Discriminant Analysis of Amphibian habitat determinants in South-East England

1985 ◽  
Vol 6 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Trevor J.C. Beebee
Keyword(s):  
Discriminant Analysis ◽  
Discriminant Functions ◽  
Habitat Features ◽  
Amphibian Habitat ◽  
South East England ◽  
Important Habitat

Abstract203 ponds and their environs in south-east England were studied with respect to the distribution of amphibians and to a number of specific habitat features. A discriminant analysis was carried out to identify the most important habitat features for each species and to derive discriminant functions capable of separating used and unused sites into characteristic groups.

Analysis of amphibian habitat preferences in a farmland area (Po plain, northern Italy)

1994 ◽  
Vol 15 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Angela S. Ildos ◽  
Nicoletta Ancona
Keyword(s):  
Discriminant Analysis ◽  
Habitat Preferences ◽  
Bufo Bufo ◽  
Northern Italy ◽  
Po Plain ◽  
Habitat Features ◽  
Hyla Arborea ◽  
Significant Difference ◽  
Lowland Area ◽  
Important Habitat

AbstractForty-two water bodies in an agricultural lowland area of northern Italy were investigated with respect to the presence of amphibians and to a number of habitat features. The following species were found: Rana kl. esculenta, R. latastei, Bufo bufo, B. viridis, Hyla arborea, Triturus carnifex and T. vulgaris meridionalis. A discriminant analysis was carried out for each species to test whether there were significant difference between ecological characteristics of used and unused sites; all analyses showed a significant difference, and they also made it possible to identify the most important habitat features for each species found. Vegetational factors seemed to be the most important.

scholarly journals Morphological evaluation of common bean diversity in Bosnia and Herzegovina using the discriminant analysis of principal components (DAPC) multivariate method

Genetika ◽  
2013 ◽  
Vol 45 (3) ◽  
pp. 963-977 ◽  
Author(s):  
Jasmin Grahic ◽  
Fuad Gasi ◽  
Mirsad Kurtovic ◽  
Lutvija Karic ◽  
Mirha Djikic ◽  
...  
Keyword(s):  
Discriminant Analysis ◽  
Common Bean ◽  
Bosnia And Herzegovina ◽  
Principal Components ◽  
Morphological Characteristics ◽  
Principal Component ◽  
Discriminant Functions ◽  
Factor Loadings ◽  
Geographical Regions ◽  
High Level

In order to analyze morphological characteristics of locally cultivated common bean landraces from Bosnia and Herzegovina (B&H), thirteen quantitative and qualitative traits of 40 P. vulgaris accessions, collected from four geographical regions (Northwest B&H, Northeast B&H, Central B&H and Sarajevo) and maintained at the Gene bank of the Faculty of Agriculture and Food Sciences in Sarajevo, were examined. Principal component analysis (PCA) showed that the proportion of variance retained in the first two principal components was 54.35%. The first principal component had high contributing factor loadings from seed width, seed height and seed weight, whilst the second principal component had high contributing factor loadings from the analyzed traits seed per pod and pod length. PCA plot, based on the first two principal components, displayed a high level of variability among the analyzed material. The discriminant analysis of principal components (DAPC) created 3 discriminant functions (DF), whereby the first two discriminant functions accounted for 90.4% of the variance retained. Based on the retained DFs, DAPC provided group membership probabilities which showed that 70% of the accessions examined were correctly classified between the geographically defined groups. Based on the taxonomic distance, 40 common bean accessions analyzed in this study formed two major clusters, whereas two accessions Acc304 and Acc307 didn?t group in any of those. Acc360 and Acc362, as well as Acc324 and Acc371 displayed a high level of similarity and are probably the same landrace. The present diversity of Bosnia and Herzegovina?s common been landraces could be useful in future breeding programs.

scholarly journals Edge-habitat Use by Northwestern Gartersnakes (Thamnophis ordinoides) in Saanich, British Columbia

2017 ◽  
Vol 131 (1) ◽  
pp. 37-45
Author(s):  
Graham P. Dixon-MacCallum ◽  
Katie A.H. Bell ◽  
Patrick T. Gregory
Keyword(s):  
British Columbia ◽  
Habitat Use ◽  
Survey Methods ◽  
Canopy Cover ◽  
Habitat Requirements ◽  
Habitat Features ◽  
Edge Habitat ◽  
Initial Assumption ◽  
Important Habitat ◽  
Habitat Variables

