and plants in the south/subtropical region, but not vice versa. We also found that the ratio of their alpha diversities (EMF to putative plant pathogens) was negatively related to plant species richness across the spatial regions (north to south), and explained ~10% of the variation of plant species richness. Overall, our findings suggest that plant-microbe interactions not only shape the local plant diversity but also may have non-negligible contributions to the large-scale patterns of plant diversity in forest ecosystems.

Plant height is a key functional trait related to aboveground biomass, leaf photosynthesis and plant fitness. However, large-scale geographical patterns in community-average plant height (CAPH) of woody species and drivers of these patterns across different life forms remain hotly debated. Moreover, whether CAPH could be used as a predictor of ecosystem primary productivity is unknown.We compiled mature height and distributions of 11 422 woody species in eastern Eurasia, and estimated geographic patterns in CAPH for different taxonomic groups and life forms. Then we evaluated the effects of environmental (including current climate and historical climate change since the Last Glacial Maximum (LGM)) and evolutionary factors on CAPH. Lastly, we compared the predictive power of CAPH on primary productivity with that of LiDAR-derived canopy-height data from a global survey.Geographic patterns of CAPH and their drivers differed among taxonomic groups and life forms. The strongest predictor for CAPH of all woody species combined, angiosperms, all dicots and deciduous dicots was actual evapotranspiration, while temperature was the strongest predictor for CAPH of monocots and tree, shrub and evergreen dicots, and water availability for gymnosperms. Historical climate change since the LGM had only weak effects on CAPH. No phylogenetic signal was detected in family-wise average height, which was also unrelated to the tested environmental factors. Finally, we found a strong correlation between CAPH and ecosystem primary productivity. Primary productivity showed a weaker relationship with CAPH of the tallest species within a grid cell and no relationship with LiDAR-derived canopy height reported in the global survey. Our findings suggest that current climate rather than historical climate change and evolutionary history determine the geographical patterns in CAPH. However, the relative effects of climatic factors representing environmental energy and water availability on spatial variations of CAPH vary among plant life forms. Moreover, our results also suggest that CAPH can be used as a good predictor of ecosystem primary productivity.

Abstract Aim Dryland ecosystems are exceedingly sensitive to climate change. Desertification induced by both climate changes and human activities seriously threatens dryland vegetation. However, the impact of climate change on distribution of dryland plant species has not been well documented. Here, we studied the potential distribution of four representative dryland plant species (Haloxylon ammodendron, Anabasis aphylla, Calligonum mongolicum, and Populus euphratica) under current and future climate scenarios in a temperate desert region, aiming to improve our understanding of the responses of dryland plant species to climate change and provide guidance for dryland conservation and afforestation. Location Junggar Basin, a large desert region in northwestern China. Methods Occurrence data of the studied species were collected from an extensive field investigation of 2,516 sampling sites in the Junggar Basin. Ensemble species distribution models using 10 algorithms were developed and used to predict the potential distribution of each studied species under current and future climate scenarios. Result Haloxylon ammodendron and A. aphylla were likely to lose most of their current suitable habitats under future climate scenarios, while C. mongolicum and P. euphratica were likely to expand their ranges or remain relatively stationary. Variable importance evaluation showed that the most important climate variables influencing species distribution differed across the studied species. These results may be explained by the different ecophysiological characteristics and adaptation strategies to the environment of the four studied species. Main conclusions We explored the responses of the representative dryland plant species to climate change in the Junggar Basin in northwestern China. The different changes in suitability of different species imply that policymakers may need to reconsider the selection and combination of the afforestation species used in this area. This study can provide valuable reference for the management and conservation of dryland ecosystems under future climate change scenarios.

Abstract Aim Although the effects of climate on species richness are known, regional processes may lead to different species richness?climate relationships across continents resulting in species richness anomalies, especially for tropical groups. Phylogenetic niche conservatism may also influence species richness?climate relationships of different lineages. Here, we tested whether regional effects also exist for temperate lineages using the genus Quercus. Location Northern Hemisphere. Time period Present day. Major taxa studied Quercus (Fagaceae). Methods We used a dated phylogeny and distribution data for Quercus to evaluate its global species richness patterns and phylogenetic niche conservatism. To evaluate the consistency in species richness?climate relationships across continents of the genus Quercus as a whole and the temperate subgenus Quercus, we conducted analyses of covariance with continent as the categorical variable and climate variables as the covariate. We calibrated four widely used models using the global data or data from each continent separately and evaluated the predictive power of each model for different continents using the root mean squared error. Results The relationships between species richness and climate were not significantly different among continents for both the genus Quercus as a whole and the subgenus Quercus. Unlike the models based on European data, those based on North American and eastern Asian data predicted both the global species richness and the richness in other continents. The species richness of a subtropical subgenus Cyclobalanopsis was most influenced by water availability, while that of a temperate subgenus Quercus was most influenced by environmental temperature. Main conclusions In contrast to the subtropical subgenus Cyclobalanopsis, our results showed a consistent richness?climate relationship and absence of regional effects on species richness across continents for the temperate subgenus Quercus, likely suggesting that the species richness of temperate lineages, for example subgenus Quercus, may have reached equilibrium with the contemporary climate in the Northern Hemisphere.

