Mechanisms underlying the assembly and succession of phyllosphere microbiota in rubber plantations are crucial for understanding ecosystem health and functionality, yet poorly understood. In this study, high-throughput sequencing was used to analyze the diversity, assembly mechanisms, and potential sources of phyllosphere microbial communities at developmental stages. Key findings include: (1) Epiphytic and endophytic bacterial diversity peaked at the budding stage, then decreased and subsequently showed a gradual increase again toward the senescence stage, primarily driven by leaf nitrogen (N), phosphorus (P), and potassium (K). However, epiphytic and endophytic fungal diversity was significantly regulated by leaf N and P. (2) Assembly processes exhibited niche differentiation: the assembly of epiphytic bacteria during the color-changing and stable stages was dominated by stochastic processes, while deterministic regulation prevailed in other stages and in endophytic communities. Both assembly and network complexity were driven by leaf N and K dynamics. Fungal network complexity and deterministic regulation, in both epiphytic and endophytic niches, were promoted by leaf N and P during early stages but gradually weakened thereafter. (3) Active material exchange occurred between epiphytic and endophytic niches, and below-ground niches contributed more significantly to the fungal community. Overall, our results underscores that leaf nutrients modulate the diversity, assembly, and resultant compositional landscape of phyllosphere microorganisms at different developmental stages. These insights contribute to deepening the fundamental understanding of plant-microbial symbiosis and inform strategies for the cultivation of rubber trees.

The mid-domain effect (MDE) has been used to explain spatial diversity patterns and flowering phenology, but its role in fruiting phenology has received limited attention to date. This study investigates whether the MDE shapes fruiting phenology and whether its influence varies with latitude. We integrated fruiting phenology data for 12,179 plant species across 28 Chinese provinces and used a null model to simulate expected fruiting richness patterns. Our results suggest that the MDE plays a significant role in explaining fruiting phenology patterns in most provinces. Crucially, the variance explained by the MDE exhibited a significant unimodal relationship with latitude across all groups, peaking at mid-latitudes (39.6° N for all species, 37.1° N for herbaceous plants, and 36.8° N for woody plants). Unlike flowering phenology—which tends to show a simple linear increase in MDE strength with latitude—fruiting exhibited a distinct peak, highlighting different ecological pressures acting on these two reproductive stages. The MDE was the primary contributor explaining fruiting richness, providing a markedly stronger fit to the data than key climate variables like temperature and precipitation, although woody plants showed a stronger secondary response to precipitation. These findings demonstrate that geometric constraints are a key driver of fruiting phenology, deepening our understanding of temporal niches and the ecological processes shaping plant reproductive phenology.

Spring phenology has noticeably changed with changes to diurnal temperature (daytime temperature vs. nighttime temperature) and seasonal temperature (winter chilling vs. spring forcing) around the globe. However, the climate cues influencing the days of interval between budburst and leaf-out have not been studied. Here, we conducted two experiments to simulate how changes in diurnal temperature or seasonal temperature influence spring leaf phenology (budburst, leaf-out and the interval between them) for subtropical woody species in eastern China. We found that prolonged chilling and higher forcing temperatures advanced both budburst and leaf-out and shortened the interval between the two, but the interval was more strongly influenced by chilling than by forcing. The budburst, leaf-out, and the interval between these events each responded more strongly to changes in daytime temperature than to changes in night-time temperature. The budburst event was more responsive to diurnal and seasonal temperatures than leaf-out event. Our findings offer insight into how seasonal and diurnal temperature regulate spring phenology. Such advancements improve our understanding and ability to accurately predict the response of woody ecosystems to a changing climate.

