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Tree diversity in Asia's tropical and subtropical forests is central to nature-based solutions. Species vulnerability to multiple threats, which affect provision of ecosystem services, is poorly understood. We conducted a region-wide, spatially explicit assessment of the vulnerability of 63 socioeconomically important tree species to overexploitation, fire, overgrazing, habitat conversion, and climate change. Trees were selected for assessment from national priority lists, and selections were validated by an expert network representing 20 countries. We used Maxent suitability modeling to predict species distribution ranges, freely accessible spatial data sets to map threat exposures, and functional traits to estimate threat sensitivities. Species-specific vulnerability maps were created as the product of exposure maps and sensitivity estimates. Based on vulnerability to current threats and climate change, we identified priority areas for conservation and restoration. Overall, 74% of the most important areas for conservation of these trees fell outside protected areas, and all species were severely threatened across an average of 47% of their native ranges. The most imminent threats were overexploitation and habitat conversion; populations were severely threatened by these factors in an average of 24% and 16% of their ranges, respectively. Our model predicted limited overall climate change impacts, although some study species were likely to lose over 15% of their habitat by 2050 due to climate change. We pinpointed specific natural areas in Borneo rain forests as hotspots for in situ conservation of forest genetic resources, more than 82% of which fell outside designated protected areas. We also identified degraded areas in Western Ghats, Indochina dry forests, and Sumatran rain forests as hotspots for restoration, where planting or assisted natural regeneration will help conserve these species, and croplands in southern India and Thailand as potentially important agroforestry options. Our results highlight the need for regionally coordinated action for effective conservation and restoration.Especies de Árboles Valoradas y Amenazadas de Asia Tropical y Subtropical Resumen La diversidad de árboles en los bosques tropicales y subtropicales de Asia es un eje central para las soluciones basadas en la naturaleza. La vulnerabilidad de las especies ante las múltiples amenazas, las cuales afectan el suministro de servicios ambientales, es un tema poco comprendido. Realizamos una evaluación regional espacialmente explícita de la vulnerabilidad de 63 especies de árboles de importancia socioeconómica ante la sobreexplotación, incendios, sobrepastoreo, conversión del hábitat y cambio climático. Los árboles se seleccionaron para su evaluación a partir de listas nacionales de prioridades, y las selecciones fueron validadas por una red de expertos de 20 países. Usamos el modelado de idoneidad Maxent para predecir el rango de distribución de las especies, conjuntos de datos espaciales de libre acceso para mapear la exposición a las amenazas y rasgos funcionales para estimar la susceptibilidad a las amenazas. Con base en la vulnerabilidad a las amenazas actuales y al cambio climático, identificamos las áreas prioritarias para su conservación y restauración. En general, el 74% de las áreas más importantes para la conservación de estos árboles quedó fuera de las áreas protegidas y todas las especies estaban seriamente amenazadas en promedio en el 47% de su distribución nativa. Las amenazas más inminentes fueron la sobreexplotación y la conversión del hábitat; las poblaciones estuvieron seriamente amenazadas por estos factores en promedio en el 24% y 16% de su distribución, respectivamente. Nuestro modelo predijo un impacto general limitado del cambio climático, aunque algunas especies estudiadas tuvieron la probabilidad de perder más del 15% de su hábitat para el 2050 debido a este factor. Identificamos áreas naturales específicas en las selvas de Borneo como puntos calientes para la conservación in situ de los recursos genéticos forestales, más del 82% de los cuales estaban fuera de las áreas protegidas designadas. También identificamos áreas degradadas en los Ghats Occidentales, los bosques secos de Indochina y las selvas de Sumatra como puntos calientes para la restauración, en donde la siembra o la regeneración natural asistida ayudarán a conservar estas especies. Además, identificamos campos de cultivo al sur de India y Tailandia como potenciales opciones importantes de agrosilvicultura. Nuestros resultados resaltan la necesidad de acciones regionales coordinadas para la conservación y restauración efectivas.【摘要】保护亚洲热带和亚热带森林的树木多样性是基于自然的解决方案的关注重点。物种面对多种威胁的脆弱性会影响生态系统服务的供给, 但目前人们对此仍知之甚少。我们对63种具有社会经济意义的树种面对过度开发、火灾、过度放牧、栖息地转换和气候变化的脆弱性进行了全区域空间显式评估。我们进行评估的树种来自国家优先保护名录, 树种的选择得到代表 20个国家的专家网络的认可。研究使用Maxent适宜性模型预测了物种分布范围, 并用可获取的空间数据集绘制了威胁暴露情况, 用功能特征估计了威胁敏感性。我们利用暴露地图和敏感性估计结果得到了物种特异的脆弱性地图, 并根据物种对当前威胁和气候变化的脆弱性, 确定了保护和恢复的优先区域。总的来说, 对这些树种的保护最重要的区域有 74%在保护区之外, 所有树种平均在其原生分布区 47%的范围内受到严重威胁。最紧迫的威胁是过度开发和栖息地转换;树木种群平均在其 24%和16%的范围内受到这些因素的严重威胁。我们的模型预测得到的气候变化整体影响有限, 尽管一些物种到2050年可能会因气候变化而失去超过15%的栖息地。我们发现婆罗洲雨林中特定的自然区域应作为森林遗传资源原地保护的热点地区, 该区域82%以上的面积位于已有保护区之外。我们还确定了西高止山、中南半岛旱林和苏门答腊雨林的退化地区为恢复热点地区, 在这些地区种植树木或辅助自然再生将有助于保护树种, 而印度南部和泰国的耕地则是潜在的重要农林地。我们的结果强调了为有效保护和恢复而采取区域性协调行动的必要性。【翻译: 胡怡思;审校: 聂永刚】.

