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Svensson Carl J - - 2007
Saltmarsh vegetation, seston and microphytobenthos are all conspicuous components of most temperate estuaries and they potentially contribute to the estuarine food chain. Yet their relative contributions are unclear, as is the significance of saltmarsh losses through natural and human-induced impacts. This study aimed to quantitatively determine the contribution of various ...
Nfon Erick - - 2007
A steady state model is developed to describe the bioaccumulation of organic contaminants by 14 species in a Baltic food web including pelagic and benthic aquatic organisms. The model is used to study the bioaccumulation of five PCB congeners of different chlorination levels. The model predictions are evaluated against monitoring ...
Johnson Christopher N - - 2007
Top predators in terrestrial ecosystems may limit populations of smaller predators that could otherwise become over abundant and cause declines and extinctions of some prey. It is therefore possible that top predators indirectly protect many species of prey from excessive predation. This effect has been demonstrated in some small-scale studies, ...
Ferro A - - 2007
NetMatch is a Cytoscape plugin which allows searching biological networks for subcomponents matching a given query. Queries may be approximate in the sense that certain parts of the subgraph-query may be left unspecified. To make the query creation process easy, a drawing tool is provided. Cytoscape is a bioinformatics software ...
Kolesar, Sarah Elizabeth
Differences in predator and prey tolerances to low dissolved oxygen (DO) concentrations are important to planktonic food webs in seasonally hypoxic environments like Chesapeake Bay. Hypoxia alters field distributions, encounter rates, and predator-prey interactions between hypoxia-tolerant ctenophores, Mnemiopsis leidyi, and less tolerant ichthyoplankton and zooplankton prey. To examine the effect ...
Smith Walker O WO - - 2007
The continental shelf of the Ross Sea is one of the Antarctic's most intensively studied regions. We review the available data on the region's physical characteristics (currents and ice concentrations) and their spatial variations, as well as components of the neritic food web, including lower and middle levels (phytoplankton, zooplankton, ...
Murphy E J - - 2007
The Scotia Sea ecosystem is a major component of the circumpolar Southern Ocean system, where productivity and predator demand for prey are high. The eastward-flowing Antarctic Circumpolar Current (ACC) and waters from the Weddell-Scotia Confluence dominate the physics of the Scotia Sea, leading to a strong advective flow, intense eddy ...
Clarke Andrew - - 2007
The Antarctic Peninsula is experiencing one of the fastest rates of regional climate change on Earth, resulting in the collapse of ice shelves, the retreat of glaciers and the exposure of new terrestrial habitat. In the nearby oceanic system, winter sea ice in the Bellingshausen and Amundsen seas has decreased ...
Häder D-P - - 2007
Recent results continue to show the general consensus that ozone-related increases in UV-B radiation can negatively influence many aquatic species and aquatic ecosystems (e.g., lakes, rivers, marshes, oceans). Solar UV radiation penetrates to ecological significant depths in aquatic systems and can affect both marine and freshwater systems from major biomass ...
Camacho J - - 2007
We analyze the local structure of model and empirical food webs through the statistics of three-node subgraphs. We study analytically and numerically the number of appearances of each subgraph for a simple model of food web topology, the so-called generalized cascade model, and compare them with 17 empirical community food ...
Beckerman Andrew P - - 2007
Predator-generated variation in prey energy intake remains the dominant explanation of adaptive response to predation risk in prey life history, morphology and physiology across a wide range of taxa. This "behavioural hypothesis" suggest that chemical or visual signals of predation risk reduce prey energy intake leading to a life history ...
Kim, Gene W
Herein, I describe research that quantifies how native and non-native (henceforth exotic) benthic organisms influence community and ecosystem processes. As aquatic ecosystems are recovering from years of excessive inputs of nutrients and industrial pollution, the influence of benthic food webs on the overall ecosystem likely will increase. By conducting a ...
