Spatial heterogeneity of vegetation and environmental factors on talus slopes of the Niagara Escarpment

1993 ◽  
Vol 71 (2) ◽  
pp. 323-332 ◽  
Author(s):  
Janet E. Cox ◽  
Douglas W. Larson
Keyword(s):  
Multivariate Analysis ◽  
Environmental Factors ◽  
Spatial Heterogeneity ◽  
Positive Feedback ◽  
Local Scale ◽  
Vegetation Development ◽  
Niagara Escarpment ◽  
Scale Heterogeneity ◽  
Vegetation Heterogeneity ◽  
Talus Slopes

Spatial heterogeneity of vegetation and environmental factors were studied on talus slopes of the Niagara Escarpment, southern Ontario, Canada. Random sampling of 197 taxa and 19 environmental variables along the length of the Escarpment permitted multivariate analysis of heterogeneity that occurred at both geographical and local scales. While previous work on these slopes had indicated that rockfall disturbance was the main organizing factor of vegetation, this variable was shown to be unimportant. Instead, we found geographical-scale control of vegetation heterogeneity related to one component of macroclimate and local-scale heterogeneity controlled by a complex of soil factors. The local-scale heterogeneity appeared to be too patchy, however, to be explained by normal soil development processes. We suggest that the talus vegetation develops in response to a positive feedback mechanism involving inputs of slowly decomposing wood from the neighbouring cliffs, followed by accelerated vegetation development on patches of fertile organic matter. Key words: talus vegetation, cliff, multivariate analysis, Niagara Escarpment, plant community, positive feedback, spatial heterogeneity.

scholarly journals Increase in the Risk of Respiratory Disorders in Adults and Children Related to Crop-Growing in Niger

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Ali Mamane ◽  
Jean-François Tessier ◽  
Ghislaine Bouvier ◽  
Roger Salamon ◽  
Pierre Lebailly ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Environmental Factors ◽  
Respiratory Symptoms ◽  
Respiratory Health ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Face To Face ◽  
Increased Risk ◽  
Adults And Children ◽  
Agricultural Areas

Background and Objective. Environmental factors are an increasing concern for respiratory health in developing countries. The objective of this study was to investigate whether Nigerien people living in cultivated areas have more respiratory symptoms than those living in pastoral areas. Method. A cross-sectional study was conducted in 2013 in two populations during the rainy season when land is cultivated. Environmental factors including pesticide use and respiratory symptoms were collected in adults and children during face-to-face interviews. Multivariate analysis between exposures and symptoms was performed in children and in adults separately. Results. The study included 471 adults and 229 children. Overall, none of the households reported the use of pesticides for agricultural purposes. However, 87.2% reported the use of insecticides at home. Multivariate analysis showed that people living in agricultural areas compared to those in pastoral areas had an increased risk of respiratory symptoms in adults (wheezing, dyspnea, sudden shortness of breath, and cough without fever) and in children (cough without fever). The use of insecticides showed no effect on respiratory symptoms after adjustment. Conclusion. This first epidemiological study on the environment and respiratory health conducted in Niger demonstrates a significant relationship between respiratory manifestations and the agricultural characteristics of the living area. However only the effect of insecticides in the home on respiratory health was observed.

Multivariate Analysis in Genetic Studies

1972 ◽  
Vol 21 (3) ◽  
pp. 204-210 ◽  
Author(s):  
Ch. Susanne
Keyword(s):  
Multivariate Analysis ◽  
Environmental Factors ◽  
The Body ◽  
Biometrical Analysis ◽  
Genetic Studies ◽  
The Face ◽  
Generalized Distances ◽  
Sib Pairs

SummaryThe results are presented of a method of generalized distances calculated by a noncentral χ2 test and applied to compare 63 twin pairs and 196 sib pairs. The advantage of this method in biometrical analysis lies in the fact that several measurements can be utilised simultaneously. Besides, it takes into account the distance of each relative to the centre of the population and also has the advantage of permitting the comparison of distances between pairs of relatives whatever their age or sex.Generalized distances were calculated for four measurements of the head, five of the body and eleven of the face. For all three sets of measurements the influence of genetical factors was demonstrated. The body seems less influenced by environmental factors and more conditioned by genetic ones.

