Vertical Distribution Patterns Research Articles

Micro-/Meso-Scale Distinction and Horizontal Migration of Tintinnid (Ciliophora: Tintinnida) Assemblages in Three Regions Around the North Pacific Ocean

We explored the relationships among different tintinnid populations on micro-, meso-, and basin-scales from three regions across the Pacific Ocean, including the Costa Rica Dome (CRD) in the Eastern Pacific Ocean, the Celebes Sea (CS), and the Tokara Strait (TS) in the Western Pacific Ocean. We quantified the species occurrence, vertical and biogeographic distribution patterns, and morphological parameters of tintinnid assemblages. A total of 46 tintinnid species were observed, with more than half (63.0%) in common among the three areas, accounting for 97.1% of the total abundances. The numerically abundant forms remained more or less the same set of species in the three areas. However, community structure analyses, in terms of species, lorica oral diameter (LOD) size classes, and genera, revealed clear distinctions among different regions, as well as among different water depths. A Lagrangian simulation of passive dispersal in ocean currents across the Pacific Ocean, supported the hypothesis that greater similarity between tintinnid populations in the CS and TS (relative to CRD), was related to ocean circulation linkages between the populations. A latitudinal decline of tintinnid species richness was observed, mainly as a result of a decline of redundant species and warm-water species in colder areas. These data provide information unique insight into population variability of microzooplankton communities on micro- to meso- and even large scales in the world oceans.

Spatial and Vertical Benthic Foraminifera Diversity in the Oxygen Minimum Zone of Mejillones Bay, Northern Chile

Mejillones Bay is located in northern Chile (23°S) and is influenced by an Oxygen Minimum Zone (OMZ), with oxygen levels below 0.5 ml l–1. This area presents particular ecological characteristics, such as circulation of currents, hotspot, high productivity and industrial activity. This extreme ecosystem generates the need to understand their dynamics and changes across time and space, as well as to identify the main differences with other OMZs. For this reason, we studied the benthic foraminifera to use them as environmental and oxygenation proxies. For this purpose, two sediment cores (ZA and Z1A) were collected, obtaining 14 samples of the first 8 cm (vertical distribution), and 18 samples with a mini boxcore (spatial distribution). When analyzing the foraminifera community, some similarities were found in environmental characteristics of other OMZs, such as the predominance of Bolivina seminuda, Bolivina costata, Epistominella exigua, Fursenkoina sp., and Nonioella stella (species typical of hypoxic conditions). In addition, a high abundance of angular-asymmetric morphologies was observed, indicating eutrophied silty substrates and low current circulation. However, the Mejillones Bay recorded a particular spatial and vertical dynamics respect to others OMZs, due to presence of other species of Bolivinids not reported for this area before, and a high abundance of Buliminella elegantissima, which is not recorded in most of OMZs. Foraminifera with rounded-symmetric morphologies were present and dominant in deeper layers, reflecting a turbulent and high-energy environment. On the basis of depth and conditions of microxia or dysoxia, no significative pattern of spatial and vertical distribution was observed. The latter can be explained by local factors such as cyclonic and anticyclonic whirlpools, wastewater from industrial activity and natural disaster such a Tsunami occurred in 1877. These factors contributed to the mixture of the benthic foraminifera and prevented the formation of spatial and vertical patterns. Finally, an intensification of hypoxia was identified, indicating microxia (0,01 ml l–1) in the superficial layers (0–3 cm from years 1996 to 2012), while the deeper layers (4–8 cm from years 1985 to 1877) presented foraminiferal species that indicated dysoxia conditions (0,07 ml l–1). The latter differs from other OMZs, which show greater oxygenation in the most superficial layers and microxia in deeper layers. This study represents the first ecological reconstruction using benthic foraminifera proxies for the Mejillones Bay, which results indicate an OMZ with ecological and environmental features that differ from other OMZs.

Fine-scale vertical distribution and diel migrations ofPyrosoma atlanticumin the northern California Current

AbstractBlooms of the colonial pelagic tunicate Pyrosoma atlanticum in 2014–2018 followed a marine heatwave in the eastern Pacific Ocean. Pyrosome blooms could alter pelagic food webs of the northern California Current (NCC) by accelerating the biological pump via active transport, fecal pellet production and mortality events. Although aggregations of P. atlanticum have the potential to shape marine trophic dynamics via carbon export, little is known about pyrosome vertical distribution patterns. In this study, we estimated the distribution of P. atlanticum in the NCC along transects off of Oregon (45°N and 124°W) and northern California (41°N and 124°W), USA during February and July 2018. Depth-stratified plankton tows provided volume-normalized pyrosome abundance and biovolume estimates that complemented fine-scale counts by a vertically deployed camera system. Pyrosomes were numerous offshore during February, especially off Oregon. Colonies were distributed non-uniformly in the water column with peak numbers associated with vertical gradients in environmental parameters, notably density and chl-a. Vertical distributions shifted over the 24-h period, indicative of diel vertical migration. Understanding the vertical distribution of these gelatinous grazers in the NCC gives insight to their behavior and ecological role in biologically productive temperate ecosystems as conditions become more favorable for recurring blooms.

Diversity and vertical distribution patterns of wildlife in Tianzhushan, Shaanxi Province, China.