Due to the intensive use of land and global warming, the response of species within the plant community to environmental changes and the developmental trend of the community have attracted global attention. Affected by human disturbance and rising sea levels, mangrove forests are undergoing a significant reduction in plant density. Due to unfavorable factors such as increased salinity and prolonged flooding time accompanying rising sea levels, it is difficult to predict how the growth and physiological processes of different mangrove individuals will respond to these factors and what impact these responses will bring to the development of mangrove plant communities. In this study, we simulated rising sea levels by controlling light intensity, seawater salinity, and flooding time, and studied the physiological and ecological response mechanisms of six representative mangrove species on Hainan Island, China, to rising sea levels with the goal to predict the development of mangrove plant communities in this region. The results showed that tree species distributed at high tidal levels were more susceptible to rising sea levels than those growing at medium and low tidal levels. Due to the rise in sea level, increasing flooding time, and high salinity stress, mangroves would naturally migrate inland. However, due to human disturbance that resulted in shoreline hardening, the mangrove retreat space is inadequate as their distribution area gradually becomes smaller and disappears. If measures are not taken to restore the natural environment of the offshore coast and allow mangroves to advance and retreat freely, global warming and rising sea levels will affect in particular the mangrove species growing at high tidal levels, such as Excoecaria agallocha, Lumnitzera littorea, Lumnitzera racemosa, Bruguiera sexangula, and Ceriops tagal.

The ongoing climate change-induced shifts in flowering phenology have emerged as a consequential force impacting biodiversity and ecosystems. Despite the globally recognized significance of flowering phenology as a key reproductive attribute, studies in subtropical regions have been relatively fewer, particularly in comparison to temperate and cold regions. Additionally, the nuanced response of deciduous and evergreen plants to climate change remains insufficiently explored. In addressing this gap, we built a phenological model and a generalized linear mixed effect model to assess the differential responses of key flowering phenological traits, that is, first flowering date (FFD), peak flowering date (PFD), end of flowering date (EFD), and flowering duration (FD), to climate factors (temperature and precipitation) between deciduous and evergreen plants. We observed distinct responses in flowering phenological traits to climate change between deciduous and evergreen plants. Specifically, the advancement of FFD, PFD, and EFD in deciduous in response to temperature rise exceeded that in evergreen plants. FD in evergreen plants exhibited a stronger extension to temperature increase compared to deciduous. Conversely, the phenological change of evergreen plants in response to decreasing precipitation was greater than that of deciduous ones. Since temperature is a decisive climatic factor in affecting phenological changes, climate change-induced advances in flowering phenology of deciduous plants are still larger than evergreen plants. Projections from our phenological model under future climate scenarios (SSP 1-2.6 and SSP 5-8.5) indicate a continuous enlargement of difference in flowering phenology between deciduous and evergreen plants, with this trend escalating into the future (2100>2070>2050>2030). The larger extension in FD of evergreens to climate change suggests a potential increase in their proportion within subtropical forest communities relative to deciduous plants. These insights contribute significantly to our understanding of the intricate dynamics of climate-induced changes in subtropical plant ecosystems.

Chrozophora sabulosa Kar. Kir. is a biennial herbaceous plant that belongs to the Euphorbiaceae family and has medicinal properties. This research aimed to identify the genetic characteristics and phylogenetic position of the Chrozophora genus within the Euphorbiaceae family. The evolutionary position of the Chrozophora genus was previously unknown due to insufficient research. Therefore, to determine the evolutionary link between C. sabulosa and other related species, we conducted a study using the NGS Illumina platform to sequence the C. sabulosa chloroplast (cp.) genome. The study results showed that the genome was 156,488 bp in length. It had a quadripartite structure consisting of two inverted repeats (IRb and IRa) of 24,649-bp, separated by an 87,696-bp LSC region and a 19,494-bp SSC region. The CP genome contained 113 unique genes, including four rRNA genes, 30 tRNA genes, and 79 CDS genes. In the second copy of the inverted repeat, there were 18 duplicated genes. The C. sabulosa lacks the petD, petB, rpl2, and rps16 intron. The analysis of simple sequence repeats (SSRs) revealed 93 SSR loci of 22 types and 78 oligonucleotide repeats of four kinds. The phylogenetic investigation showed that the Chrozophora genus evolved paraphyletically from other members of the Euphorbiaceae family. To support the phylogenetic findings, we selected species from the Euphorbiaceae and Phyllanthaceae families to compare with C. sabulosa for Ks and Ka substitution rates, InDels investigation, IR contraction and expansion, and SNPs analysis. The results of these comparative studies align with the phylogenetic findings. We identified six highly polymorphic regions shared by both families, which could be used as molecular identifiers for the Chrozophora genus (rpl33-rps18, rps18-rpl20, rps15-ycf1, ndhG-ndhI, psaI-ycf4, petA-psbJ). The cp. genome sequence of C. sabulosa reveals the evolution of plastid sequences in Chrozophora species. This is the first time the cp. genome of a Chrozophora genus has been sequenced, serving as a foundation for future sequencing of other species within the Chrozophoreae tribe and facilitating in-depth taxonomic research. The results of this research will also aid in identifying new Chrozophora species.

