Mean Annual Temperature Range Research Articles

Main drivers of productivity of Acacia mangium plantations in Vietnam

Acacia mangium is one of the most important hardwood plantation species in the tropics. The question of how to grow Acacia productively and sustainably remains a major issue for the forestry sector in many tropical countries. We analyzed the productivity of A. mangium plantations across five contrasting ecological zones in Vietnam. These covered gradients in rainfall from 1750 mm to 3060 mm and a mean annual temperature range of 22 – 27 0C. Plantation productivity across these zones varied from an MAI of 6 m3 ha y−1 to 31 m3 ha y−1. A comprehensive suite of statistical methods was utilized for variable and model selection to minimize confounding and multicollinearity issues among predictors and identify determinants of plantation productivity using 27 biophysical variables. These variables encompass plantation age, climate parameters, as well as site and soil properties. Results showed that, apart from plantation age, the factors influencing plantation productivity and explaining a majority of variation in mean annual timber increment are soil organic carbon content and the number of foggy days. Soil carbon is probably an index of overall soil fertility and its significance reflects the fact that the plantations have often been established on relatively degraded sites. The lower productivity at sites having a higher frequency of foggy days (up to 57 days per year in some regions) may arise from lower solar radiation and temperature during fog. The results of this study can inform site selection and plantation management tools aimed at maximizing Acacia mangium productivity in Vietnam and other countries with similar ecological conditions. Planting A. mangium in high-intensity fog areas is not recommended. Further studies on the ecophysiological mechanisms of how fog influences the growth of tropical A. mangium plantations are also needed.

Rapoport's rule explains the range size distribution of butterflies along the Eastern Himalayan elevation gradient

AbstractUnderstanding elevational range size distribution of organisms can provide valuable insights on biogeographic pattern of species and their conservation. Rapoport's rule posits that the elevational range size of species increases with increasing elevation. However, the validity of this rule is often questioned due to variations in methodologies across studies and inconsistencies among different groups of organisms. In this study, we examined the elevational range size distribution of butterflies in the Eastern Himalaya, and assessed the applicability of Rapoport's rule using different approaches, which perhaps is the first of its kind in the Himalaya. We sampled butterflies along the elevational gradient of 16 elevational bands (300–3300 m) using point count method along the transect. The sampled butterflies were grouped into various sub‐groups based on family, biogeographic affinity, and larval feeding pattern. We found that the majority of the butterfly species (total as well as sub‐groups) had small range sizes, and their elevational range distribution showed support for the Rapoport's rule. Increase in variation in temperature as measured by temperature seasonality and mean annual temperature range were the most important predictors of range size distribution pattern of the overall butterfly community. However, the relationship between range size and climatic variability differed among various sub‐groups implying that the perceived pattern may vary even within the species of the same taxon.Abstract in Nepali is available with online material.

Responses of Three Pedicularis Species to Geological and Climatic Changes in the Qinling Mountains and Adjacent Areas in East Asia.

The Qinling Mountains in East Asia serve as the geographical boundary between the north and south of China and are also indicative of climatic differences, resulting in rich ecological and species diversity. However, few studies have focused on the responses of plants to geological and climatic changes in the Qinling Mountains and adjacent regions. Therefore, we investigated the evolutionary origins and phylogenetic relationships of three Pedicularis species in there to provide molecular evidence for the origin and evolution of plant species. Ecological niche modeling was used to predict the geographic distributions of three Pedicularis species during the last interglacial period, the last glacial maximum period, and current and future periods, respectively. Furthermore, the distribution patterns of climate fluctuations and the niche dynamics framework were used to assess the equivalence or difference of niches among three Pedicularis species. The results revealed that the divergence of three Pedicularis species took place in the Miocene and Holocene periods, which was significantly associated with the large-scale uplifts of the Qinling Mountains and adjacent regions. In addition, the geographic distributions of three Pedicularis species have undergone a northward migration from the past to the future. The most important environmental variables affecting the geographic distributions of species were the mean diurnal range and annual mean temperature range. The niche divergence analysis suggested that the three Pedicularis species have similar ecological niches. Among them, P. giraldiana showed the highest niche breadth, covering nearly all of the climatic niche spaces of P. dissecta and P. bicolor. In summary, this study provides novel insights into the divergence and origins of three Pedicularis species and their responses to climate and geological changes in the Qinling Mountains and adjacent regions. The findings have also provided new perspectives for the conservation and management of Pedicularis species.

