Dynamic response to climate change in the radial growth of Picea schrenkiana in western Tien Shan,ChinaOA

Forests are important ecosystems for economic and social development. However, the response of tree radial growth to climate has produced ‘divergent problems’ at high latitudes under global warming. In this study, the response stability and trend of Picea schrenkiana radial growth to variability in climate factors were analyzed in the mid-latitudes of the western Tien Shan Mountains. Radial growth of P.schrenkiana was mainly limited by minimum and mean temperatures. The divergent responses of ra...     

Influence of climatic conditions,topography and soil attributes on the spatial distribution of site productivity index of the species rich forests of Jalisco,Mexico

This paper presents an approach based on field data to model the spatial distribution of the site productivity index （SPI） of the diverse forest types in Jalisco, Mexico and the response in SPI to site and cli-matic conditions. A linear regression model was constructed to test the hypothesis that site and climate variables can be used to predict the SPI of the major forest types in Jalisco. SPI varied significantly with topog-raphy （elevation, aspect and slope）, soil attributes （pH, sand and silt）, climate （temperature and precipitation zones） and forest type. The most important variable in the model was forest type, which accounted for 35% of the variability in SPI. Temperature and precipitation accounted for 8 to 9% of the variability in SPI while the soil attributes accounted for less than 4% of the variability observed in SPI. No significant differences were detected between the observed and predicted SPI for the individual forest types. The linear regression model was used to develop maps of the spatial variability in predicted SPI for the individual forest types in the state. The spatial site productivity models developed in this study provides a basis for understanding the complex relationship that exists between forest productivity and site and climatic conditions in the state. Findings of this study will assist resource managers in making cost-effective decisions about the management of individual forest types in the state of Jalisco, Mexico.     

Vertical patterns of the flora of seed plants in Dawei Mountain in Yunnan Province, Southwest China

Vertical gradients incorporate multiple resources gradients which vary continuously. Therefore, research on mountain flo-ristic patterns along vertical gradients is important to reveal regular patterns of the flora along environmental gradients and to under-stand the changes in biodiversity along these gradients and their biological fitness. This study was designed to explore the character-istics of the floral compositions and ecological significance of floristic patterns along the vertical gradients of the National Nature Reserve of Dawei Mountain, located in the southeast of Yunnan Province. We analyzed the structural characteristics of the flora and the distribution patterns of its floristic components as a function of elevation on the basis of our field investigations along vertical vegetation transects. We carried out a systematic cluster analysis in order to determine the dividing line of floristic changes by eleva-tion along gradients and studied the effects of mountain climate on the vertical variation of floristic composition. The study shows: 1) that the obvious boundary, which differentiates tropical distribution, is located at an elevation of approximately 1,500 m, which separates the tropical rain forests from the evergreen broad-leaved forests; 2) that humid rain forests are found below 700 m elevation, mountain rain forests between 700 and 1,500 m, monsoon evergreen broad-leaved forests between 1,300 and 1,800 m and mountain mossy evergreen broad-leaved forests above 1,800 m. Non-representative mountain mossy dwarf forests (above 2,100 m) in the area are found on the windward sides and barren lands on mountain slopes; 3) that Hopea mollissima is one of the major component species of mountain rain forests, but it should not be considered as the major indicator species in humid rain forests as is generally accepted.     

Spatiotemporal evidence of tree-growth resilience to climate variations for Yezo spruce(Picea jezoensis var. komarovii) on Changbai Mountain,Northeast China