The timing of flowering is an important driver of species distribution and community assembly patterns. However, we still have much to learn about the factors that shape flowering diversity (i.e., number of species flowering per period) in plant communities. One potential explanation of flowering diversity is the mid-domain effect, which states that geometric constraints on species ranges within a bounded domain (space or time) will yield a mid-domain peak in diversity regardless of ecological factors. Here, we determine whether the mid-domain effect explains peak flowering time (i.e., when most species of communities are flowering) across China. We used phenological data of 16,267 herbaceous and woody species from the provincial Flora in China and species distribution data from the Chinese Vascular Plant Distribution Database to determine relationships between the observed number of species flowering and the number of species flowering as predicted by the mid-domain effect model, as well as between three climatic variables (mean minimum monthly temperature, mean monthly precipitation, and mean monthly sunshine duration). We found that the mid-domain effect explained a significant proportion of the temporal variation in flowering diversity across all species in China. Further, the mid-domain effect explained a greater proportion of variance in flowering diversity at higher latitudes than at lower latitudes. The patterns of flowering diversity for both herbaceous and woody species were related to both the mid-domain effect and environmental variables. Our findings indicate that including geometric constraints in conjunction with abiotic and biotic predictors will improve predictions of flowering diversity patterns.

The quantification of large-scale leaf-age-dependent leaf area index has been lacking in tropical and subtropical evergreen broadleaved forests (TEFs), despite the recognized importance of leaf age in influencing leaf photosynthetic capacity in this biome. Here, we simplified the canopy leaves of TEFs into three age cohorts (i.e., young, mature, and old, with different photosynthesis capacities; i.e., Vc,max) and proposed a novel neighbor-based approach to develop the first gridded dataset of a monthly leaf-age-dependent leaf area index (LAI) product (referred to as Lad-LAI) at 0.25∘ spatial resolution over the continental scale during 2001–2018 from satellite observations of sun-induced chlorophyll fluorescence (SIF) that was reconstructed from MODIS and TROPOMI (the TROPOspheric Monitoring Instrument). The new Lad-LAI products show good performance in capturing the seasonality of three LAI cohorts, i.e., young (LAIyoung; the Pearson correlation coefficient of R=0.36), mature (LAImature; R=0.77), and old (LAIold; R=0.59) leaves at eight camera-based observation sites (four in South America, three in subtropical Asia, and one in the Democratic Republic of the Congo (DRC)) and can also represent their interannual dynamics, validated only at the Barro Colorado site, with R being equal to 0.54, 0.64, and 0.49 for LAIyoung, LAImature, and LAIold, respectively. Additionally, the abrupt drops in LAIold are mostly consistent with the seasonal litterfall peaks at 53 in situ measurements across the whole tropical region (R=0.82). The LAI seasonality of young and mature leaves also agrees well with the seasonal dynamics of the enhanced vegetation index (EVI; R=0.61), which is a proxy for photosynthetically effective leaves. Spatially, the gridded Lad-LAI data capture a dry-season green-up of canopy leaves across the wet Amazonian areas, where mean annual precipitation exceeds 2000 mm yr−1, consistent with previous satellite-based analyses. The spatial patterns clustered from the three LAI cohorts also coincide with those clustered from climatic variables over the whole TEF region. Herein, we provide the average seasonality of three LAI cohorts as the main dataset and their time series as a supplementary dataset. These Lad-LAI products are available at https://doi.org/10.6084/m9.figshare.21700955.v4 (Yang et al., 2022).

