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Cohen Joel E - - 2009
Many studies have aimed to understand food webs by investigating components such as trophic links (one consumer taxon eats one resource taxon), tritrophic interactions (one consumer eats an intermediate taxon, which eats a resource), or longer chains of links. We show here that none of these components (links, tritrophic interactions, ...
Davis John M - - 2010
Increased nutrient mobilization by human activities represents one of the greatest threats to global ecosystems, but its effects on ecosystem productivity can differ depending on food web structure. When this structure facilitates efficient energy transfers to higher trophic levels, evidence from previous large-scale enrichments suggests that nutrients can stimulate the ...
Walsh Matthew R - - 2010
Early theories of life-history evolution predict that increased predation on young/small individuals selects for delayed maturation and decreased reproductive effort, but such theory only considers changes in mortality. Predators reduce prey abundance and increase food to survivors. Theory that incorporates such indirect effects yields different predictions. Trinidadian killifish, Rivulus hartii, ...
Hironaga Ryo - - 2010
Extinction affected food web structure in paleoecosystems. Recent theoretical studies that examined the effects of extinction intensity on food web structure on ecological time scales have considered extinction to involve episodic events, with pre-extinction food webs becoming established without dynamics. However, in terms of the paleontological time scale, food web ...
Kaspari Michael - - 2009
Litter invertebrates are notoriously patchy at small scales. Here we show that the abundance of 10 litter taxa also varies 100-fold at landscape and regional scales across 26 forest stands in Peru and Panama. We contrast three hypotheses that link gradients of abundance to ecosystem biogeochemistry. Of 14 factors considered ...
De Laender Frederik - - 2010
The majority of ecotoxicological enclosure experiments monitor species abundances at different chemical concentrations. Here, we present a new modelling approach that estimates changes in food web flows from such data and show that population- and food web level effects are revealed that are not apparent from abundance data alone. For ...
Stouffer Daniel B - - 2010
Understanding food-web persistence is an important long-term objective of ecology because of its relevance in maintaining biodiversity. To date, many dynamic studies of food-web behaviour--both empirical and theoretical--have focused on smaller sub-webs, called trophic modules, because these modules are more tractable experimentally and analytically than whole food webs. The question ...
B?naru Daniela - - 2010
The present study shows how marine commercial fish food webs dramatically changed in the north-western Black Sea on both pelagic and benthic environments. Fisheries landings, diversity and equitability strongly decreased between 1965-1970 and 2001-2005. Fishes adapted their feeding behaviour to the increasingly low species diversity of the Black Sea communities. ...
Hammill Edd - - 2010
A vast body of literature exists documenting the morphological, behavioural and life history changes that predators induce in prey. However, little attention has been paid to how these induced changes feed back and affect the predators' life history and morphology. Larvae of the phantom midge Chaoborus flavicans are intermediate predators ...
Yeakel Justin D - - 2009
Cooperation is the cornerstone of lion social behavior. In a notorious case, a coalition of two adult male lions from Tsavo, southern Kenya, cooperatively killed dozens of railway workers in 1898. The "man-eaters of Tsavo" have since become the subject of numerous popular accounts, including three Hollywood films. Yet the ...
Metzger Keith A - - 2009
Studies of the functional morphology of feeding have typically not included an analysis of the potential for the kinematics of the gape cycle to vary based on the material properties of the prey item being consumed. Variation in prey properties is expected not only to reveal variation in feeding function, ...
Faria L D B - - 2009
Food webs usually display an intricate mix of trophic interactions where multiple prey are common. In this context omnivory has been the subject of intensive analysis regarding food web stability and structure. In a three species omnivory setting it is shown that the modeling of prey preference by the top ...
Haynes Kyle J - - 2009
In many study systems, populations fluctuate synchronously across large regions. Several mechanisms have been advanced to explain this, but their importance in nature is often uncertain. Theoretical studies suggest that spatial synchrony initiated in one species through Moran effects may propagate among trophically linked species, but evidence for this in ...
Beninc?? Elisa - - 2009
Coupling of several predator-prey oscillations can generate intriguing patterns of synchronization and chaos. Theory predicts that prey species will fluctuate in phase if predator-prey cycles are coupled through generalist predators, whereas they will fluctuate in anti-phase if predator-prey cycles are coupled through competition between prey species. Here, we investigate predator-prey ...
Vucic-Pestic Olivera - - 2010
1. Functional responses quantify the per capita consumption rates of predators depending on prey density. The parameters of these nonlinear interaction strength models were recently used as successful proxies for predicting population dynamics, food-web topology and stability. 2. This study addressed systematic effects of predator and prey body masses on ...