Global warming-induced changes in tree-growth resilience to climate variations have been widely reported for mid-and high-latitude regions around the world. Most studies have focused on the spatial variability of trees in radial growth-climate relationships on Changbai Mountain in Northeast China, but little is known about temporal changes in tree growth in response to climate. We explored the stability of effect of climate variables on radial growth of Yezo spruce [Picea jezoensis Carr. var. komarovii(V.Vassil.) Cheng et L.K.Fu] at 1200, 1400, and 1600 m above sea level, representing low, middle, and upper ranges of the spruce-fir mixed forest on Changbai Mountain. The results showed that the relation between tree growth and climate did not vary with altitude, but the stability of the tree-growth-climate relationship did vary with altitude as the climate changed. Radial growth of Yezo spruce at allthree elevations was influenced primarily by maximum temperature during May(Tmax5) and mean minimum temperature from January to March(Tmin1-3). More specifically, the relationship strengthened significantly at lower elevations, but weakened significantly at higher elevation, and fluctuated at mid elevations since 1980.Increase in Tmin1-3 and decrease in Tmax5 were the main reasons for the decrease in the radial growth at three altitudes. The findings of this study clarified that the decrease in radial growth on Changbai Mountain is not a “divergence problem” of an unexpected decrease in tree growth in response to an increase in mean temperature and provides a reference for using tree-ring data to reconstruct climate patterns and/or predict the growth of trees under various climate change scenarios.     

Effects of climate changes on distribution of Eremanthus erythropappus and E.incanus(Asteraceae) in Brazil

Phylogeographic patterns of endemic species are critical keys to understand its adaptation to future climate change.Herein,based on chloroplast DNA,we analyzed the genetic diversity of two endemic and endangered tree species from the Brazilian savanna and Atlantic forest(Eremanthus erythropappus and Eremanthus incanus).We also applied the climate-based ecological niche modeling(ENM) to evaluate the impact of the Quaternary climate(last glacial maximum ～21 kyr BP(thousand years before present) and Mid-Holocene ～6 kyr BP) on the current haplotype distribution.Moreover,we modeled the potential effect of future climate change on the species distribution in 2070 for the most optimistic and pessimistic scenarios.One primer/enzyme combination(SFM/Hinf I)revealed polymorphism with very low haplotype diversity,showing only three different haplotypes.The haplotype 1 has very low frequency and it was classified as the oldest,diverging from six mutations from the haplotypes 2 and 3.The E.erythropappus populations are structured and differ genetically according to the areas of occurrence.In general,the populations located in the north region are genetically different from those located in the center-south.No genetic structuring was observed for E.incanus.The ENM revealed a large distribution during the past and a severe decrease in geographic distribution of E.erythropappus and E.incanus from the LGM until present and predicts a drastic decline in suitable areas in the future.This reduction may homogenize the genetic diversity and compromise a relevant role of these species on infiltration of groundwater.     

Future of Abies pindrow in Swat district,northern Pakistan

Swat district is a biodiversity hub of Pakistan. The plant species, especially trees, in the Swat District are exposed to extinction threat from global climate change. Maximum entropy （MaxEnt） modelling of species distribution, using HADCM3 A2a global climate change scenario, pre-dicted a considerable change in the future distribution ofAbies pindrow （Royle ex D.Don） Royle. AUC （area under the curve）values of 0.972 and 0.983 were significant for the present and future distribution models of the species, respectively. It is clear that bioclimatic variables such as the mean temperature of the warmest quarter （bio_10） and the annual temperature range （bio_7） contribute significantly to the model and thus affect the predicted distribution and density of the species. The future model predicts that by the year 2080 population density will have decreased significantly. The highest density of the species is recorded in the eastern and western borders of the Valley in the areas of Sulatanr and Mankial. The changes in density and distribution of the species can have considerable impact, not only on the tree species itself, but on the associated subflora as well.     

Spatially differentiated changes in regional climate and underlying drivers in southwestern ChinaOA

The climate in Southwest China are predominantly under the influences of three contrasting climate systems,namely the East Asian monsoon,the South Asian monsoon,and the westerlies.However,it is unclear if the diversified climate systems,in combination with the complex terrain and varying vegetation types,would result in contrasting patterns of changes in climate across the region.Based on the CRU TS data for the period 1901-2017,we examined the spatiotemporal characteristics of the regional clim...     

