Two-way Indicator Species Analysis Classification Research Articles

Composition and environmental interpretation of the weed communities in the main planting base of jujube (Ziziphus jujuba Mill. cv. 'LingwuChangzao'), Ningxia province of China.

BackgroundZiziphus jujuba Mill. cv. ‘LingwuChangzao’ is a traditional jujube cultivar in northwest China. It is of great significance to explore the weed community composition and environmental characterization for the ecological control and comprehensive management of weeds in jujube orchards. In this article, a total of 37 species were recorded in 40 sample plots (1 m × 1 m). Moreover, fourteen environmental indicators to characterize the spatial locations, climate and soil nutrient characteristics of the plant communities were adopted.MethodologyThrough the two-way indicator species analysis (TWINSPAN) quantity classification and canonical correspondence analysis (CCA) ranking methods, the types of weed communities in the main planting base of jujube ‘LingwuChangzao’ and the main environmental factors affecting the change and distribution of weed types were analyzed.ResultsThe weed communities within the study area were divided into 15 types by the TWINSPAN classification. There were significant differences in soil factors to the species diversity indices of the weed communities, the diversity of weed communities was negatively correlated with available potassium, whereas positively correlated with soil water content. The CCA results showed that community structure and spatial distribution of weed communities were affected by soil water content, total potassium, soil organic carbon, total phosphorus, total nitrogen. Our results can be used as a reference for orchard weed management and provide a theoretical basis for weed invasion control and creating a higher biodiversity in arable land under the background of environmental change.

Akyazı İlçesi'nin (Sakarya, Türkiye) Epifitik Briyofit Toplulukları: Topluluk-Habitat İlişkilerinin Çok Değişkenli Bir Çalışması

In this study, epiphytic bryophyte vegetation of the Akyazı District in Sakarya Province (Turkey) was investigated. In the different vegetation periods of the year 2017, a total of 85 relevés taken from the trunks of trees and were classified by Braun-Blanquet method and regulated by using Detrended Correspondence Analysis (DECORANA) and Two-Way Indicator Species Analysis (TWINSPAN). TWINSPAN classification technique produced two main vegetation groups include eight clusters at the third level. The results of DECORANA indicated that the distribution patterns of epiphytic communities change from xeric to mesic and along the lower base and upper zones. The most important ecological factor for the epiphytic community differentiation in the study area, according to the ordination diagram, is humidity of the epiphytic habitats. Consequently, six epiphytic bryophyte associations and two subassociations were determined in the present paper. Among them; Orthotrichetum pallentis for the second time and Pterigynandretum filiformis -leucodontetosum sciuroidis were recorded for the first time in Turkey. Moreover, Orthotrichetum pallentis - isothecietosum alopecuroidis subass. nova was described as a new epiphytic association from the Akyazı District of Sakarya Province. Floristic and ecological characteristics such as; (humidity, light, acidity) of these new syntaxa are given with detailed descriptions.

Ecological Study on Three Plantago Species and their Associates in Nile Delta Region

The present work aims at the following objectives: 1) vegetation analysis of the Plantago communities (P. major, P. lagopus, and P. squarrosa) in Nile Delta of Egypt using multivariate analysis, 2) analysis of variations in the edaphic variables controlling the abundance and distribution of the recognized plant communities, and 3) evaluation of the biodiversity of the Plantago communities in the study area. The sampled stands are distributed in four Governorates, namely: El-Dakahlia, Kafr El-Sheikh, El-Behira, and El-Sharkia. The plant cover and density of the recorded species were investigated in 60 sampled stands, and the vegetation classification and ordinated were achieved. Soil samples were collected and the physical and chemical properties were determined. The species richness and eveness in the three communities were aslo calculated. The application of Two-Way Indicator Species Analysis (TWINSPAN) classification based on the importance values of 105 plant species led to the recognition of four vegetation groups. Group A and B dominated by Plantago squarrosa. However, group C comprises dominated by Plantago lagopus. Group D dominated by Plantago major. The stand ordination is given by Detrended Correspondence Analysis (DCA) showed that the vegetation groups obtained by TWINSPAN classification are remarkable distinguishable and having a clear pattern of segregation on the ordination plane. Canonical Correspondence Analysis (CCA) exhibited that organic carbon, electrical conductivity, sand fraction, and pH value showed high significant corrections with the first and second axes. However, calcium carbonate, sodium, potassium and calcium cations as well as water-holding capacity, total dissolved phosphorus, silt and clay fractions exhibited a moderate significant correlation. P. squarrosa community was affected with many soil variables such as calcium carbonate, sodium, organic carbon, pH value, sand and magnesium. However, P. lagopus was affected by bicarbonates, potassium, sulfates and total nitrogen. Moreover, P. major showed a close relationship with electrical conductivity, water-holding capacity, total dissolved phosphorus, silt, clay, and porosity. The diversity measurements showed that the P. major community attained the highest richness and evenness, while the community of P. squarrosa showed the lowest diversity and eveness.