Abstract The mechanisms underlying elevation patterns in species and phylogenetic diversity remain a central issue in ecology and are vital for effective biodiversity conservation in the mountains. Gongga Mountain, located in the southeastern Qinghai–Tibetan Plateau, represents one of the longest elevational gradients (ca. 6,500 m, from ca. 1,000 to 7,556 m) in the world for studying species diversity patterns. However, the elevational gradient and conservation of plant species diversity and phylogenetic diversity in this mountain remain poorly studied. Here, we compiled the elevational distributions of 2,667 native seed plant species occurring in Gongga Mountain, and estimated the species diversity, phylogenetic diversity, species density, and phylogenetic relatedness across ten elevation belts and five vegetation zones. The results indicated that species diversity and phylogenetic diversity of all seed plants showed a hump-shaped pattern, peaking at 1,800–2,200 m. Species diversity was significantly correlated with phylogenetic diversity and species density. The floras in temperate coniferous broad-leaved mixed forests, subalpine coniferous forests, and alpine shrublands and meadows were significantly phylogenetically clustered, whereas the floras in evergreen broad-leaved forests had phylogenetically random structure. Both climate and human pressure had strong correlation with species diversity, phylogenetic diversity, and phylogenetic structure of seed plants. Our results suggest that the evergreen broad-leaved forests and coniferous broad-leaved mixed forests at low to mid elevations deserve more conservation efforts. This study improves our understanding on the elevational gradients of species and phylogenetic diversity and their determinants and provides support for improvement of seed plant conservation in Gongga Mountain.

<p id="C2">蔷薇科(Rosaceae)是在中国广泛分布并具有重要经济价值的植物类群, 但蔷薇科资源植物的物种多样性格局及其保护状况尚缺乏较系统的评估。该文旨在: 1)整理中国蔷薇科资源植物名录, 显示其物种多样性格局及热点地区, 并探究这一格局的形成机制。2)评估中国蔷薇科资源植物的保护状况, 为其保护规划提供基础数据。通过广泛收集整理《中国植物志》、省级植物志等资料中关于蔷薇科的记录, 建立了中国蔷薇科物种名录(共914种), 确定了物种的主要经济用途(包括食用植物、园林绿化植物、药用植物和水果种质资源), 并建立了每种植物的高精度分布图。在此基础上, 估算了蔷薇科全部物种及主要资源植物类别的物种多样性格局, 并利用广义线性模型和冗余分析探讨了蔷薇科物种多样性格局与环境的关系。最后将物种分布与中国国家级和省级自然保护区进行叠加分析, 评估了蔷薇科植物的保护现状。结果显示: 1)四川盆地北部、东部和西部山区以及横断山区是中国蔷薇科植物的热点地区。2)蔷薇科植物多样性主要受水分因子影响。3)横断山区、云南东南部和西藏东南部等地是保护薄弱物种集中的区域, 而悬钩子属(<i>Rubus</i>)等类群的保护不足。</p>

Biogeographic patterns and drivers of soil microbial diversity have been extensively studied in the past few decades. However, most research has focused on the topsoil, while the subsoil is assumed to have microbial diversity patterns similar to those of the topsoil. Here we compared patterns and drivers of microbial alpha and beta diversity in and between topsoils (0 to 10 cm) and subsoils (30 to 50 cm) of temperate grasslands in Inner Mongolia of China, covering an ∼1,500-km transect along an aridity gradient. Counter to the conventional assumption, we find contrasting biogeographic patterns of diversity and influencing factors for different bacterial and archaeal groups and between depths. While bacterial diversity remains constant or increases with increasing aridity in topsoil and decreases in subsoil, archaeal diversity decreases in topsoil and remains constant in subsoil. Microbial diversity in the topsoil is most strongly influenced by aboveground vegetation and contemporary climate but is most strongly influenced by the factor historical temperature anomaly since the Last Glacial Maximum (LGM) and by soil pH in the subsoil. Moreover, the biogeographic patterns of topsoil-subsoil community dissimilarities vary for different microbial groups and are overall most strongly influenced by soil fertility differences between depths for bacteria and by contemporary climate for archaea. These findings suggest that diversity patterns observed in the topsoil may not be readily applied to the subsoil horizons. For the subsoil in particular, historical climate plays a vital role in the spatial variation of bacterial diversity. Overall, our study provides novel information for understanding and predicting soil microbial diversity patterns at depth.IMPORTANCE Exploring the biogeographic patterns of soil microbial diversity is critical for understanding mechanisms underlying the response of soil processes to climate change. Using top- and subsoils from an ∼1,500-km temperate grassland transect, we find divergent patterns of microbial diversity and its determinants in the topsoil versus the subsoil. Furthermore, we find important and direct legacy effects of historical climate change on the microbial diversity of subsoil yet indirect effects on topsoil. Our findings challenge the conventional assumption of similar geographic patterns of soil microbial diversity along soil profiles and help to improve our understanding of how soil microbial communities may respond to future climate change in different regions with various climate histories.