Altitude Gradient Research Articles

In plateaus, land cover replaced climate as the vital environmental factor on the spatial composition of bumblebees with the altitude rising

Abstract Bumblebees show a series of advantages over other pollinating insects in offering pollination services for both the ecosystem and agricultural production, especially in high‐altitude areas. With climate warming, their diversity at high altitudes will be threatened. Therefore, more attention should be paid to the management of bumblebee resources at high altitudes to prevent their decline here. Discovering drivers responsible for the spatial variation of biodiversity is a benefit for developing appropriate management. Here, based on the bumblebee diversity on three plateau areas with an altitude gradient, the roles of different environmental factors, the climate, land cover, topography, habitat heterogeneity and soil, in the bumblebee composition were assessed by generalised dissimilarity modelling. And the relative importance of variables was evaluated by the impact on the magnitude of total biological change and the per cent change in deviance explained by models. According to the results, in the low‐altitude area, the climate played a vital role and the most important variable was the climate variable. Then, with the altitude rising, the effect of land cover continually increased. In the medium‐altitude area, the effects of different factors were detected to be similar, and the most important variables were a climate variable and a land cover variable. In the high‐altitude area, land cover finally replaced the climate as the most important factor, and one land cover variable was assessed as the most important variable. Our study revealed that the relative importance of different environmental factors on the biodiversity of bumblebees can differ as the altitude rises.

C:N:P stoichiometric characteristics of mosses in Picea crassifolia forest in Helan Mountains, Ningxia, China.

To explore the stoichiometric characteristics of C, N and P and adaptive mechanism of mosses in mountain forest ecosystems, we set up 15 plots along the altitude gradient in Picea crassifolia forest in Helan Mountains, Ningxia. We analyzed the C:N:P stoichiometry of moss aboveground tissues and its relationship with environmental factors. The results showed the mean values of C, N and P concentration in moss aboveground tissues were 336.67, 20.31 and 0.66 mg·g-1, respectively. The mean value of aboveground tissue N:P was 33.4, indicating that the growth of mosses was limited by P. The C concentration in the aboveground tissues of mosses was positively correlated with soil total nitrogen concentration and negatively correlated with soil total phosphorus concentration. The N concentration in aboveground tissues of mosses was significantly negatively correlated with soil organic carbon and soil total nitrogen concentrations. Results of redundancy analysis showed that the interpretation rate of environmental factors on the stoichiometry was 48.5%, with canopy closure, soil total nitrogen and soil total phosphorus as the main factors. Canopy closure was the main environmental factor affecting the growth of mosses in P. crassifolia forest in Helan Mountains. High canopy closure facilitated the growth of mosses.

Recent warming and its risk assessment on ecological and societal implications in Nepal

A predominantly mountainous country Nepal has a complex climatic pattern that varies from tropical in the south (Terai region) to arctic in the north (Himalayas). The gradual rise in temperature in the mountainous region has attracted great interest among the scientific community in general over recent years. However, recent warming in Nepal’s east-west and south-north temperature gradients and its implications for ecology and society based on facts and figures are still lacking. In this context, temperature data (1970–2016) of 76 meteorological stations from the Terai region to the Mountains were used in this study to analyze the annual and seasonal warming trends in the different physiographic regions of Nepal. We performed a hybrid analytical approach i.e. integrated statistical and theoretical tools to detect the warming trend and its ecological and societal implications across the country. The Eastern part of the country was found to be more warming than the Central and Western parts, showing an increased climatic sensitivity across the Khumbu (Mt. Everest region). The increasing trends of temperature have been found in all physiographic regions along an altitude gradient, i.e. Terai, Siwaliks, Lower Hills, and Upper Hills observed 0.15, 0.26, 0.68, and 0.57 °C per decade, respectively. Higher warming trend in Lower Hills than the Upper Hills showed that higher elevations experienced lesser degrees of warming trends than the lower elevations in the mountainous regions. Further, a higher warming trend was observed in the winter season than the other seasons in all regions except for Terai. Based on the warming trends in different physiographic regions, we also found a similar pattern of ecological impacts, where a higher warming region also experienced higher ecological impacts such as changes in water resources, phenology, etc. Lower Hills, Upper Hills, and Mountains experienced higher adverse impacts than the Terai and Siwaliks in the current global warming scenarios.

