A combination of fuzzy set ordination with detrended correspondence analysis: One way to combine multi-environmental variables with vegetation data

This paper examines one possible way of Fuzzy Set Ordination by using multi-environmental variables. FSO's function is improved through combination with Detrended Correspondence Analysis which is used to summarize environmental information. It can be used to analyse the relationships between vegetation and environment no matter how many environmental variables are involved. An example with vegetation and environmental data collected from upland grasslands in Northern Snowdonia, Wales, is presented. Its results are consistent with that of CCA and DCCA.Abbreviations FSO Fuzzy set ordination - DCA Detrended correspondence analysis - CCA Canonical correspondence analysis - DCCA Detrended canonical correspondence analysis     

Ordination as a tool for analyzing complex data sets

Summary Ordination has proven to be a useful tool for examining relationships between environment and vegetation in data sets with a simple underlying environmental strueture. Complex data sets have proven much less tractable. A strategy is offered for dealing with complex data sets based on progressive removal of sets of stands along identified gradients, and subsequent reordination. This strategy is demonstrated using forests of the North Carolina piedmont.The author gratefully acknowledges the continuing collaboration of Dr. Norman L. Christensen of Duke University. This research was supported by National Science Foundation grants DEB-7708743 and DEB-7804043 to R.K.P. and DEB-7707532 and DEB-7804041 to N.L.C.     

Adaptive leaf structures in a Myrica-Erica stand on Tenerife (Canary Islands)

This study is based on a phytosociological table and a matrix of species and morphological characters. The relevés were taken along a transect in a Myrica faya-Erica arborea formation on Tenerife (Canary Islands). The analysis of the phytosociological table reveals a vegetational succession and a corresponding ecological gradient. The study of correlations between morphological and ecological data leads to the creation of groups of species with different combinations of characters, and to a discussion of the adaptive values of each character combination. The species of each group occupy similar niches.Abbreviations AOC= Analysis of Concentration - P/C= index ratio between the perimeter of a leaf and the circumference of a circle having the same area as the leaf     

Segmentation of electron tomographic data sets using fuzzy set theory principles

In electron tomography the reconstructed density function is typically corrupted by noise and artifacts. Under those conditions, separating the meaningful regions of the reconstructed density function is not trivial. Despite development efforts that specifically target electron tomography manual segmentation continues to be the preferred method. Based on previous good experiences using a segmentation based on fuzzy logic principles (fuzzy segmentation) where the reconstructed density functions also have low signal-to-noise ratio, we applied it to electron tomographic reconstructions. We demonstrate the usefulness of the fuzzy segmentation algorithm evaluating it within the limits of segmenting electron tomograms of selectively stained, plastic embedded spiny dendrites. The results produced by the fuzzy segmentation algorithm within the framework presented are encouraging.     

An application of fuzzy set ordination to determine tree habitat suitability of sites from a regional data set

Abstract. Fuzzy set ordination is employed to evaluate sites on the basis of their suitability for particular tree species. The technique orders sites along an axis defined by the presences and absences of a given species of interest. A rationale is given in terms of noise reduction; in many situations the overall vegetation of a site will reflect habitat conditions better than the presence, absence, or quantitative performance of any single species. A data set of tree presence/absence covering a large part of the southeastern United States was analyzed and habitat suitability scores were calculated for each species. Monte-Carlo tests were used to measure the statistical power of the data set with regard to habitat preferences; 38 of the 49 species have cumulative frequency distributions showing significant departures from random expectation. Most statistically significant habitat preferences seem to be related to geographic range limits located within the study area, but some species found throughout the area also show significant departures from random expectation. The method may find applications in autecological studies of species, selection of representative site conditions for simulation modeling, and the solution of certain technical problems in ordination.     