scholarly journals The weed vegetation of the bean “Fagiolo Cannellino di Atina” and the red pepper “Peperone di Pontecorvo” PDO crops (Latium, central Italy)

2020 ◽  
Vol 57 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Marta Latini ◽  
Emanuele Fanfarillo ◽  
Elisa De Luca ◽  
Mauro Iberite ◽  
Giovanna Abbate
Keyword(s):  
Multivariate Analysis ◽  
Phaseolus Vulgaris ◽  
Environmental Factors ◽  
Capsicum Annuum ◽  
Central Italy ◽  
Agricultural Management ◽  
Red Pepper ◽  
Vegetation Types ◽  
Protected Designation Of Origin

The weed vegetation of the bean “Fagiolo Cannellino di Atina” (Phaseolus vulgaris L.) and the red pepper “Peperone di Pontecorvo” (Capsicum annuum L.) PDO (Protected Designation of Origin) crops was surveyed by means of 16 relevés, sampled in four farms of southern Latium during July 2019. The relevés were subjected to multivariate analysis, which revealed that the two crops are weeded by vegetation types referable to two different subassociations of Panico-Polygonetum persicariae (Spergulo-Erodion, Eragrostietalia, Digitario-Eragrostietea). Namely, communities colonizing bean fields, which are more mesophilous and richer in Eurasian taxa, are ascribable to the subassociation sorghetosum halepensis. Communities colonizing red pepper fields, which are more thermophilous and richer in Mediterranean taxa, are ascribable to the subassociation cyperetosum rotundi. Floristic, structural, and chorological features of the communities are discussed in relation to environmental factors and agricultural management.

scholarly journals New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere: a comparison between permafrost and non-permafrost areas

2019 ◽  
Vol 13 (2) ◽  
pp. 693-707 ◽  
Author(s):  
Olli Karjalainen ◽  
Miska Luoto ◽  
Juha Aalto ◽  
Jan Hjort
Keyword(s):  
Environmental Factors ◽  
Solar Radiation ◽  
Soil Properties ◽  
Northern Hemisphere ◽  
Effect Size ◽  
Thermal Regime ◽  
Thermal State ◽  
Local Scale ◽  
The Arctic ◽  
Active Layer Thickness

Abstract. The thermal state of permafrost affects Earth surface systems and human activity in the Arctic and has implications for global climate. Improved understanding of the local-scale variability in the global ground thermal regime is required to account for its sensitivity to changing climatic and geoecological conditions. Here, we statistically related observations of mean annual ground temperature (MAGT) and active-layer thickness (ALT) to high-resolution (∼1 km2) geospatial data of climatic and local environmental conditions across the Northern Hemisphere. The aim was to characterize the relative importance of key environmental factors and the magnitude and shape of their effects on MAGT and ALT. The multivariate models fitted well to both response variables with average R2 values being ∼0.94 and 0.78. Corresponding predictive performances in terms of root-mean-square error were ∼1.31 ∘C and 87 cm. Freezing (FDD) and thawing (TDD) degree days were key factors for MAGT inside and outside the permafrost domain with average effect sizes of 6.7 and 13.6 ∘C, respectively. Soil properties had marginal effects on MAGT (effect size =0.4–0.7 ∘C). For ALT, rainfall (effect size =181 cm) and solar radiation (161 cm) were most influential. Analysis of variable importance further underlined the dominance of climate for MAGT and highlighted the role of solar radiation for ALT. Most response shapes for MAGT ≤0 ∘C and ALT were non-linear and indicated thresholds for covariation. Most importantly, permafrost temperatures had a more complex relationship with air temperatures than non-frozen ground. Moreover, the observed warming effect of rainfall on MAGT≤0∘C reverted after reaching an optimum at ∼250 mm, and that of snowfall started to level off at ∼300–400 mm. It is suggested that the factors of large global variation (i.e. climate) suppressed the effects of local-scale factors (i.e. soil properties and vegetation) owing to the extensive study area and limited representation of soil organic matter. Our new insights into the factors affecting the ground thermal regime at a 1 km scale should improve future hemispheric-scale studies.

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