Interpolating Topographic and Climatic Data for Spatial Analysis of Environment in China

Climate is a dominant environmental factor in building ecosystem structure and driving biotic dynamics with topographic dependence on spatial distribution. This paper demonstrates the application of interpolation technique to describe spatial climate distribution. A digital elevation model (DEM) in resolution of 0.01 degree of latitude and longitude has been developed because the incorporation of spatial dependence on topography is crucial to accuracy of interpolation. Climate data from sparse and discrete network stations were used to fit thin plate smoothing spline surfaces for monthly temperature and precipitation, which enable the regular gridded climate data set to be produced by coupling spline surfaces with underlying DEM. The summary statistics show the interpolation errors of monthly temperature varying between 0.4-0.9 ℃ and monthly precipitation, within 6%~ 11%, much better than the results of other methods. The fine resolution DEM and spatial climate data can be used as baseline of climate c     

Premature losses of leaf area in response to drought and insect herbivory through a leaf lifespan gradientOA

Implications of the differences in leaf life span are still subject to debate in the field of ecophysiology. Since leaf traits associated with these differences may be decisive for determining the distribution of tree species, this topic is particularly relevant in the context of climate change. This study analyzes the effects of the differences in leaf life span on premature losses of leaf area owing to insect herbivory and to abiotic stress. Loss of leaf area may be an important determinant of...     

Responses of terrestrial bryophytes to simulated climate change in a secondary evergreen broad-leaved forest in southern ChinaOA

Tropical regions are biodiversity hotspots and are well-suited to explore the potential influence of global climate change on forest ecosystems.Bryophytes have essential ecological functions in tropical forest ecosystems,but knowledge of the potential impact of global warming and possible changes in water availability patterns on terrestrial bryophytes is limited.We transplanted eight terrestrial moss species from two elevations(900 and 500 m) to warmer and drier elevations(500 and 100 m) during...     

濒危植物格木天然种群的表型多样性及变异

【目的】通过对濒危植物格木在我国中心分布区种群的果荚和种子表型性状测量分析,研究其表型多样性及变异规律,结合地理气候信息探讨影响表型变异的关键因子,为格木天然种群的遗传多样性保护恢复和引种栽培提供科学依据。【方法】对8个格木天然种群114个单株的13个果荚及种子表型性状进行测量,利用巢式方差分析、多重比较、相关性分析、主成分分析、聚类分析等分析方法,探讨格木天然种群的表型多样性水平、进化和适应性潜力、表型变异规律、表型分化水平、种群聚类特征及其与地理气候因子的相关性。【结果】格木表型多样性水平中等,13个性状的Shannon-Wiener指数在1. 911 1(种形指数)～2. 103 9(果荚周长)之间,平均2. 027 8;8个种群的Shannon-Wiener指数在0. 920 9(P6)～1. 885 6(P8)之间,均值为1. 474 7。格木表型性状离散程度较轻,13个性状的变异系数在7. 544 6%(种子长)～18. 868 5%(果荚面积)之间,均值为12. 410 9%; 8个种群的变异系数在8. 852 9%(P1)～13. 984 8%(P5)之间,均值为12. 410 9%。13个表型性状的极大值为极小值的1. 395 2(种形指数)～2. 805 6(每荚种子数)倍,均值为1. 791 7。巢式方差分析表明,格木13个表型性状在种群间和种群内均存在极显著差异(P<0. 01),说明这些性状在种群间和种群内均存在丰富的变异;种群内的变异(40. 387 1%)远大于种群间(11. 948 9%)。种群平均表型分化系数为21. 857 9%,各性状的分化系数变化幅度在7. 476 5%(种形指数)～38. 674 0%(果荚宽)之间。相关性分析表明,13个表型性状之间大多存在显著或极显著相关,果荚宽度、种子周长等性状和温度指标呈负相关,与纬度呈正相关,格木在气温高、降雨量大的地区往往具有小果荚、小种子的特征,随着温度指标降低和纬度增加,格木果荚及种子有变大的趋势。格木13个表型性状可提炼为4个主成分,累积贡献率为87. 382%。8个天然群体基于欧氏距离可分为3类:第1类2个种群呈现果荚小、种子小的特征,该类表型主要出现在格木分布区的南端;第2类5个种群呈现果荚大、种子大的特征,该类表型主要出现在格木分布区的北部,仅1个种群位于分布区的南部;第3类1个种群呈现果荚小、种子少、种子大而薄的特征,该类表型出现在格木南北分布区的中间衔接部。【结论】格木的表型多样性处于中等水平,在个体上存在较为丰富的变异。在群体及物种水平上,格木表型性状离散程度较轻,各个性状分布相对集中,较为稳定,不易发生群体分化,拥有特殊表型的格木单株具有较高的保存价值。果荚及种子大小进化及适应性潜力相对较大,种形指数最不易产生变异。种群内的变异是格木表型变异的主要来源,格木的种质资源收集保存可减少种群数量,增加种群内个体数量,并优先收集有特殊表型的单株。广西省容县和龙圩区的格木种群是格木遗传多样性保护及种质资源收集保存的重点区域。年均温等温度因子是影响格木表型及分布的最主要因子。果荚及其中种子的大小是格木种群间聚类的主要依据。     

