Detrended Canonical Correspondence Analysis Research Articles

Soil microbial biomass carbon and nitrogen in historic convent gardens under long‐term horticultural cultivation in Krakow, Poland

AbstractThis paper evaluates the seasonal changes of microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) contents as an indicator of urban soil health. Our research was conducted in six horticultural urban soils in Krakow that have been cultivated for centuries. We investigated the temporal dynamics of microbial biomass C and N in soil samples from 0 to 20 cm depth taken in spring, summer and autumn. The study plots were placed in suburban areas as well as in the centre of the city to distinguish whether the detected effect of altered soil properties is similar to suburban areas. Soil microbial biomass was determined by the chloroform fumigation–extraction (CFE) method. The concentrations of MBC and MBN were measured in the field‐moist soil samples. MBC in the soil ranged from 226.5 to 742.7 mg kg−1 and MBN from 62.7 to 359.6 mg kg−1 expressed in dry mass. Repeated‐measures analysis of variance (ANOVAR, match‐model) was performed to test the main effects and interactions of temporal changes for MBC and MBN. There were significant differences only between MBN concentration in summer and autumn (p < .05). Principle component analysis (PCA) gave insightful results for the whole soil profile. Detrended canonical correspondence analysis (DCCA) indicated that the most explanatory variables in the studied time period were concentration of silt, total nitrogen, MBN and MBC content in the surface layer. Molar ratios of total organic carbon and total nitrogen (TOC:TN) indicated that microbial activity for C and N is enhanced by stoichiometry demands and therefore may be important for vegetation.

Impact of groundwater depth and soil salinity on riparian plant diversity and distribution in an arid area of China

Riparian plant diversity in arid regions is sensitive to changes in groundwater. Although it is well known that groundwater has a significant influence on plant diversity, there have been few studies on how groundwater and soil salinity impact plant community in desert riparian ecosystems. Therefore, we surveyed 77 quadrats (100 m × 100 m) to examine the relationship between groundwater depth, groundwater salinity, soil salinity and plant community in the upper reaches of the Tarim River. Data were analyzed with two-way indicator species analysis (TWINSPAN), detrended canonical correspondence analysis (DCCA) and principal component analysis (PCA). The results indicated that Populus euphratica, Tamarix ramosissima, and Phragmites australis were the dominant plants among trees, shrubs and herbs, respectively. Five plant community types were classified. There were significant differences in species diversity, soil moisture, soil salinity, groundwater depth and groundwater salinity across the community types. The composition and distribution of plant community are significantly influenced by groundwater depth, groundwater salinity, soil moisture, distances from the river to the quadrats, soil pH, electrical conductivity, total salt, CO32−, Cl−, SO42−, Ca2+, Mg2+, Na+ and K+. Shallow groundwater depth, low groundwater salinity, and high soil moisture and soil salinity were associated with higher plant diversity.

Pollen-based quantitative land-cover reconstruction for northern Asia covering the last 40 ka cal BP

Abstract. We collected the available relative pollen productivity estimates (PPEs) for 27 major pollen taxa from Eurasia and applied them to estimate plant abundances during the last 40 ka cal BP (calibrated thousand years before present) using pollen counts from 203 fossil pollen records in northern Asia (north of 40∘ N). These pollen records were organized into 42 site groups and regional mean plant abundances calculated using the REVEALS (Regional Estimates of Vegetation Abundance from Large Sites) model. Time-series clustering, constrained hierarchical clustering, and detrended canonical correspondence analysis were performed to investigate the regional pattern, time, and strength of vegetation changes, respectively. Reconstructed regional plant functional type (PFT) components for each site group are generally consistent with modern vegetation in that vegetation changes within the regions are characterized by minor changes in the abundance of PFTs rather than by an increase in new PFTs, particularly during the Holocene. We argue that pollen-based REVEALS estimates of plant abundances should be a more reliable reflection of the vegetation as pollen may overestimate the turnover, particularly when a high pollen producer invades areas dominated by low pollen producers. Comparisons with vegetation-independent climate records show that climate change is the primary factor driving land-cover changes at broad spatial and temporal scales. Vegetation changes in certain regions or periods, however, could not be explained by direct climate change, e.g. inland Siberia, where a sharp increase in evergreen conifer tree abundance occurred at ca. 7–8 ka cal BP despite an unchanging climate, potentially reflecting their response to complex climate–permafrost–fire–vegetation interactions and thus a possible long-term lagged climate response.