The altitudinal distribution characteristics of functional traits reflect the resource allocation strategy of Abies georgei var. smithii in southeast Tibet

To explore the adaptation strategies of the aboveground and underground functional traits of alpine plants along an altitudinal gradient, a typical stand of primitive dark coniferous forests (Abies georgei var. smithii.) in southeastern Tibet was taken as the research object in the present study. PCA and correlation analyses were carried out for different organ functional traits (19 key indicators in total), then RDA analysis was done in conjunction with 12 environmental factors. The variation characteristics of the functional traits of leaves, current-year twigs, trunks and fine roots in 6 continuous altitude gradients and the relationships between functional traits and environmental factors were explored. The results showed that soil organic carbon (SOC) may exert a positive effect on the construction of plant defense tissue via changes in functional traits, altitude (Alt) represents the primary influencing factor of wood density (WD) variation, particulate organic carbon (POC) content mainly affected fine root dry matter (RDWC) content and specific root length (SRL), and total potassium (TK) content was the main factor that affected fine root tissue density (RTD). Leaves, current-year twigs, and fine roots exhibited high production or nutrient acquisition capacity at an altitude of 4,000m and showed strong defense and relatively stable water and nutrient transport capacity. In conclusion, the ecological strategy of Abies georgei var. smithii. in Sejila Mountain was more conservative, and the optimal survival area of Abies georgei var. smithii. was located at 4, 000m on the shady slope of Sejila Mountain. It is of paramount significance for exploring the essence of terrestrial ecosystems and their functional processes in extremely high-altitude environments.

Effects of Environmental Factors on the Spatial Distribution Pattern and Diversity of Insect Communities along Altitude Gradients in Guandi Mountain, China

Understanding the distribution patterns and underlying maintenance mechanisms of insect species is a core issue in the field of insect ecology. However, research gaps remain regarding the environmental factors that determine the distribution of insect species along altitudinal gradients in Guandi Mountain, China. Here, we explored these determinants based on the distribution pattern and diversity of insect species from 1600 m to 2800 m in the Guandi Mountain, which covers all typical vegetation ecosystems in this area. Our results showed that the insect community showed certain differentiation characteristics with the altitude gradient. The results of RDA and correlation analysis also support the above speculation and indicate that soil physicochemical properties are closely related to the distribution and diversity of insect taxa orders along the altitude gradient. In addition, the soil temperature showed an obvious decreasing trend with increasing altitude, and temperature was also the most significant environmental factor affecting the insect community structure and diversity on the altitude gradient. These findings provide a reference for exploring the maintenance mechanisms affecting the structure, distribution pattern, and diversity of insect communities in mountain ecosystems, and the effects of global warming on insect communities.

Increased Production of Tara (Caesalpinia spinosa) by Edaphoclimatic Variation in the Altitudinal Gradient of the Peruvian Andes

Tara production occurs mainly in the altitude gradient, where the edaphoclimatic conditions that affect the production of pods still need to be understood. The goal was to determine the altitudinal and edaphoclimatic effect on the production of tara pods in agroforestry and natural remnants in Cajamarca, Peru. Data analyses performed were the following: principal component analysis (PCA), regression analysis, the bootstrap method, and Pearson correlation analysis. For each 1 °C increase in temperature, the length and width of the pod decreased by 2.1 and 0.62 mm, and of the seed by 0.17 and 0.12 mm in the agroforestry environment; likewise, pod, valve, seed and gum weights were reduced by 23.9, 10.9, 13 and 2.3 g in the agroforestry environment, and 22.3, 13, 9.3 and 2.1 g in the natural environment. Activities such as association with annual crops and perennial pasture possibly favor the length and width of the pod and seed and the weight of the pod, valve, seed and gum in the agroforestry environment when compared to the natural environment. Larger pod and seed dimensions and higher pod, valve, seed and gum weights are related to higher soil CaCO3 contents in the natural environment and higher soil P and B contents in the agroforestry environment at higher altitudes. Higher Fe contents in the soil suggest an improvement in tara’s tannin weight (valve) in the natural and agroforestry environment. The effective response of tara, reflected in its weight and size of pods, was higher in an agroforestry environment than in a natural environment. Further studies on the production of tara pods are necessary for a better understanding of the interaction between altitude and soil fertility to expand the revenue and employment of Peruvian tara farmers.

