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Aim: Woody and herbaceous habits represent one of the most distinct contrasts among angiosperms, and the proportion of woody species in floras (i.e., "woodiness" hereafter) represents a fundamental structural element of plant diversity. Despite its core influence on ecosystem processes, spatio‐temporal patterns in woodiness remain poorly understood. Here, we aim to demonstrate the global spatio‐temporal patterns in angiosperm woodiness and their relationship with environmental factors. Location: Global. Time period: Cenozoic, 66 Ma to present. Major taxa studied: Angiosperms. Methods: Using newly compiled data on the growth forms and distributions of c. 300,000 angiosperm species and an angiosperm phylogeny, we mapped the current global geographical patterns in angiosperm woodiness, reconstructed ancestral states of growth forms through the angiosperm phylogeny and demonstrated the Cenozoic evolutionary dynamics of woodiness. We evaluated the relationships between woodiness and current climate and palaeoclimate. Results: We found that c. 42.7% of angiosperms are woody. Woodiness decreased spatially from the equator towards high latitudes, temporally since the early Cenozoic. Temperature was the best predictor of the spatio‐temporal decline in woodiness and was positively correlated with woodiness. Despite the temporal decline in woodiness, macroevolutionary herbaceous‐to‐woody transitions increased through time and contributed to the evolution of woody floras in temperate drylands, whereas the opposite transitions decreased through time and contributed to herbaceous floras in tropical and subtropical drylands. Main conclusions: Our study improves understanding of the spatio‐temporal dynamics of angiosperm woodiness. Our findings suggest that temperature is likely to be a determinant of spatio‐temporal variations in woodiness, highlighting the role of temperature in maintaining the growth form composition of ecosystems. Our study also calls for attention to growth form transitions (e.g., secondary woodiness) in temperate drylands that have been neglected before. [ABSTRACT FROM AUTHOR]

The effects of contemporary climate, habitat heterogeneity and long-term climate change on species richness are well studied for woody plants in forest ecosystems, but poorly understood for herbaceous plants, especially in alpine–arctic ecosystems. Here, we aim to test if the previously proposed hypothesis based on the richness–environment relationship could explain the variation in richness patterns of the typical alpine–arctic herbaceous genus Saxifraga. Using a newly compiled distribution database of 437 Saxifraga species, we estimated the species richness patterns for all species, narrow- and wide-ranged species. We used generalized linear models and simultaneous autoregressive models to evaluate the effects of contemporary climate, habitat heterogeneity and historical climate on species richness patterns. Partial regressions were used to determine the independent and shared effects of different variables. Four widely used models were tested to identify their predictive power in explaining patterns of species richness. We found that temperature was negatively correlated with the richness patterns of all and wide-ranged species, and that was the most important environmental factor, indicating a strong conservatism of its ancestral temperate niche. Habitat heterogeneity and long-term climate change were the best predictors of the spatial variation of narrow-ranged species richness. Overall, the combined model containing five predictors can explain ca. 40%–50% of the variation in species richness. We further argued that additional evolutionary and biogeographical processes might have also played an essential role in shaping the Saxifraga diversity patterns and should be considered in future studies. [ABSTRACT FROM AUTHOR]

Although contemporary climate has been identified as one of the major determinants of large‐scale species diversity patterns, its effect on species diversity greatly varies among clades. Understanding the drivers of the variation in species diversity–climate relationships (DCRs) across clades, which is critical for developing general mechanisms underlying the effects of climate on species diversity patterns, remains a current challenge. Using newly compiled distribution data of 914 Rosaceae species in China and a dated genus‐level phylogeny, we first assessed the DCRs for the entire family, the two major growth forms (woody versus herbaceous), and each genus separately, and then explored the drivers underlying the variation in DCRs across different clades. We found that the DCRs significantly differed between woody and herbaceous plants and among different genera in this family. Closely related genera had more similar species diversity patterns and DCRs than expected. Both the ancestral climate niches of different genera and the discrepancy between contemporary and ancestral climate niches explained the variations in DCR slopes across genera with high explanatory power, indicating the effect of niche conservatism on DCRs. Our study suggests that niche conservatism is a major driver of DCR variations between clades, which enhances our understanding of the mechanisms underlying large‐scale species diversity patterns. [ABSTRACT FROM AUTHOR]