Effect of Microenvironment on Species Distribution Patterns in the Regeneration Layer of Forest Gaps and Non-Gaps in a Subtropical Natural Forest, China

The aim of this study was to explore the effect of gap environmental factors on the plant population regeneration pattern in the Castanopsis kawakamii natural forest. We used the detrended canonical correspondence analysis (DCCA) method to study coupling relationships between species distribution in the regeneration layer and environmental factors. The results showed that: (1) The main environmental factors that influenced species distribution in the forest gaps and non-gaps were different, and the highest explanation rate of environmental factors was the soil temperature below the surface 10 cm (ST10); (2) The relationships between species distribution in the regeneration layer of the forest gaps and non-gaps were mainly restricted by environmental factors, given the environmental factors complied with the ecological niche hypothesis; and (3) For the endangered C. kawakamii population, there were positive and negative relationships between the environmental factors and the various species in the forest gaps and non-gaps, whilst the effects of such relationships were varied. Some management operations, including the creation of artificial gaps and adequate fertilization in the non-gaps, could more effectively promote the growth and regeneration of the C. kawakamii population.

Vegetation patterns and causal factors in different reaches of an endorheic basin in arid China

ABSTRACTUnderstanding the response of vegetation to a changing global climate is important. The relationships among 33 topographic, soil and climatic variables and 74 vegetation assemblages were analyzed by detrended canonical correspondence analysis (DCCA) to determine the most important variables that affect vegetation patterns and their distribution in different reaches of the Heihe River Basin. Altitude was the most significant factor across the entire basin and in the middle reach (oasis-desert area, 1289–3920 m). Mean temperature of the warmest month and mean annual evapotranspiration were the most significant factors in the upper reach (mountain area, 2180–5547 m) and the lower reach (desert area, 820–2593 m), respectively. The annual average insolation and the aridity index also had significant relationships with vegetation distribution in the mountain area. Mean temperature of the coldest month and annual cumulated temperatures ≥ 10°C also were important in the oasis-desert area, and soil organic matter and groundwater depth in the desert area. Conservation of varying tree, shrub and grass species should be considered based on their thermal and water requirements in the mountain area.

Vegetation Pattern in Northern Tibet in Relation to Environmental and Geo-spatial Factors

Environmental and Geo-spatial factors have long been considered as crucial determinants of species composition and distributions. However, quantifying the relative contributions of these factors for the alpine ecosystems is lacking. The Tibetan Plateau has a unique ecological environment and vegetation types. Our objectives are to quantify the spatial distributions of plant communities on the Northern Tibetan Alpine grasslands and to explore the relationships between vegetation composition, Geo-spatial factors and environmental factors. We established 63 field plots along a 1200-km gradient on the Northern Tibetan Plateau Alpine Grassland and employed the two-way indicator species analysis (TWINSPAN) and the detrended canonical correspondence analysis (DCCA). Fourteen communities of alpine grassland were identifiable along the transect and consisted of three vegetation types: Alpine meadow, Alpine steppe, and desert steppe. Vegetation composition and spatial distribution appeared to be largely determined by mean annual precipitation and less influenced by temperature. A large fraction (73.5%) of the variation in vegetation distribution was explained by environmental variables along this transect, somewhat less by Geo-spatial factors (56.3%). The environmental and Geo-spatial factors explained 29.6% and 12.3% of the total variation, respectively, while their interaction explained 43.9%. Our findings provide strong empirical evidence for explaining biological and environmental synergetic relationships in Northern Tibet.

Relationship between vegetation types, soil and topography in southern forests of Iran

For sustainable forest management, understanding the ecological factors that determine vegetation composition are important. Here, the relation between the vegetation composition and environmental factors (elevation, aspect, slope, CaCO3, K, P, C, N, C/N, bulk density, soil porosity, saturation moisture content, EC, pH, sand, silt and clay) was investigated in the Khonj forests, Fars Province, Iran. Characteristic land units, each 200 m2, were chosen for sampling to analyze species composition, soil characteristics and topographic factors. The floristic data were classified using a two-way indicator species analysis (TWINSPAN). Means were then compared using an ANOVA and Duncan multiple range test to detect any variations between groups. Also, the Kaiser–Meyer–Olkin index and Bartlett test were used to measure sampling adequacy. The four vegetation groups identified comprised the species Achillea wilhelmsii, Tanacetum parthenium, Convolvulus spinosus, Capparis spinosa. A detrended canonical correspondence analysis (DCCA) ordination diagram clearly illustrated the relationship between vegetation and environmental factors. According to the results, group 1 with A. wilhelmsii as the indicator species has a positive relation with slope and elevation. T. parthenium was the indicator species of group 2, that appears in areas with high silt and low bulk density and sand. The results showed that group 3 with Convolvulus spinosus as the indicator species was distributed in soils with high bulk density, low silt and pH as well. Group 4 with C. spinosa as the indicator species occurs in sandy soils and low slopes. Using DCCA, we determined the relationship between species and environmental factors more accurately. Results of this study can be used to restore vegetation or maintain species composition in ecological sensitive areas.