AIM: A better understanding of plant communities can be achieved by incorporating data of traits and dynamics into surveys. Wood density is a good predictor for growth and mortality in trees, but to date, no studies of lianas include all three. We examine how liana communities respond to environmental gradients and forest fragmentation in terms of abundance, diversity, size structure, mortality, relative growth rate and wood density, and tested how the latter three are related to each other in liana species. LOCATION: Xishuangbanna, SW China. METHODS: We repeated a survey of lianas (stems >0.5 cm diameter) in 47 plots, distributed in forest fragments of various size, on different bedrock (limestone or sandstone), over an elevational range and across different topographic elements (ridge, slope, valley). We gathered wood density data for 116 of 166 species, covering 90% of all surveyed stems. We also determined relative growth rate, mortality, stem diameter and basal area. RESULTS: At the species level, liana mortality and relative growth rate were lower at higher wood density, and mortality was higher with greater relative growth rate. At the plot level, liana communities in valleys had high relative growth and mortality rates as well as high abundance and diversity. Forest on limestone hosted few species but more large‐stemmed liana individuals, and communities had higher wood density weighted by basal area. Liana abundance, relative growth rates and mortality were greater and average wood density lower towards fragment edges, but the explanatory power of these models was low. CONCLUSION: Habitat was the major factor shaping liana communities, whereas fragmentation was not an important predictor in our study. Resource‐rich environments such as valleys harbour diverse liana communities with high mortality and relative growth rates. This pattern matches earlier studies on survival/growth trade‐offs among plant species. The relationship between growth rates, mortality and wood density in lianas follows the same trade‐offs as found in trees.