Drivers of arthropod biodiversity in an urban ecosystem

Our world is becoming increasingly urbanized with a growing human population concentrated around cities. The expansion of urban areas has important consequences for biodiversity, yet the abiotic drivers of biodiversity in urban ecosystems have not been well characterized for the most diverse group of animals on the planet, arthropods. Given their great diversity, comparatively small home ranges, and ability to disperse, arthropods make an excellent model for studying which factors can most accurately predict urban biodiversity. We assessed the effects of (i) topography (distance to natural areas and to ocean) (ii) abiotic factors (mean annual temperature and diurnal range), and (iii) anthropogenic drivers (land value and amount of impervious surface) on the occurrence of six arthropod groups represented in Malaise trap collections run by the BioSCAN project across the Greater Los Angeles Area. We found striking heterogeneity in responses to all factors both within and between taxonomic groups. Diurnal temperature range had a consistently negative effect on occupancy but this effect was only significant in Phoridae. Anthropogenic drivers had mixed though mostly insignificant effects, as some groups and species were most diverse in highly urbanized areas, while other groups showed suppressed diversity. Only Phoridae was significantly affected by land value, where most species were more likely to occur in areas with lower land value. Los Angeles can support high regional arthropod diversity, but spatial community composition is highly dependent on the taxonomic group.

Divergent mechanisms of reduced growth performance in Betula ermanii saplings from high-altitude and low-latitude range edges

The reduced growth performance of individuals from range edges is a common phenomenon in various taxa, and considered to be an evolutionary factor that limits the species’ range. However, most studies did not distinguish between two mechanisms that can lead to this reduction: genetic load and adaptive selection to harsh conditions. To address this lack of understanding, we investigated the climatic and genetic factors underlying the growth performance of Betula ermanii saplings transplanted from 11 populations including high-altitude edge and low-latitude edge population. We estimated the climatic position of the populations within the overall B. ermanii’s distribution, and the genetic composition and diversity using restriction-site associated DNA sequencing, and measured survival, growth rates and individual size of the saplings. The high-altitude edge population (APW) was located below the 95% significance interval for the mean annual temperature range, but did not show any distinctive genetic characteristics. In contrast, the low-latitude edge population (SHK) exhibited a high level of linkage disequilibrium, low genetic diversity, a distinct genetic composition from the other populations, and a high relatedness coefficient. Both APW and SHK saplings displayed lower survival rates, heights and diameters, while SHK saplings also exhibited lower growth rates than the other populations’ saplings. The low heights and diameters of APW saplings was likely the result of adaptive selection to harsh conditions, while the low survival and growth rates of SHK saplings was likely the result of genetic load. Our findings shed light on the mechanisms underlying the reduced growth performance of range-edge populations.

Coherence of terrestrial vertebrate species richness with external drivers across scales and taxonomic groups

AbstractAimUnderstanding connections between environment and biodiversity is crucial for conservation, identifying causes of ecosystem stress, and predicting population responses to changing environments. Explaining biodiversity requires an understanding of how species richness and environment covary across scales. Here, we identify scales and locations at which biodiversity is generated and correlates with environment.LocationFull latitudinal range per continent.Time PeriodPresent day.Major Taxa StudiedTerrestrial vertebrates: all mammals, carnivorans, bats, songbirds, hummingbirds, amphibians.MethodsWe describe the use of wavelet power spectra, cross‐power and coherence for identifying scale‐dependent trends across Earth's surface. Spectra reveal scale‐ and location‐dependent coherence between species richness and topography (E), mean annual precipitation (Pn), temperature (Tm) and annual temperature range (ΔT).Results>97% of species richness of taxa studied is generated at large scales, that is, wavelengths km, with 30%–69% generated at scales km. At these scales, richness tends to be highly coherent and anti‐correlated with E and ΔT, and positively correlated with Pn and Tm. Coherence between carnivoran richness and ΔT is low across scales, implying insensitivity to seasonal temperature variations. Conversely, amphibian richness is strongly anti‐correlated with ΔT at large scales. At scales km, examined taxa, except carnivorans, show highest richness within the tropics. Terrestrial plateaux exhibit high coherence between carnivorans and E at scales km, consistent with contribution of large‐scale tectonic processes to biodiversity. Results are similar across different continents and for global latitudinal averages. Spectral admittance permits derivation of rules‐of‐thumb relating long‐wavelength environmental and species richness trends.Main ConclusionsSensitivities of mammal, bird and amphibian populations to environment are highly scale dependent. At large scales, carnivoran richness is largely independent of temperature and precipitation, whereas amphibian richness correlates strongly with precipitation and temperature, and anti‐correlates with temperature range. These results pave the way for spectral‐based calibration of models that predict biodiversity response to climate change scenarios.