拉萨河谷草地群落的数量分类与排序

PDF HTML阅读 XML下载 导出引用 引用提醒 拉萨河谷草地群落的数量分类与排序 DOI: 10.5846/stxb201708121455 作者: 作者单位: 中国人民大学环境学院,中国科学院地理科学与资源研究所,中国人民大学环境学院,中国人民大学环境学院,中国科学院地理科学与资源研究所,中国科学院地理科学与资源研究所,中国人民大学环境学院,山东建筑大学测绘地理信息学院 作者简介: 通讯作者: 中图分类号: 基金项目: 西藏自治区重点科技计划项目（Z2016C01G01/08-004，Z2016C01G01/03）；国家重点研发计划（2016YFC0502006） Quantitative classification and ordination of grassland communities in Lhasa River Valley Author: Affiliation: Renmin University of China,Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences,,,,,, 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:采用TWINSPAN数量分类和DCA、CCA排序的方法，对拉萨河谷草地23个样点进行统计分析。结果显示：（1） TWINSPAN数量分类将拉萨河谷草地群落划分成8种类型，拉萨河谷的草地群落分布呈现明显的垂直地带性分布格局。（2） TWINSPAN分类所划分的各群落在DCA排序图上都有各自的分布范围和界限，说明DCA排序能较好的反应各群落与其环境资源之间的关系，同时，TWINSPAN的分类结果也在排序图上得到较好的印证。（3）样点DCA排序的第一轴基本反映了海拔高度的变化梯度，第二轴基本反映了坡向的变化。（4）样点CCA排序表明，影响群落分布的主要环境因子是海拔，其次是坡向。CCA排序进一步阐明了拉萨河谷草地群落分布决定于海拔和坡向等环境因子，并间接验证了TWINSPAN的分类结果。（5）物种CCA排序和TWINSPAN分类结果表明：植物群落中物种的分布格局与植物群落类型的分布格局存在一定的相似性，物种的分布格局在很大程度上影响着群落的分布格局。 Abstract:Alpine grasslands on the Qinghai-Tibetan Plateau play an important role in safeguarding the economic sustainability of local animal husbandry. However, these alpine grasslands have been degraded due to increased human disturbance and changing climate in the past few decades. Quantitative classification and ordination are necessary to reveal how alpine grasslands respond to the changing environments. In this study, the Two-way indicator species analysis (TWINSPAN) was used to classify 23 plots of alpine grassland communities in the Lhasa River Valley. Canonical correspondence analysis (CCA) and detrended canonical correspondence analysis (DCA) were used to clarify the geographical distribution patterns of these alpine grassland communities. Our results indicate that:(1) Alpine meadows in the study area can be classified into 8 subtypes:Elymus nutans + Tripogon bromoides; Carex moorcroftii; Kobresia pygmaea + Carex moorcroftii; Potentilla fruticose + Kobresia pygmaea; Rhododendron primuliflorum + Kobresia pygmaea; Rhododendron primuliflorum + Rhododendron nivale + Kobresia pygmaea; Rhododendron nivale + Kobresia pygmaea; and Kobresia pygmaea. (2) Each subtype identified by TWINSPAN had a specific distribution and boundaries on the DCA ordination diagram, suggesting that DCA ordination can explain the relationship between community composition and environmental factors, (3) The first and second axes of DCA reflected the influences of plot elevation and aspect, respectively, (4) CCA ordination also confirmed that altitude, followed by aspect, was the primary environmental factor controlling the distribution of alpine grassland communities, (5) The CCA of species and TWINSPAN of community subtypes were similar, indicating that the distribution patterns of the grassland community were largely affected by the species distribution pattern. Quantitative analysis is suggested to examine and assess the relative contributions of anthropogenic and natural factors to changes in the Tibetan alpine grasslands in the future. 参考文献 相似文献 引证文献

