scholarly journals Regeneration of black ash (Fraxinus nigra Marsh.) in hardwood swamps of the Great Lakes – St. Lawrence Forest Region

2021 ◽  
Vol 97 (3) ◽  
pp. 343-358
Author(s):  
Amanda Springer ◽  
Jeffery P. Dech
Keyword(s):  
Great Lakes ◽  
Abiotic Factors ◽  
Principal Component ◽  
High Standard ◽  
Diameter Distribution ◽  
Topographic Wetness Index ◽  
Randomized Sampling ◽  
High Soil Moisture ◽  
Forest Region ◽  
Black Ash

An inductive, ordination-based approach was used to explore patterns in the microenvironment and natural regeneration of black ash across a range of representative stands in the central Ontario portion of the Great Lakes -St. Lawrence Forest Region (GLSL) near Lake Nipissing, Ontario, Canada. The objective of this study was to describe patterns of regeneration of black ash and determine the associations between multiple indicators of black ash regeneration success and biotic and abiotic factors. Using a randomized sampling design with specific selection criteria, 12 black ash stands were sampled, each with three 400 m2 circular sample plots that contained three 4 m2 sub-plots. A suite of environmental variables such as elevation, topographic wetness index, slope, and soil characteristics (percent moisture, pH, total nitrogen, exchangeable phosphorus, potassium, magnesium) were determined for each stand. Variables capturing regeneration potential, including density, diameter, and height of all germinants, seedlings, saplings and sprouts were also collected. A sample of 15 dominant or co-dominant trees in each stand, as well as numerous black ash seedlings, saplings and sprouts were examined using dendrochronological methods to estimate ages. Principal component analysis ordinations were performed exploring the variation in environment and black ash regeneration variables among the stands. High soil moisture and the presence of canopy gaps, (as indicated by high standard deviation of canopy closure), were key variables associated with greater abundance of regeneration. Black ash was the dominant species in all stands, which were also generally characterized by a common reverse-J diameter distribution. It was observed that black ash in the sapling layer reached substantial ages (up to 60 years), indicating they are capable of withstanding long periods of suppression below the canopy. Collectively, these findings suggest that black ash-dominated stands in the study area are regenerating in multiple cohorts. Based on these patterns, it appears that regeneration in these stands is occurring through gap-phase mechanisms, suggesting single tree selection as the best management option for black ash in the GLSL.

scholarly journals Leaf geometric morphometrics among populations of Dalbergia ecastaphyllum (L.) Taub.

2019 ◽  
Vol 35 (6) ◽  
Author(s):  
Daniel Vieira de Morais ◽  
Lorena Andrade Nunes ◽  
Vandira Pereira da Mata ◽  
Maria Angélica Pereira de Carvalho Costa ◽  
Geni da Silva Sodré ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Geometric Morphometrics ◽  
Cross Validation ◽  
Abiotic Factors ◽  
Principal Component ◽  
Canonical Variate ◽  
Validation Test ◽  
Significant Difference ◽  
Variate Analysis ◽  
Geographical Distances

Leaves are plant structures that express important traits of the environment where they live. Leaf description has allowed identification of plant species as well as investigation of abiotic factors effects on their development, such as gases, light, temperature, and herbivory. This study described populations of Dalbergia ecastaphyllum through leaf geometric morphometrics in Brazil. We evaluated 200 leaves from four populations. The principal component analysis (PCA) showed that the first four principal components were responsible for 97.81% of variation. The non-parametric multivariate analysis of variance (NPMANOVA) indicated significant difference between samples (p = 0.0001). The Mentel test showed no correlation between geographical distances and shape. The canonical variate analysis (CVA) indicated that the first two variables were responsible for 96.77 % of total variation, while the cross-validation test showed an average of 83.33%. D. ecastaphyllum leaves are elliptical and ovate.

scholarly journals Diversity and spatial distribution of black flies (Diptera: Simuliidae) in the Ijuí river drainage basin, Rio Grande do Sul, Brazil

2019 ◽  
Vol 12 (2) ◽  
pp. 47-56
Author(s):  
Tieli Cláudia Menzel ◽  
Sirlei Maria Hentges ◽  
David Augusto Reynalte Tataje ◽  
Milton Norberto Strieder
Keyword(s):  
River Basin ◽  
Indicator Species ◽  
Drainage Basin ◽  
Abiotic Factors ◽  
Principal Component ◽  
Rio Grande ◽  
Anthropogenic Pressure ◽  
Black Flies ◽  
Rio Grande Do Sul ◽  
Significant Difference