Regional and local variation in tallgrass prairie remnants of Iowa and eastern Nebraska

Tallgrass prairie vegetation, persisting as numerous small relics scattered across central North America, exhibits a complex pattern of community structure and composition. We sampled vegetation from 11 prairie preserves in Iowa and eastern Nebraska spanning three physiographic regions and a wide variety of upland habitats. Numerical classification and partitioned ordination revealed a complex pattern of both local and geographical variation in the vegetation. The primary coenocline is a complex topographic-moisture gradient. Secondary factors influencing the vegetation include subsoil permeability, chorological differences, and local peculiarities of stand history and dynamics. Local patterns of interaction between the primary and secondary environmental factors vary among Quaternary landscapes resulting in regional vegetation complexity.Nomenclature follows Gleason (1952) except for the grasses which follow Pohl (1966).Supported by the National Science Foundation (No. GU 2795 and GU 3373), The Nature Conservancy, and the Iowa State Advisory Board for Preserves. We thank T. L. Roberts, S. Taylor, and S. Lundquist for help with field work, and R. K. Peet, A. T. Harrison, and J. K. White for advice, comments, and criticisms.     

香港岛森林群落的聚类的排序

 本文应用聚类、极点排序、主分量分析等多元分析方法,对香港岛的森林群落进行了分类与排序。根据组平均法、离差平方和法、最近邻体法等三种聚类分析的结果,香港岛的森林群落可划分为三个植被亚型和七个群系。极点排序较好地反映了植被的连续性,以及群落所在地的海拔、干湿程度、土壤类型等生境条件的梯度变化,主分量分析表示出13个森林群落的相互关系,可以从原来60个彼此相关的变量降为13个互相独立的变量。主分量分析的二维排序图较好地划分出南亚热带常绿阔叶林为低地林,低山林和山地林等三个植被亚型。     

Improving the interpretation of fuzzy partitions in vegetation science with constrained ordinations

Classification and ordination techniques based in fuzzy set theory are now being commonly used in vegetation studies. However, several problems have been detected in spite of the significant theoretical advantages of the theory. In this paper we have improved the interpretability of fuzzy partitions by combining fuzzy partitions with correspondence analysis (CA) and detrended canonical correspondence analysis (DCCA) in an analysis of the beech forests of Basque Country, northern Spain. Our results seem to overcome difficulties in the interpretation of multi-group partitions.     

A simple method to analyze the similarity of biological sequences based on the fuzzy theory

In this paper, we propose a simple method to analyze the similarity of biological sequences. By taking the average contents of biological sequences and their information entropies as the variables, the fuzzy method is used to cluster them. From the results of application, it finds that the method is relatively easy and rapid. Unlike other methods such as the graphical representation methods, which is usually very complex to compute some invariants of matric derived from graphical representation, our method pays more attention to the information of biological sequences themselves. Especially with the help of the software (SPSS), it seems to be very convenient. Therefore, it may be used to study the new biological sequences such as their evolution relationship and structures.     

Distribution of submerged macrophytes in the Camargue in relation to environmental factors

Abstract. The species composition of stands of submerged macrophytes was studied in relation to the main environmental factors in oligohaline wetlands of the Camargue, southern France. Correlations were sought between the environmental factors and the abundance of the different species using canonical analysis. 24 species of submerged macrophytes, including 10 species of Charophyta, were recorded in the 60 sites studied. The hydrological regime and the salinity appeared to be the main factors controlling the abundance of the different species. This is related to the management of the marshes in the Camargue, which is carried out using these two controlling factors, particularly the hydrological regime, and also includes the destruction of emergent vegetation, mechanically or by grazing. The bivariate ecological amplitude of the individual species was calculated from field data along the gradients of flooding duration and conductivity of the water. My-riophyllum spicatum, Potamogetón pectinatus and Ruppia cirrhosa dominate permanent marshes along the conductivity gradient. In temporary marshes, all having a low conductivity, Zannichellia pedunculata, Ranunculus baudotii, Chara áspera and Callitriche truncata dominate.     