Determining reference conditions of hemiboreal lakes in Latvia, NE Europe: a palaeolimnological approach

The current status of a lake can be evaluatedviamonitoring, but such data can only provide information about the last few decades to a century at best. In most cases, the natural state of a lake cannot be ascertained. This is even more challenging if the apparent anthropogenic effects on the environment over the last millennia are considered. We used data on fossil algae from five evenly distributed hemiboreal lakes in geographically different regions in Latvia, NE Europe to assess the amount of compositional change or turnover (i.e., the beta-diversity) in the algae datasets for the last 2000 years by using a Detrended Canonical Correspondence Analysis. Our results show that the algae turnover increases towards the present day with distinct shifts during times characterised by extensive and intensive agriculture establishment, and political and economic changes. Because the anthropogenic impact on the landscape and lakes before AD 1200 was relatively minor, we propose that algae composition at that time can be assumed to represent the natural reference conditions for most Latvian lakes.

Factors driving diversity and succession of diatom assemblages in a Neotropical rainforest stream

This study assessed short-term succession and related changes in diversity and succession of benthic diatom assemblages in a tropical rainforest stream in the biogeographic region of Chocó, Colombia. Diatom colonizationin situwas studied over a 60-day period, in which we analyzed the number of valves and the taxonomic changes. The Shannon index ranged from 2.06 to 3.02 bits. A total of 127 species were identified and the most abundant were acidophilic species such asEunotia intermedia,E. veneris,E. bilunaris var. mucophila,E. pirlaandE. bilunaris. A Detrended Canonical Correspondence Analysis (DCCA) was used to explore the succession of diatom assemblages and its driving environmental factors. The DCCA explained 74.1% of the correlation between environmental variables and diatom species and 16.2% of the data variance. The species fell into four groups, the first group (Eunotia incisa,Frustulia saxonica,Fragilaria capucina var. acatu, among others) was related to lower nitrate concentrations, acidic pH and lower water temperature. The second group (Fragilaria capensis,Gomphonema olivaceum,Cymbella gracilis, among others) was associated to higher alkalinity and lower solar radiation availability. The third group (Nitzschia obtusa,N. amphibia,Naviculadicta vitabunda,Navicula cryptocephala, among others) was related to lower phosphate, higher nitrate concentrations, lower pH, and higher temperatures. The fourth group (Eunotia soleirolli,Frustulia vulgarisandF. rhomboides)was associated with higher solar radiation and lower alkalinity. These results underscore the importance of diatom diversity in Neotropical streams and the relevance of small variations in environmental factors on the composition of reference assemblages of Neotropical fluvial systems.

Vertical patterns in plant diversity and their relations with environmental factors on the southern slope of the Tianshan Mountains (middle section) in Xinjiang (China)

The investigation of distribution patterns of species diversity is significant for successful biodiversity conservation. The spatial patterns of vegetation and different life-forms species diversity along an elevation gradient in the middle section of the southern slope of the Tianshan Mountains in Xinjiang, China were explored, using the detrended canonical correspondence analysis (DCCA) and the generalized additive model (GAM) methods based on a field survey of 53 sampling plots. In this work 158 species of seed plants were recorded, including 141 herbaceous, 14 shrub, and 2 tree species, in which the woody plants are very limited. 53 sampling plots were classified into 9 major plant communities. The results indicate that the herb communities were the most sensitive to changes in elevation gradient. The diversity indices of the community as a whole presented bimodal patterns. The peak values for the species diversities were found in the transition region between mountain steppe desert and mountain desert steppe (2,200–2,300m), and in the alpine grassland region (2,900–3,100m), while maximum species diversities were in the areas of intermediate environmental gradient. The main environmental factors on the distribution patterns in plant diversity were the elevation, soil water, total nitrogen, available nitrogen, organic matter, and total salt. The response tendency of the four diversity indices for the whole community to the soil environment was the same as that of the herb layers.

Quantitative classification of natural plant communities in the Saihanba National Nature Reserve, Hebei Province, China.