Biodiversity monitoring is an important means by which to evaluate management effectiveness and develop sound conservation plans. In this study, 52 cameras were installed in the study area of Tianzhushan to assess wildlife diversity and elevational patterns from 2018 to 2019. In total, 9 541 independent photos were collected within 26 565 camera-days. We analysed the relative abundance index (RAI), activity patterns and seasonal activity rhythms of the five most abundant species at 200-m elevational intervals throughout the study area (elevation range 1 400–2 000 m a.s.l.). Based on RAI results, the activity patterns of the five most abundant species (i.e. Susscrofa, Naemorhedusgriseus, Muntiacusreevesi, Arctonyxcollaris and Capricornismilneedwardsii) were analysed. Amongst the detected wild mammals, Susscrofa had the highest RAI value of 9.91, while the occurrence of Tamiopsswinhoei had the lowest RAI at 0.004. In addition, there were significant differences in species activity during the daytime and night-time. RAI of the ungulate community peaked at the 1 600–1 800 m a.s.l. elevational range, thus showing a mid-elevational peak pattern. Differences in vertical distribution patterns were detected for the five most abundant species. Mainland serows and wild boars preferred mid-elevation habitats (1 600–1 800 m a.s.l.), long-tailed gorals preferred mid- and high altitudes (1 600–2 000 m a.s.l.) elevation habitats and Chinese muntjacs and hog badgers preferred low elevation habitats (1 400–1 600 m a.s.l.). Taken together, this is the first study to reveal the five dominant species activity patterns in Tianzhushan, which is of importance for wildlife conservation.

Large, old trees define the vertical, horizontal, and seasonal distributions of a poison frog.

In tropical forests, large, old trees (LOTs) can be considered keystone structures for provisioning unique habitats such as decaying wood, roots, cavities, and epiphytes, including those that hold water (phytotelmata). These habitats may also be stratified in vertical space, for example, root structures occur at ground level and below, whereas epiphytes occur above-ground. Canopy habitat is utilized by a diversity of amphibians, but canopy habitat may only be viable in the wet season when epiphytes and surfaces are sufficiently saturated. Here, we examine how the provisioning of microhabitats and structures by LOTs influence the horizontal, vertical, and seasonal distribution patterns of phytotelmata-breeding poison frogs. We conducted ground-to-canopy surveys over 4years, constituting 6 seasons, in Panama and used mark-recapture techniques on a population of the yellow-bellied poison frog, Andinobates fulguritus. We found that A. fulguritus migrated vertically, tracking seasonal rainfall, and displayed strong philopatry to individual trees. Furthermore, A. fulguritus almost exclusively inhabited the largest trees at the study location, which provided disproportionately high-quality microhabitats and epiphytes compared to other trees. LOTs, and specifically Anacardium excelsum at our site, appear to serve as keystone structures with high conservation value due to their provisioning of unique habitats. We conclude that the distribution of A. fulguritus is defined vertically by the stratification of arboreal microhabitat resources, horizontally by the presence of LOTs providing the resources, and temporally by the seasonal viability of the resources.

Macrozooplankton and micronekton diversity and associated carbon vertical patterns and fluxes under distinct productive conditions around the Kerguelen Islands

Mesopelagic communities are characterized by a large biomass of diverse macrozooplankton and micronekton (MM) performing diel vertical migration (DVM) connecting the surface to the deeper ocean and contributing to biogeochemical fluxes. In the Southern Ocean, a prominent High Nutrient Low Chlorophyll (HNLC) and low carbon export region, the contribution of MM to the vertical carbon flux of the biological pump remains largely unknown. Furthermore, few studies have investigated MM communities and vertical flux in naturally iron fertilized areas associated with shallow bathymetry. In this study, we assessed the MM community diversity, abundance and biomass in the Kerguelen Island region, including two stations in the HNLC region upstream of the islands, and two stations in naturally iron fertilized areas, one on the Plateau, and one downstream of the Plateau. The MM community was examined using a combination of trawl sampling and acoustic measurements at 18 and 38 kHz from the surface to 800 m. A conspicuous three-layer vertical system was observed in all areas - a shallow scattering layer, SSL, between 10 and 200 m; mid-depth scattering layer, MSL, between 200 and 500 m; deep scattering layer, DSL, between 500 and 800 m - but communities differing among stations. While salps ( Salpa thompsoni ) dominated the biomass at the productive Kerguelen Plateau and the downstream station, they were scarce in the HNLC upstream area. In addition, crustaceans (mainly Euphausia vallentini and Themisto gaudichaudii ) were particularly abundant over the Plateau, representing a large, although varying, carbon stock in the 0–500 m water layer. Mesopelagic fish were prominent below 400 m where they formed permanent or migrant layers accounting for the main source of carbon biomass. Through these spatial and temporal sources of variability, complex patterns of the MM vertical distribution and associated carbon content were identified. The total carbon flux mediated by migratory myctophids at the four stations was quantified. While this flux was likely underestimated, this study identified the main components and mechanisms of active carbon export in the region and how they are modulated by complex topography and land mass effects. • Macrozooplankton and micronekton communities are described in the Kerguelen area using trawl and acoustic • Despite different assemblages, a consistent three-layers system occurred in the first 800 m over the Kerguelen seascape • Salps dominated global biomass in productive areas but not in HNLC region while crustaceans were abundant on the Plateau • Myctophids dominated below 400 m as permanent or migrant layers accounting for the main source of carbon biomass • We estimate total carbon flux mediated by migratory myctophids in the contrasting productive areas

