Edge effects on insect–plant food webs: assessing the influence of geographical orientation and microclimatic conditions

2020 ◽  
Vol 45 (4) ◽  
pp. 806-820
Author(s):  
María Laura Bernaschini ◽  
Graciela Valladares ◽  
Adriana Salvo
Keyword(s):  
Food Webs ◽  
Edge Effects ◽  
Plant Food ◽  
Microclimatic Conditions

Reverse latitudinal trends in species richness of pitcher-plant food webs

2003 ◽  
Vol 6 (9) ◽  
pp. 825-829 ◽  
Author(s):  
Hannah L. Buckley ◽  
Thomas E. Miller ◽  
Aaron M. Ellison ◽  
Nicholas J. Gotelli
Keyword(s):  
Species Richness ◽  
Food Webs ◽  
Plant Food ◽  
Pitcher Plant

Habitat Fragmentation Effects on Trophic Processes of Insect-Plant Food Webs

2006 ◽  
Vol 20 (1) ◽  
pp. 212-217 ◽  
Author(s):  
GRACIELA VALLADARES ◽  
ADRIANA SALVO ◽  
LUCIANO CAGNOLO
Keyword(s):  
Habitat Fragmentation ◽  
Food Webs ◽  
Plant Food

Complex edge effects on soil moisture and microclimate in central Amazonian forest

1995 ◽  
Vol 11 (2) ◽  
pp. 205-221 ◽  
Author(s):  
J. L. C. Camargo ◽  
V. Kapos
Keyword(s):  
Soil Moisture ◽  
Edge Effects ◽  
Vegetation Structure ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Forest Edge ◽  
Vertical Profiles ◽  
Control Soil ◽  
Neutron Probe ◽  
Microclimatic Conditions

ABSTRACTWe investigated the influence of a four-year-old forest edge near Manaus, Brazil, on soil moisture and vertical profiles of air vapour pressure deficit (VPD) within the forest. Soil moisture was measured (with a neutron probe) 0, 5, 10, 20, 40, 60, 80, 100, 150 and 200 m into the forest from the edge, in undisturbed control areas, and in the pasture. Control soil moisture was better explained by rainfall in the previous 2 or 10 days than by longer-term totals. Soil water potentials ≤ – 1.5 MPa occurred at some forest locations during the driest period. The variation in soil moisture with distance from the forest edge was complex, with higher values just inside the edge and depleted zones at the edge and 40–80 m inside it. At a given height, VPD (standardized relative to measurements in the open) was not related to distance from the edge, but VPD increased more with height near the edge than in control areas. The complexity of the edge's influence and the contrast with earlier data from the same edge can be explained by the changing vegetation structure near the edge. Regrowth ‘seals’ the edge with more leaves that transpire and deplete soil moisture, while protecting the understorey just inside the edge from desiccating conditions. A mosaic of gaps of differing ages develops behind the edge, increasing the variation in microclimatic conditions near the ground and consequently in evapotranspiration and soil moisture.

scholarly journals Analyzing the edge effects in a Brazilian seasonally dry tropical forest

2016 ◽  
Vol 76 (1) ◽  
pp. 169-175 ◽  
Author(s):  
D. M. Arruda ◽  
P. V. Eisenlohr
Keyword(s):  
Edge Effects ◽  
Tree Species ◽  
Forest Canopy ◽  
Canopy Cover ◽  
Dry Forest ◽  
Forest Edges ◽  
Dry Forests ◽  
Seasonally Dry ◽  
Dry Tropical Forests ◽  
Microclimatic Conditions

Abstract Due to the deciduous nature of dry forests (widely known as seasonally dry tropical forests) they are subject to microclimatic conditions not experienced in other forest formations. Close examinations of the theory of edge effects in dry forests are still rare and a number of questions arise in terms of this topic. In light of this situation we examined a fragment of the dry forest to respond to the following questions: (I) Are there differences in canopy cover along the edge-interior gradient during the dry season? (II) How does the microclimate (air temperature, soil temperature, and relative humidity) vary along that gradient? (III) How does the microclimate influence tree species richness, evenness and abundance along that gradient? (IV) Are certain tree species more dominant closer to the forest edges? Regressions were performed to address these questions. Their coefficients did not significantly vary from zero. Apparently, the uniform openness of the forest canopy caused a homogeneous internal microclimate, without significant differentiation in habitats that would allow modifications in biotic variables tested. We conclude that the processes of edge effect commonly seen in humid forests, not was shared with the dry forest assessed.

Insect–Plant Food Webs Could Provide New Clues for Pest Management

1999 ◽  
Vol 28 (4) ◽  
pp. 539-544 ◽  
Author(s):  
Graciela R. Valladares ◽  
Adriana Salvo
Keyword(s):  
Food Webs ◽  
Pest Management ◽  
Plant Food

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.

Vitamin A Value of Plant Food Provitamin A - Evaluated by the Stable Isotope Technologies

2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 25-29 ◽  
Author(s):  
Guangwen Tang
Keyword(s):  
Stable Isotope ◽  
Vitamin A ◽  
Provitamin A ◽  
Animal Origin ◽  
Plant Food ◽  
Plant Foods ◽  
A Value ◽  
Provitamin A Carotenoids ◽  
Β Carotene

Humans need vitamin A and obtain essential vitamin A by conversion of plant foods rich in provitamin A and/or absorption of preformed vitamin A from foods of animal origin. The determination of the vitamin A value of plant foods rich in provitamin A is important but has challenges. The aim of this paper is to review the progress over last 80 years following the discovery on the conversion of β-carotene to vitamin A and the various techniques including stable isotope technologies that have been developed to determine vitamin A values of plant provitamin A (mainly β-carotene). These include applications from using radioactive β-carotene and vitamin A, depletion-repletion with vitamin A and β-carotene, and measuring postprandial chylomicron fractions after feeding a β-carotene rich diet, to using stable isotopes as tracers to follow the absorption and conversion of plant food provitamin A carotenoids (mainly β-carotene) in humans. These approaches have greatly promoted our understanding of the absorption and conversion of β-carotene to vitamin A. Stable isotope labeled plant foods are useful for determining the overall bioavailability of provitamin A carotenoids from specific foods. Locally obtained plant foods can provide vitamin A and prevent deficiency of vitamin A, a remaining worldwide concern.

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