Quantitative analysis of the relationships between the distribution of natural plant communities and environmental factors was studied using two-way indicator species analysis (TWINSPAN) and detrended canonical correspondence analysis (DCCA) methods, in the Saihanba National Nature Reserve in Hebei Province. The results showed that the natural plant communities in the Saihanba Reserve could be classified into eight types, i.e., Sanguisorba officinalis + Carex heterostachya + Trollius chinensis community, S. officinalis + Elymus sibiricus + Geranium platyanthum community, C. lanceolata + Ophiopogon chingii community, Spiraea pubescens - Tripolium vulgare community, Armeniaca sibirica + S. pubescens - T. vulgare + C. lanceolata community, Quercus mongolica + Betula costata - Lespedeza bicolor + S. pubescens - C. lanceolata community, Betula platyphylla + Populus davidiana - Corylus mandshurica + Rosa davurica - Phlomis umbrosa + C. lanceolata + Thalictrum aquilegifolium community and Picea asperata + B. platyphylla - Rosa davurica + Salix taishanensis var. hebeinica - C. lanceolata + Commelina diffusa community. DCCA analysis indicated that slope position and soil nutrients were the main influence factors for the spatial distribution of natural plant communities in the Saihanba National Nature Reserve. Topographic, spatial and soil factors accounted for 34.02% of the variation of species pattern. Of the variation, soil factors accounted for 15.67%, topographic factors 10.05% and spatial factors 6.00%. In the interactions among all factor combinations (2.30%), the interaction between soil and topographic factors was the largest (0.93%), and the interaction among soil, topographic and spatial factors was the least (0.16%). The unexplained portion accounted for 65.98% of spatial distribution, which might be due to anthropogenic disturbance or interspecific competition.

白云山自然保护区植物群落多样性分布格局研究

根据白云山自然保护区6个植物群落的样地调查资料，为研究白云山自然保护区植物群落物种多样性的空间分布格局，采用DCCA (detrended canonical correspondence analysis)排序法，从丰富度指数、物种多样性指数、均匀度指数、优势度指数等方面的关系进行了分析。结果表明：在调查样地区域内，乔木层多样性平均指数较低，为1.344，灌木层植物多样性平均指数为3.054，草本植物的多样性指数为2.753，高于乔木层的指数。乔木层丰富度平均指数较低，为2.734，灌木层植物丰富度平均指数为6.447，草本植物的丰富度指数为5.467。通过重要值分析得出华山松的各种指数均高于锐齿槲栎，华山松在调查的群落里占更大优势，更加适应样地内的生长环境，地带性植被总体上表现为向锐齿槲栎(Quercus aliena var. acuteserrata Maxim.)、华山松(Pinus armandii Franch.)林的方向更新。此外，乔木优势树种较为单一，可适当引入当地的其他树种，丰富样地内的物种丰富度，使林分组成更加健全。 According to Baiyun Mountain Nature Reserve, six plots of plant community survey data for the study of Baiyun Mountain Nature Reserve of plant species diversity spatial distribution pattern, using DCCA (detrended canonical correspondence analysis) sort, from the species richness index, relationships between species diversity index, evenness index, dominance index and other aspects were analyzed. Research suggests in the sample plots, the average tree layer diversity index was lower, which was 1.344, the average diversity index of shrub layer was 3.054, and the diversity index of herbaceous plants was 2.753, which was higher than that of QiaoMuceng. The average richness index of the tree layer was low, which was 2.734, and the average index of shrub layer was 6.447, and the richness index of herb was 5.467. Through the analysis of the important values, various index of Huashan pine is higher than the Quercus aliena var. acuteserrata, Huashan pine in the investigation of the community has a greater advantage, more adapted to the growth environment of the sample plots, zone of vegetation on the whole performance for updates to the direction of the Sharptooth oak (Quercus aliena var. acuteserrata Maxim.) Huashan pine (Pinus armandii Franch.). In addition, the dominant tree species is single, other tree species can appropriately be introduced into the local area, so that the species richness of the samples can be enriched, and the composition of the forest will be more perfect.

Climate and tectonic effects on Holocene development of an alpine lake (Muge Co, SE margin of Tibet)

South-west China is an important area for determining variability of the SW Asian Monsoon; it is, however, also tectonically very active. Palaeolimnological studies in this region generally focus on climate as a direct driver of ecological change, rarely considering the effects of tectonic activity and catchment ontogeny. We present diatom and organic matter data from a Holocene sediment record from Muge Co, an alpine lake located on an active fault zone in the southeast margin of Tibet, and explore the possible drivers of ecological change. A major change occurred at 9000 cal. BP, when the diatom assemblage switched from benthic to predominantly planktonic forms, and organic matter content decreased rapidly. Comparison of the Holocene diatom record with a regional data set of lake surface sediments using detrended canonical correspondence analysis (DCCA) suggests that this change in diatom development was mainly associated with changing water depth, most likely linked to a seismically triggered landslide (which deepened the lake) rather than climate-driven hydrological change. However, diatom changes associated with principal components analysis (PCA) axis 2 agree well with inferred Holocene temperature changes. From the mid-Holocene, shifts in planktonic diatom species were probably related to indirect climate forcing, notably water column mixing depth and catchment vegetation–driven changes in dissolved organic carbon (DOC) and nutrient export. The diatom stratigraphy at Muge Co reflects a complex range of indirect climate- and catchment-controlled processes that were superimposed over a change in lake morphology resulting from tectonic activity.