Modeling the Distribution of the Chytrid Fungus Batrachochytrium dendrobatidis with Special Reference to Ukraine.

Amphibians are the most threatened group of vertebrates. While habitat loss poses the greatest threat to amphibians, a spreading fungal disease caused by Batrachochytrium dendrobatidis Longcore, Pessier & D.K. Nichols 1999 (Bd) is seriously affecting an increasing number of species. Although Bd is widely prevalent, there are identifiable heterogeneities in the pathogen's distribution that are linked to environmental parameters. Our objective was to identify conditions that affect the geographic distribution of this pathogen using species distribution models (SDMs) with a special focus on Eastern Europe. SDMs can help identify hotspots for future outbreaks of Bd but perhaps more importantly identify locations that may be environmental refuges ("coldspots") from infection. In general, climate is considered a major factor driving amphibian disease dynamics, but temperature in particular has received increased attention. Here, 42 environmental raster layers containing data on climate, soil, and human impact were used. The mean annual temperature range (or 'continentality') was found to have the strongest constraint on the geographic distribution of this pathogen. The modeling allowed to distinguish presumable locations that may be environmental refuges from infection and set up a framework to guide future search (sampling) of chytridiomycosis in Eastern Europe.

Climate change shrinks environmental suitability for a viviparous Neotropical skink

AbstractAnthropogenic global warming and deforestation are significant drivers of the global biodiversity crisis. Ectothermic and viviparous animals are especially vulnerable since high environmental temperatures can impair embryonic development, but we lack knowledge about these effects upon Neotropical organisms. Here, we estimate how much of the current area with suitable habitats overlaps with protected areas and model the combined effects of climate change and deforestation on the geographic distribution of the viviparous Neotropical lizard Notomabuya frenata (Scincidae). This species ranges in Brazil, Argentina, Paraguay, and Bolivia. We use environmental and physiological variables (locomotor performance and hours of activity) to predict suitable present and future areas, considering different scenarios of greenhouse gas emissions and deforestation. The most critical predictors of habitat suitability were isothermality (i.e., the ratio between mean diurnal temperature range and annual temperature range), precipitation during winter, and hours of activity under lower thermal extremes. Still, our models predict a contraction of suitable habitats in all future scenarios and the displacement of these areas towards eastern South America. In addition, protected areas are not enough to ensure suitable habitats for this species. Our findings highlight the vulnerability of tropical and viviparous ectotherms and suggest that even widely distributed species, such as N. frenata, may have their conservation compromised shortly due to the low representativeness of their suitable habitats in protected areas combined with the synergistic effects of climate change and deforestation. We stress the need for decision‐makers to consider the impact of range shifts in creating protected areas and managing endangered species.

Открытые источники данных для моделирования ареалов: информационные системы о биоразнообразии и наборы пространственных данных условий среды

Открытые источники данных для моделирования ареалов: информационные системы о биоразнообразии и наборы пространственных данных условий среды

Evolution of palaeoclimate, palaeoenvironment and vegetation in Central Europe during the Miocene Climate Optimum

The Miocene Climate Optimum was an interval of global climatic warmth characterized by significant global palaeoceanographic changes. In this paper, we describe the parastratotype section of the regional Karpatian stage (late Burdigalian) at Hevlín quarry in the Czech Republic, to improve knowledge of evolving palaeoenvironment and palaeoclimate during the Miocene Climate Optimum. Strontium isotope stratigraphy (87Sr/86Sr) and biostratigraphy allows precise identification of Burdigalian/Langhian boundary, and the studied section is inferred to represent the late Burdigalian time interval (17.2–16 Ma). Analysis of palynological assemblages using the Coexistence Approach and the Plant Functional Type method supported by biomarker study indicates an existence of a warm temperate to subtropical palaeoclimate pattern with a mean annual temperature range of 17–19.5 °C and a high degree of seasonality. The mean annual precipitation range was 1050–1600 mm. The zonal vegetation cover was characterized as transitional between subtropical broad-leaved evergreen forest and warm–temperate to subtropical mixed mesophytic forest. Our palaeoclimatic findings in Central Europe agree with global trends (high temperatures and a high sea level) and indicates the occurrence of rather widespread humid conditions. The proximity to our study site of the Mediterranean-Paratethys sea probably played a critical role in moderating regional palaeoclimate.