山西高原草地景观的数量分类与排序

PDF HTML阅读 XML下载 导出引用 引用提醒 山西高原草地景观的数量分类与排序 DOI: 10.5846/stxb201307291977 作者: 作者单位: 山西林业职业技术学院,山西大学黄土高原研究所;山西省中阳县第一中学,山西大学黄土高原研究所,山西林业职业技术学院 作者简介: 通讯作者: 中图分类号: 基金项目: 山西省自然科学基金项目（2012011033-4）； 山西省林业厅科技创新项目（201021） Classification and ordination of grassland landscape in the Shanxi Plateau Author: Affiliation: Shanxi Forestry Technological college,,Institute of Loess Plateau, Shanxi 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:草地植被空间格局研究是草地景观研究中一项重要的基础工作。空间格局研究不仅限于描述景观的空间特征，而是要深入分析空间格局的分布规律及影响格局形成的原因及机制。以1：50万《山西省草地类型图》、《山西省行政区域图》及《山西省地形图》为主要信息源，借助GIS技术，应用TWINSPAN和DCA对山西高原草地景观的1127个样方进行研究。结果表明：（1）在TWINSPAN分类结果中，31个群丛组从左到右的排列顺序很好地揭示了山西高原草地景观的纬向地带性分布规律。即从40°43’N向34°34’N依次分布着北部草原、中部灌草丛和草丛及南部的暖温带草丛。（2）1127个样方DCA排序图纵轴揭示了明显的海拔梯度，即由上至下海拔逐渐降低，相应地草地景观变化为亚高山草甸、灌草丛、草原及河漫滩草甸；DCA排序图的横轴揭示了明显的水分梯度，即从左到右水分逐渐增加。两大优势群丛组样方及44个优势群丛组物种DCA的排序图都很好地刻画了山西高原水热组合的变化，即从西北向东南由于地形地貌引起的水热组合由冷干向暖湿逐渐变化，水热组合的梯度变化进一步影响了草地景观整体的空间分布格局。（3）GIS技术与数量生态学方法相结合有助于丰富景观生态学研究的技术体系。 Abstract:Spatial pattern is a reflection of the landscape heterogeneity over a region. Research on this pattern is a fundamental work in understanding the landscape structure, and has both theoretical and practical significance for exploring the composition and distribution laws of landscape components and their mechanisms. The key methods for realizing the spatial pattern include the comparison of pattern indices and spatial characteristics; the analysis of transition matrix of Markov Chain, and the dynamic simulation of spatial pattern based on cellular automata model. While these methods are proved to be usefull, the theoretical and technical framework has not yet been formed for the comprehensive research. The methods of quantitative ecology have been successfully used in vegetation pattern analysis on meso\ and mico\ scales. The integrated application of the methods in quantitative ecology and other modern techniques like GIS and RS might enrich the methodology of landscape study. In this study, based on the Grassland Type Map of Shanxi Province (1:500 000), Topography Map of Shanxi Province (1:500 000) and Administration Division Map of Shanxi Province (1:500 000), the Present Grassland Map of Shanxi Plateau (1:500 000) was compiled. Through the GIS techniques, 20mm×20 mm quadrat grids were set up on the Present Map, and then a set of 1127 effective quadrats was obtained. After the calculation of the importance values of individual quadrats, all the 1127 quadrats were analyzed using the quantitative methods of TWINSPAN (Two-Way Indicator Species Analysis) and DCA (Detrended Correspondence Analysis). The results showed that (1) the 31 association groups obtained from the TWINSPAN classification revealed the latitudinal zonality of grassland landscape in the plateau, i.e., the temperate grassland in the north, the shrub-grassland and grassland in the middle, and the warm temperate grassland in the south from 40°43'N to 34°34'N. (2) The vertical axis of DCA ordination plot indicated that, with the decrease in altitude from top to bottom, the grassland landscape changed gradually from the sub-alpine meadow to shrub-grassland, grassland and floodplain meadow; and the horizontal axis exhibited a clear water gradient, i.e., a gradual increase of wetness from left to right. The plots of DCA ordination for the quadrats of two dominant association groups and for the species of 44 dominant association groups reflected the gradient of rainfall and temperature changes, i.e., from the cold-arid conditions in the north-west to warm-wet conditions in the south-east across the plateau. This gradient of water-heat regime further influenced the spatial pattern of grassland landscape. (3) The integrated application of GIS technique and the methods of quantitative ecology could enrich the technical system of landscape ecology. The findings in this study suggest that either TWINSPAN or DCA was very useful for characterizing the distribution patterns of grassland landscape, and for exploring the possible causes of the patterns. The integrated application of GIS technique and quantitative techniques in ecology might have great potential for studies of landscape pattern dynamics, the drivers and the driving mechanisms. Further research on the dynamic characteristics and the driving factors of the grassland landscape in Shanxi Plateau should be conducted. 参考文献 相似文献 引证文献