Bernreuther, Matthias
The general aim of this work was to investigate the feeding ecology of the main planktivorous fish species in the Baltic Sea, herring and sprat. Extensive diet analyses on herring and sprat in the Bornholm Basin from April 2002 to November 2003 revealed that diets of both dominant planktivores were ...
Dannheim, Jennifer
Trawling impact, fishing effects, trophic functioning, trophic structure, resistance, macrozoobenthos, North Sea, stable isotope ratios. - This thesis aims at achieving deeper insights into the ecological functioning of German Bight benthos, i.e. ecosystem trophic properties that might explain resistance of the system in the light of decades of frequent bottom ...
Byrnes Jarrett E - - 2007
The biodiversity of ecosystems worldwide is changing because of species loss due to human-caused extinctions and species gain through intentional and accidental introductions. Here we show that the combined effect of these two processes is altering the trophic structure of food webs in coastal marine systems. This is because most ...
Zahedi-Golpayegani Azadeh - - 2007
While searching for food, predators may use volatiles associated with their prey, but also with their competitors for prey. This was tested for the case of Zetzellia mali (Ewing) (Acari: Stigmaeidae), an important predator of the hawthorn spider mite, Amphitetranychus viennensis (Zacher) (Acari: Tetranychidae), in black-cherry orchards in Baraghan, Iran. ...
Layman Craig A - - 2007
Stable isotope ratios (typically of carbon and nitrogen) provide one representation of an organism's trophic niche and are widely used to examine aspects of food web structure. Yet stable isotopes have not been applied to quantitatively characterize community-wide aspects of trophic structure (i.e., at the level of an entire food ...
Schaerlaeken Vicky - - 2007
Most organisms feed on a variety of prey that may differ dramatically in their physical and behavioural characteristics (e.g. mobility, mass, texture, etc.). Thus the ability to modulate prey capture behaviour in accordance with the characteristics of the food appears crucial. In animals that use rapid tongue movements to capture ...
Logan J David - - 2007
We model the development of an individual insect, a grasshopper, through its nymphal period as a function of a trade-off between prey vigilance and nutrient intake in a changing environment. Both temperature and food quality may be variable. We scale up to the population level using natural mortality and a ...
Spiller David A - - 2007
Major abiotic disturbance can be an important factor influencing food-web dynamics, particularly in areas impacted by the recent increase in hurricane activity. We present a unique set of data on key food-web processes occurring on 10 small islands for three relatively calm years and then four subsequent years during which ...
Marczak Laurie B - - 2007
Studies of the effects of cross-habitat resource subsidies have been a feature of food web ecology over the past decade. To date, most studies have focused on demonstrating the magnitude of a subsidy or documenting its effect in the recipient habitat. Ecologists have yet to develop a satisfactory framework for ...
Verghese Abraham - - 2007
Foraging behaviour of three aphidophagous predators, viz., Cheilomenes sexmaculata (Fabricius), Scymnus sp. (Coleoptera: Coccinellidae) and Paragus serratus (Fabricius) (Diptera: Syrphidae) on prey Aphis punicae Passerini (Homoptera: Aphididae) was studied in the laboratory at Indian Institute of Horticultural Research, Bangalore (12 degrees 58' N; 77 degrees 35'E) during 2002-03 to understand ...
Iwami Tadashi - - 2007
Organisms often exhibit phenotypic plasticity in multiple traits in response to impending environmental change. Multiple traits phenotypic plasticity is complex syndrome brought on by causal relations in ecological and physiological context. Larvae of the salamander Hynobius retardatus exhibit inducible phenotypic plasticity of two traits, when at risk of predation by ...
Popa-Lisseanu Ana G - - 2007
Along food chains, i.e., at different trophic levels, the most abundant taxa often represent exceptional food reservoirs, and are hence the main target of consumers and predators. The capacity of an individual consumer to opportunistically switch towards an abundant food source, for instance, a prey that suddenly becomes available in ...