Understanding habitat requirements of species is fundamental for their conservation and urban parks can provide key habitat for species in otherwise disturbed settings. Northwestern Gartersnakes (Thamnophis ordinoides) are common in parks in Saanich, British Columbia, but their specific habitat requirements are poorly understood. Based on previous studies and thermoregulatory needs of snakes, we predicted that edges, particularly field margins, would be heavily used by active snakes. We therefore used surveys that focused on edges to find snakes and measured edge-habitat use by comparing habitat variables at locations where snakes were found to the same variables at nearby random locations. Habitat variables included composition and structure of vegetation, substrate temperature, aspect, and slope. Overall, litter depth, canopy cover, a lack of bare ground and woody vegetation were the most important habitat variables for determining where snakes were found. our results provide a preliminary assessment to improve our understanding of habitat use for this species. The abundance of snakes found while surveying edges supports our initial assumption that edges are important habitat features but more work is required using multiple survey methods to further test this hypothesis.

scholarly journals Using Linear Discriminant Analysis to Classify Snowfall Situations into Avalanching and Non-Avalanching Ones

1977 ◽  
Vol 19 (81) ◽  
pp. 679-680
Author(s):  
N.F. Drozdovskaya
Keyword(s):  
Discriminant Analysis ◽  
Statistical Methods ◽  
Training Sample ◽  
Dispersion Analysis ◽  
Snow Accumulation ◽  
Discriminant Functions ◽  
Prognostic Information ◽  
Individual Parameter ◽  
Linear Discriminant ◽  
Avalanche Forecasting

Abstract The existing methods of predicting avalanche danger often do not meet users’ demands because of the empiric character of the insufficient volume of information used. In such forecasts the contribution of each individual parameter into the prognostic information is unknown, and this is very important when studying such an event as avalanche formation, which is conditioned by a complex interaction of numerous factors, including snow accumulation, the state of snow thickness, and the conditions of its development. It is obvious that such problems can be successfully solved by statistical methods, and that explains the growing interest in numerical methods of avalanche forecasting. Problems of multi-dimensional observations arises in many scientific fields. The method suited for this problem is discriminant analysis, the purpose of which is to divide a multi-dimensional observation vector into predetermined classes. This study considers the prognostic (diagnostic) problems of fresh-snow avalanches released during snowfall or in the two days after it has ceased. The theoretical basis is a complex of statistical methods: correlation and dispersion analysis, “sifting" for the choice of predictors’ informative groups, construction of linear parametric discriminant functions, predictions based on training sample, and verification of discriminant functions based on independent material. The archive used in the study consisted of 500 avalanching cases and 1 300 non-avalanching ones. All situations were grouped according to geomorphological characteristics. Each situation is described by eight meteorological characteristics. The results of classification of snowfall situations into avalanching and non-avalanching ones are as follows: reliability of ρ is from 75% to 91%, H from 0.15 to 0.51; based on independent material the reliability of ρ is from 63% to 85%, H from 0.10 to 0.56. This paper has been accepted in revised form for publication in a later issue of the Journal of Glaciology.

scholarly journals Asexual Reproduction of Phytophthora capsici as Affected by Extracts from Agricultural and Nonagricultural Soils

2007 ◽  
Vol 97 (7) ◽  
pp. 873-878 ◽  
Author(s):  
S. Sanogo
Keyword(s):  
New Mexico ◽  
Chemical Composition ◽  
Discriminant Analysis ◽  
Phytophthora Capsici ◽  
Organic Matter Content ◽  
Discriminant Functions ◽  
Chile Pepper ◽  
Soil Extracts ◽  
Significant Difference ◽  
History Of