Nucleotide polymorphisms associated with climate,phenology and physiological traits in European beech (<Emphasis Type="Italic">Fagus sylvatica</Emphasis> L.)

Although European beech (Fagus sylvatica L.) is one of the most widespread and ecologically and commercially most important deciduous trees in Europe, little is known about its adaptive genetic variation. We explored single-nucleotide polymorphism (SNP) variation in candidate genes for budburst and drought resistance in beech populations sampled across most of the distribution range, represented in an international provenance trial. SNP variation was monitored for six candidate genes, in 114 individuals from 19 natural populations. Population structure was deduced from the analysis of 20 nuclear microsatellite markers. Different methods to detect imprints of natural selection were used (F _ST-outlier, SNP-climate regression, association tests). The F _ST-outlier approach identified the COV gene with unambiguous signal of selection, which is an orthologue of Arabidopsis gene for a membrane protein previously reported as phenology-related. Based on environmental association analysis at the population level, the dehydrin gene was found associated with drought-related climatic variables. At the individual level, dehydrin gene also showed a significant association with chlorophyll fluorescence parameters, which are considered stress markers. The importance of the knowledge of physiological variation and geographical patterns of adaptive genetic variation for guiding reproductive materials transfer under climate change is stressed.     

Plant functional types rather than climate or soil determine leaf traits in the forest biomes of eastern China

Nitrogen (N) has great ecological importance, but the biogeographic pattern across forest biomes in China has only recently been explored. Here we conducted a systematic census of leaf C and N following the same protocol to explore the variations of leaf traits, and their possible responses to plant functional types (PFTs) and environmental factors. Results showed that leaf traits varied substantially across biomes, and the relationships of PFTs to climatic factors were stronger than those of PFTs versus soil nutrient proxies, indicating that plant species composition might be a better predictor of plant species distribution with climate than leaf traits. Soil nutrient proxies explained more variation of leaf traits than climate, which demonstrates that leaf traits reflect important aspects of plant responses to soil nutrients. Importantly, partial general linear models analyses found that PFTs showed the greatest direct influence for leaf traits, and climate and soil affected leaf traits mainly through the change in plant species composition rather than having direct impacts. Hence, we concluded that leaf traits were largely controlled by PFTs rather than climate or soil at the biome scale. The results favored the species composition hypothesis, indicating that leaf nutrient concentration is mainly determined by PFTs.     

林芝云杉天然群体针叶与种实的变异及其地理趋势

在西藏地区11个有代表性的林芝云杉天然群体内分别随机抽取15～30个个体为试材,测量了针叶与种实共9个表型性状,采用统计分析方法研究了在群体内和群体间的变异和分化趋势.结果显示:林芝云杉9个表型性状在群体内和群体间的差异显著.群体间表型分化系数均值为29.55％,与云杉属其他树种相比处于中等水平;群体内的方差分量占70...     