Determining soil enzyme activities for the assessment of fungi and citric acid-assisted phytoextraction under cadmium and lead contamination.

Microorganism or chelate-assisted phytoextraction is an effective remediation tool for heavy metal polluted soil, but investigations into its impact on soil microbial activity are rarely reported. Consequently, cadmium (Cd)- and lead (Pb)-resistant fungi and citric acid (CA) were introduced to enhance phytoextraction by Solanum nigrum L. under varied Cd and Pb pollution levels in a greenhouse pot experiment. We then determined accumulation of Cd and Pb in S. nigrum and the soil enzyme activities of dehydrogenase, phosphatase, urease, catalase, sucrase, and amylase. Detrended canonical correspondence analysis (DCCA) was applied to assess the interactions between remediation strategies and soil enzyme activities. Results indicated that the addition of fungi, CA, or their combination enhanced the root biomass of S. nigrum, especially at the high-pollution level. The combined treatment of CA and fungi enhanced accumulation of Cd about 22-47 % and of Pb about 13-105 % in S. nigrum compared with the phytoextraction alone. However, S. nigrum was not shown to be a hyperaccumulator for Pb. Most enzyme activities were enhanced after remediation. The DCCA ordination graph showed increasing enzyme activity improvement by remediation in the order of phosphatase, amylase, catalase, dehydrogenase, and urease. Responses of soil enzyme activities were similar for both the addition of fungi and that of CA. In summary, results suggest that fungi and CA-assisted phytoextraction is a promising approach to restoring heavy metal polluted soil.

Spatial variation of soil properties and plant colonisation on cut slopes: a case study in the semi-tropical hilly areas of China

Background: Transport infrastructure has severe impacts on ecosystems and results in large numbers of cut slopes, which are difficult to revegetate. To increase successful revegetation, it is crucial to understand the relationships of soil properties and vegetation during spontaneous vegetation recovery on cut slopes.Aims: To assess the effects of different slope positions on soil properties and vegetation on a cut slope and to determine the key factor(s) affecting vegetation distribution on a cut slope in a semi-tropical environment.Methods: Soil samples were collected in three slope positions: upper slope (US), middle slope (MS) and foot slope (FS). Soil pH, moisture and bulk density and concentrations of soil organic carbon (C), total nitrogen (NT), available nitrogen (NA), total phosphorus (PT), available phosphorus (PA), total potassium (KT) and available potassium (KA) were determined. Vegetation composition and cover were recorded along the slope. One-way analysis of variance (ANOVA), indicator species analysis (ISA) and detrended canonical correspondence analysis (DCCA) were applied to analyse differences in soil properties among slope positions and vegetation distributions.Results: NT, NA, PT, PA, KA, C and pH tended to increase from the US to the FS. Two indicator species were abundant in their respective slope positions: Achyranthes bidentata in the FS and Dicranopteris dichotoma in the US. DCCA showed that pH and some soil nutrients (NA, PT, PA and C) influenced the vegetation distribution on cut slope.Conclusions: Soil pH and some soil nutrients including NA, PT, PA and C had large impacts on vegetation distribution along slope positions in a semi-tropical area of China. We suggest increasing soil pH to provide a better soil environment for plant colonisation in further research concerning the restoration of such cut slopes.