Vertical distribution patterns and drivers of soil bacterial communities across the continuous permafrost region of northeastern China

BackgroundSoil microorganisms in the thawing permafrost play key roles in the maintenance of ecosystem function and regulation of biogeochemical cycles. However, our knowledge of patterns and drivers of permafrost microbial communities is limited in northeastern China. Therefore, we investigated the community structure of soil bacteria in the active, transition and permafrost layers based on 90 soil samples collected from 10 sites across the continuous permafrost region using high-throughput Illumina sequencing.ResultsProteobacteria (31.59%), Acidobacteria (18.63%), Bacteroidetes (9.74%), Chloroflexi (7.01%) and Actinobacteria (6.92%) were the predominant phyla of the bacterial community in all soil layers; however, the relative abundances of the dominant bacterial taxa varied with soil depth. The bacterial community alpha-diversity based on the Shannon index and the phylogenetic diversity index both decreased significantly with depth across the transition from active layer to permafrost layer. Nonmetric multidimensional scaling analysis and permutation multivariate analysis of variance revealed that microbial community structures were significantly different among layers. Redundancy analysis and Spearman’s correlation analysis showed that soil properties differed between layers such as soil nutrient content, temperature and moisture mainly drove the differentiation of bacterial communities.ConclusionsOur results revealed significant differences in bacterial composition and diversity among soil layers. Our findings suggest that the heterogeneous environmental conditions between the three soil horizons had strong influences on microbial niche differentiation and further explained the variability of soil bacterial community structures. This effort to profile the vertical distribution of bacterial communities may enable better evaluations of changes in microbial dynamics in response to permafrost thaw, which would be beneficial to ecological conservation of permafrost ecosystems.

Changes in Reconstructed Soil Physicochemical Properties in an Opencast Mine Dump in the Loess Plateau Area of China.

Soil construction and revegetation are essential for ecological restoration in mining areas. The influence of vegetation on the horizontal and vertical distribution patterns of soil properties should be fully understood. However, most studies on reconstructed soils in mining areas only concentrate on the surface soil, without exploring the vertical variations in soil properties. Overall, this study aims to explore the potential mechanisms by which surface vegetation exerts some influence on the spatial distribution of soil physicochemical properties, and to provide some insight into revegetation and soil reclamation in mining areas. Descriptive statistics and one-way analysis of variance (one-way ANOVA) were employed to evaluate the differences in the soil physicochemical properties in horizontal and vertical directions under different land-use types in the south dump of Antaibao opencast mine in Pingshuo, Shanxi Province, China. The main results of this study are as follows: (1) In the horizontal direction, except for the strong variation (variation coefficient ≥ 100%) in soil organic matter (SOM) content at some depths, the degree of variation in other soil physicochemical properties at various depths was moderate or weak (variation coefficient < 100%). The soil physicochemical properties gradually remained constant after years of reclamation. In the vertical direction, the soil bulk density (SBD), soil porosity, SOM content, soil C/N ratio, soil total nitrogen (STN) content, soil available phosphorus (SAP) content, and soil available potassium (SAK) content showed significant variations (p < 0.05) between soil depths. In contrast, no significant difference was found for other physicochemical properties. (2) The SBD, STN, SAK, soil porosity, and soil clay content were significantly different (p < 0.05) under different vegetation cover types, but the influence of vegetation on other soil physicochemical properties seemed to be limited. The results reveal that trees have a stronger ability to reduce soil grain sizes and enhance SAP contents than shrubs or herbs; however, the beneficial effects of herbs on the physicochemical properties of shallow soil are more obvious than those of trees and shrubs. (3) This study indicates that more shrubs and trees should be planted in the areas with low vegetation coverage, and more measures should be taken to improve soil physicochemical properties in order to prevent the occurrence of large-scale degradation. The reconstruction of soil structure should be preferentially considered in the process of soil reconstruction and revegetation in areas under similar conditions. Herbs should first be planted in the early reclamation stage. At the same time, shrubs or trees can be adopted in the middle and late stages of vegetation reconstruction in order to achieve comprehensive revegetation.

Diel Vertical Distribution Patterns of Pelagic Fish Larvae in Yilan Bay, Taiwan

To study the diel migration distribution of larval fish in an area adjacent to the Kuroshio Current, samples were collected from six depths by using a Motoda horizontal net at a fixed station in Yilan Bay on July 30 and 31, 2007. A total of 591 larval fish were collected and assigned to at least 34 families and 57 species. The first five dominant species were Benthosama pterotum (40.95%), Diaphus B type (12.18%), Callionymidae spp. (8.46%), Gobiidae spp. (6.60%), and Apogonidae spp. (4.0%). The density of larval fish varied across time. The maximum larval density was 1220.34 individuals/1000 m3 at 19:00, and the minimum larval density was 81.84 ind./1000 m3 at 14:00. The vertical distribution of species accounting for more than 10% of all fish caught was determined by the diurnal and nocturnal migration of the dominant species B. pterotum, which migrated from a depth of 50 m at night to 200 m in the afternoon. The distribution models for other species (e.g., Diaphus B type) were also analyzed in this study.