AIM: Why some lineages are species‐rich and widespread, while others are species‐poor and localized, is a fundamental question in evolutionary biology and ecology. Diversification and range expansion relate to lineage‐specific niche characters, but this link has seldom been quantified across multiple lineages and environments. This study explored the link between local dominance and soil niche in rain forest plants, and tested the hypothesis that local soil niche patterns can be used to predict the global diversity and occupancy of equal‐aged plant lineages. LOCATION: The study was carried out in Brunei Darussalam (Borneo) and projected worldwide. METHODS: Our approach involved the subdivision of vascular plants into the lineages found 120 Mya, a time preceding the explosive radiation of the eudicots. We quantified the representation of the 120 Mya lineages in different forest types associated with dramatically different soils, but sharing the same climatic conditions. The forest types included primary and secondary lowland rain forest, flooded and nutrient‐impoverished inland forests, and mangroves. Niche breadth and position, estimated from the soil types that a lineage occupied, were used to predict global diversity and occupancy patterns, after accounting for relatedness to the dominant eudicots. RESULTS: Despite marked differences in soil characteristics among the forest types, three eudicot lineages (Malvidae, Fabidae, Asteridae) were consistently dominant over the other 28 lineages present. A broad, intermediate soil niche, relatedness to eudicots, and the interaction between these factors were found to be strong predictors of global diversity and occupancy. MAIN CONCLUSIONS: We show that vegetation plot data from one of the world's most diverse regions (in terms of plant species richness and ancient lineage representation) can be used to successfully predict lineage diversity and occupancy on a global scale. However, because lineage dominance likely depends on the interaction between soil niche and above‐ground factors, including above‐ground niche features should improve the accuracy of predicting global distribution and diversity—particularly when explaining eudicot dominance.

AIM: Small, old‐growth forest fragments generally have more small‐seeded plants than large patches, due to the disappearance of large seed dispersing vertebrates. This pattern may differ for secondary forest fragments where differential migration ability rather than persistence of seed dispersers may be driving plant community assembly. In this study, we investigated the effect of habitat fragmentation on seed dispersers and plant community structure in regenerating forests. LOCATION: The Thousand Island Lake, China. TAXON: Plants, birds and mammals. METHODS: We compiled diversity and abundance data for birds and mammals on islands in the Thousand Island Lake, China. We also surveyed the secondary plant communities and measured seed dispersal traits. RESULTS: Community‐weighted mean seed size of woody plants decreased with island size. This pattern was related to compositional difference of the dispersers. We found that mammal diversity and abundance was only weakly or not related to island size; whereas bird diversity and abundance increased strongly with island size. Density of bird‐dispersed plants was significantly positively related with island size. Since birds tend to disperse smaller seeds than mammals, the trend in seed size may have been a consequence of the shift in relative abundance of the two disperser guilds. MAIN CONCLUSIONS: Differential responses of seed dispersers to habitat fragmentation may lead to pervasive shifts in the plant community structure of regenerating forest fragments. Our study highlights the importance of keeping large continuous forests in order to retain mammals and their dispersal capabilities.

It remains unclear whether the latitudinal diversity gradients of micro- and macro-organisms are driven by the same macro-environmental variables. We used the newly completed species catalog and distribution information of bryophytes in China to explore their spatial species richness patterns, and to investigate the underlying roles of energy availability, climatic seasonality, and environmental heterogeneity in shaping these patterns. We then compared these patterns to those found for woody plants. We found that, unlike woody plants, mosses and liverworts showed only weakly negative latitudinal trends in species richness. The spatial patterns of liverwort richness and moss richness were overwhelmingly explained by contemporary environmental variables, although explained variation was lower than that for woody plants. Similar to woody plants, energy and climatic seasonality hypotheses dominate as explanatory variables but show high redundancy in shaping the distribution of bryophytes. Water variables, that is, the annual availability, intra-annual variability and spatial heterogeneity in precipitation, played a predominant role in explaining spatial variation of species richness of bryophytes, especially for liverworts, whereas woody plant richness was affected most by temperature variables. We suggest that further research on spatial patterns of bryophytes should incorporate the knowledge on their ecophysiology and evolution.