To what extent is altitudinal variation of functional traits driven by genetic adaptation in European oak and beech?

The phenotypic responses of functional traits in natural populations are driven by genetic diversity and phenotypic plasticity. These two mechanisms enable trees to cope with rapid climate change. We studied two European temperate tree species (sessile oak and European beech), focusing on (i) in situ variations of leaf functional traits (morphological and physiological) along two altitudinal gradients and (ii) the extent to which these variations were under environmental and/or genetic control using a common garden experiment. For all traits, altitudinal trends tended to be highly consistent between species and transects. For both species, leaf mass per area displayed a positive linear correlation with altitude, whereas leaf size was negatively correlated with altitude. We also observed a significant increase in leaf physiological performance with increasing altitude: populations at high altitudes had higher maximum rates of assimilation, stomatal conductance and leaf nitrogen content than those at low altitudes. In the common garden experiment, genetic differentiation between populations accounted for 0-28% of total phenotypic variation. However, only two traits (leaf mass per area and nitrogen content) exhibited a significant cline. The combination of in situ and common garden experiments used here made it possible to demonstrate, for both species, a weaker effect of genetic variation than of variations in natural conditions, suggesting a strong effect of the environment on leaf functional traits. Finally, we demonstrated that intrapopulation variability was systematically higher than interpopulation variability, whatever the functional trait considered, indicating a high potential capacity to adapt to climate change.     

Characterization of Phytophthora cinnamomi from common walnut in Southern Europe environment

Forty‐eight isolates of Phytophthora cinnamomi obtained from common walnut were analysed according to their variability in growth at different temperatures, virulence, sensitivity to metalaxyl and in genomic DNA. Isolates were obtained from commercial common walnut orchards located in northern Italy and in southern France. Inter‐simple sequence repeat (ISSR) were analysed for the 49 isolates, 43 of which were Italian, 6 French; an isolate of the same species obtained from Viburnum spp. was used as an outgroup. ANOVA on phenotypic characters showed a significant impact of the geographic location of the orchard on isolate variability in terms of reaction to temperatures and aggressiveness. In turn, clustering obtained with UPGMA analysis on genetic data was almost exclusively dependant on isolate variability, nevertheless the 48 isolates seem to share a common variability that differentiates the group from the isolate from Viburnum spp. Correlation between phenotypic and genetic traits was not statistically significant. In conclusion, phenotypic variability like virulence seemed to be conditioned from geographic origin while the genetic variability of P. cinnamomi isolates from walnut was associated to the single genotype.     

Genetic and functional leaf traits variability of Quercus laurina along an oak diversity gradient in Mexico

The ecological literature has documented the effects of plant hybridization on phenotypic variation, and dominant, intermediate, or novel morphological, chemical and physiological traits in hybrids. It is important to understand the ecological consequences of hybridization by evaluating their impact on phenotypic expression of functional traits. We evaluated the relationship between genetic diversity of Quercus laurina and functional foliar traits along an oak diversity gradient. We selected five study sites that represent an oak diversity gradient where Q. laurina is present. Using chloroplast and nuclear microsatellites, we evaluated genetic diversity, measured functional foliar traits of Q. laurina in each site and assessed the effects of local climate variables on the oak community and functional traits. We found a greater abundance of Q. laurina in all study sites. We did not find a relationship between the number of accompanying red oak species and the population genetic diversity in Q. laurina, but higher genetic diversity was found in all study sites in comparison with European oak species. Sites with more oak species had more variation of foliar functional traits. Our results do not support the hypothesis that predicts higher levels of genetic diversity of Q. laurina in communities with greater oak diversity from the same section, but we demonstrated an increase in the foliar functional traits of Q. laurina associated with oak richness and climate variables. We highlight the need to consider environmental and ecological variables linkages as regulatory mechanisms of the phenotypic plasticity expressed in changes of some functional attributes of oaks.