Vertical distribution patterns of ichthyoplankton in temperate waters of New Zealand

Multifactorial sampling designs were used to determine the vertical distribution of ichthyoplankton at multiple temporal and spatial scales in New Zealand. Hypotheses concerning the vertical distribution of fish larvae were tested in the following: depth strata, surface, near-surface, mid-depth and deep, and near the substratum. The consistency of abundance patterns was examined at three sites separated by 2–20 km over 2 months. We also tested for differences in shallow water columns of two depths (20 and 40 m) and both day and night. Although peak abundance of total larval fish was found at upper and lower strata, regardless of total depth of the water column, consistent taxa specific patterns of vertical distribution were also found. Some taxa were most abundant at the surface (e.g. mullids, hemiramphids, and kyphosids), whereas others were found at multiple depths below the surface and throughout the water column, regardless of site, time or depth of water column (e.g. carangids, engraulids, clupeids, scombrids, sparids and pleuronectids). Some taxa were most abundant in shallow water columns (e.g. mullids, tripterygiids and gobiids). Rank abundance by depth stratum for non-surface dwelling species varied among sites and times. Diel vertical movements were detected, some taxa (e.g. clupeids, scombrids and bothids) that were most abundant at the surface at night whereas for other taxa this pattern was more variable (e.g. carangids). We conclude that diel depth-related patterns in shallow water columns will influence interactions among taxa and the importance of different transport mechanisms for larval transport.

祁连山北坡主要木本植物功能性状及其海拔分异

PDF HTML阅读 XML下载 导出引用 引用提醒 祁连山北坡主要木本植物功能性状及其海拔分异 DOI: 10.5846/stxb202110212974 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划（2019YFC0507405） The main woody plant functional traits and altitude differences on the northern slope of Qilian Mountains Author: Affiliation: Fund Project: National Key R&D Program of China（2019YFC0507405） 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:植物功能性状是植物对生境长期适应所形成的可测量特征，受植物遗传特性和环境因子的共同影响。祁连山是我国干旱区的一条重要山脉，北坡海拔介于2000-5000 m，分布着青海云杉、祁连圆柏等10余种木本植物。深入了解祁连山区木本植物功能性状随海拔梯度分异特征对认识山地植物的适应性和植被垂直地带分布具有重要意义。选取祁连山北坡天然分布的11种木本植物，其中灌木9种，分别是金露梅（Potentilla fruticosa）、银露梅（Potentilla glabra）、水栒子（Cotoneaster multiflorus）、猫儿刺（Ilex pernyi）、吉拉柳（Salix gilashanica）、鬼箭锦鸡儿（Caragana jubata）、刚毛忍冬（Lonicera hispida）、高山绣线菊（Spiraea alpina）和鲜黄小檗（Berberis diaphana），乔木2种，分别是青海云杉（Picea crassifolia）和祁连圆柏（Juniperus przewalskii），调查了木质密度、胡伯尔值、叶面积、叶干物质含量、叶含水率和比叶面积6个枝、叶功能性状。结果表明：（1）灌木的木质密度、胡伯尔值、叶含水率和比叶面积显著高于乔木，但叶面积和叶干物质含量显著低于乔木；（2）木质密度和叶干物质含量随海拔升高显著下降，其他功能性状沿海拔分异不显著；（3）生长季气温与叶干物质含量正相关，与胡伯尔值和叶含水率负相关，生长季降水与各功能性状相关关系不显著。说明乔木和灌木植物采取不同的枝、叶资源利用策略来适应高山生境；随海拔升高，降低结构性碳投资可能限制了高山植被的分布上限；生长季气温是引起性状沿海拔分异的重要环境因子，但不能完全解释性状沿海拔分异规律。 Abstract:Plant functional traits are the measurable characteristics of plants which are formed by long-term adaptation to habitat environmental conditions. The characterization of plant functional traits is mainly influenced by both the plants specific genetic basis and the shifted environmental factors. Qilian Mountains, with an elevation ranging from 2000 to 5000 m, is one of the major mountains in the dry land in Northwest China, where naturally distributed more than 10 kinds of woody plants such as Picea crassifolia and Juniperus przewalskii on the northern slope. It is of great academic and practice significance to understand the acclimation strategy and the vertical distribution pattern of alpine woody plants by deeply investigating the woody plant functional traits variation and the behind driving mechanism along with the altitude gradients in the Qilian Mountains. In the present study, we investigated 11 naturally distributed woody plant species along with the altitude in the Qilian Mountains, which included 9 shrub species (Potentilla fruticosa, Potentilla glabra, Cotoneaster multiflorus, Ilex pernyi, Salix gilashanica, Caragana jubata, Lonicera hispida, Spiraea alpine, and Berberis diaphana, respectively) and 2 tree species (Picea crassifolia and Juniperus przewalskii, respectively). A total of six plant functional traits of shoot and leaf were investigated in this study, and which include woody density, huber value, leaf area, leaf dry matter content, leaf water content, and specific leaf area, respectively. The results showed that:(1) woody density, huber value, leaf water content, and specific leaf area of shrub species were significantly greater than those of tree species, and leaf area and leaf dry matter content of shrub species were significantly lower than those of tree species. (2) Woody density and leaf dry matter content declined significantly along with the altitude gradients increased, and the other functional traits changed insignificantly along with the altitude gradients increased. (3) Growing-season air temperature was positively correlated with leaf dry matter content, and was negatively correlated with huber value and leaf water content; however, non-significant relationships between growing-season precipitation and plant functional traits were found. The results showed that tree and shrub plants adapted to the alpine habitats by adopting different branch and leaf resources utilization strategies; the decreasing structure carbon investment with the altitude gradients increased possibly has limited the upshift of alpine plants; the growing-season air temperature was one of the key environmental factors tuning woody plant functional traits variation pattern along with the altitudes gradients but could not explain all the variance. 参考文献 相似文献 引证文献

