Seismic line edge effects on plants, lichens and their environmental conditions in boreal peatlands of northwest Alberta (Canada)

2021 ◽  
Author(s):  
Anna Dabros ◽  
Kellina L. Higgins ◽  
Jaime Pinzon
Keyword(s):  
Edge Effects ◽  
Environmental Conditions ◽  
Seismic Line ◽  
Boreal Peatlands

scholarly journals Effects of environmental conditions associated to the cardinal orientation on the reproductive phenology of the cerrado savanna tree Xylopia aromatica (Annonaceae)

2011 ◽  
Vol 83 (3) ◽  
pp. 1007-1020 ◽  
Author(s):  
Maria Gabriela G. Camargo ◽  
Regina M. Souza ◽  
Paula Reys ◽  
Leonor P.C. Morellato
Keyword(s):  
Edge Effects ◽  
Environmental Conditions ◽  
Fruit Production ◽  
Sensu Stricto ◽  
Southeastern Brazil ◽  
Reproductive Phenology ◽  
Canopy Openness ◽  
Cerrado Savanna ◽  
Cardinal Direction ◽  
Floral Visitation

The Brazilian cerrado has undergone an intense process of fragmentation, which leads to an increase in the number of remnants exposed to edge effects and associated changes on environmental conditions that may affect the phenology of plants. This study aimed to verify whether the reproductive phenology of Xylopia aromatica (Lam.) Mart. (Annonaceae) differs under different light conditions in a cerrado sensu stricto (a woody savanna) of southeastern Brazil. We compared the reproductive phenology of X. aromatica trees distributed on east and south cardinal faces of the cerrado during monthly observations, from January 2005 to December 2008. The east face had a higher light incidence, higher temperatures and canopy openness in relation to south face. X. aromatica showed seasonal reproduction at both faces of the cerrado, but the percentage of individuals, the synchrony and duration of phenophases were higher at the east face. The study demonstrated the influence of the environmental conditions associated to the cardinal orientation of the cerrado faces on the phenological pattern of X. aromatica. Similar responses may be observed for other species, ultimately affecting patterns of floral visitation and fruit production, which reinforces the importance of considering the cardinal direction in studies of edge effects and fragmentation.

Road-associated edge effects in Amazonia change termite community composition by modifying environmental conditions

2013 ◽  
Vol 21 (5) ◽  
pp. 279-285 ◽  
Author(s):  
Cristian de Sales Dambros ◽  
Valéria Natália Vasconcelos da Silva ◽  
Renato Azevedo ◽  
José Wellington de Morais
Keyword(s):  
Community Composition ◽  
Edge Effects ◽  
Environmental Conditions

scholarly journals Seismic Lines in Treed Boreal Peatlands as Analogs for Wildfire Fuel Modification Treatments

Fire ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 21
Author(s):  
Patrick Jeffrey Deane ◽  
Sophie Louise Wilkinson ◽  
Paul Adrian Moore ◽  
James Michael Waddington
Keyword(s):  
Seismic Waves ◽  
Fire Spread ◽  
Fuel Load ◽  
Natural Ecosystems ◽  
Seismic Line ◽  
Wildfire Management ◽  
Sphagnum Mosses ◽  
Boreal Peatlands ◽  
In Fire ◽  
Seismic Lines

Across the Boreal, there is an expansive wildland–society interface (WSI), where communities, infrastructure, and industry border natural ecosystems, exposing them to the impacts of natural disturbances, such as wildfire. Treed peatlands have previously received little attention with regard to wildfire management; however, their role in fire spread, and the contribution of peat smouldering to dangerous air pollution, have recently been highlighted. To help develop effective wildfire management techniques in treed peatlands, we use seismic line disturbance as an analog for peatland fuel modification treatments. To delineate below-ground hydrocarbon resources using seismic waves, seismic lines are created by removing above-ground (canopy) fuels using heavy machinery, forming linear disturbances through some treed peatlands. We found significant differences in moisture content and peat bulk density with depth between seismic line and undisturbed plots, where smouldering combustion potential was lower in seismic lines. Sphagnum mosses dominated seismic lines and canopy fuel load was reduced for up to 55 years compared to undisturbed peatlands. Sphagnum mosses had significantly lower smouldering potential than feather mosses (that dominate mature, undisturbed peatlands) in a laboratory drying experiment, suggesting that fuel modification treatments following a strategy based on seismic line analogs would be effective at reducing smouldering potential at the WSI, especially under increasing fire weather.

scholarly journals Identifying Conifer Tree vs. Deciduous Shrub and Tree Regeneration Trajectories in a Space-for-Time Boreal Peatland Fire Chronosequence Using Multispectral Lidar

Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 112
Author(s):  
Humaira Enayetullah ◽  
Laura Chasmer ◽  
Christopher Hopkinson ◽  
Dan Thompson ◽  
Danielle Cobbaert
Keyword(s):  
Environmental Conditions ◽  
Tree Regeneration ◽  
Boreal Peatlands ◽  
Composition And Structure ◽  
Conifer Tree ◽  
Disturbance Vegetation ◽  
Northern Peatlands ◽  
Structural Metrics ◽  
Conifer Trees ◽  
Deciduous Shrub

Wildland fires and anthropogenic disturbances can cause changes in vegetation species composition and structure in boreal peatlands. These could potentially alter regeneration trajectories following severe fire or through cumulative impacts of climate-mediated drying, fire, and/or anthropogenic disturbance. We used lidar-derived point cloud metrics, and site-specific locational attributes to assess trajectories of post-disturbance vegetation regeneration in boreal peatlands south of Fort McMurray, Alberta, Canada using a space-for-time-chronosequence. The objectives were to (a) develop methods to identify conifer trees vs. deciduous shrubs and trees using multi-spectral lidar data, (b) quantify the proportional coverage of shrubs and trees to determine environmental conditions driving shrub regeneration, and (c) determine the spatial variations in shrub and tree heights as an indicator of cumulative growth since the fire. The results show that the use of lidar-derived structural metrics predicted areas of deciduous shrub establishment (92% accuracy) and classification of deciduous and conifer trees (71% accuracy). Burned bogs and fens were more prone to shrub regeneration up to and including 38 years after the fire. The transition from deciduous to conifer trees occurred approximately 30 years post-fire. These results improve the understanding of environmental conditions that are sensitive to disturbance and impacts of disturbance on northern peatlands within a changing climate.

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

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