Carbon isotope composition of land snail shells as a proxy for precipitation amount in the East Asian Monsoon region: A case study from Hainan Island

The carbon isotopic composition of land snail shells (δ13Cshell) potentially reflects changes in vegetation composition and thus precipitation. To better assess the response of δ13Cshell to East Asian monsoon (EAM) precipitation in different regions, we investigated the δ13C of modern snail shells and the corresponding surface soil and vegetation in Hainan Island, in the tropical monsoon region of China. This region spans a large mean annual rainfall gradient (1250–2300 mm), but it has a very small range of mean annual temperature (∼2 °C). We found that the most depleted δ13Cshell value (−18.5‰) reported in this study is more negative than previously reported in the literature, and that δ13Cshell in Hainan Island mainly reflects the δ13C of C3 plants, indicating the C3 dietary preference of snails. After confirming that δ13Cshell is a reliable precipitation proxy in Hainan Island, we produced a new general equation between δ13Cshell and precipitation, combining our data from Hainan Island with that from previous studies in the EAM region: δ13Cshell = −0.0025 (±0.0002) MAP – 9.0841 (±0.23) (n = 131, r = −0.73, p < 0.01). A comparison of the slope of the linear equation for Hainan Island (δ13Cshell = −0.003 (± 0.0007) MAP - 7.5619 (± 1.27), n = 18, r = −0.74, p < 0.01) with that of Bao et al. (2019), with a larger temperature range (>10 °C), enabled us to validate that temperature in the EAM region has little effect on δ13Cshell compared to precipitation. We also conducted a theoretical evaluation of the effect of temperature on δ13Cshell using a flux balance model, which confirmed that the δ13Cshell–precipitation proxy is insensitive to temperature variations, considering temperature effects on the fractionation coefficient and the δ13C of C3 plants, where C3 plants are the dominant plant type. Our results potentially enable the quantitative reconstruction of paleo-precipitation via the δ13Cshell of snail fossils in the sedimentary deposits of the EAM region.

Evaluation of the wider applications of the alkanol index BNA15 as temperature proxy in a broad distribution of peat deposits

The BNA15 biomarker proxy, which reflects the relative abundance of the branched over the normal C15 alkan-1-ols, was recently proposed as a novel terrestrial paleothermometer and applied to ancient peat deposits to reconstruct past temperature variations across the Holocene. However, to date, a peat-specific calibration for this novel temperature proxy does not exist. Here we analyzed a set of surface and downcore peat samples from Chinese peatlands with a broad range in mean annual air temperature (MAAT) (–3.2 °C to 18.5 °C) and pH (4.7 to 8) to understand the relationship between the BNA15 proxy and temperature in peat deposits. Downcore samples from three peatlands outside China were also obtained to test its wider applicability. Our results show that the variations in BNA15 across multiple surface samples from a single peatland are relatively large, suggesting that we must be careful with the application of BNA15 to reconstruct small amplitude temperature variations. In addition, the BNA15 changes significantly with depth, with higher values in the anoxic catotelm in mid/low latitude peatlands and slightly higher values in the oxic acrotelm in high latitude/altitude peatlands. Combined with concentrations of alkan-1-ols in a subtropical peat core retrieved from central China, we propose that branched alkan-1-ols are predominantly produced at the acrotelm-catotelm boundary. BNA15 has a moderate correlation with the growth temperature (including the months that the daily temperature is over 0 °C) in surface peat samples. In contrast, a strong positive correlation exists between BNA15 and MAAT using catotelm samples from Chinese peatlands (MAAT = 2.03 × BNA15 – 2.33; R2 = 0.95, p < 0.01, RMSE = 2.3 °C). We find no clear correlation between BNA15 and pH in the surface peat samples. The application of the BNA15 index to two forest/woody wetlands from outside of China highlights that care should be taken when applying this index in these environments.

Promoting the Development of Astragalus mongholicus Bunge Industry in Guyang County (China) Based on MaxEnt and Remote Sensing.