Topography intensifies variations in the effect of human activities on forest NPP across altitude and slope gradients

The distribution pattern of forest net primary productivity (NPP) is mainly driven by biotic (climate) and abiotic (topography and human activity) factors. However, the influence of these factors on NPP's distribution along the elevation and slope gradient is uncertain. Additionally, it remains uncertain whether the pattern of NPP at the regional scale with significant altitude variations is comparable to that at the mountain scale. This study analyzed the NPP distribution pattern in the Yangtze River Basin, a region with high altitude heterogeneity, and investigated the impact of climate and human activity on the NPP along the elevation and slope gradient. The results revealed that as altitude increased, NPP first rose and then declined, reaching a peak at 2200–2300 m above sea level, This is in line with the distribution of NPP in mountainous areas and suggests that regions with large elevation differences may also experience vertical effects. NPP displayed an “N” shaped distribution along the slope gradient and the effect of climatic factors varied at different altitudes. Precipitation has a greater effect on NPP than the temperature in regions with less than 2300 m altitude, whereas temperature has the opposite effect in high-elevation regions (>2300 m). The study also found that afforestation and the returning farmland to forestland mainly occurred in low- and middle-altitude regions and middle-slope regions, leading to rapid NPP growth. These findings reveal that topography influences climate and human impacts on forest NPP, and future forest management strategies should consider the terrain's impact on tree growth and protect forests in high-altitude and steep-slope areas.

Influence of altitude as a proxy for temperature on key Musa pests and diseases in watershed areas of Burundi and Rwanda

Pests and diseases are key biotic constraints limiting banana production among smallholder farmers in Eastern and Central Africa. Climate changemay favour pest and disease development and further exacerbate the vulnerability of smallholder farming systems to biotic constraints. Information on effects of climate change on pests and pathogens of banana is required by policy makers and researchers in designing control strategies and adaptation plans. Since altitude is inversely related to temperature, this study used the occurrence of key banana pests and diseases along an altitude gradient as a proxy for the potential impact of changes in temperature associated with global warming on pests and diseases. We assessed the occurrence of banana pests and diseases in 93 banana fields across three altitude ranges in Burundi and 99 fields distributed in two altitude ranges in Rwanda watersheds. Incidence and prevalence of Banana Bunchy Top Disease (BBTD) and Fusarium wilt (FW) was significantly associated with temperature and altitude in Burundi, revealing that increasing temperatures may lead to upward movement of banana diseases. No significant associations with temperature and altitude were observed for weevils, nematodes and Xanthomonas wilt of banana (BXW). Data collected in this study provides a baseline to verify and guide modelling work to predict future pest and disease distribution according to climate change scenarios. Such information is useful in informing policy makers and designing appropriate management strategies.

Altitudinal pattern and driving factors of soil fungal community in the tropical forest of Jianfengling, Hai-nan, China