Regional interpretation of environmental gradients which influence Trachypogon savannas in the Orinoco Llanos

Multivariate structural data describing Trachypogon savanna relationships were used to characterize the sources of variation among savannas as a function of the environmental characteristics of the Orinoco Llanos. Twenty-six savannas including major physiognomic types of the Orinoco Llanos ranging from herbaceous to bush island savannas were ordinated on a regional scale. Results of Detrented Canonical Correspondence Analysis (DCCA) using floristics variables indicated that savannas were ordinated along two complex gradients. A soil physical and chemical gradient as expressed by changes in bulk density and magnesium concentration were evident after the analysis of the first DCCA axis. The second axis was a climatic gradient of decreasing annual precipitation and incresing monthly precipitation during the dry season. The impact of human disturbance on the savanna composition was also an explanatory variable of the second DCCA axis. Savanna sites overlapped considerably in composition and most species were widely distributed, with aboveground phytomass abundance depending upon the site.     

Fuzzy set ordination along an elevation gradient on a mountain in Vermont,USA

Abstract. Fuzzy set ordination was used to examine relationships between tree species and site factors on Mt. Ascutney, Vermont, USA. Prism plots were established at four elevations (455, 610, 760 and 915 m) along contour lines that encircled the mountain. In addition to elevation, which was the most important factor affecting tree species composition, slope, aspect and exposure to solar radiation all affected composition; however, these latter three factors were important only at 455 m. Topographic position was important at higher elevations as well. The responses of tree species to any of these factors were highly individualistic. Plots of the upper bounds of relative basal area of each species against the apparent elevation of sites where that species was found were useful in predicting how important an individual species could become over the course of forest succession. For example, northern hardwoods, which comprise the most common forest type of this region, are not very common on this mountain. This approach shows, however, that they are currently at levels well below their potential maximum; this is probably due to past disturbance.     

Gradient structure of forest vegetation in the central Washington cascades

Summary Forest vegetation located in three areas of the central Washington Cascades, arrayed along a gradient of increasing continentality and decreasing rainfall, were compared using ordination methods. Within each region, lower and upper elevation sites were analyzed separately and for each set of sites, trees and ground story vegetation were analyzed independently. Principal components analysis, reciprocal averaging, weighted averaging, and polar ordination were applied to each set. The characteristics of the data determined which method gave the most readily interpretable results, but RA and WA usually best ordered the stands along a complex, combined coenocline, while PO often decomposed the gradient into moisture and temperature components. PCA was of little use, even with relatively low beta diversity.Results are presented in the form of stand by species tables for each data set and the most appropriate two dimensional ordination. Both are correlated to the classification. A mosaic diagram for each region is synthesized from these analyses and habitat data. These diagrams indicate that community types occupy a smaller portion of the habitat as continentality increases.The ordination results were in close agreement with our earlier classification of these stands. The maritime (west) region contains stands of low richness and with relatively little coenocline differentiation. In contrast, the continental (east) region has high alpha and beta diversity. Species in the west tend to occupy a broad portion of the available habitat range, while species in the east do not. The analyses reveal that ordinations by different strata may produce similar stand sequences if both strata are responding directly to the same factors, but that the correspondence degenerates where the understory responds primarily to the nature of the canopy dominant species. Thus stand sequence correlations are highest in the lowland eastern region and lowest in the lowland western region.This study demonstrates that none of these metric ordination methods is fool-proof and that none should be used exclusively or in isolation. RA and PO are demonstrated to be useful general methods; WA gave results similar to those of RA. PCA never produced uniquely superior results. Analyses with too few species and moderate beta diversity often produce distortions as pronounced as those with many species and high beta diversity.Nomenclature follows Hitchcock & Conquist (1973).Funds provided by the Graduate School Research Fund, University of Washington and by grants GB-20963 and GB-36810X to the Coniferous Forest Biome, U.S.I.B.P. This is contribution # 318 to the Coniferous Forest Biome. M.F. Denton, R.S. Fleming, A.R. Kruckeberg, and R.H. Whittaker each made significant suggestions. We thank R.S. Fleming, S.G. Fleming, C. Brewer, B.C. Cannon, K.E. Wade, K. Loughney, and J.E. Canfield for their assistance with field work and data analysis.     