河西走廊沙漠人工植被区土壤种子库特征

土壤种子库作为地上植被更新的重要的种源储备库，在植被自然恢复和演替过程以及生态系统建设中起着重要作用。以河西走廊不同区域沙漠人工植被为研究对象，研究了土壤种子库物种组成、时空分布和数量变化特征。结果表明：河西走廊沙漠人工林土壤种子库共出现27种植物，分属8科22属，以藜科植物最多，生活型以草本植物种子比例最高，占到90.6%-95.06%；土壤种子库密度介于19.29粒/m²-858.57粒/m²之间，从东到西呈水平地带性分布，土壤种子库分布主要集中在0-2cm土层中，不同样地土壤种子库密度均呈明显的垂直分布，在0-10cm土层内，随着土层深度增加，种子库密度先减小后增大；土壤种子库多样性（Simpson指数）在河西走廊东段沙漠人工植被区最高，在0.671-0.812之间，河西走廊中段沙漠人工植被区为0.417-0.809之间，河西走廊西段沙漠人工植被区为0.256-0.707之间，从东到西呈下降趋势，Shannon-Wiener指数、Margalett丰富度指数、Peilow均匀度指数也表现出相同的趋势，说明由于生境的植被的异质性程度高，使土壤种子库之间的差异性显著；河西走廊沙漠人工植被区的土壤种子库和地上植被的相似性系数均在0.45以下，为中等不相似水平，说明在组成上差异显著；土壤种子库以一年生、多年生草本为主，也有少量灌木种子，表明土壤种子库对灌木层更新和演替影响较小。研究证明了土壤种子库中的大量种子，是地上植被自然恢复的重要物质基础，并对了解沙漠人工植被区植被自然恢复特点具有重要的贡献。;Soil seed bank, generally acknowledged as an important seed reserve for vegetation regeneration, plays an important role in the vegetation restoration and succession, as well as the ecosystems construction. The species composition, spatio-temporal distribution, and quantitative changes of re-vegetated desert areas in Hexi Corridor were investigated in this study. Results showed that there were 27 species of plants in the soil seed bank, belonging to 22 genera and 8 families, with the most common species in Chenopodiaceae. In terms of life-form, the seeds from herbs accounted for 90.6-95.06%. The density of soil seed bank was between 19.29-858.57 grains/m², showing a horizontal distribution pattern from east to west. The soil seed banks was mainly concentrated in the 0-2 cm soil layer in vertical direction. In the rang of 0-10 cm soil layer, there was an obvious vertical distribution pattern of seed density:with increase of soil depth, seed density first decreased then increased. Simpson Index in the soil seed bank was the highest in the re-vegetated areas of the east Hexi Corridor Desert (0.671-0.812), 0.417-0.809 of the middle Hexi Corridor Desert, and 0.256-0.707 of west Hexi Corridor Desert, with a downward trend from east to west. Shannon-Wiener Index, Margalett Richness Index and Peilow Evenness Index also showed the same trend. The large variation in species diversity indices among sites was most likely attributed by the high degree of inter-site vegetation heterogeneity. The similarity coefficients between soil seed bank and vegetation in the desert re-vegetated areas in Hexi Corridor were all below 0.45, indicating a significant difference in species composition. The soil seed bank was dominated by annual and perennial herbs, with a few shrubs, which indicated that the soil seed bank played a minor role in the regeneration and succession of the shrub layer in the desert re-vegetated ecosystems. This study proved that a sufficient amount of seeds in soil seed bank is an important foundation for the natural restoration of vegetation in desert, and advanced our understanding of the natural vegetation restoration in the re-vegetated desert areas.

