نتایج جستجو برای: aspen dynamic
تعداد نتایج: 408689 فیلتر نتایج به سال:
—We addressed the following question: Do conifers within aspen stands (conifer invasion) increase bird species diversity in western landscapes? We tested the hypotheses that bird species diversity, measured as species richness or with the Shannon-Weiner diversity index, responds to aspen-conifer ratios (from 0% to 100% conifer) in a quadratic manner with a maximum occurring at an intermediate r...
We examined current and possible future aspen stand dynamics and cavity-nesting bird abundances for Yellowstone’s northern ungulate winter range. Our measurements suggest aspen stands located within Yellowstone National Park (YNP) are in a different condition than those located in the Gallatin National Forest (GNF), immediately outside the park. Stands inside YNP were composed of more snags and...
Atmospheric chemical composition affects foliar chemical composition, which in turn influences the dynamics of both herbivory and decomposition in ecosystems. We assessed the independent and interactive effects of CO2 and O3 fumigation on foliar chemistry of quaking aspen (Populus tremuloides) and paper birch (Betula papyrifera) at a Free-Air CO2 Enrichment (FACE) facility in northern Wisconsin...
Rising atmospheric carbon dioxide (CO2) concentration ([CO2]) could alter terrestrial carbon (C) cycling by affecting plant growth, litter chemistry and decomposition. How the concurrent increase in tropospheric ozone (O3) concentration ([O3]) will interact with rising atmospheric [CO2] to affect C cycling is unknown. A major component of carbon cycling in forests is fine root production, morta...
BACKGROUND AND AIMS A wide variety of plants produce extrafloral nectaries (EFNs) that are visited by predatory arthropods. But very few studies have investigated the relationship between plant genetic variation and EFNs. The presence of foliar EFNs is highly variable among different aspen (Populus tremuloides) genotypes and the EFNs are visited by parasitic wasps and predatory flies. The aim h...
Litter quality is often considered the main driver of rates of decomposition. Litter decomposes faster in its home environment than in any other environment, which is called the home-field advantage (HFA). However, evidence for this phenomenon has not been universal. In addition, litter mixtures of different species can induce a non-additive effect (NAE) on decomposition processes. However, the...
Globally documented widespread drought-induced forest mortality has important ramifications for plant community structure, ecosystem function, and the ecosystem services provided by forests. Yet the characteristics of drought seasonality, severity, and duration that trigger mortality events have received little attention despite evidence of changing precipitation regimes, shifting snow melt tim...
Ci.—Aspen stands and riparian areiis are important to breeding birds in ihe southwestern U.S. because they provide tesources such as food atid shelter. We investigated how this importance varies throughoul the year for bolh resident and migratory birds. We sampled hitds in 96 sites, half in small isolated aspen stands and half in the ponderosa pine forest in northern Ariirona thiring tlie sumiu...
During transportation, there will be vaporization of LNG producing boil-off gas (BOG) and its re-liquefaction is required considering that large volume of BOG to be vented out. A cryogenic refrigeration cycle is utilized in order to re-liquefy the BOG and returns it to the cargo tank. Kapitza and claude are the usually used LNG re-liquefaction cycles. The developments in the processes adopted f...
Behaviorally mediated trophic cascades (BMTCs) occur when the fear of predation among herbivores enhances plant productivity. Based primarily on systems involving small-bodied predators, BMTCs have been proposed as both strong and ubiquitous in natural ecosystems. Recently, however, synthetic work has suggested that the existence of BMTCs may be mediated by predator hunting mode, whereby passiv...
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