Abstract. In southern Brazil there are several problems regarding the hematophageal activity of black flies, and the information on the distribution of species are still insufficient. In this study, our main goals were to recognize Simuliidae species and to analyze abiotic factors regarding the distribution of immature stages (larva and pupa) in streams from the Ijuí River basin, Northwest of Rio Grande do Sul, Brazil. We sampled simulids specimens in 27 study sites, covering three regions (high, intermediate and low altitude). Concomitantly, we recorded abiotic factors in the studied sites, such as: temperature, electrical conductivity, dissolved oxygen, atmospheric pressure, pH, altitude and stream width. For data analysis, we performed Kruskal-Wallis, ANOVA, Principal Component Analysis (PCA), Analysis of Indicator Species and Canonical Correspondence (CCA). A total of 10 species of black Flies was recorded. Simulium pertinax Kollar, Simulium incrustatum Lutz and Simulium orbitale Lutz were the most frequent. There was no significant difference in richness and density of the species between the different regions studied, except for Simulium jujuyense Paterson & Shannon. The sampled environments were segregated according to the location within the basin, and only S. jujuyense was considered an indicator species of the upper region. These results can be explained by the homogeneous conditions of the Ijuí River basin, which have suffered anthropogenic pressure mainly due to agricultural activities, resulting in losses in local aquatic biodiversity. Also, it may indicate that the control must be conducted considering the basin as a whole, and not only as isolated stretches of the streams.Diversidade e distribuição espacial de borrachudos (Diptera: Simuliidae) na bacia hidrográfica do rio Ijuí, Rio Grande do Sul, BrasilResumo. No sul do Brasil existem problemas com atividade hematofágica de borrachudos e as informações referentes à distribuição das espécies ainda são insuficientes. O presente estudo visa reconhecer as espécies de Simuliidae e analisar fatores abióticos quanto a distribuição dos estágios imaturos (larva e pupa) em riachos da Bacia do Rio Ijuí, no Noroeste do Rio Grande do Sul, Brasil. Foram coletados simulídeos em 27 pontos de estudo, cobrindo três regiões da bacia (alta, intermediária e baixa altitude). Concomitantemente, foi feito o registro de fatores abióticos nos trechos estudados, tais como: temperatura, condutividade elétrica, oxigênio dissolvido, pressão atmosférica, pH, altitude e largura do riacho. Foram realizadas análises de Kruskal-Wallis ou ANOVA, Análise de Componentes Principais (PCA), Análise de Espécie Indicadora e de Correspondência Canônica (CCA). Foi registrado um total de 10 espécies de Simuliidae. Simulium pertinax Kollar, Simulium incrustatum Lutz e Simulium orbitale Lutz foram as mais frequentes. Não ocorreu diferença na riqueza e na densidade das espécies entre as diferentes regiões estudadas, exceto para Simulium jujuyense Paterson & Shannon. Os ambientes nos pontos de amostragem foram segregados de acordo com a sua localização na bacia, e apenas S. jujuyense foi considerada uma espécie indicadora da região alta. Tais resultados podem ser explicados pelas condições homogêneas da Bacia do Rio Ijuí, que vêm sofrendo pressão antropogênica principalmente devido às atividades agrícolas, resultando em perdas na biodiversidade aquática local. Também, indicam que o controle deve ser realizado considerando a bacia como um todo e não apenas em trechos isolados dos riachos.

scholarly journals Morphological variability between diploid and tetraploid taxa of the genus Betula L. in the Czech Republic

2017 ◽  
Vol 63 (No. 12) ◽  
pp. 531-537 ◽  
Author(s):  
Linda Rostislav ◽  
Kuneš Ivan ◽  
Baláš Martin ◽  
Gallo Josef
Keyword(s):  
Principal Component Analysis ◽  
Czech Republic ◽  
Reliable Method ◽  
Morphological Variability ◽  
Principal Component ◽  
The Czech Republic ◽  
Forest Region ◽  
Blade Width ◽  
The Bohemian Forest ◽  
Classification Function

The aim of this work was to suggest a reliable method for distinguishing between diploid and tetraploid taxa of the genus Betula Linnaeus, based on leaf measurements. In total, 97 individuals from 6 locations within the Bohemian Forest region (Czech Republic) were selected. Four leaves from each individual were evaluated. On each leaf, twenty parameters were measured. Each sample was analysed by flow cytometry to determine its actual ploidy. Measured parameters were analysed by principal component analysis and tested for differences between diploid and tetraploid taxa. For actual ploidy prediction, a classification function was designed. The reliability of the classification function was verified on samples from three different regions of the Czech Republic and compared with functions as suggested by other authors. The classification function designed in this work (based on 3 parameters – blade width in the upper 1/4 of blade length, first vein angle and number of leaf teeth between 3<sup>rd</sup> and 4<sup>th</sup> vein) correctly determined actual ploidy in 89% of all tested samples.

Aire minimum d'échantillonnage ou nombre de points de prisme nécessaires pour établir la structure d'un peuplement inéquienne

1991 ◽  
Vol 21 (11) ◽  
pp. 1632-1638 ◽  
Author(s):  
Yvon Grenier ◽  
Louis Blais ◽  
Éric Lavoie
Keyword(s):  
Sampling Methods ◽  
Statistical Testing ◽  
Diameter Distribution ◽  
Good Representation ◽  
Grid System ◽  
Probability Level ◽  
American Beech ◽  
Randomized Sampling ◽  
Breast Height ◽  
Forest Survey

A complete forest survey was conducted on an 18-ha maple stand mixed with yellow birch and American beech. Diameter at breast height of all merchantable stems was recorded. The location of all those stems was reported on a grid system to allow subsequent simulation of sampling by varying the size of rectangular sample plots. Prism sampling was also carried out in the same area. Statistical testing (χ2) were used to verify if randomized sampling gave the same diameter distribution as the original stand. Both sampling methods were adequate. Rectangular sample plots, 2 m wide by 5000 m long, representing an area of 10 000 m2 (i.e., 5.6% of the original stand) or 36-point sample (2 points per hectare) gave a good representation of the entire population at a probability level of 90%, with a confidence level of α = 0.05. For both sampling methods, sampling units must be scattered as much as possible in the forest area to be surveyed.