To provide high-quality Astragalus mongholicus Bunge to domestic and foreign markets and maintain sustainable development of the A. mongholicus industry, Firstly, we evaluated the impact of environmental factors and planting areas on the A. mongholicus industry. The maximum entropy method (MaxEnt) was utilized to simulate the suitability distribution of A. mongholicus and establish the relationship between the active component contents of A. mongholicus and ecological factors through linear regression analysis. The random forest algorithm was subsequently used to perform feature selection and classification extraction on Sentinel-2 imagery covering the study area. Furthermore, the planting, processing, and sales of A. mongholicus in Guyang County were investigated, and the roles of stakeholders in the value chains were analyzed. The results demonstrated that precipitation of the warmest quarter, minimum temperature of the coldest month, standard deviation of seasonal temperature changes, range of mean annual temperature, and mean diurnal range [mean of monthly (max temp - min temp)] were the five environmental variables that contributed the most to the growth of A. mongholicus. The most influential factor on the distribution of high-quality A. mongholicus was the mean temperature of the coldest quarter. The classification results of image features showed that the planting areas of A. mongholicus was consistent with the suitable planting areas predicted by MaxEnt, which can provide data support to the relevant departments for the macro development of the A. mongholicus industry. In the production of A. mongholicus, 10 value chains were constructed, and the study demonstrated that the behavior of stakeholders, target markets, and the selected planting area had a significant impact on the quality of A. mongholicus.

International Biological Flora:Ginkgo biloba

AbstractThis account presents information on all aspects of the biology ofGinkgo bilobaL. (Ginkgo, Maidenhair tree) that are relevant to understanding its ecological characteristics. The main topics are presented within the standard framework of theInternational Biological Flora: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, reproductive and seed characters, herbivores and disease, history, conservation and global heterogeneity.Globally, Ginkgo survives a wide range of mean annual temperature (−3.3 to 23.3°C) and annual precipitation (34–3925 mm) conditions, according to a meta‐analysis. It prefers a warm, humid, open‐canopy and a well‐drained environment. The species shows strong tolerance to drought, freezing, fire, air pollution, heavy metals and low‐level salt, whereas it is intolerant to long‐time shade and waterlogging. Six Ginkgo trees even survived the atom bomb in Hiroshima, Japan, during World War II.Ginkgo is susceptible to few diseases. Those occurring in nursery seedlings and juvenile trees involve stem rot and leaf blight. The former is caused byMacrophomina phaseoli, which could lead to a mortality rate of 5%–12% (up to 31.8%) for seedlings. This disease can be mitigated by a 4‐h shading treatment and applying organic fertilisers. The pathogens inducing leaf blight includeAlternaria alternata,Colletotrichum gloeosporioidesandPestalotia ginkgo, which may infect 100% juvenile trees in some regions. The application of 45% carbendazim or 50% Tuzet can effectively prevent leaf blight.Ginkgo bilobais one of the world’s most distinctive trees with an important position in plant evolution and human society. It is a tall deciduous dioecious tree native to China. Refugial populations were identified in three glacial refugia located in eastern, southern and south‐western China, respectively, with a patchy distribution pattern and a small population size. It typically grows along flood‐disturbed streamsides in warm‐temperate deciduous (and evergreen mixed) broadleaved forests. Ginkgo may have been introduced repeatedly out of China since the sixth century. It has been planted as a landscape tree world‐wide, except in Antarctica. Ginkgo is also of great value for edible nuts, herbal medicine, religion and art. It is a natural and cultural symbol of China.

Long-Term Effects of Climate and Litter Chemistry on Rates and Stable Fractions of Decomposing Scots Pine and Norway Spruce Needle Litter—A Synthesis