Fungi are an important group of soil microorganisms. Exploring the altitudinal pattern and driving factors of fungal composition and diversity is an important topic in the field of biodiversity and ecosystem function. We employed the Illumina high-throughput sequencing technology to investigate the variation and environmental control of fungal α-diversity and β-diversity at the topsoil (0-20 cm) and subsoil (20-40 cm) across an altitudinal gra-dient of 400-1500 m in a tropical forest of Jianfengling Nature Reserve. The results showed that Ascomycota and Basidiomycota dominated soil fungal community, reaching a relative abundance of more than 90%. Fungal α-diversity at the topsoil exhibited no obvious altitudinal pattern, and that of the subsoil decreased with the increases in altitude. Higher fungal α-diversity was observed in the topsoil. Soil fungi β-diversity was significantly affected by altitude. Morover, temperature was the driving force of the altitude pattern of fungi β-diversity. The similarity of fungal community decreased significantly with the increases in geographical distance, but did not change with the increases in environmental distance. The similarity of rare phyla (Mortierellomycota, Mucoromycota and Rozellomycota) was significantly lower than that of rich phyla (Ascomycota and Basidiomycota), indicating that diffusion restriction determined the differentiation of fungal community structure along the altitude gradient. Our study demonstrated that the diversity of soil fungal community was affected by altitude. The rare phyla, rather than rich phyla, determined the altitudinal variation of fungi β-diversity in Jianfengling tropical forest.

Plant species diversity and density patterns along altitude gradient covering high-altitude alpine regions of west Himalaya, India

ABSTRACT Understanding species richness and diversity patterns and their governing factors in less-to-unexplored regions across Himalaya provide invaluable insights into exploring drivers which shape as well as influence plant community structures. The present investigation explores plant species richness and diversity patterns across different growth forms and its association with environmental parameters along altitudinal gradient (3200 m-4800 m) in alpine regions of west Himalaya, India. A total of 265 plant taxa were documented from study area with higher proportion of herbs (212), followed by shrubs (44) and trees (9). Species richness, diversity, and density patterns were estimated for each growth form along altitude gradients using polynomial regression and an apparent monotonically decreasing trend (p < 0.05) was seen across transects, with highest values for herbs. Beta diversity, estimated for each transect, was low in Darma for herbs exhibiting high species packaging and homogenous composition, and high in Mana showing more scope for occurrence of rare/occasional herbs. Four major distinct altitudinal zones were identified for Uttarakhand alpines using cluster dendrogram, i.e., 3200 to 3500 m, 3600 to 3900 m, 4000 to 4500 m and 4600 to 4800 m with respect to their vegetation composition. NMDS of combined dataset along altitude gradient across transects also exhibited proximity among lower altitudesof transects with similar species composition (like Anaphalis, Danthonia, Geranium, Pedicularis, Potentilla), while high-altitude plots were scattered towards both ends of axesinhabiting specialized plant species (like Gentiana, Nardostachys, Saussurea, Sedum, Swertia). The relationship between vegetation variables (richness, diversity and density) and climate variables was modelled using Pearson’s correlation (P < 0.001) and temperature, precipitation, and solar radiation exhibited positive correlation, while windspeed showed negative correlation. Relative effect of climatic parameters on species composition, analysed by CCA, showed strongest influence of precipitation in vegetation zones with high axes correlation, followed by temperature, isothermality and wind speed, while influence solar radiation was lowest. Thus, under the current climate change scenario, any change in these factors may alter the composition of these high-altitude area and threaten the unique flora as well as the fauna dependent on it. Hence, any effort made towards conservation would eventually benefit a significant proportion of Himalayan biodiversity.

The content of nutrients, lignin and cellulose in plants and lichens in the forest-tundra ecotone of the Khibiny mountain massif

The results of studies of the chemical composition of plants and lichens in the altitude gradient on the slope of Yumechorr of the Khibiny mountain massif (Murmansk region) are presented. The species specificity of the accumulation of macro- and microelements by the assimilating organs of plants and lichens in the in the main altitude zones is shown. The leaves of Betula pubescens and Vaccinium myrtillus are the most rich of elements of mineral nutrition. Lichens are characterized by a low content of N, Ca, K, P, Mg, S, as well as Zn and Mn and high - Fe, Cu, Ni. In spruce and pine needles, similar patterns of the distribution of elements by age classes were revealed. Changes in the content of nitrogen, mineral elements, secondary metabolites in the altitude gradient in the assimilating organs of plants and lichens, during the transition from the forest belt to the mountain forest, have been established. It has been established that with increasing growth height, the N content increases in Pinus sylvestris needles, in the leaves of Arctostaphyllos uva-ursi, in the leaves of the current year Empetrum hermaphroditum. Plants growing in the mountain tundra and forest tundra are characterized by a high content of K. The Zn content also increases with increasing absolute height in the conifers/leaves of P. sylvestris, B. pubescens, V. uliginosum. During the transition from the forest belt to the mountain tundra, the content of Ca and Mg decreases in plant leaves. In the leaves of E. hermaphroditum, minimal concentrations of Mn were also detected in the mountain tundra. The content of lignin and cellulose in the leaves of shrubs, with the exception of V. myrtillus, in the belt of coniferous forests is lower than in the belt of birch forests and tundra. The content of lignin in the leaves of B. nana and B. pubescens increases, and cellulose practically does not change with an increase in absolute height in the Khibiny Mountains. Accumulation of lignin is observed in needles of P.sylvestris in the belt of birch woodlands.