Question: Lianas depend on support to reach optimal growing conditions. They can infest trees unevenly, and host selection may depend on functional characteristics of the potential hosts, such as growth rate, bark type or tree architecture. In this context we hypothesized that (1) simple proximity to the rooting point of the liana is the overriding property predicting the probability of selection as the host; (2) the distance to the host decreases with increasing stem density in the surrounding community; (3) host distance becomes more variable with liana age (similar to diameter), as some larger lianas probably have already lost their first host, whereas small lianas should use the nearest available stem to climb; and (iv) liana infestation of plant families is proportional to family abundance. Location: Montane forest in southwest China. Methods: We surveyed lianas (>= 0.5-cm diameter) in 17 plots consisting of 153 subplots, recording the rooting point of lianas and the closest used host and nearest possible support, species identity and diameter of both liana and host. Results: Of the analysed host-liana pairs, half of all lianas used the host that was closest to their rooting points. Distance to the nearest support was the most important predictor for host distance. Tree stem density had no major influence on liana-host distance. The variance in host distance did not increase with liana diameter. Liana infestation of plant families increased with family abundance. Conclusion: We conclude that the proximity of a host is the most important of the tested factors determining climbing host selection in lianas, however we only considered stem, not crown, infestation.

AimForest fragmentation is often accompanied by an increase in hunting intensity. Both factors are known drivers of species extirpations, but understanding of their independent effects is poor. Our goal was to partition the effects of hunting and fragmentation on bird species extirpations and to identify bird traits that make species more vulnerable to these two stressors. LocationMenglun, Yunnan, SW China MethodsWe studied the landscape within 10km radius of Menglun town, where forests have become highly fragmented by monoculture rubber plantations. We compiled data on birds recorded between 1954 and 1983 before forest loss and compared it with a checklist prepared between 2011 and 2014. We used countryside and matrix-calibrated species-area models (SAMs) to estimate the observed slope of forest bird extirpations in Menglun and compared it with the slope expected in the absence of hunting. We also investigated six ecological traits to determine those that best explained bird extirpation probability (EP). ResultsWe found that 34% of the bird fauna had been extirpated from the study landscape, and the estimated slopes of countryside and matrix-calibrated SAMs for forest birds were around 1.4 and 1.7 times higher, respectively, than the 0.35 expected without hunting. Bird EP was strongly associated with size, and understorey insectivores that are known to be susceptible to fragmentation were less susceptible to hunting than frugivores. Given evidence of past and present hunting activity in the area, and the lack of support for alternative explanations, we suggest that hunting increased forest bird extirpations by around 1.3- to 1.6-fold. ConclusionsThis study highlights the importance of using species-area relationships to separate area effects from the impacts of hunting. Our results suggest that hunting substantially increases species extirpations in tropical fragmented landscapes and conservation interventions that only target deforestation will therefore be inadequate.

Previous research found that phylogenetic clustering increased with disturbance for tropical trees, suggesting that community assembly is mainly influenced by abiotic factors during early succession. Lianas are an important additional component of tropical forests, but their phylogenetic community structure has never been investigated. Unlike tropical trees, liana abundance is often high in disturbed forests and diversity can peak in old secondary forest. Therefore, phylogenetic structure along a disturbance gradient might also differ from tropical tree communities. Here we determined phylogenetic community structure of lianas along a disturbance gradient in a tropical montane forest in China, using the net relatedness index (NRI) from 100 equivalent phylogenies with varying branch length that were constructed using DNA-barcode sequences. Three additional phylogenetic indices were also considered for comparison. When NRI was used as index phylogenetic clustering of liana communities decreased with decreasing tree basal area, suggesting that liana competitive interactions dominate during early succession, which is in contrast to the pattern reported for trees. Liana communities in mature forests, on the other hand, were phylogenetic clustered, which could be caused by dispersal limitation and/or environmental filtering. The three additional phylogenetic indices identified different, sometimes contradicting predictors of phylogenetic community structure, indicating that caution is needed when generalizing interpretations of studies based on a single phylogenetic community structure index. Our study provides a more nuanced picture of non-random assembly along disturbance gradients by focusing on a non-tree forest component.

We apply a process-based model, called 3-PG (physiological principles for predicting growth), to estimate aboveground biomass for the primary forests of Borneo. Using publicly available soil and climate data, and parameterized with physiological traits of Bornean forest, the modeled aboveground biomass and basal area showed statistically significant relationships with field-measured data from 85 sites across four major forest types. Our results highlight the possibility to expand the application of 3-PG to forests of varying condition, which would facilitate inclusion of modeled forest biomass data for developing a Tier 3 carbon inventory system for Borneo.