Ecological situation and management of Bothriochloa ischaemum grasslands in China

Abstract Bothriochloa ischaemum grasslands cover a large area of central China. A total of 81 grassland quadrats of 2 m × 2 m were established randomly in nine counties of central China. Data for species composition, abundance, coverage and height, plus several environmental variables were measured and recorded in each quadrat. Dry biomass and productivity for three associations within three counties were also determined. Species data of importance values were used in the two‐way indicator species analysis (TWINSPAN) and the detrended correspondence analysis (DCA) ordination. A total of 11 main grassland associations were distinguished by the TWINSPAN classification; all of them being secondary vegetation. Each association had its own characteristics in composition, structure, productivity and environment. The results of DCA show that the distribution of B. ischaemum grasslands and associated species are closely related to longitude, that is, related to a moisture gradient. Precipitation was one of the most important factors affecting the distribution of the studied grasslands. In addition, topographic factors, such as elevation, aspect, slope and soil types, were also correlated to grassland vegetation. The distribution of grassland associations was consistent to that of their dominant species. TWINSPAN and DCA revealed the same ecological gradients in this study. These grasslands are important for regional development of animal husbandry and economy, although their productivity is not very high. Effective protocols for the conservation and management of B. ischaemum grasslands are needed.

Urban plant ecology patterns and processes: a case study of the flora of the City of Plymouth, Devon, U. K.

Summary AimUsing a large database that has been created over the past 5 years with the RECORDER package, presence/absence data for 829 species of vascular plants in the 103 1‐km2 squares that cover the city of Plymouth (pop. 243,373) have been analysed by two‐way indicator species analysis (TWINSPAN) and canonical correspondence analysis (CCA) to establish the major species assemblages and to examine their spatial distribution across the city in relation to variation in land use. LocationThe City of Plymouth. MethodsNine groupings of squares emerged and their distribution was mapped across the city. Interpretation of those groups and their variation in relation to the land use ordination axes showed that TWINSPAN groups lying along the first axis of variation correlated floristic variation with the process of urban development and the historical evolution of urban structure. The second axis appeared to be related to particular remnant semi‐natural habitats within the city that could be regarded as ‘hot‐spots’ for survival of many plant species. Species were categorized into four types on the basis of their recency and mode of arrival in the city and by using the historical flora of Plymouth produced by T. R. Archer‐Briggs in 1880. Variations in the sources of species in relation to the TWINSPAN classification groups were then examined. A second ordination was also computed; this time with geological, altitudinal and distance variables. TWINSPAN groups were then superimposed on the ordinations using polygons to assist with biogeographical interpretation. Results and conclusions The results of both the multivariate analyses and distribution of species by source are then discussed in the context of previous research into urban plant ecology, particularly in Central Europe. The problems of inferring process from pattern in this meso‐scale study are reviewed and suggestions are made for further research into urban ecology and biogeography in the city.