     

油橄榄品种表型和SSR标记的多样性及聚类分析

[目的]利用表型性状和分子标记,对我国油橄榄品种进行鉴定和遗传多样性研究,有利于种质资源保存和利用,对了解油橄榄品种的组成结构及未来的引种和育种工作都具有重要意义。[方法]以甘肃省陇南市17个油橄榄品种为研究材料,利用表型上15个数量性状、18个质量性状和8个SSR荧光标记分别进行多样性和聚类分析。[结果]各性状在品种间存在显著差异,数量性状和质量性状的表型多样性指数分别介于1.579 2.089和0.3621.091,8个SSR位点共检测到51个等位基因变异,平均每个位点等位基因数为6.375个,利用表型性状和SSR标记可以将17个品种完全区分开。[结论]17个油橄榄品种具有较丰富的表型和遗传多样性,基于表型数量性状、质量性状和SSR标记的聚类分析结果,判别品种间遗传关系的结果有一致的,也存在一定差异。对于表型性状相似的品种,需结合SSR标记进行品种鉴定。     

Genotypic variability and phenotypic plasticity of cavitation resistance in Fagus sylvatica L. across Europe

Xylem cavitation resistance is a key physiological trait correlated with species tolerance to extreme drought stresses. Little is known about the genetic variability and phenotypic plasticity of this trait in natural tree populations. Here we measured the cavitation resistance of 17 Fagus sylvatica populations representative of the full range of the species in Europe. The trees were grown in three field trials under contrasting climatic conditions. Our findings suggest that the genotypic variability of cavitation resistance is high between genotypes of a given population. By contrast, no significant differences were found for this trait across populations, the mean population cavitation resistance being remarkably constant in each trial. We found a significant site effect and a significant site?×?population interaction, suggesting that cavitation resistance has a high phenotypic plasticity and that this plasticity is under genetic control. The implications of our findings for beech forest management in a context of climate change are discussed.     

Xylem hydraulic adjustment and growth response of Quercus canariensis Willd. to climatic variability

Global change challenges forest adaptability at the distributional limit of species. We studied ring-porous Quercus canariensis Willd. xylem traits to analyze how they adjust to spatio-temporal variability in climate. Trees were sampled along altitudinal transects, and annual time series of radial growth (ring width (RW)) and several earlywood vessel (EV) traits were built to analyze their relationships with climate. The trees responded to increasing water constraints with decreasing altitude and changes in climate in the short term but the analyses showed that xylem did not acclimate in response to long-term temperature increase during the past 30 years. The plants' adjustment to climate variability was expressed in a different but complementary manner by the different xylem traits. At low elevations, trees exhibited higher correlations with water stress indices and trees acclimated to more xeric conditions at low elevations by reducing radial growth and hydraulic diameter (D(H)) but increasing the density of vessels (DV). Average potential conductivity (K(H)) was similar for trees at different altitudes. However, inter-tree differences in xylem traits were higher than those between altitudes, suggesting a strong influence of individual genetic features or micro-site conditions. Trees exhibited higher RW those years with larger D(H) and particularly the linear density of vessels (DV(l)), but partly, climatic signals expressed in RW differed from those in EVs. Trees produced larger D(H) after cold winters and wet years. Ring width responded positively to wet and cool weather in fall and spring, whereas the response to climate of DV and K(H) was generally opposite to that of RW. These relationships likely expressed the negative impact of high respiration rates in winter on the carbon pools used to produce the EVs in the next spring and the overall positive influence of water availability for trees. Our results showed that trees at different sites were able to adjust their hydraulic architecture to climatic variability and temperature increase during recent decades coordinating several complementary traits. Nonetheless, it should be monitored whether they will succeed to acclimate to future climatic scenarios of increasing water stress.