Aim A wide range of forests distributed across steep environmental gradients are found in Yunnan, southwest China. Climate change could profoundly change these forests by affecting species ranges. We produce predictions about species suitable habitat shifts and use these to (1) evaluate species range size change, loss and turn-over under no- and full-dispersal and nine climate change scenarios and (2) identify environmental variables responsible for current species richness and future local species losses. Location Yunnan Province, Southwest China. Methods Using MaxEnt, we modelled current distributions of 2319 woody plant species, corrected for collecting bias and found that 1996 had significant spatial association with environmental factors. Using three General Circulation Models (GCMs: CGCM, CSIRO and HADCM3) for the years 2070–2099 (2080s), based on three emission scenarios for each GCM (A1b, A2a and B2a), we predicted the future geographic position of suitable habitat for each species. Results Although most species were predicted to persist within Yunnan, with a maximum extinction rate of c. 6% under the most extreme climate change scenario, up to 1400 species (of the 1996 tested) are expected to lose more than 30% of their current range under the most extreme climate change scenario. Assuming no- or unlimited dispersal minimally affected these outcomes. Species losses were associated with increasing temperature variability and declining precipitation during the dry season. Main conclusions To conserve Yunnan’s woody flora, management efforts should focus on providing elevational migration routes at local scales, with priority for those areas located within previously identified conservation hotspots. As almost all species show range contractions, storage of genetic diversity in seed banks and botanical gardens would be sensible. A change in Yunnan’s conservation policy will be needed to counter the predicted negative impacts of climate change on its flora.

Summary 1. Increasingly, ecologists are using functional and phylogenetic approaches to quantify the relative importance of stochastic, abiotic filtering and biotic filtering processes shaping the pattern of species co-occurrence. A remaining challenge in functional and phylogenetic analyses of tropical tree communities is to successfully integrate the functional and phylogenetic structure of tree communities across spatial and size scales and habitats in a single analysis. 2. We analysed the functional and phylogenetic structure of tree assemblages in a 20-ha tropical forest dynamics plot in south-west China. Because the influence of biotic interactions may become more apparent as cohorts age, on local scales, and in resource-rich environments, we perform our analyses across three size classes, six spatial scales and six distinct habitat types, using 10 plant functional traits and a molecular phylogeny for the >400 tree taxa found in the plot. 3. All traits, except leaf area and stem-specific resistance, had significant, albeit weak phylogenetic signal. For canopy species, phylogenetic clustering in small and medium size classes turned to phylogenetic overdispersion in the largest size class and this change in dispersion with size was found in each habitat type and across all spatial scales. On fine spatial scales, functional dispersion changed from clustering to overdispersion with increasing size classes. However, on larger spatial scales assemblages were functionally clustered for all size classes and habitats. 4. Phylogenetic and functional structure across spatial and size scales and habitats gave strong support for a deterministic model of species co-occurrence rather than for a neutral model. The results also support the hypothesis that abiotic determinism is more important at larger scales, while biotic determinism is more important on smaller scales within habitats.

Aim Large trees (d.b.h. 70 cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, poten- tially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore which intrinsic (species trait) and extrinsic (environment) variables are associated with the density of large trees and forest biomass at continental and pan-tropical scales. Location Pan-tropical.

While many plant species are considered threatened under anthropogenic pressure, it remains uncertain how rapidly we are losing plant species diversity. To fill this gap, we propose a Global Legume Diversity Assessment (GLDA) as the first step of a global plant diversity assessment. Here we describe the concept of GLDA and its feasibility by reviewing relevant approaches and data availability. We conclude that Fabaceae is a good proxy for overall angiosperm diversity in many habitats and that much relevant data for GLDA are available. As indicators of states, we propose comparison of species richness with phylogenetic and functional diversity to obtain an integrated picture of diversity. As indicators of trends, species loss rate and extinction risks should be assessed. Specimen records and plot data provide key resources for assessing legume diversity at a global scale, and distribution modeling based on these records provide key methods for assessing states and trends of legume diversity. GLDA has started in Asia, and we call for a truly global legume diversity assessment by wider geographic collabora- tions among various scientists.