Early summer near-shore fish assemblage and environmental correlates in an Arctic estuary

Abstract Knowledge of reference conditions and species–environment associations is required to ascertain ongoing aquatic biodiversity changes in Arctic regions. The objective of this study was to establish a baseline of fish community structure (species composition, incidence and relative abundance) in relation to salinity, pH and temperature gradients in an Arctic estuary, the Husky Lakes, Canada. Sampling involved an early-summer, standardized, experimental netting survey around the entire perimeter of all estuary basins and peninsulas. Detrended canonical correspondence analysis (DCCA) was used to evaluate species–environment associations. The ecosystem sustains an abundant and diverse fish community, characterized by co-dominance of coregonids and a marine schooling fish, Clupea pallasii , and high abundance of freshwater/freshwater-amphidromous species in the innermost basins. Highest richness and total abundance were related to mixing conditions, warmest temperatures, connectivity to nearby ecosystems, and diversity in species life histories. Salinity determined spatial patterns of fish species abundance and distribution. The incidence of freshwater fish was limited by the availability of low salinity habitat and potential community interactions. These fish, particularly Salvelinus namaycush and Thymallus arcticus , are considered as the most vulnerable to changes in freshwater habitat availability. The fish assemblage reflects environmental information from surrounding fluvial, freshwater, coastal marine and catchment ecosystems, and is thus a prime candidate for monitoring environmental change in the region. The results provide a benchmark against which future studies of fish communities can be compared to evaluate potential effects of climate change and anthropogenic development on fish populations from Husky Lakes and similar Arctic aquatic ecosystems.

Diversity and distribution of ground bryophytes in broadleaved forests in Mabian Dafengding National Nature Reserve, Sichuan, China

Bryophytes, represented by mosses, liverworts, and hornworts, contribute substantially to forest ecosystems in terms of nutrient cycling, water retention, water availability, plant biomass, and plant community maintenance. Forests provide numerous types of habitat for bryophytes, especially the ground floor. To clarify the ground bryophyte diversity and distribution in broadleaved forests, we used microcoenose sampling to investigate ground bryophytes in 34 sample plots (10 × 10 m) in the Mabian Dafengding National Nature Reserve (MDNR), Sichuan Province. Species diversity and environmental factor relationships were analyzed by using α and β diversity indexes, as well as Pearson's correlation analysis. Detrended canonical correspondence analysis (DCCA) was applied to analyze the relationships between species distribution and environmental factors. A total of 230 bryophyte species were identified in MDNR. These species include 67 liverwort species belonging to 26 genera of 20 families and 163 moss species belonging to 65 genera of 28 families. Diversity of ground bryophytes was negatively correlated to shrub cover, canopy cover, and tree number, but without significant correlations to altitude, slope, aspect, vegetation type, and herb cover. The DCCA ordination of relationships between ground bryophytes and environmental factors showed that altitude, aspect, vegetation type, and shrub cover were important to the distribution of dominant ground bryophyte species. This study quantitatively related bryophytes diversity and distribution to environmental factors, which is helpful in understanding the ecological niche of various bryophytes.