Stevens, Maarten
Animals are influenced by both biotic and abiotic factors when selecting a habitat. The final decision of an organism to select a habitat generally depends on the fitness increase that can be expected. Within a selected habitat, interactions with conspecifics and other species also affect its quality. This thesis describes ...
Miyashita Tadashi - - 2006
The Araneoidea comprises a diverse group of web-building spiders, and part of this diversity is believed attributable to habitat expansion to bright environments. We clarified the fitness-related advantages of living in such environments by examining prey availability and the growth rates of 10 species in three families inhabiting grassland (bright) ...
Sibert John - - 2006
Fisheries have removed at least 50 million tons of tuna and other top-level predators from the Pacific Ocean pelagic ecosystem since 1950, leading to concerns about a catastrophic reduction in population biomass and the collapse of oceanic food chains. We analyzed all available data from Pacific tuna fisheries for 1950-2004 ...
Bagdassarian Carey K - - 2007
Although the food web is one of the most fundamental and oldest concepts in ecology, elucidating the strategies and structures by which natural communities of species persist remains a challenge to empirical and theoretical ecologists. We show that simple regulatory feedbacks between autotrophs and their environment when embedded within complex ...
dos Santos Lucélia M - - 2007
Previous studies from our laboratory have shown that insect hunting is associated with a distinct Fos up-regulation in the ventrolateral caudoputamen at intermediate rostro-caudal levels. It is largely known that ventrolateral striatum participates in the control of orofacial movements and forepaw usage accompanying feeding behavior, but there has been no ...
McIntyre Jenifer K - - 2007
Understanding the mechanisms of bioaccumulation in food webs is critical to predicting which food webs are at risk for higher rates of bioaccumulation that endanger the health of upper-trophic predators, including humans. Mercury and organochlorines were measured concurrently with stable isotopes of nitrogen and carbon in key fishes and invertebrates ...
Arim Matías - - 2007
The effects of energy on food web structure have been debated for at least 80 years. Nevertheless, the empirical evidence is meager, especially from terrestrial ecosystems. We analyzed long-term temporal variation in food chain length in a semiarid continental ecosystem, where productivity shows large interannual variations. Incidence of nonherbivorous prey ...
Cloern James E - - 2007
The import of resources (food, nutrients) sustains biological production and food webs in resource-limited habitats. Resource export from donor habitats subsidizes production in recipient habitats, but the ecosystem-scale consequences of resource translocation are generally unknown. Here, I use a nutrient-phytoplankton-zooplankton model to show how dispersive connectivity between a shallow autotrophic ...
Stouffer Daniel B - - 2006
Intervality of a food web is related to the number of trophic dimensions characterizing the niches in a community. We introduce here a mathematically robust measure for food web intervality. It has previously been noted that empirical food webs are not strictly interval; however, upon comparison to suitable null hypotheses, ...
Deng Bo - - 2006
The intraspecific interference of a top-predator is incorporated into a classical mathematical model for three-trophic food chains. All chaos types known to the classical model are shown to exist for this comprehensive model. It is further demonstrated that if the top-predator reproduces at high efficiency, then all chaotic dynamics will ...
Vargas Cristian A - - 2006
Recruitment success at the early life stages is a critical process for zooplankton demography. Copepods often dominate the zooplankton in marine coastal zones and are prey of the majority of fish larvae. Hypotheses interpreting variations of copepod recruitment are based on the concepts of "naupliar predation," "nutritional deficiency," and "toxic ...
Trussell Geoffrey C - - 2006
Food chain length is an important property of ecosystems, but the mechanisms maintaining it remain elusive. Classical views suggest that energetic inefficiencies (the "energy-flow hypothesis") limit food chain length, but others have argued that better explanations reside in more complex scenarios that consider the stability of food webs or the ...
Wood Matthew J - - 2007
Food webs are a fundamental concept in ecology in which parasites have been virtually ignored. In a recent article, Lafferty et al. address this imbalance, finding that the inclusion of parasites in food webs could be of greater importance to ecosystem stability than was previously thought. Furthermore, the bottom of ...