A morphometric study of geographic variation in the snowshoe hare (Lepus americanus)

1985 ◽  
Vol 63 (3) ◽  
pp. 567-579 ◽  
Author(s):  
David W. Nagorsen
Keyword(s):  
North America ◽  
Great Lakes ◽  
Geographic Variation ◽  
Principal Component ◽  
Lepus Americanus ◽  
Morphometric Study ◽  
Western North America ◽  
Environmental Selection ◽  
Local Selection ◽  
Central Canada

Geographic variation in Lepus americanus was studied by multivariate analyses of 15 cranial measurements. A total of 1494 specimens from the entire geographic range were grouped into 37 geographic samples of males and females. Principal component analyses demonstrated that hares are largest in eastern North America, Alaska, and northwestern Canada, and smallest in the Pacific Northwest. Size clines exist in the Appalachian Mountains and western North America but size is relatively uniform throughout central Canada and the Great Lakes. A multiple regression of size with 16 climatic variables factors demonstrated that size and climate are strongly correlated; the size trends may reflect environmental selection. The differentiation of hares from the western Cordillera and Pacific coast, the similarity of populations from central Canada and the Great Lakes, and the clines in the Appalachians and western North America were evident in discriminant analyses. These patterns of variation among populations can be attributed to both gene flow and local selection. There is no evidence from the morphometric analyses for classifying populations into the 15 subspecies currently recognized.

scholarly journals Digital Morphometrics: A Tool for Leaf Morpho- Taxonomical Studies

2021 ◽  
Vol 1 (2) ◽  
pp. 1-7
Author(s):  
Kavi K. Oza ◽  
Rinku J. Desai ◽  
Vinay M. Raole*
Keyword(s):  
Principal Component Analysis ◽  
Abiotic Factors ◽  
Leaf Shape ◽  
Principal Component ◽  
Component Analysis ◽  
Herbarium Specimens ◽  
Fourier Descriptors ◽  
Shape Variation ◽  
Quantitative Analysis Method ◽  
Elliptic Fourier Descriptors

Leaves are most important part of the plant and can be used for the identification of a taxon. An appropriate understanding of leaf development in terms of shape and responsible abiotic factors is necessary for improvement in plant. Leaf shape variation could be evaluated successfully, and the symmetrical and asymmetrical elements of the overall shape variation could be detected. The aim of the present study was to establish a quantitative analysis method of leaf shape by elliptic Fourier descriptors and principal component analysis (EF-PCA). EF-PCA describes an overall shape mathematically by transforming coordinate information concerning its contours into elliptic Fourier descriptors (EFDs) and summarizing the EFDs by principal component analysis. We can be able to extract six variables by using leaf specimen images from field and herbarium specimens. In the present study, total leaf area with respect to notch area is more variable within species. Within a species the major source of the symmetrical elements may be governed by genotypic features and the asymmetrical elements are strongly affected by the environment. We could discuss the value of morphometrics to detect subtle morphological variation which may be undetectable by human eye.

scholarly journals Environmental forcing as a main determinant of bloom dynamics of the Chrysochromulina algae

2006 ◽  
Vol 273 (1605) ◽  
pp. 3047-3055 ◽  
Author(s):  
Kyrre Lekve ◽  
Espen Bagøien ◽  
Einar Dahl ◽  
Bente Edvardsen ◽  
Morten Skogen ◽  
...  
Keyword(s):  
Seasonal Dynamics ◽  
Regression Models ◽  
Moving Average ◽  
Abiotic Factors ◽  
Principal Component ◽  
Seasonal Development ◽  
Nutrient Concentrations ◽  
Environmental Forcing ◽  
Nonlinear Regression Models ◽  
Marine Algal

In this paper, we demonstrate that the seasonal dynamics in the abiotic factors, without including seasonal changes in the biological relationships, can appropriately account for the seasonal dynamics of Chrysochromulina spp. This is through the analysis of data on the population dynamics of Chrysochromulina spp. off southern Norway that is evaluated in relation to environmental factors and season by the analyses of 12 year monthly time-series. Chrysochromulina spp. abundance, nutrient concentrations, hydrographical properties, as well as current and wind data were analysed on a monthly scale by means of autoregressive moving average models, principal component analyses (PCA), and linear and nonlinear regression models. Seasonal development of the Chrysochromulina assemblage was well predicted from regression models forced with two PCA components representing seasonal variation in nutrient and chlorophyll a levels and ratios, inflow of North Seawater to the Skagerrak and northeasterly wind along the Norwegian coast. Assuming these to be general results, we might hypothesis that marine algal communities are governed by seasonally varying abiotic factors to a large extent.

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