Global warming is having an unprecedented impact on plant phenology and vitality worldwide, potentially leading to significant changes in the food web, carbon, water cycling and ecosystem functions. Environmental drivers explaining spring phenology, mainly including temperature (chilling in late autumn and winter and forcing in late winter and spring) and photoperiod, have been extensively investigated in temperate trees, but these factors have been rarely studied in subtropical forests and their potential effects are therefore relatively unknown. This knowledge gap is especially important to fill because these ecosystems harbor the largest portion of the world's biodiversity. In this study, we sought to test the effects of chilling (low vs. high) and forcing temperatures (20 vs. 25 degrees C) on spring phenology for seedlings of five subtropical woody species using six climate chambers. We compared forcing requirements for budburst and leaf-out in the different treatments by calculating the number of degree days achieved from the start of the experiment to the time of budburst and leaf-out, and we examined seedlings' survival under the different treatments. Although the survival of subtropical seedlings was found to be little affected by variation in chilling or forcing, longer chilling duration and warmer forcing tem-perature led to a lower forcing requirement for budburst, which advanced both budburst and leaf-out. This suggests that the seedlings experienced a non-linear accumulation of forcing with generally a higher efficiency at 25 degrees C than at 20 degrees C. Interestingly, shorter exposure to chilling conditions disrupted the sequence of budburst / leaf-out timings among the study species. This study confirms that the sensitivity of spring leaf phenology to forcing and chilling is not only found in temperate perennial plants but also in subtropical trees that undergo a dormancy period. It offers new perspectives for a comprehensive analysis of subtropical plant phenology in response to global climate change.

该文选取浙江省古田山亚热带常绿阔叶林72种木本植物,探究气候因素、系统发育关系和功能性状对亚热带常绿阔叶林叶衰老物候的影响.结果表明,叶变色期在9—12月,落叶期在10—12月.每月落叶物种数与月均温、月均降水量和月均日照时数没有显著相关性,每月叶变色物种数与月均温和月均日照时数呈弱相关;落叶性对叶变色期和落叶期具有显著影响;植物间系统发育关系对叶变色期和落叶期没有显著影响.因此,生物和非生物因子都会影响常绿阔叶树种的叶衰老,这对于提高秋季物候预测模型具有重要价值.

The cortex-to-stele ratio (CSR), as it increases from thin- to thick-root species in angiosperms, is theorised to effectively reflect a compensation for the 'lag' of absorption behind transportation. But it is still not known if this compensatory effect exists in gymnosperm species or governs root structure and function within species. Here, anatomical, morphological, and tissue chemical traits of absorptive roots were measured in three temperate angiosperm and three gymnosperm species. Differences in the CSR and the above functional traits, as well as their intraspecific associations, were analyzed and then compared between angiosperms and gymnosperms. At the intraspecific level, the CSR decreased with increasing root order for all species. The expected functional indication of the CSR was consistent with decreases in specific root length (SRL) and N concentration and increases in the C to N ratio (C:N ratio) and the number of and total cross-sectional area of conduits with increasing root order, demonstrating that the CSR indicates the strength of absorption and transportation at the intraspecific level, but intraspecific changes are due to root development rather than the compensatory effect. These trends resulted in significant intraspecific associations between the CSR and SRL (R 2 = 0.36 ~ 0.80), N concentration (R 2 = 0.48 ~ 0.93), the C:N ratio (R 2 = 0.47 ~ 0.91), and the number of (R 2 = 0.21 ~ 0.78) and total cross-sectional area (R 2 = 0.29 ~ 0.72) of conduits in each species (p< 0.05). The overall mean CSR of absorptive roots in angiosperms was four times greater than in gymnosperms, and in angiosperms, the CSR was significantly higher in thick- than in thin-rooted species, whereas in gymnosperms, the interspecific differences were not significant (p > 0.05). This suggests that the compensation for the lag of absorption via cortex thickness regulation was stronger in three angiosperm species than in three gymnosperm species. In addition, there was poor concordance between angiosperms and gymnosperms in the relationships between CSRs and anatomical, morphological, and tissue chemical traits. However, these gymnosperm species show a more stable intraspecific functional association compared to three angiosperm species. In general, absorptive root CSRs could manifest complex strategies in resource acquisition for trees at both intra- and interspecific levels.