Formation of sporangia and zoospores in species of Phytophthora is known to be influenced by soil microbial and chemical composition. In Phytophthora capsici, the study of the relationship of soil chemical composition to production of sporangia and zoospores has been limited. P. capsici is a soilborne pathogen of a wide array of vegetable crops, including chile pepper (Capsicum annuum) in New Mexico. Production of sporangia and zoospores by P. capsici was evaluated in extracts of soils from three different environments in New Mexico: (i) agricultural environments with a long history of chile pepper cropping and occurrence of P. capsici (CP), (ii) agricultural environments with no history of chile pepper cropping and no occurrence of P. capsici (Non-CP), and (iii) nonagricultural environments consisting of forests and rangelands (Non-Ag). There was a significant difference in production of P. capsici asexual propagules, expressed as natural log (number of sporangia × number of zoospores), among the three environments (P = 0.0298). Production of propagules was 9 to 13% greater in Non-Ag than in CP or Non-CP environments. Stepwise multiple discriminant analysis and canonical discriminant analysis identified the edaphic variables Na, pH, P, organic matter content, and asexual propagule production as contributing the most to the separation of the three environments. Two significant (P < 0.0001) canonical discriminant functions were derived with the first function, accounting for ≈75% of the explained variance. Based on the two discriminant functions, ≈93, 86, and 89% of observations in CP, Non-CP, and Non-Ag environments, respectively, were classified correctly. Soils from agricultural and nonagricultural environments differentially influence production of sporangia and zoospores in P. capsici, and soil samples could be effectively classified into agricultural and nonagricultural environments based on soil chemical properties and the production of asexual propagules by P. capsici in soil extracts.

scholarly journals Variability of leaf blade characters of some microspecies from Alchemilla L. (Rosaceae) in nature coenopopulations and culture on the territory of Mari El Republic

2020 ◽  
Vol 9 (4) ◽  
pp. 66-71
Author(s):  
Olga Valerevna Zhukova
Keyword(s):  
Discriminant Analysis ◽  
Geometric Morphometrics ◽  
Plant Community ◽  
Leaf Blade ◽  
Discriminant Functions ◽  
Classification Result ◽  
Morphometric Characters ◽  
Ecological Characteristics ◽  
Blade Shape ◽  
Similar Classification

The genus Alchemilla L. is one of the largest in angiosperm. This paper deals with variability of leaf blade characters of some microspecies from Alchemilla L. genus. The studies were conducted in 3 natural regions on the territory of Mari El Republic and in culture. A consensus configuration of leaf blade for A. acutiloba Opiz, A. gracilis Opiz, A. monticola Opiz, A. sarmatica Juz., A. schistophylla Juz., A. substrigosa Juz. was obtained by a geometric morphometrics method. The variability of the leaf blade shape for A. acutiloba, A. gracilis, A. sarmatica in natural cenopopulation was described. The study has shown that the size and shape of leaf blade for A. gracilis in ecologically contrasting conditions differ. The size of leaf blade for A. substrigosa differs in conditions with some differences in the ecological characteristics of soils, the shape does not differ. According to a discriminant analysis based on a complex of morphometric characters of leaf blades for microspecies A. litwinowii, A. monticola, A. substrigosa in meadow plant community are classified with an accuracy of about 80%. A similar classification result of leaf blades for A. acutiloba, A. gracilis, A. hirsuticaulis in culture was revealed. Leaf blades for different microspecies form distinct, but overlapping clouds in the plane of discriminant functions.

Factor Analysis in Discriminating the Racial Origin of Sockeye Salmon (Oncorhynchus nerka)

1974 ◽  
Vol 31 (1) ◽  
pp. 1-10 ◽  
Author(s):  
H. B. Messinger ◽  
H. T. Bilton
Keyword(s):  
Factor Analysis ◽  
Discriminant Analysis ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Factor Scores ◽  
Discriminant Functions ◽  
Varimax Rotation ◽  
Racial Origin ◽  
Usual Procedure ◽  
New Variables

A comparison was made between the procedure of factoring variables before using them in discriminant analysis and the usual procedure of using the original variables in discriminant analysis. The results indicated factoring seven scale measurements on sockeye salmon (Oncorhynchus nerka) with varimax rotation produced four new variables which gave more valid results in classifying sockeye salmon by area of origin than the original variables when discriminant functions were computed. Although the results on the basic data from which the functions were derived were not as good using the four factor scores as the seven original variables, the accuracy of classification was much more consistent in the test data with the factor scores. The loss in accuracy was at least [Formula: see text] times as great for functions based on the original variables as for ones based on factor scores. The errors in classifying fish to their individual places of origin were perhaps too large for the procedure to be useful in the field, but the accuracy of classification to the British Columbia or Alaska region was quite high.