Summary 1. Stem xylem characteristics have a great impact on growth and adult stature of trees because of their role in mechanical support, long-distance water transport and whole-plant carbon allocation. Yet, despite the potential causal link between xylem traits and plant growth ⁄ adult stature, most studies have tried to link wood density, an indirect but easy to measure proxy for wood properties, to tree growth and size. 2. To determine whether xylem traits outperform wood density as predictors of tree growth and stature, we evaluated the covariation among wood density, xylem anatomical traits, tree diameter growth rate and adult stature in 40 Asian tropical tree species through principal component analyses and through bivariate correlation, both across species and across phylogenetically independent contrasts. 3. Vessel diameter exhibited a tight negative relationship with vessel frequency. Wood density showed a significant correlation with vessel diameter and density, but not with vessel fraction. Most correlations between functional traits indicate adaptive coordination, demonstrated by significant correlations between phylogenetically independent contrasts. 4. Across species, diameter growth rate and adult stature were positively correlated with vessel lumen diameter and potential hydraulic conductivity, but not with wood density. Thus, our results suggest that xylem anatomical traits that are linked to hydraulic conductivity are better predictors of tree growth rate and adult stature than wood density. 5. Synthesis. We found that xylem anatomical traits have a more significant influence on wholeplant performance due to their direct association with stem hydraulic conductivity, whereas wood density is decoupled from hydraulic function due to complex variations in xylem components.

Large parts of the everwet tropics have been burned, leaving many unburned–burned forest edges. Here we studied a Bornean forest edge to determine: (1) how unburned and burned forest differ in vegetation structure, diversity, composition and plant functional traits 7 yr after fire, and (2) if these variables showed significant edge effects. Environmental and inventory data from 120 plots (0.01 ha each), covering both sides of a � 1.3 km forest boundary were sampled. Differences in vegetation structure, diversity, composition and plant functional traits were analyzed in relation to disturbance type (Mann–Whitney tests) and edge distance (partial correlation analysis that controlled for confounding effects of elevation, slope and fire intensity). Seven years after fire, burned forest differed significantly from unburned forest in most measured variables while few significant edge effects were detected, i.e., there existed a sharp delimitation between the two forest types. The regeneration of the burned forest depended almost entirely on in situ recruitment with little input of late successional species from the neighboring old growth forest. On the other hand, old growth forest showed few signs of edge degradation. A possible explanation for these results might be related to the absence of a mast fruiting event during these first 7 yr of forest recovery, resulting in low levels of late successional species seed input into the burned forest, combined with the quick development of a closed canopy in the burned forest by early successional species that shielded the unburned forest from adverse edge effects.

Aim Wood properties are related to tree physiology and mechanical stability and are influenced by both phylogeny and the environment. However, it remains unclear to what extent geographical gradients in wood traits are shaped by either phylogeny or the environment. Here we aimed to disentangle the influences of phylogeny and the environment on spatial trends in wood traits.

Inventories of tree species are often conducted to guide conservation efforts in tropical forests. Such surveys are time consuming, demanding of expertise, and expensive to perform and interpret. Approaches to make survey efforts simpler or more effective would be valuable. In particular, it would be good to be able to easily identify areas of old-growth forest. The average density of the wood of a tree species is closely linked to its successional status. We used tree inventory data from eastern Borneo to determine whether wood density can be used to quantify forest disturbance and conservation importance. The average density of wood in a plot was significantly and negatively related to disturbance levels, with plots with higher wood densities occurring almost exclusively in old-growth forests. Average wood density was unimodally related to the diversity of tree species, indicating that the average wood density in a plot might be a better indicator of old-growth forest than species diversity. In addition, Borneo endemics had significantly heavier wood than species that are common throughout the Malesian region, and they were more common in plots with higher average wood density. We concluded that wood density at the plot level could be a powerful tool for identifying areas of conservation priority in the tropical rain forests of Southeast Asia.