Aim: Biodiversity hotspots are widely used as conservation priorities to preserve the tree of life. However, many conservation practices identify biodiversity hotspots without considering phylogenetic diversity (PD), which reflects total evolutionary history and feature diversity of a region. Moreover, conservation planning rarely distinguishes between neo‐ and palaeo‐biodiversity hotspots despite their differences. Here, we (a) estimated large‐scale patterns in PD of woody plants, (b) identified neo‐ and palaeo‐biodiversity hotspots and (c) demonstrated their implication in conservation planning, with special focus on Hengduan Mountains and southern China. Location: China. Methods: Distributions of 11,405 woody species from the Atlas of Woody Plants in China were updated and were transformed into a grid of 50 × 50 km2. By integrating distribution maps with a genus‐level phylogeny of angiosperms, we estimated Faith's PD of each grid cell and evaluated the contribution of species relatedness to PD at given levels of species diversity (i.e. standardized PD, sPD) using regressions and three null models. Then, we identified areas with significantly lower or higher sPD than expected as neo‐ and palaeo‐hotspots and estimated the coverage of protected areas in these regions. Results: Species diversity and PD decreased towards the north. Southern China had high species diversity, PD and sPD, while Hengduan Mountains had high species diversity and PD but low sPD. The coverage of protected areas in southern China was less than half of that in Hengduan Mountains and entire China. Main conclusions: Our results identified Hengduan Mountains as a neo‐hotspot and southern China as a palaeo‐hotspot, highlighting their importance for biodiversity conservation. Compared to Hengduan Mountains, southern China has low coverage of protected areas, which calls for more conservation attention. Our study demonstrates a way of incorporating the phylogenetic component in the identification of neo‐ and palaeo‐hotspots, and hence of achieving a more complete perception of biodiversity patterns for conserving the tree of life. [ABSTRACT FROM AUTHOR]

Mechanisms underlying species richness patterns remain a central yet controversial issue in biology. Climate has been regarded as a major determinant of species richness. However, the relative influences of different evolutionary processes, (i.e. niche conservatism, diversification rate and time for speciation) on species richness–climate relationships remain to be tested. Here, using newly compiled distribution maps for 11 422 woody plant species in eastern Eurasia, we estimated species richness patterns for all species and for families with tropical and temperate affinities separately, and explored the phylogenetic signals in species richness patterns of different families and their relationships with contemporary climate and climate change since the Last Glacial Maximum (LGM). We further compared the effects of niche conservatism (represented by contemporary‐ancestral climatic niches differences), diversification rate and time for speciation (represented by family age) on variation in the slopes of species richness–climate relationships. We found that winter coldness was the best predictor for species richness patterns of most tropical families while Quaternary climate change was the best predictor for those of most temperate families. Species richness patterns of closely‐related families were more similar than those of distantly‐related families within eudicots, and significant phylogenetic signals characterized the slopes of species richness–climate relationships across all angiosperm families. Contemporary‐ancestral climatic niche differences dominated variation in the relationships between family‐level species richness and most climate variables. Our results indicate significant phylogenetic conservatism in family‐level species richness patterns and their relationships with contemporary climate within eudicots. These findings shed light on the mechanisms underlying large‐scale species richness patterns and suggest that ancestral climatic niche may influence the evolution of species richness–climate relationships in plants through niche conservatism. [ABSTRACT FROM AUTHOR]

Aims 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. Methods 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. Important Findings 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 FROM AUTHOR]

Aim Leaf margin states have been found to be strongly related to temperature, and hence have been used to reconstruct palaeotemperatures. Here, we aimed to explore the uncertainties and conditions of use of this technique in China by testing the influences of plant life-form, precipitation and evolutionary history on the relationship between percentage of untoothed species and temperature. Location China. Methods Using distribution maps and leaf margin states (untoothed versus toothed) of 10,480 Chinese woody dicots and dated family-level phylogenies, we evaluated the phylogenetic signal of leaf margin state, and demonstrated the variation in the patterns of leaf margin percentage and the relationship with temperature across different life-forms (evergreen and deciduous; trees, shrubs and lianas), regions with different precipitation and species quartiles with different family ages. Results Significant phylogenetic signals were found for the percentage of untoothed species within families. Relationships between leaf margin percentage and temperature were: (1) weak or insignificant for all woody dicots, shrubs, evergreen and deciduous dicots, but strong for trees and lianas; (2) significantly enhanced with increasing precipitation, and (3) significantly weakened for trees belonging to old families. Main conclusions Our results showed the complete leaf margin spectrum found in China and revealed great uncertainties in its relationship with temperature induced by life-form, precipitation and evolutionary history. These findings suggest that analysis of leaf margins for palaeotemperature reconstruction should be done cautiously: (1) only dicot trees with a relatively young family age can be used and their leaf margin states are more strongly affected by winter cold than by mean annual temperature; (2) the transfer function between leaf margin percentage and temperature is only reliable in humid and semi-humid regions of China. [ABSTRACT FROM AUTHOR]