Relationships between Hordeum bulbosum L. subsp. bulbosum and H. bulbosum subsp. nodosum comb, et stat. nov.

1985 ◽  
Vol 63 (4) ◽  
pp. 735-743 ◽  
Author(s):  
Bernard R. Baum ◽  
L. Grant Bailey
Keyword(s):  
Data Analysis ◽  
Discriminant Analysis ◽  
Exploratory Data Analysis ◽  
Correct Identification ◽  
Hordeum Bulbosum ◽  
Discriminant Functions ◽  
Morphometric Characters ◽  
Linear Discriminant ◽  
Group Assignment ◽  
Exploratory Data

Material of the diploid (HBD) and tetraploid (HBT) Hordeum bulbosum collected in the Mediterranean and Near East areas was examined for 14 morphometric characters. Exploratory data analysis revealed that cilia on the margins of the glumes of the central spikelets may or may not be present in HBT but are never present in HBD. The data were submitted to various kinds of discriminant analysis in which group assignment was based on ploidy level. When presence–absence of cilia on glume margins is used in combination with the resulting linear discriminant functions (DF) there is about 91% probability of correct identification; with DF alone there is about 81% probability. The results of discriminant analysis provided justification, in the opinion of the authors, to regard HBD and HBT as separate taxa at the level of subspecies, namely H. bulbosum subsp. bulbosum and H. bulbosum L. subsp. nodosum (L.) Baum.

Factorizations of the residual likelihood criterion in discriminant analysis

1966 ◽  
Vol 62 (4) ◽  
pp. 743-752 ◽  
Author(s):  
J. Radcliffe
Keyword(s):  
Discriminant Analysis ◽  
Confidence Intervals ◽  
Goodness Of Fit ◽  
Discriminant Functions ◽  
Approximate Factorization ◽  
Analytic Proof ◽  
Independent Variables ◽  
Canonical Variables ◽  
Residual Likelihood ◽  
The Difference

Certain exact tests were developed by Williams (1952) to deal with the goodness of fit of a single hypothetical discriminant function. Bartlett (1951) generalized these results by the use of the geometric method to any number of dependent and independent variables. Bartlett's paper is divided into two parts. The first deals with an approximate factorization of the residual likelihood criterion into an effect due to the difference between the hypothetical and sample functions, and an effect due to non-collinearity. A method is given for constructing confidence intervals from the first factor. The second part of the paper gives two possible exact factorizations of the likelihood criterion, expressing the results in terms of the sample canonical variables. Kshirsagar (1964a) has expressed these results in terms of the original variables and given an analytic proof of the distribution of the factors. Williams (1955, 1961) has outlined a generalization of these results to several discriminant functions and given the result for one of the possible factorizations.

Biochemical individuality and the recognition of personal profiles with a computer.

1980 ◽  
Vol 26 (1) ◽  
pp. 30-36 ◽  
Author(s):  
E A Robertson ◽  
A C Van Steirteghem ◽  
J E Byrkit ◽  
D S Young
Keyword(s):  
Discriminant Analysis ◽  
Continuous Flow ◽  
Nonlinear Mapping ◽  
Biochemical Profile ◽  
Discriminant Functions ◽  
Linear Discriminant ◽  
Testing Period ◽  
Linear Maps ◽  
Non Linear

Abstract Multitest analysis of an individual's blood provides a biochemical profile that reflects his identity and pathophysiological state. During a six-week period we repeatedly profiled 10 volunteers for 22 different analytes, using continuous-flow and discrete analyzers (SMAC, KA 150 enzyme analyzer, ABA-100, AutoAnalyzers) and manual procedures. Two years later, we obtained multiple follow-up profiles. Using linear discriminant functions derived from the first five (or first 10) specimens from each subject, we were able correctly to identify 96% (or 100%) of the specimens collected during the remainder of the six-week testing period. Ninety percent of the two-year follow-up specimens were correctly identified when we used all the original profiles to calculate the discriminant functions. Deliberately mislabeled specimens were also correctly identified by discriminant analysis. Profiles of individual samples (and average profiles for each subject) were graphically displayed as computer-drawn faces and non-linear maps. Covariances between pairs of tests on repeated profiles differed significantly for different subjects. Inter-test relationships were graphically displayed by nonlinear mapping.

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