亚热带不同植被恢复阶段生态系统N、P储量的垂直分配格局

PDF HTML阅读 XML下载 导出引用 引用提醒 亚热带不同植被恢复阶段生态系统N、P储量的垂直分配格局 DOI: 10.5846/stxb202102240504 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家林业公益性行业科研专项（201504411）；国家自然科学基金项目（30771720，31170426） Vertical distribution pattern of N and P storage of ecosystem at different vegetation restoration periods in the subtropical region of China 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:氮（N）、磷（P）是影响生态系统生产力的主要养分因子，为科学评估植被恢复对生态系统N、P积累、分配及其耦合关系的影响，采用时空互代法，以湘中丘陵区地域相邻、环境条件基本一致，且处于不同恢复阶段的4个植物群落（4-5年灌草丛、10-12年灌木林、45-46年马尾松针阔混交林和>90年常绿阔叶林）作为一个恢复序列，设置固定样地，采用收获法和建立主要树种各器官生物量相对生长方程估算群落生物量，采集植被层（叶、枝、干、根）、凋落物层（未分解层、半分解层、已分解层）、土壤层（0-10、10-20、20-30、30-40 cm）样品，测定全N、全P含量，估算生态系统各组分（植被层、凋落物层、土壤层）全N、全P储量。结果表明：植被层全N、全P储量均随植被恢复增加，全N储量增长速率呈先慢后快的特征，而全P储量则呈慢-快-慢增长，地上（叶、枝、干）、地下（根）部分表现为异速增长；随植被恢复，凋落物层全N、全P储量先增加后下降，增长速率为先快后慢，4-5年灌草丛全N、全P储量最低；土壤层全N、全P储量随植被恢复显著增加（P<0.05），全N储量增长速率呈快-慢-快特征，而全P储量呈先慢后快特征；从4-5年灌草丛到>90年常绿阔叶林，生态系统全N、全P储量分别增加了6031.5、454.7 kg/hm2，增幅分别为231.5%、41.1%；不同恢复阶段生态系统全N、全P均主要存储于土壤中，分别占生态系统全N、全P储量的87.3%-99.0%、96.5%-99.9%；生态系统全N、全P储量的垂直分配格局随植被恢复而变化，植被层全N、全P储量贡献率增加，而土壤层全N、全P储量贡献率下降，凋落物层变化较小；植被层、凋落物层、土壤层全N、全P含量之间呈极显著正相关关系（P<0.01），随植被恢复，植被层、凋落物层、土壤层N、P含量协同发展，P变化滞后于N。因此，可通过合理的经营管理措施促进植被恢复，提高植被层生物量以及N、P间的耦合协调性，以提高生态系统养分固持潜力和促进养分间的高效协调利用。 Abstract:Nitrogen (N) and phosphorus (P) are the main nutrient factors affecting ecosystem productivity. This study investigated the response of coupling relationship between N and P to environmental change during vegetation restoration, and assessed the effects of vegetation restoration on N and P accumulation and distribution in ecosystem. According to the restoration gradient, four fixed plots were respectively established in four distinct plant communities:4-5 years scrub-grassland, 10-12 years shrubs, 45-46 years Pinus massoniana coniferous and broadleaved mixed forest, and >90 years evergreen broad-leaved forest by using the space-for-time substitution method. The community biomass was estimated by using the total harvesting method to establish the relative growth equation of organ biomass of main tree species. The samples of vegetation layer (leaves, branches, stems and roots), litter layer (un-decomposed, semi-decomposed and decomposed), and soil layer (0-10, 10-20, 20-30, 30-40 cm) were collected to determine total N and total P contents, and estimated the N and P storage of each component of ecosystem. The results showed that the N and P storage in vegetation layer increased with vegetation restoration, in which the growth rate of N storage was slow first and then fast, while the P storage presented slow-fast-slow. The aboveground (leaves, branches, stems) and underground (roots) parts showed allometric growth. As vegetation restoration, the N and P storage in litter layer increased first and then decreased, and the growth rates were fast first and then slow. The N and P storage in soil layer increased significantly with vegetation restoration (P<0.05), in which the growth rate of N storage showed fast-slow-fast, while the P storage was slow first and then fast. From 4-5 years scrub-grassland to > 90 years evergreen broad-leaved forest, ecosystem N and P storage increased by 6031.5 kg/hm2 and 454.7 kg/hm2, with the increase ranges of 231.5% and 41.1%, respectively. In different restoration periods, soil N and P storage were the primary component in ecosystem, accounting for 87.27%-98.99% and 96.5%-99.9% of N and P storage in ecosystem, respectively. The vertical distribution pattern of N and P storage in ecosystem varied with vegetation restoration, among which the contribution rate of N and P storage in vegetation layer increased, but that in soil layer decreased, and that in litter layer changed little. The contents of total N and total P in vegetation layer, litter layer and soil layer had significantly positively correlation (P<0.01). During vegetation restoration, N and P contents in vegetation layer, litter layer and soil layer developed synergistically, but the change of P lagged behind that of N. Therefore, reasonable management measures can be adopted to promote vegetation restoration, improve the biomass of vegetation layer and the coupling and balance of N and P, so as to enhance the nutrient fixation potential of ecosystem, and facilitate the efficient and coordinated utilization of nutrients. 参考文献 相似文献 引证文献

Impact of abiotic and biogeochemical processes on halogen concentrations (Cl, Br, F, I) in mineral soil along a climatic gradient.