A proposal of a fuzzy rule-based system for the analysis of health and health environments in Brazil

A challenging activity in the promotion of sustainable development is to synthesise indicators that can support decision-making. In developing countries such as Brazil, the use of information in support of the health and health-related environment of humans needs improvement. This paper presents a proposal for a system that can evaluate human health and urban environment sanitation in an integrated manner. The indicators selected for human health were child mortality rate, mortality rate due to acute diarrhoea for all ages and 1–4-year-old mortality rate due to acute respiratory tract infections. Environmental sanitation has been represented by indicators of sanitation coverage, such as sewerage. The paper describes the design of a fuzzy linguistic model that synthesises these indicators. The designed fuzzy rule-based system has proved to be a useful tool to integrate information and assist in the public planning of interrelated areas.     

Use of the β‐function to estimate the skewness of species responses

Abstract. Response of a species to an environmental variable may be modeled and predicted using a wide spectrum of different functions. Contrary to other functions (Gaussian, polynomial etc), all parameters of the β‐function are interpretable in ecological terms. However, computational difficulties in the determination of the β‐function parameters initiated controversial debates on the applicability and usefulness of this function in vegetation modelling and gradient analysis. We propose a simple algorithm for fitting the β‐function to observed data. Analytic properties of the algorithm (its ability to recover the known species responses along gradients) are tested using a series of simulated data. In most cases the algorithm correctly estimated parameters of the simulated responses.     

粗糙集模糊聚类分析法在昆虫分类研究中的应用

本文根据昆虫图像,对半翅目、鳞翅目、鞘翅目的28种昆虫提取的形状参数、叶状性、球状性等7项数学形态特征进行了粗糙集模糊聚类分析。在粗糙集处理的基础上,分别进行7指标和3指标（相对约简）两种不同的模糊聚类分析法相比较。结果显示,在作为目级阶元分类指标时,各项特征的重要性依次为：(似圆度、偏心率)＞（亮斑数、球状性、圆形性）＞（叶状性、形状参数）;粗糙集分类正确率优于模糊聚类分析法;粗糙集处理后的3指标分类正确率优于未处理的7指标分类正确率。结论认为,粗糙集理论在昆虫依据数学形态特征进行分类方面与统计分析方法相比更有优势,粗糙集滤过指标后再进行模糊聚类法分析在昆虫分类研究上具有重要意义。     

Ecological boundaries in the context of hierarchy theory

Ecological boundaries have been described as being multiscalar or hierarchical entities. However, the concept of the ecological boundary has not been explicitly examined in the context of hierarchy theory. We explore how ecological boundaries might be envisioned as constituents of scalar hierarchical systems. Boundaries may be represented by the surfaces of constituents or as constituents themselves. Where surfaces would correspond to abrupt transition zones, boundary systems might be quite varied depending on hierarchical context. We conclude that hierarchy theory is compatible with a functional vision of ecological boundaries where functions can be largely represented as the processing or filtering of ecological signals. Furthermore, we postulate that emergent ecological boundaries that arise on a new hierarchical level may contribute to the overconnectedness of mature ecosystems. Nevertheless, a thermodynamic approach to the emergence and development of boundary systems does indicate that in many situations, ecological boundaries would persist in time by contributing to the energy production of higher hierarchical levels.     

Density functional theory calculations of optical rotation: employment of ADZP and its comparison with other basis sets

Density function theory calculations of frequency dependent optical rotations ([alpha]omega) for 30 rigid chiral molecules are reported. Calculations have been carried out at the sodium D line frequency, using the augmented double zeta valence quality plus polarization functions (ADZP) basis set and the BP86 nonhybrid and B3LYP hybrid functionals. Gauge-invariant atomic orbitals were used to guarantee origin-independent values of [alpha]D. Comparison between corresponding results obtained with nonhybrid and hybrid functionals as well as with theoretical optical rotations reported in the literature is done. Excited electronic states of three molecules are also discussed in light of circular dichroism spectra and B3LYP and BP86 calculated excitation energies and rotatory strengths. One verifies that the B3LYP/ADZP results are in better agreement with experiment.