Deadwood affects the soil organic matter fractions and enzyme activity of soils in altitude gradient of temperate forests

The main objective of our study has been to determine the role of deadwood in the shaping of the amount of soil organic matter fractions in mountain forest soils. For this purpose, a climosequence approach comprising north (N) and south (S) exposure along the altitudinal gradient (600, 800, 1000 and 1200 ​m a.s.l.) was set up. By comparing the properties of decomposing deadwood and those of the soils located directly beneath the decaying wood we drew conclusions about the role of deadwood in the shaping of soil organic matter fractions and soil carbon storage in different climate conditions. The basic properties, enzymatic activity and fractions of soil organic matter (SOM) were determined in deadwood and affected directly by the components released from decaying wood. Heavily decomposed deadwood impacts soil organic matter stabilization more strongly than the less decayed deadwood and the light fraction of SOM is more sensitive to deadwood effects than the heavy fraction regardless of the location in the altitude gradient. Increase in SOM mineral-associated fraction C content is more pronounced in soils under the influence of deadwood located in lower locations of warmer exposure. Nutrients released from decaying wood stimulate the enzymatic activity of soils that are within the range of deadwood influence.

Species Diversity of Amphibians along Altitude Gradient at Hala – Bala Wildlife Sanctuary, Narathiwat Province

Species Diversity of Amphibians along Altitude Gradient at Hala – Bala Wildlife Sanctuary, Narathiwat Province

Relationship between plant functional diversity and ecosystem multifunctionality in Bayanbulak alpine meadow along an altitude gradient

Relationship between plant functional diversity and ecosystem multifunctionality in Bayanbulak alpine meadow along an altitude gradient

Characteristics and vertical distribution of insect functional groups along an altitude gradient in Guandi Mountains

Characteristics and vertical distribution of insect functional groups along an altitude gradient in Guandi Mountains