We have reviewed information on early-, late- and limit-value decomposition stages for litter of Norway spruce (Picea abies) and Scots pine (Pinus silvestris). This synthesis covers c 16 studies/papers made along a climatic gradient; range in mean annual temperature (MAT) from −1 to +7 °C and mean annual precipitation (MAP) from 425 to 1070 mm. Scots pine has an early stage dominated by carbohydrate decomposition and a late stage dominated by decomposition of lignin; Norway spruce has just one stage dominated by lignin decomposition. We used data for annual mass loss to identify rate-regulating factors in both stages; climate data, namely, MAT and MAP, as well as substrate properties, namely, nitrogen (N), acid unhydrolyzable residue (AUR), manganese (Mn). Early-stage decomposition for Scots pine litter was dominated positively by MAT; the late stage was dominated negatively by MAT, N, and AUR, changing with decomposition stage; there was no effect of Mn. Norway spruce litter had no early stage; decomposition in the lignin-dominated stage was mainly negative to MAP, a negative relationship to AUR and non-significant relationships to N and MAT. Mn had a positive relationship. Limit values for decomposition, namely, the accumulated mass loss at which decomposition is calculated to be zero, were related positively to Mn and AUR for Scots pine litter and negatively to AUR for Norway spruce litter. With different sets of rate-regulating factors as well as different compounds/elements related to the limit values, the decomposition patterns or pathways are different.

气候变化对新疆雪岭云杉潜在适宜分布及生态位分化的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 气候变化对新疆雪岭云杉潜在适宜分布及生态位分化的影响 DOI: 10.5846/stxb202105111226 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 新疆维吾尔自治区自然科学基金项目（2019D01C022）；国家自然科学基金项目（31760142） Effects of climate change on potential distribution and niche differentiation of Picea schrenkiana in Xinjiang Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:探究气候变化对天山森林植物潜在空间分布的影响及其模拟预测有助于揭示中尺度下植物分布格局对气候变化的适应对策和反馈机制，对促进干旱区山地森林生态系统的生物多样性保育和森林资源可持续管理有着重要的科学和实践意义。基于雪岭云杉的分布点数据和环境因子数据，利用最大熵（MaxEnt）模型、GIS工具及R软件估计其在基准气候（1970-2000年）及2050（2041-2060年）和2070（2061-2080年）时段基于RCPs气候情景下的潜在分布范围、空间格局变化及生态位分化。结果表明：（1）雪岭云杉在基准气候下的潜在分布与2019年秋季的NDVI植被覆盖变化基本保持一致，高适生分布区主要分布在东疆的哈密、巴里坤和伊吾，北疆主要分布在天山北坡、博格达山、北塔山和伊犁河谷，南疆主要分布在天山南坡。另外，在阿尔泰山南坡、塔城、裕民、托里、西昆仑山和小帕米尔山地也有分布。（2）限制雪岭云杉潜在分布的关键因子为降水（最干月降水量、最冷季降水量和降水季节性）和温度（最干季平均温度、年均温、等温性和气温年较差）、土壤剖面有效含水量、土壤碳密度及海拔，其累计贡献率之和达到87.28%。（3）2050和2070时段，雪岭云杉的适宜分布范围均呈不显著的增加趋势，但RCP6.0情景比RCP2.6较显著，分别扩增了3.33%和3.47%；低、中、高适生区均保持相对稳定的变化，从RCP2.6到RCP6.0情景下增幅分别在1.78%、1.26%和0.98%左右；适生分布区的重心总体上呈现出向高纬度、向东北迁移的趋势，但变化幅度不显著。（4） PCA分析表明雪岭云杉在南疆的气候生态位最广泛、北疆次之、东疆最窄，生态位分化检测表明北疆、南疆和东疆未发生明显分化。 Abstract:Exploring the impact of climate change on the potentially spatial distribution of forest plants in Tianshan Mountain and its simulation and prediction can help to reveal the adaptation strategies and feedback mechanisms of plant distribution patterns to climate change at the mesoscale. It has important scientific and practical significance for promoting biodiversity conservation and sustainable management of forest resources in Arid Mountainous Forest Ecosystem. Based on the data of distribution points of Picea schrenkiana and environmental factors data, the maximum entropy (MaxEnt) model, GIS tools and R software were used to estimate the potential distribution range, spatial pattern changes and niche differentiation of P. schrenkiana under the reference climatic (1970-2000), Representative Concentration Pathways (RCPs) based climate scenarios in 2050 (2041-2060) and 2070 (2061-2080). The results showed that:(1) the potential distribution of P. schrenkiana in the reference climatic was basically consistent with the Normalized Difference Vegetation Index (NDVI) vegetation cover change in autumn of 2019. The high suitability distribution areas are mainly distributed in Hami, Balikun and Yiwu in Eastern Xinjiang, the north slope of Tianshan Mountain, Bogda Mountain, Beita Mountain and Yili Valley in Northern Xinjiang, and the south slope of Tianshan Mountain in Southern Xinjiang. In addition, it was also distributed in the southern slope of Altay Mountain, Tacheng, Yumin, Tuoli, Western Kunlun Mountain and little Pamirs mountain. (2) The key factors limiting the potential distribution of P. schrenkiana were precipitation (Precipitation of driest month, Precipitation of coldest quarter and Precipitation seasonality), temperature (Mean temperature of driest quarter, Annual mean temperature, Isothermality and Annual temperature range), soil profile available water capacity, soil carbon density, and altitude. Their cumulative contribution rate reached 87.28%. (3) In 2050 and 2070 periods, the suitable distribution range of P. schrenkiana showed no significant increasing trend, but the RCP6.0 scenario was more significant than the RCP2.6, with an increase of 3.33% and 3.47%, respectively; The low, middle and high suitable areas maintained relatively stable changes, the growth rates from RCP2.6 to RCP6.0 scenarios are about 1.78%, 1.26%, and 0.98%, respectively; and the center of gravity of suitable distribution areas showed a trend towards higher latitude and northeastward, but the change amplitude was not significant. (4) PCA analysis showed that the climate niche of P. schrenkiana was the most extensive in Southern Xinjiang, followed by Northern Xinjiang, and the narrowest in Eastern Xinjiang. Niche differentiation test indicated that there was no significant differentiation in the Northern, Southern and Eastern Xinjiang. 参考文献 相似文献 引证文献