Sandberg J - - 2007
In this study it was evaluated whether the ECOPATH with ECOSIM software could be used as a platform to facilitate the construction of models and study of transport and accumulation of radionuclides in aquatic food webs. The evaluation was based upon a food web model of carbon (C) and carbon-14 ...
Ngai Jacqueline T - - 2006
Conventional ecological theory predicts that predators affect nutrient cycling by decreasing the abundance or activity of prey. By using a predator-detritivore-detritus food chain in bromeliads, we show that predators can increase nutrient cycling by a previously undescribed, but broadly applicable, mechanism: reducing nutrient export by prey emigration. Contrary to expectations, ...
Sanders Dirk - - 2007
In most terrestrial ecosystems ants (Formicidae) as eusocial insects and spiders (Araneida) as solitary trappers and hunters are key predators. To study the role of predation by these generalist predators in a dry grassland, we manipulated densities of ants and spiders (natural and low density) in a two-factorial field experiment ...
Wagner Annekatrin - - 2007
Temperature-driven changes in interactions between populations are crucial to the estimation of the impact of global warming on aquatic food webs. We analysed inter-annual variability in two data sets from Bautzen reservoir, Germany. In a long-term data set (1981-1999) we examined the pelagic phenology of Daphnia galeata, a keystone species, ...
Worm Boris - - 2006
Human-dominated marine ecosystems are experiencing accelerating loss of populations and species, with largely unknown consequences. We analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales. Overall, rates of resource collapse increased and recovery potential, ...
Brose Ulrich - - 2006
Classic local stability theory predicts that complex ecological networks are unstable and are unlikely to persist despite empiricists' abundant documentation of such complexity in nature. This contradiction has puzzled biologists for decades. While some have explored how stability may be achieved in small modules of a few interacting species, rigorous ...
Trussell Geoffrey C - - 2006
Classical views of trophic cascades emphasize the primacy of consumptive predator effects on prey populations to the transmission of indirect effects [density-mediated indirect interactions (DMIIs)]. However, trophic cascades can also emerge without changes in the density of interacting species because of non-consumptive predator effects on prey traits such as foraging ...
Wrona Frederick J - - 2006
Changes in climate and ultraviolet radiation levels in the Arctic will have far-reaching impacts, affecting aquatic species at various trophic levels, the physical and chemical environment that makes up their habitat, and the processes that act on and within freshwater ecosystems. Interactions of climatic variables, such as temperature and precipitation, ...
Frederiksen Morten - - 2006
1. Abundant mid-trophic pelagic fish often play a central role in marine ecosystems, both as links between zooplankton and top predators and as important fishery targets. In the North Sea, the lesser sandeel occupies this position, being the main prey of many bird, mammal and fish predators and the target ...
Kuhn Carey E - - 2006
For many marine predators knowledge of foraging behavior is limited to inferences based on changes in diving or movement patterns at sea. This results in an incomplete and potentially inaccurate view of the foraging ecology of a species. This study examined the use of stomach temperature telemetry to identify and ...
Gebühr C - - 2006
The phytotelmata of the North American pitcher plant Sarracenia purpurea are colonised by a great variety of aquatic organisms and, thus, provide an ideal model to study trophic interactions in small freshwater ecosystems. Although algae are discussed as a potential food source for predators, little is known about the structure ...
Boonstra Rudy - - 2006
1. Across the vast boreal forests of North America, no population cycles in Clethrionomys species occur. In Eurasia, by contrast, some Clethrionomys populations of the same species undergo regular 3-5-year cycles. We examined the effects of nutrients, food, competitors, predators and climate on population limitation in the northern red-backed vole ...
Haven Jackie - - 2006
To assess consumer response to potential graphics, slogans, and messages for the consumer interface of the MyPyramid Food Guidance System. Qualitative research conducted in two phases, composed of focus groups and Web-TV testing. Professional market research facilities in Baltimore, MD, and Chicago, IL, and Web-TV. Phase 1,77 adults in 10 ...
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