Hainan Tropical Rainforest National Park is located in the middle mountainous region of Hainan Province, and it has a diverse landscape with 95.56% forest coverage. Studying the evolutionary aspects of the landscape pattern in time and space in Hainan Tropical Rainforest National Park is extremely important for preserving and enhancing Hainan Province's ecological security barrier. The landscape pattern index, single-motion landscape dynamic attitude and landscape transfer matrix were used to examine the geographical and temporal evolution features of the landscape pattern of 10 land cover patterns in Hainan Tropical Rainforest National Park between 2015 and 2020. This study used ground cover data from the Hainan Tropical Rainforest National Park between 2015 and 2020 to develop a landscape pattern distribution system based on actual ecological situations. Other elements that affected the evolution of the landscape pattern in Hainan Tropical Rainforest National Park included policies, climate and other natural and human factors. The results were as follows: (1) The overall landscape fragmentation of Hainan Tropical Rainforest National Park reduced from 2015 to 2020, increasing spatial agglomeration of the landscape, decreasing integrated dynamic attitude, and generally steady development of landscape patterns. (2) The area of evergreen broad-leaved forest in the tropical rainforest increased in five years, with an increase of 531.38 km2, a decrease in fragmentation, and a positive growth trend, and the landscape tends to be concentrated in patches; on the other hand, the area of needle-leaved forest and shrubwood significantly reduced, with losses of 189.53 km2 and 294.74 km2 respectively; there was also a partial transformation of water, and the area of the water landscape had been somewhat reduced, and the patches tended to be concentrated and spread; the remainder of the landscape patterns accounted for a relatively modest amount, and developed and changed in the direction of natural succession. (3) The landscape pattern evolution of Hainan Tropical Rainforest National Park was primarily based on natural succession of the rainforest, followed by a comprehensive impact of policy, climate and other factors, which reduced human factors on the tropical rainforest landscape interference and was conducive to improving the rainforest ecosystem's self-healing capacity. To summarize, the landscape pattern of Hainan Tropical Rainforest National Park has been stable since the commencement of the pilot project, and policy direction has played an essential constructive role. The targeted conservation and restoration of the tropical rainforest landscape will help to the Hainan Tropical Rainforest National Park's sustainable development.

The timing of flowering and fruiting plays a critical role in the reproduction, population size, and range of fruit-eating animals. The Hainan Tropical Rainforest National Park, China, hosts one of the world’s most endangered primate species, the Hainan gibbon (Nomascus hainanus). Understanding the phenological patterns of the principal food sources of the Hainan gibbon is crucial for the effective management of their habitats and the conservation of this threatened population. To that end, we conducted a regression analysis to better understand how climate may impact the timing and availability of fruits known to support the Hainan gibbon. We observed significant seasonal and inter-annual variations in the reproductive phenology of these fruiting species, with most species flowering from March to June and fruiting from August to December. Importantly, we found that Hainan gibbons face severe food scarcity between January and April. We show that sunshine exerts a significant effect on the flowering time, while fruiting phenology is most sensitive to temperature. We suggest that the restoration of the Hainan gibbon habitat should include planting more tree species which that produce fruit in the time of low food availability between January-April, including the species Memecylon ligustrifolium, Wrightia pubescens, Sarcosperma laurinum, Eurya ciliata, and Pouteria annamensis.

World natural heritage sites are some of the most important and valuable protected areas in the world, and their designation aims to give recognition to the uniqueness and protect the integrity of the sites, which are of global outstanding universal value. Understanding the global uniqueness and value of natural heritage will help to better manage and protect them, support the functioning of ecosystems, and promote sustainable development of humans and nature. A systematic review was conducted to determine the potential for the Hainan tropical rainforest to become a world natural heritage site. Based on a large number of literatures, we took the native plants, animals and vegetation communities of Hainan’s potential natural world heritage site (Hainan Tropical Rainforest National Park) as the research objects, and evaluated the global outstanding universal value of Hainan’s potential natural world heritage site from the aspects of biological ecological processes such as vegetation types, species diversity, fauna composition and endemic species. The results are as follows: (1) Hainan potential world natural heritage site has 3 653 vascular plant species. There are 540 species of terrestrial vertebrates, which account for 10%-30% of the wild animal species in the country. This indicates that biodiversity in this area is extremely high. (2) The flora found in the Hainan tropical rainforest is unique. Vegetation on Hainan Island can be categorized in the Indo-Malay rainforest group, and within the Malay region, and vegetation is tropical in nature and has a common origin with the South China mainland. This is indicative of the transition between the South China flora into the Asian rainforest. (3) The plant species specificity of flora is lower, there are only seven endemic genera in the flora, and about one out of every 10 species is endemic to the island. Lower specificity shows some characteristics of continental origin and the flora on the island are an irreplaceable element of biodiversity, and make up a valuable ecosystem. This study clarifies the outstanding universal values of the Hainan tropical rainforest and makes the case using empirical scientific evidence for nominating this area as a world natural heritage site.