Climate and Competitive Status Modulate the Variation in Secondary Metabolites More in Leaves Than in Fine Roots of Betula pendula.

Plant secondary metabolites have many important functions; they also determine the productivity and resilience of trees under climate change. The effects of environmental factors on secondary metabolites are much better understood in above-ground than in below-ground part of the tree. Competition is a crucial biotic stress factor, but little is known about the interaction effect of climate and competition on the secondary chemistry of trees. Moreover, competition effect is usually overlooked when analyzing the sources of variation in the secondary chemistry. Our aim was to clarify the effects of competitive status, within-crown light environment, and climate on the secondary chemistry of silver birch (Betula pendula Roth). We sampled leaves (from upper and lower crown) and fine roots from competitively dominant and suppressed B. pendula trees in plantations along a latitudinal gradient (56–67° N) in Fennoscandia, with mean annual temperature (MAT) range: −1 to 8°C. Secondary metabolites in leaves (SML) and fine roots (SMFR) were determined with an HPLC-qTOF mass spectrometer. We found that SML content increased significantly with MAT. The effect of competitive stress on SML strengthened in colder climates (MAT<4°C). Competition and shade initiated a few similar responses in SML. SMFR varied less with MAT. Suppressed trees allocated relatively more resources to SML in warmer climates and to SMFR in colder ones. Our study revealed that the content and profile of secondary metabolites (mostly phenolic defense compounds and growth regulators) in leaves of B. pendula varied with climate and reflected the trees’ defense requirements against herbivory, exposure to irradiance, and competitive status (resource supply). The metabolic profile of fine roots reflected, besides defense requirements, also different below-ground competition strategies in warmer and colder climates. An increase in carbon assimilation to secondary compounds can be expected at northern latitudes due to climate change.

Palaeovegetation and paleoclimate in the SW Turkey – a study based on the early-middle Miocene coal-bearing sediments from the Büyük Menderes Graben

This study provides the age of coal-bearing sediments of the Büyük Menderes Graben (BMG) and palaeoclimatic and palaeovegetational change from the early to late Miocene. Two palynofloras, the Başçayır and Kızılcayer, are distinguished in the late Burdigalian-early Langhian, and Serravallian-Tortonian boundary. According to the microfloral composition of the Başçayır palynoflora is characterized by subtropical elements, and palaeoclimate is warm subtropical, with the coldest month mean temperature (CMT) 8–13 oC. Based on the palynoflora, the coal-bearing sediments were deposited in the fluvial-lacustrine environments. The abundances of gymnosperm species and the mean annual range of temperature (MART) point out high and middle altitude areas during the deposition of coal-bearing sediments. Based on the Kızılcayer palynofloral composition, palaeoclimate is the warm temperate (CMT: 3.1–13.3 oC), also the abundant presence of herbaceous species indicate open land areas in the Aydın-Kızılcayer area despite the existences of swampy-lowland environments.According to described palynofloral composition, the palaeotopographic conditions of the southern part of the BMG (Aydın-Kuloğulları) are generally higher than the northern parts (Aydın-Başçayır), and deposition areas in this graben are significantly uplifted from the late Burdigalian to early Tortonian. The regional palaeoclimatic condition from the early to late Miocene changed from warm subtropical to temperate in western Anatolia. The palaeotopographic changes related to the tectonic events and/or uplift of the Menderes Massive in western Anatolia could have been effective on regional paleoclimate during the deposition in the BMG, and this uplifting existed in the late Burdigalian and continued until the late Miocene.