武夷山不同海拔毛竹细根功能性状

PDF HTML阅读 XML下载 导出引用 引用提醒 武夷山不同海拔毛竹细根功能性状 DOI: 10.5846/stxb202112143536 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（32071555）；福建省科技厅产学合作项目（2019N5009）；福建省教育厅项目（JAT190084） Fine root traits of Phyllostachys edulis at different altitudes in Wuyi Mountain Author: Affiliation: Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 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:细根作为植物最重要的资源获取功能器官，是影响陆地生态系统的重要组成部分。定量化毛竹的细根功能性状对于理解其生理生态特征响应及生活史策略至关重要。为揭示毛竹细根功能性状随海拔梯度的变化规律以及细根的适应策略，对武夷山不同海拔（840 m、1040 m、1240 m）毛竹细根的碳（C）、氮（N）、磷（P）含量和比根长（SRL）、比根面积（SRA）等性状进行测定，分析细根性状在海拔上的差异及其异速生长关系。结果表明：（1）不同海拔毛竹细根养分性状存在显著差异。毛竹细根C含量在海拔1040 m最大。随海拔升高，细根N、P含量均呈下降趋势，细根C ： N、C ： P随着海拔的升高而增加。（2）细根的结构性状在海拔梯度上差异显著。随海拔升高，细根平均根直径（AvgDiam）、SRL及SRA均呈下降趋势，而根组织密度（RTD）呈升高趋势。（3）细根性状间存在显著的异速生长关系。细根N与P含量存在显著的等速生长关系，二者与C含量存在显著异速生长关系；SRL与SRA存在显著的等速生长关系，二者与RTD存在显著的负等速生长关系，与N含量存在显著的异速生长关系；细根AvgDiam与RTD存在显著的负异速生长关系。毛竹细根功能性状海拔梯度差异显著且细根性状之间呈显著的异速生长关系，表明毛竹细根获取型性状（如SRL）与保守型性状（如RTD）存在权衡，在海拔840 m毛竹倾向于增加根长来获取养分和水分，随海拔升高则采取保守策略，如增加根组织密度。因此，毛竹能够通过自身表型可塑性机制合理权衡细根性状之间的资源配置以适应环境变化。 Abstract:As the most important resource-obtaining functional organ of plants, fine roots are an important part affecting terrestrial ecosystems. Quantifying the fine root functional traits of Phyllostachys edulis is critical to our understanding of the physiological response and ecological characteristics for bamboo's life-history strategies. To investigate the variation of fine root traits of Phyllostachys edulis with altitude gradient and the adaptation strategies of fine roots, the contents of carbon (C), nitrogen (N), phosphorus (P), specific root length (SRL), specific root area (SRA) and other traits of Ph.edulis's fine roots were measured in Wuyi Mountain at different altitudes (840 m, 1040 m, 1240 m), and the differences of fine root traits at different altitudes and the allometric relationship between them were analyzed. The results showed that:(1) there were significant differences in the contents of C, N, P and the ecological stoichiometry among different altitudes. The content of C in fine roots was the highest at the altitude of 1040 m, with the increase in altitude, the content of N and P decreased, leading to the increase of the ratio of C:N and C:P. (2) There were significant differences on the structural traits of fine roots among different altitudes. As the altitude increased, the average root diameter (AvgDiam), SRL, SRA of fine roots all showed a downward trend, while the root tissue density (RTD) showed an upward trend. (3) There was a significant allometric relationship between fine root traits. The significant isometric relationships were found between N and P content in fine roots, but they showed a significant allometric relationship between C content. There was a significant isometric relationship between SRL and SRA, but they showed a significantly negative isometric relationship with RTD, and showed a significant allometric relationship with N content. The significantly negative allometric relationships were found between AvgDiam and RTD. There was a significant difference of fine root functional traits among different altitudes, and a significant allometric relationship between them. Our research showed that there was a trade-off between fine root acquisitive traits (such as SRL) and conservative traits (such as RTD). Ph.edulis tended to increase root length for increasing nutrient absorption at altitude of 840 m, and adopted the conservative strategy (such as increasing root tissue density) with increasing altitude. Therefore, Ph.edulis can rationally balance resource allocation among fine root traits to adapt to environmental changes through phenotypic plasticity mechanism. 参考文献 相似文献 引证文献

Variability of morphological features of Dracocephalum multicaule (Lamiaceae) in natural populations of Dagestan

The structure of intra- and inter-population variability of Dracocephalum multicaule Montbr. et Auch. ex Benth. along the altitude gradient was studied on the basis of a complex of morphological features of plants. Two populations of D. multicaule were collected from different altitude levels (800 and 1130 m above sea level). Differences between populations by place of growth (microclimatic conditions), communities in which the species grows, age composition, as well as morphological features were revealed. A decrease in the average values of quantitative and dimensional traits with the increase in altitude has been recorded, with the exception of two (the length of the inflorescence and the number of verticils). Intra- and inter-population variability of traits are at medium and high levels. Variability of the number of flowers in the inflorescence (43.5–51.5) and weight characteristics (36.1–50.0) are high. The interpopulation variability of species traits is the result of the influence of a complex of factors of the altitude gradient and the population age. The areas differ in ecological habitat conditions and the degree of anthropogenic load. The increasing anthropogenic impact in the places where the species grows disrupts the stability of natural populations and affects plant reproduction. In order to preserve the species of D. multicaule in natural habitats, it is necessary to reduce anthropogenic pressure, as well as to introduce the species into culture.