Biodiversity is and always has been an important issue in ecological research. Biodiversity can reflect niche partitioning among species at several spatial and temporal scales and is generally highest in the tropics. One theory to explain it is that low-latitude tropical ecosystems are dominated by species that are generally only distributed over a narrow area. This principle is known as Rapoport's rule. One previously unconsidered extension of Rapoport's rule may be reproductive phenology, where variation in flowering and fruiting length may reflect a temporal range. Herein, we collected reproductive phenology data for more than 20,000 species covering almost all angiosperm species in China. We used a random forest model to quantify the relative role of seven environmental factors on the duration of reproductive phenology. Our results showed that the duration of reproductive phenology decreased with latitude, although there was no obvious change across longitudes. Latitude explained more of the variation in the duration of flowering and fruiting phases in woody plants than in herbaceous plants. Mean annual temperature and the length of the growing season strongly influenced the phenology of herbaceous plants, and average winter temperature and temperature seasonality were important drivers of woody plant phenology. Our result suggests the flowering period of woody plants is sensitive to temperature seasonality, while it does not influence herbaceous plants. By extending Rapoport's rule to consider the distribution of species in time as well as space, we have provided a novel insight into the mechanisms of maintaining high levels of diversity in low-latitude forests.

全球变暖导致的物候变化已经对生物多样性和生态系统产生了重要影响,与温带和寒带相比,亚热带物候学的研究相对较少,秋季物候的研究也十分缺乏,不同功能群植物的物候对气候变化的响应是否存在差别,都有待进一步研究.为了研究亚热带植物春季和秋季物候对气候变化的响应以及不同功能群间的差异性,该研究利用湖南省长沙植物园25种木本植物20 a的物候观测数据,根据AIC信息标准,先筛选各物种最佳温度和降水模型,并利用Wilcoxon秩和检验分析不同功能群的物种对温度的响应是否一致.结果表明:(1)大多数物种的春季物候和秋季物候都对温度变化响应显著,展叶与开花的提前速率分别是3.76 d·℃-1和6.53 d·℃-1,叶变色与落叶的推迟速率分别是16.66 d·℃-1和3.50 d·℃-1.(2)部分物种的春季(展叶物候:60％,开花物候:35％)和秋季(叶变色物候:25％,落叶物候:13％)对降水显著响应.(3)除不同落叶性物种(常绿和落叶之间)的展叶物候表现出对气候的响应有显著差异外,其他不同功能群的物种对气候的响应均无显著差异.该研究认为,亚热带地区植物春季物候显著提前,秋季物候显著推迟,且亚热带地区不同功能群的物种对温度的响应大部分无显著差异,表明气候变化对亚热带地区不同功能群的影响程度大部分趋同.

The southwestern mountains of Hainan Island are distributed in the southernmost tropical karst landscape of China, and the unique hydrological structure and frequent solifluction droughts lead to double water stress for local plants. Highly heterogeneous water environments affect the water–use characteristics of plants. Plants develop local adaptative mechanisms in response to changes in the external environment. In this paper, hydrogen–oxygen and carbon stable isotope technology, and physiological index measurements were applied to determine the leaf traits, water–use efficiency, and photosynthetic characteristics of Impatiens hainanensis leaves in dry and foggy seasons, hoping to expound the adaptation mechanism of I. hainanensis leaves to the water dynamics in dry and foggy seasons. In dry and foggy seasons (November 2018 to April 2019), the leaves of I. hainanensis at low and medium altitudes have the following combination of traits: larger leaf dry weights, leaf areas, and specific leaf areas; smaller leaf thicknesses and leaf dry matter contents; and higher chlorophyll contents. In comparison, the leaves of I. hainanensis at high altitudes have the following combination of traits: smaller leaf dry weights, leaf areas, and specific leaf areas; larger leaf thicknesses and leaf dry matter contents; and lower chlorophyll contents. The leaves of I. hainanensis can absorb fog water through their leaves. When the leaves are sprayed with distilled water, the water potential is low, the water potential value gradually increases, and the leaves have a higher rate of water absorption. The leaves of I. hainanensis at low and medium altitudes have the following water–use characteristics: high photosynthesis, high transpiration, and low water–use efficiency. At high altitudes, the Pn of I. hainanensis decreases by 8.43% relative to at low altitudes and by 7.84% relative to at middle altitudes; the Tr decreased by 4.21% relative to at low altitudes and by 3.38% relative to at middle altitude; the WUE increased by 16.61% relative to at low altitudes and increased by 40.79% relative to at middle altitudes. The leaves of I. hainanensis at high altitudes have the following water–use characteristics: low photosynthesis, low transpiration, and high water–use efficiency. I. hainanensis develop different physiological mechanisms of water adaptation by weighing the traits of the leaves and their use of light and water to obtain resources during dry and foggy seasons.