丹江口水库水滨带植物群落空间分布及环境解释

PDF HTML阅读 XML下载 导出引用 引用提醒 丹江口水库水滨带植物群落空间分布及环境解释 DOI: 10.5846/stxb201304230786 作者: 作者单位: 华中农业大学园艺林学学院园艺植物生物学教育部重点实验室,华中农业大学园艺林学学院园艺植物生物学教育部重点实验室,华中农业大学资源与环境学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家"十二五"科技支撑计划项目(2012BAC06B03) Spatial distribution of plant communities and environmental interpretation in the riparian zone of Danjiangkou Reservoir Author: Affiliation: Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agriculture University,Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agriculture University, 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:探讨了环境因素对丹江口水库(南水北调中线水源地)水滨带植物群落空间分布的影响。通过对水滨带植物群落和环境因素的实地调查,用双向指示种分析(TWINSPAN)对201个水滨带植物群落进行分类;结合地形、土壤和水文因素用除趋势典范对应分析法(DCCA)分析环境因素对水滨带植物群落的影响;并对环境因素的解释能力进行定量分离。结果表明:(1)水滨带植物群落包括7种类型,分别是萹蓄群落、苘麻群落、细叶水芹+狗牙根群落、狗牙根群落、响叶杨-狗牙根群落、杜梨-白刺花-狗牙根群落和侧柏-牡荆-三穗苔草群落;(2)海拔和水淹影响对水滨带植物群落空间分布具有主导作用。海拔升高,水淹影响减弱,植物群落呈现由草本植物群落向木本植物群落变化的格局;(3)土壤因素的解释能力大于地形因素,水文因素的解释能力最小。各类环境因素之间存在交互作用,地形、水文和土壤因素三者间的交互作用最大,地形和土壤因素之间的交互作用最小。环境因素共解释水滨带植物群落空间分布的21.99%,未解释部分为78.01%。结果证明环境对植被的解释能力是由植被的复杂程度决定的,植被越复杂,环境的解释能力越低。 Abstract:Riparian vegetation performs important ecological functions in protecting water quality, stabilizing the bank, maintaining habitats connectivity and enhancing local biodiversity. Yet, riparian vegetation has been degraded severely throughout the world mainly due to anthropogenic disturbances. This study focused on the riparian vegetation communities and the impact of environmental factors on spatial distribution of plant communities in the riparian zone of Danjiangkou Reservoir, the water source for the Middle-Route of the South-to-North Water Transfer Project. Field survey was carried out from April to May, 2011. The 201 plant communities were investigated. And three topographic factors (elevation, slope and aspect), eight soil factors (soil thickness, soil texture, soil pH, organic matter, total nitrogen, total phosphorus, available nitrogen, and available phosphorus), and two hydrological factors (flooding duration and flooding frequency) were measured. On the basis of the investigation of riparian plant communities and environmental factors, the 201 plant communities were classified into different community types by means of Two Way Indicator Species Analysis (TWINSPAN); the impact of environmental factors on riparian plant communities were analyzed by using Detrended Canonical Correspondence Analysis (DCCA) combined with topographic, hydrologic and soil factors. And the explanatory power of environmental factors on the riparian plant community was quantitatively partitioned. The results showed that (1) the riparian plant communities were classified into seven types of Polygonum aviculare community, Abutilon theophrasti community, Oenanthe dielsii var. stenophylla + Cynodon dactylon community, Cynodon dactylon community, Populus adenopoda-Cynodon dactylon community, Pyrus betulifolia-Sophora davidii-Cynodon dactylon community and Platycladus orientalis-Vitex negundo var. cannabifolia-Carex tristachya community; (2) the results of DCCA indicated that riparian vegetation and environmental factors had a significant correlation. The first axis had a significant correlation with elevation, flood duration and flood frequency, it indicated that elevation and flooding played a dominant role in spatial distribution of the riparian plant communities. Soil organic matter content, pH and total nitrogen content presented a significant correlation with the second axis, which indicated that soil nutrient also played a role in spatial distribution of the riparian plant communities. (3) the effects of soil factors, hydrology factors, topographic factors and their interaction on the total variation of riparian vegetation were quantitatively partitioned and showed that the contribution rate of the soil factors was 10.24% separately, and the contribution rate of the topographic factors was 3.15% and the hydrological factors was 3.04% separately. 0.73% for soil factors coupled with topographic factors, 1.22% for topographic factors and hydrological factors, 0.75% for hydrology factors with soil factors, and the interactive effect of topographic, soil and hydrological factors was 2.86%. The collected environmental factors accounted for 21.99% of spatial distribution of the riparian plant communities, the unexplained portion for 78.01%. Our results demonstrated that the explanatory power of environmental factors was determined by the complexity of vegetation, and the more complexity of vegetation, the less explanatory power by environmental factors. The riparian zone is a typical ecotone, and environment and vegetation are complicated and varied. These caused that the explanatory power of environmental factors was low. The unexplained portion may be caused by climate, biotic interaction, interference and random factors. 参考文献 相似文献 引证文献

Combined influence of hydrological gradient and edaphic factors on the distribution of macrophyte communities in Dongting Lake wetlands, China

Hydrological regime and edaphic factors may operate synergistically to influence plant distribution in wetlands. However, this phenomenon has rarely been examined in freshwater lacustrine wetlands in China. Here, we investigated plant species compositions, hydrological gradients, and soil variables in four dominant plant communities and examined the relationships between plant communities and abiotic factors by using detrended canonical correspondence analysis (DCCA) in wetlands associated with Dongting Lake. The first and second axes of the DCCA ordination explained approximately 52.8 and 26.3 % of the total variance of the species–environment relationship, respectively. Water table depth was the strongest factor related to plant community composition and reflected the spatial distribution of vegetation in wetlands. Water-related soil variables (soil moisture content, bulk density, oxidation–reduction potential, and electrical conductivity) were significantly related to plant distribution. Soil nutrient factors (soil organic matter, total nitrogen, available potassium, and Olsen phosphorus) also played a role in plant distribution. Our findings emphasized the importance of hydrological gradients and related edaphic factors in determining the distribution of vegetation in freshwater wetlands. These findings have implications for conservation of freshwater lacustrine wetlands, which are often subjected to hydrological alteration and nutrient enrichment caused by anthropogenic disturbances and climate change.