Classification of vegetation communities in which geese rear broods on the Yukon – Kuskokwim delta, Alaska

Plant communities are described from an area on the Yukon – Kuskokwim (Y-K) delta of Alaska that is used extensively for brood rearing by three species of geese. Earlier studies identified plant species important as food for young geese, but few studies describe or quantify plant communities. We classified species presence or absence information from over 700 quadrats using a two-way indicator species analysis (TWINSPAN) and then tested for agreement of signatures on colour infrared air photos with the identified communities. Sedges were found to dominate all but the wettest and driest communities. Most of the brood-rearing area was covered by Carex ramenskii and Carex rariflora meadows, ponds, Carex mackenziei-dominated pond margins, and C. ramenskii and grass levee meadows. Our interpretation of airphotos accurately predicted vegetation community classes, which will facilitate future studies of habitat selection by geese during the time they are rearing young. The TWINSPAN classification was comparable to classifications of studies conducted elsewhere on the Y-K delta. The interpretation of air photos will enable the identification and evaluation of wetland vegetation complexes and potential goose brood-rearing areas away from our study site. Key words: air-photo interpretation, Alaska, plant communities, salt marsh, Yukon – Kuskokwim delta.

Ecological Site Classification of Florida Keys Terrestrial Habitats

Site and vegetation characteristics were examined in 113 Florida Keys locations that had been undisturbed for at least 50 years. Detrended correspondence analysis (DECORANA) indicated that Keys vegetation was arranged along two major environmental gradients: an elevational gradient within islands, and a geographic gradient associated with position along the NE-SW trending island chain. Both were complex gradients, with soil depth and type, periodicity of tidal inundation, ground water depth and salinity, climate, and geological substrate as potential contributing factors. Two-way indicator species analysis (TWINSPAN) was used to divide the samples into 14 major groups on the basis of plant species composition. Finally, the TWINSPAN classification was modified to recognize 13 Ecological Site Units which were homogeneous in important site factors as well as vegetation characteristics. Plant species diversity increased from intertidal to upland site units, while canopy height, basal area, and fine litter production increased both upslope and downslope of the supratidal units.

A synecological investigation of Matteuccia struthiopteris ? dominanted stands in Western Norway

This investigation is based on phytosociological and ecological analyses of stands dominated by M. struthiopteris within its main distributional area in Western Norway. The distribution and floristical composition of such stands are related to different environmental parameters such as regional climate, soil and topography. The data are analysed by numerical methods, of which two-way indicator species analysis (TWINSPAN), canonical correspondence analysis (CCA), and simple discriminant functions (DISCRIM) are the most useful. Few stands occur in areas where the mean July temperature is below 12.0 °C, and where the mean January temperature is higher than 0 °C. The soil is rich in metal cations, with a base saturation mostly higher than 50% in the B-layer. Based on a TWINSPAN classification of the 230 investigated stands, 9 different groups (types) are distinguished. Many stands have a tree layer of Alnus incana, while stands with a canopy of Betula pubescens, Fraxinus excelsior and Ulmus glabra are considered to be marginal sites for M. struthiopteris. The types described are interpreted as belonging to the Pruno padi-Alnetum incanae, Alno incanae-Fraxinetum excelsioris and Alno incanae-Ulmetum glabrae associations within the Alno-Ulmion alliance. The floristic composition of the quadrats is highly correlated with the altitude/temperature gradient. The other important factor is interpreted to be soil moisture. Soil richness is poorly correlated with the floristic composition of the different stands. Several stands represent a regeneration stage after cessation in cultivation, while others appear to have been very little influenced by human activity.