Study of the geomagnetic field’s regional gradients in Chinese continent using three-dimensional surface Spline model

We combined domestic ground-based and satellite magnetic measurements to create a regional three-dimensional surface Spline (3DSS) gradient model of the main geomagnetic field over the Chinese continent. To improve the precision of the model, we considered the data gap between the ground and satellite data. We compared and analyzed the results of the Taylor polynomial, surface Spline, and CHAOS-6 (the CHAMP, Ørsted and SAC-C model of Earth’s magnetic field) gradient models. Results showed that the gradients in the south−north and east−west directions of the four models were consistent. The 3DSS model was able to express not only gradients at different altitudes, but also average gradients inside the research area. The two Spline models were able to capture more information on gradient anomalies than were the fitted models. Strong local anomalies were observed in northern Xinjiang, Beijing, and the junction area between Jiangsu and Zhejiang, and the total intensity <italic>F</italic> decreased whereas the altitude increased. The gradient decreased by 21.69% in the south−north direction and increased by 11.78% in the east−west direction. In addition, the altitude gradient turned from negative to positive while the altitude increased. The Spline model and the two fitted models differed mainly in the field sources they expressed and the modeling theory.

Different biomass allocation strategies of geophytes and non-geophytes along an altitude gradient

Biomass allocation strategies among geophytes and non-geophytes generally determine the ecological adaptation and impacts of herbaceous plants. Although geophytes and non-geophytes are key components of the biodiversity of subtropical forest ecosystems, strategies for biomass allocation of both remain unknown. In this study, 695 individual herbaceous plants were collected from low, middle, and high altitude regions in Qianjiangyuan National Park. We analyzed the biomass and allometric trajectories of the leaves, stems, roots, and underground storage organs of whole herbs, geophytes, and non-geophytes. The results showed that: (1) The overall allometric trajectory of understory herbs changed with increase in altitude. Allocation was reduced to stems and leaves and increased to roots. (2) In geophytes, the allocation was reduced to leaves and stems and increased to underground storage organs and roots, which follows the optimal partitioning theory. In the biomass trade-off of the aboveground parts, the stem is preferred. (3) However, the allometric trajectories of non-geophytes are less susceptible to changes in the altitude, and the biomass allocation strategy depends only on plant size which follows allometric partitioning theory. In the biomass trade-off of the aboveground parts, the leaves are preferred. Totally, geophytes and non-geophytes adopted different biomass allocation strategies as adaptations to altitudinal changes in the environment. The plant functional type is the major determinant of biomass allocation in herb species. This study has implications for the management practices of herbaceous plants and predicting changes in understory vegetation.

The difference in soil organic carbon distribution between natural and planted forests: A case study on stony soils mountainous area in the Upper Min River Arid Valley, China

AbstractFew studies have been conducted on the factors and distribution of soil organic carbon (SOC) in plantation forests in arid mountainous regions, especially in orchards. We aimed to unravel the SOC distribution among land‐use types and the effects of altitude gradients and rock fragment content (RFC) on SOC accumulation and sequestration in the Upper Min River Arid Valley, China. The differences in SOC distribution among land‐use types were quantified. The correlation analysis of SOC with various factors, such as altitude and RFC, was conducted. The variation percentage in SOC content and stocks was explained by the factors' contribution using mixed‐effects models. SOC distribution was characterized by high content and low stocks in native forests and shrubs, high content and high stocks in eco‐forest, and low content and high stocks in orchards. At the surface (0–30 cm), SOC content and stocks in orchards (cherry, plum, and apple) were significantly lower than those in eco‐forests. There was a significant positive correlation between altitude and SOC content at the surface but not at the subsoil (30–60 cm). With RFC increased, the surface SOC content decreased in native forests, shrubs, and eco‐forests, while it increased in orchards. Our results suggest that land management is the main factor controlling the variation in SOC distribution. Enhancing the surface SOC stability in orchards by land management is a priority for soil carbon pool management in the Arid Valleys.