The mechanisms regulating spring phenology have been extensively studied in angiosperm species. However, given that gymnosperms and angiosperms diverged 300 million years ago, phenology may be triggered by different cues in gymnosperm species. The regulatory mechanisms of phenology in subtropical regions remain largely unknown. In combination, it remains untested whether subtropical gymnosperm species have chilling requirements and are photosensitive. We conducted a climate chamber experiment with three chilling and three photoperiod treatments to investigate budburst during an 8-week forcing period. We tested whether budburst of eight gymnosperms species (Cryptomeria japonica, Cunninghamia lanceolata, Cupressus funebris, Ginkgo biloba, Metasequoia glyptostroboides, Pinus massoniana, Pseudolarix amabilis and Podocarpus macrophyllus) was photoperiod sensitive or has strong chilling requirements and whether photoperiod or chilling was more important for advancing budburst. Chilling advanced budburst and increased the percentage of budburst for gymnosperm species. Gymnosperm species required moderate chilling days to advance budburst. Interestingly, the forcing requirement for gymnosperm species was higher than that for angiosperms in the same forest, suggesting that gymnosperms may need more cumulative forcing to initiate budburst than do angiosperms. Compared with temperate gymnosperm species in Germany (194-600 degrees C days), the subtropical species studied here had a much higher forcing requirement (814-1150 degrees C days). The effects of photoperiod were minor, suggesting that chilling outweighs photoperiod in advancing budburst of gymnosperm species in this subtropical region. These results reveal that increased winter temperatures with continued global warming may impact not only angiosperms but also gymnosperms, leading to their delayed spring budburst.

Studying the distribution of samara species is of ecological and economic significance. This information helps us with understanding species dispersal mechanisms, evaluating the risk of invasive species, and the management of ecological forests. However, limited research has explored, on a large scale, the geographic distribution of samara species and their influential abiotic factors. Here, we use the distribution data of 835 vascular samara species and growth form data to explore their geographic patterns in China and the environmental determinants. We divided China into 984 grid cells and examined the relationship between the proportion of samara species and climate variables using both ordinary and spatial linear regressions for each grid cell. Total samara species richness is higher in southern China in low altitude regions and the proportion of woody samara species is significantly higher than that of herbaceous samara species. The proportion of woody samara species is higher in the northeast regions where precipitation is sufficient, winters are dry and mild, and temperature seasonality and land surface relief degree values are high. Annual precipitation and temperature seasonality are the most important climatic drivers for the distribution of woody samara species. In contrast, herbaceous samara species prefer to distribute to the areas where climate is warm and dry but have higher temperature seasonality. Temperature related variables (mean annual temperature, mean diurnal range, and temperature seasonality) are the most important drivers for the distribution of herbaceous samara species. Samara species can better adapt to climatic regions with large temperature fluctuations and dry winters. The present distribution patterns of samara species are formed by the combined adaptation of fruit traits and growth form to climate. This work contributes to predictions of the global distribution of samara species under future climate change scenarios and conservation and management for the samara species.

国家公园是我国自然保护地最重要的类型之一,具有较高的生态价值和较完整的生态系统.由于我国国家公园建设管理体制的不完善,在发展的过程中存在盲目开发、权责不明等诸多问题,适时地总结和梳理发展中存在的问题,有助于推动国家公园的发展进程.因此,基于国家公园概念的演变,结合国家公园的百度关注度和学界关注度,本文从政策视角梳理了中国国家公园的发展历程及阶段特征,并结合中国国家公园发展的内在逻辑,从协调人地关系、完善立法机制、健全管理体制、协调好利益相关者等方面提出了我国国家公园未来重点发展的方向与目标.