Grazing Effects on Mongolian Steppe Vegetation—A Systematic Review of Local Literature

The Mongolian steppes with a long history of nomadic pastoralism cover a large area of the Palaearctic steppe biome and are still relatively intact. As livestock number has increased over the last two decades, grazing has been considered as the main reason of pasture degradation. However, the impact of grazing on vegetation dynamics, and its interaction with climate, is still not clear. We reviewed 44 publications in Mongolian language, covering 109 sites in five main steppe types, i.e., desert, dry, meadow, mountain, and high mountain steppe, with a mean annual precipitation and temperature range from 120 to 370 mm and from −6 to +5°C, respectively. We calculated relative changes in vegetation cover, species richness, and aboveground biomass from heavily grazed with respect to lightly/non-grazed conditions. Multiple linear regression models were used to test the impact of environmental factors, i.e., mean annual precipitation, coefficient of variation for precipitation, mean annual temperature and elevation. Grazing had a stronger effect on the vegetation of dry, desert and high mountain steppes, whereas its effect was less pronounced in the meadow and mountain steppes with mesic climate and high productivity. Vegetation cover, species richness and aboveground biomass were reduced by heavy grazing in the dry, desert and high mountain steppes. In the meadow steppes, grazing reduced vegetation cover, but increased richness and had nearly no effect on biomass. In the mountain steppe, richness and cover were not affected, but biomass was reduced by heavy grazing. Additionally, grazing effects on biomass tended to be more pronounced at sites with higher amounts of annual precipitation, and effects on cover changed from negative to positive as elevation increased. In conclusion, grazing effects in Mongolian steppes are overall negative in desert, dry and high mountain steppes, but no or even positive effects are found in meadow and mountain steppes. Especially, heavy grazing showed a detrimental effect on all vegetation variables in desert steppes, indicating the existence of combined pressure of climate and grazing in arid habitats, making them potentially sensitive to overgrazing and climate change. Grassland conservation and management should consider characteristics of different steppe types and give importance to local environmental conditions.

Metacommunity structure reveals that temperature affects the landscape compositional patterns of avian malaria and related haemosporidian parasites across elevations

Metacommunity ecology studies how species compositional patterns and their distributions vary across local and regional scales and provides insights on processes driving the distribution of communities. Avian haemosporidians comprise a diverse and widely distributed parasite taxon; some studies have analyzed their alpha and beta diversity patterns. Yet, metacommunity structures of avian haemosporidians and thus relevant biotic and abiotic variables explaining such structures at the landscape scale (i.e., 10–200 km) have not been assessed. We studied the metacommunity structure of avian haemosporidian mtDNA cyt b lineages and the infected avian host assemblage across four different elevations in Central Veracruz, Mexico. We performed variation-partitioning analyses to evaluate the contribution of host-related traits and climatic variables to the metacommunity. We found a richness of 78 lineages within 38 infected species of birds. At the component community level, we observed that bird species infected with a lower number of parasite lineages (e.g., <3) represented a nested subset of those with a higher number of parasite lineages (e.g., >8) (i.e., nested structure). However, this nested pattern was due to the restricted spatiotemporal co-occurrence of hosts and parasites, given the high degree of turnover across elevations. Host-related traits (functional, transmission-associated, and phylogenetic relationships) only explained a small fraction of the variation (4.4%) in parasite lineage composition across avian hosts. At the habitat level, there was a group turnover by parasite genera across elevation (i.e., quasi-Clementsian structure), which was partly explained by climatic variables (mean annual temperature and annual diurnal range; 27.6%) that may constrain parasite reproduction and vector distribution across the environmental gradient. At the scale of our study, environmental conditions represented a more important driver of avian haemosporidian metacommunity structure than host-related traits, suggesting an important role of environmental filtering structuring parasite assemblages at the landscape level.