In contrast to earlier ideas that halogens behave inertly in soil, extensive biogeochemical cycling of fluorine (F), chlorine (Cl), bromine (Br) and iodine (I) has been shown for temperate forests. To further advance our understanding of halogen behaviour in soil beyond humid temperate forests, we sampled soil profiles in protected areas along the Chilean Coastal Cordillera, representing a pronounced climatic gradient spanning from arid to humid. Halogen concentrations in soil were analysed by combustion ion chromatography. Highest average total halogen concentrations occurred at the arid site (Cl, F: 4270 and 897 mg kg-1) as well as the humid end of the climatic gradient (Br, I: 42.6 and 9.8 mg kg-1). Vertical distribution patterns of halogens were most pronounced at the humid end of the gradient and became less distinct under drier climate. The climatic gradient demonstrates the important role of biotic processes (e.g. the halogenation of organic matter) on the retention of halogens in the soil. However, this climate-specific role may be overridden by mainly abiotic processes within a given climate zone (e.g. weathering, leaching, sorption to secondary soil minerals, evaporative enrichment), resulting in vertical relocation of halogens in the soil. Since some of these processes oppose each other, complex interactions and depth distributions of F, Cl, Br and I occur in the soil. In summary, our findings provide new insights into the fate of halogens in mineral soil of different climatic zones, which is important, for example, when radiohalogens are deposited on a large scale after nuclear accidents.

Seasonal Variation of Zooplankton Communities and the Effects of Environmental Factors in the Seawater Near Taishan Nuclear Power Station

In the seawater near Taishan Nuclear Power Station, Zooplankton community composition and abundance, the biomass of major taxa, vertical distribution pattern, together with several environmental factors were investigated to evaluate the variation tendency as the seasons change. The structure characteristics of the zooplankton community were analyzed by Margalef species richness (d), Shannon-wiener species diversity index (H’), Pielou evenness index(J’), zooplankton dominant (Y), and dominant species replacement rate (R). There are 48 species within 11 classes of zooplankton identified, including 32 species of copepods. Zooplankton species richness changed obviously in the four seasons, Spring saw the highest (8010.00 ind.m-3), followed by winter (5100.00 ind.m-3), autumn (1713.75 ind.m-3), and summer (1196.25 ind.m-3). Similar trends were observed for the wet biomass, which was highest in spring (215.90 mg.m-3), followed by winter (181.70 mg.m-3), summer (78.56 mg.m-3), and autumn (24.69 mg.m-3), which gave an annual average of 125.21 mg.m-3. The results indicate that the abundance and biomass in spring were significantly higher than those in other seasons. Altogether 8 dominant species were identified along the whole year: Acrocalanmus gibber, Bestiolina amoyensis, Paracalanus parvus, Acartia danae, Mesocyclops leuckarti, Noctiluca scientillans, Penilla avirostris, and Lucifer penicilliger. The annual average Shannon-Wiener diversity index, Margalef diversity index, Pielou evenness index were 1.75, 1.83, and 0.74, respectively. The effects of environmental factors on the zooplankton community were studied by R and canonical correspondence analysis (CCA). According to Pearson correlation analysis and canonical correspondence analysis, the most important environmental factors influencing the changes of zooplankton species composition, abundance and distribution were water temperature, salinity, and pH in the whole year.

Spatial distribution of toxic metal(loid)s at an abandoned zinc smelting site, Southern China.

Toxic metal(loid) (TM) soil pollution at large-scale non-ferrous metal smelting contaminated sites is of great concern in China, but there are no detailed reports relating to them. A comprehensive study was conducted to determine contamination characteristics and horizontal and vertical spatial distribution patterns of soils at an abandoned zinc smelting site in Southern China. The spatial distribution of TMs revealed that soil environmental quality was seriously threatened, with Cd, Zn, As, Pb and Hg being the main contaminants present. The distribution of all TMs showed strong spatial heterogeneity and were expressed as a "patchy aggregation" pattern due to strong anthropogenic and production activities. Vertical migration of TMs indicated that the pollutants were mainly concentrated in the fill layers. Different contaminants had various migration depths, with migration occurring as: Cd > Hg > As > Zn > Pb> Cu> Mn> Sb. Analysis of their spatial variability showed that As, Pb, Cd and Hg had strong regional spatial variability. This research provides a new approach to comprehensively analyze TM pollution characteristics of non-ferrous smelting sites. It provides valuable information for guiding post-remediation strategies at abandoned non-ferrous metal smelting sites.

Effects of stand age and inter-annual precipitation variability on fine root biomass in poplar plantations in the eastern coastal China

Although we know that fine roots play an important role in carbon and nutrient cycling in forest ecosystems, knowledge on how fine root biomass (FRB) and its vertical distribution change with stand age and inter-annual precipitation variability is limited. In this study, we conducted a field experiment to explore the effects of stand age and inter-annual precipitation variability on FRB and its vertical distribution along the soil profile (0–100 cm) in poplar plantations on the eastern coast of China. We found that both poplar and understory vegetation FRB increased with increasing stand age. While the vertical distribution of fine roots in understory vegetation was not significantly affected by stand age, the distribution of FRB of poplar trees in deep soil layers was highest at the intermediate stand age (9-year-old). Poplar and understory vegetation FRB varied among sampling years and importantly, variation differed among stand ages. Compared with normal years, FRB of young poplar trees increased in the drought year (2019), while that in old stands decreased. In the subsequent drought recovery year, poplar FRB decreased in all stand ages; especially old stands. We found that poplar trees also optimize water absorption by changing the vertical distribution pattern of fine roots in the drought year. Moreover, unlike poplar trees, FRB of understory vegetation in all stand ages increased significantly in the drought year, but with little difference between the drought recovery and normal years. Structural equation models showed that variation in FRB of both poplar trees and understory vegetation were predominantly determined by soil total nitrogen while the vertical distribution of fine roots was regulated by soil water content. Our findings not only provide a scientific basis for sustainable management of poplar plantations, but also improve the ability to predict carbon dynamics of plantation ecosystems in confronting global climate change.