A synecological investigation of Athyrium distentifolium‐dominated stands in Western Norway

This paper presents results of a study on the synecology of Athyrium distentifolium. The investigation is based on phytosociological and ecological analyses of stands dominated by A. distentifolium within its whole distributional area in Western Norway. The distribution and floristic composition of the stands are related to different environmental parameters such as climate, soil and topography. The data are analysed by numerical methods, of which two‐way indicator species analysis (TWINSPAN), canonical correspondence analysis (CCA), and simple discriminant functions (DISCRIM) are the most useful. Based on a TWINSPAN classification of the 211 investigated stands, 9 different groups (types) are distinguished. These belong mainly to three phytosociological alliances: Cryptogrammo‐Athyrion alpestris (1 group), Lactucion alpinae (5 groups) and Vaccinio‐Piceion (3 groups). The quadrats are in most cases very poor in species, even in edaphically rich areas. Soil richness in the stands is very variable. A. distentifolium may be dominant in edaphically rich areas and it is not a calciphobe species in W. Norway. Most stands show no signs of human influence. Length of snow‐lie is assumed to be of major importance for the development and distribution of A. distentifolium stands.

On the ecology of Thelypteris limbosperma — a synecological investigation of T. limbosperma‐dominated stands in W Norway

The investigation is based on phytosociological and ecological analyses of T. limbosperma‐dominated stands from different parts of W Norway. The distribution and floristical composition of the stands are related to different environmental parameters, such as climate, soil and topography. The data are analysed by numerical methods, of which two‐way indicator species analysis (TWINSPAN), canonical correspondence analysis (CCA), and simple discriminant functions (DISCRIM) are the most useful. The broad‐scale distribution of T. limbosperma stands is determined by climatic factors. Within its distribution area soil factors and human influence govern the floristic composition and development of different types of such stands. Based on the TWINSPAN classification 9 different stand types are distinguished.The first major division of the TWINSPAN classification is mainly correlated with soil factors. Most of the stands growing on the richest soils are interpreted as representing regeneration stages after intensive human influence. Divisions at lower levels are well correlated with altitude and temperature conditions.The stands are all characterized by low pH and base saturation. Some types are concentrated to certain geographical regions, indicating that both altitudinal and west‐east‐gradients are important in influencing the floristic composition of the different types. The investigations indicate that T. limbosperma has a rather narrow realised phytosociological niche. It is mainly concentrated to stands that are floristically most related to the poorest part of Vaccinio‐Piceion communities. Occasionally it is also dominant in Alno‐Padion and Lactucion alpinae communities.

Vegetation patterns in James Bay coastal marshes. III. Salinity and elevation as factors influencing plant zonations

Plant zonations and selected environmental variables were studied in a subarctic coastal marsh at Ekwan Point, James Bay, Ont. Eight distinct community types were identified using two-way indicator species analysis classification (TWINSPAN). These were interpreted as a primary successional sequence. The eight communities were found to conform closely to the classical marsh zonations based on elevation and tidal influence: (1) lower salt marsh, (2) middle salt marsh, (3) upper salt marsh, (4) saline meadow, (5) freshwater meadow, and (6) freshwater fen. Environmental data collected along the vegetation transects indicated that changes in elevation and soil-water salinity probably influence species distributions. A species ordination using detrended correspondence analysis (DECORANA) revealed several trends in plant distribution patterns. Consideration of the environmental affinities of species separated along three ordination axes suggested that salinity and elevation, water content, and soil texture were probably important factors influencing successional processes in the marsh during at least the last century. An inverse salinity gradient, which has been reported at many sites along the west coast of Hudson and James bays, was not found at Ekwan Point.

Vegetation patterns in James Bay coastal marshes. I. Environmental factors on the south coast

Coastal wetlands of the Hudson Bay Lowlands along southern James Bay are generated by a positive water balance, low relief, and a rising land surface. Marshes, dominated by sedges and grasses, and separated by beach ridges, occur between unvegetated intertidal flats and the inland boreal forest. Bay waters, affected by currents, shallow depths, and large freshwater inputs from major rivers in the Hudson Bay drainage, are brackish. Off the coast at the Harricanaw River, surface salinity in the bay is <4 ppt while soil water salinities in the adjacent marsh are higher. Standing water and tidal water in contact with vegetation often measure 0 ppt salinity. Plant communities adapted to brackish water have developed. Using two-way indicator species analysis classification, twelve widespread community types were recognized. Ordination using detrended correspondence analysis revealed gradients of salinity, elevation, drainage, vegetation development, complexity, and peat formation, and separated coastal from estuarine communities. An inverse salinity gradient, which has been reported elsewhere in James Bay, was not found; explanations are proposed for isolated areas of high salinity.