Distribution and diel vertical migration of mesopelagic fishes in the Southern Sargasso Sea \u2014 observations through hydroacoustics and stratified catches

Vertical distribution patterns and relative abundance of mesopelagic fish species and other major taxonomic groups were investigated through vertically stratified trawl sampling and hydroacoustic analyses along the subtropical convergence zone from 52° W to 70° W in the oligotrophic Sargasso Sea. Persistent stationary layers and several migrating components of different scattering characteristics were detected. The results reveal varying vertical migration patterns, including different times of onset of diel vertical migration in different depths and a migrant pathway emerging daily from the lower deep scattering layer (DSL) at dusk and migrating through the upper DSL without affecting its composition. Fish species identification was made based on morphological characteristics and confirmed by genetic barcoding analyses of subsamples. In total, 5022 fish specimens from 27 families, 62 genera and 70 species were caught. In terms of relative abundance (A) and biomass (M), catches were dominated by species of the families Myctophidae (A=59.1%, M=47.4% of total fish catch) and Melamphaidae (A=22.5%, M=17.1%). Myctophidae and Stomiidae were the most species-rich families with 31 and 12 species, respectively. Catches at the two easternmost stations were dominated by Scopelogadus mizolepis and Nannobrachium cuprarium, while Bolinichthys photothorax and Ceratoscopelus warmingii were the most abundant species in catches from the two westernmost stations. This study provides insights into distribution and vertical migration behaviour of mesopelagic fish in the Sargasso Sea and adds to our understanding of the mesopelagic community in this large oceanic area.

Coupling Suspect and Nontarget Screening with Mass Balance Modeling to Characterize Organic Micropollutants in the Onondaga Lake–Three Rivers System

Characterizing the occurrence, sources, and fate of organic micropollutants (OMPs) in lake–river systems serves as an important foundation for constraining the potential impacts of OMPs on the ecosystem functions of these critical landscape features. In this work, we combined suspect and nontarget screening with mass balance modeling to investigate OMP contamination in the Onondaga Lake–Three Rivers system of New York. Suspect and nontarget screening enabled by liquid chromatography–high-resolution mass spectrometry led to the confirmation and quantification of 105 OMPs in water samples collected throughout the lake–river system, which were grouped by their concentration patterns into wastewater-derived and mixed-source clusters via hierarchical cluster analysis. Four of these OMPs (i.e., galaxolidone, diphenylphosphinic acid, N-butylbenzenesulfonamide, and triisopropanolamine) were prioritized and identified by nontarget screening based on their characteristic vertical distribution patterns during thermal stratification in Onondaga Lake. Mass balance modeling performed using the concentration and discharge data highlighted the export of OMPs from Onondaga Lake to the Three Rivers as a major contributor to the OMP budget in this lake–river system. Overall, this work demonstrated the utility of an integrated screening and modeling framework that can be adapted for OMP characterization, fate assessment, and load apportionment in similar surface water systems.

An integrated, multi-level analysis of thermal effects on intertidal molluscs for understanding species distribution patterns.

Elucidating the physiological mechanisms that underlie thermal stress and discovering how species differ in capacities for phenotypic acclimatization and evolutionary adaptation to this stress is critical for understanding current latitudinal and vertical distribution patterns of species and for predicting their future state in a warming world. Such mechanistic analyses require careful choice of study systems (species and temperature-sensitive traits) and design of laboratory experiments that reflect the complexities of in situ conditions. Here, we critically review a wide range of studies of intertidal molluscs that provide mechanistic accounts of thermal effects across all levels of biological organization - behavioural, organismal, organ level, cellular, molecular, and genomic - and show how temperature-sensitive traits govern distribution patterns and capacities for coping with thermal stress. Comparisons of congeners from different thermal habitats are especially effective means for identifying adaptive variation. We employ these mechanistic analyses to illustrate how species differ in the severity of threats posed by rising temperature. Counterintuitively, we show that some of the most heat-tolerant species may be most threatened by increases in temperatures because of their small thermal safety margins and minimal abilities to acclimatize to higher temperatures. We discuss recent molecular biological and genomic studies that provide critical foundations for understanding the types of evolutionary changes in protein structure, RNA secondary structure, genome content, and gene expression capacities that underlie adaptation to temperature. Duplication of stress-related genes, as found in heat-tolerant molluscs, may provide enhanced capacity for coping with higher temperatures. We propose that the anatomical, behavioural, physiological, and genomic diversity found among intertidal molluscs, which commonly are of critical importance and high abundance in these ecosystems, makes this group of animals a highly appropriate study system for addressing questions about the mechanistic determinants of current and future distribution patterns of intertidal organisms.