Nakata Kensuke - - 2010
Focusing attention is a way for animals to search for and to obtain food efficiently. This study examines whether a sit-and-wait forager, the orb-web spider Cyclosa octotuberculata, focuses its attention on limited foraging areas. Video records of foraging activity revealed that the spiders detected prey trapped in the west and ...
Azanza Rhodora V - - 2010
For the first time the potential of Noctiluca scintillans, a non-toxic mixotrophic dinoflagellate, in bioconverting and/or excreting saxitoxin has been illustrated, thus contributing to the limited knowledge on the aspects of toxin pathways in the food chain/web and predator-prey preferences. Noctiluca growth rate increased with higher Pyrodinium concentration but the ...
Cagnolo Luciano - - 2009
Not all species are likely to be equally affected by habitat fragmentation; thus, we evaluated the effects of size of forest remnants on trophically linked communities of plants, leaf-mining insects, and their parasitoids. We explored the possibility of differential vulnerability to habitat area reduction in relation to species-specific and food-web ...
Ponton Dominic E - - 2010
Nickel (Ni) is a widespread contaminant present at toxic concentrations in aquatic systems in the vicinity of some mining and smelting operations. However, its accumulation by aquatic animals has been little studied and there are few biomonitors for this metal. Recently, larvae of the aquatic insect Chaoborus were shown to ...
Malzahn Arne M - - 2010
Nutritional imbalances between predator and prey are the rule rather than the exception at the lower end of food webs. We investigated the role of different grazers in the propagation of nutritionally imbalanced primary production by using the same primary producers in a three-trophic-level food chain and a four-trophic-level food ...
Carey Michael P - - 2010
Top predators can have different foraging modes that may alter their interactions and effects on food webs. Interactions between predators may be non-additive resulting from facilitation or interference, whereas their combined effects on a shared prey may result in emergent effects that are risk enhanced or risk reduced. To test ...
Barton Brandon T - - 2009
This experimental study tests new theory for multiple predator effects on communities by using warming to alter predator habitat use and hence direct and indirect interactions in a grassland food web containing two dominant spider predator species, a dominant grasshopper herbivore and grass and herb plants. Experimental warming further offers ...
Ford John K B - - 2010
Killer whales (Orcinus orca) are large predators that occupy the top trophic position in the world's oceans and as such may have important roles in marine ecosystem dynamics. Although the possible top-down effects of killer whale predation on populations of their prey have received much recent attention, little is known ...
Estók Péter - - 2010
Ecological pressure paired with opportunism can lead to surprising innovations in animal behaviour. Here, we report predation of great tits (Parus major) on hibernating pipistrelle bats (Pipistrellus pipistrellus) at a Hungarian cave. Over two winters, we directly observed 18 predation events. The tits specifically and systematically searched for and killed ...
Kohzu Ayato - - 2009
Overgrazing often lowers species richness and productivity of grassland communities. For Mongolian grassland ecosystems, a lack of detailed information about food-web structures makes it difficult to predict the effects of overgrazing on species diversity and community composition. We analysed the delta13C and delta15N signatures of herbaceous plants, arthropods (grouped by ...
Henry Anna E - - 2009
To identify food and beverage brand Web sites featuring designated children's areas, assess marketing techniques present on those industry Web sites, and determine nutritional quality of branded food items marketed to children. Systematic content analysis of food and beverage brand Web sites and nutrient analysis of food and beverages advertised ...
Barton Brandon T - - 2009
Climate change is expected to alter trophic interactions within food chains, but predicting the fate of particular species is difficult because the predictions hinge on knowing exactly how climate influences direct and indirect interactions. We used two complementary approaches to examine how climate change may alter trophic interactions within an ...
O'Connor Mary I - - 2009
[This corrects the article on p. e1000178 in vol. 7, PMID: 19707271.].
Siriwong W - - 2009
The presence of DDT and derivatives in the food web of freshwater ecosystems of Rangsit agricultural area, Pathum Thani Province, Thailand were investigated from June 2004 to May 2007. By using gas chromatography (GC) with micro electron capture detector (mu ECD), DDT and derivatives in water, sediment, and fifteen indicator ...
López Javier A - - 2009
The study of the feeding ecology of amphibians is an old issue in herpetology. Notwithstanding, the lack of food resources data in many studies of amphibians feeding has lead to partial understanding of frog feeding strategies. In this study we evaluate the trophic selectivity of a red spotted green frog ...
Reiss Julia - - 2009
Two decades of intensive research have provided compelling evidence for a link between biodiversity and ecosystem functioning (B-EF). Whereas early B-EF research concentrated on species richness and single processes, recent studies have investigated different measures of both biodiversity and ecosystem functioning, such as functional diversity and joint metrics of multiple ...
Montoya José M - - 2009
The prediction of the effects of disturbances in natural systems is limited by the general lack of knowledge on the strength of species interactions, i.e., the effect of one species on the population growth rate of another, and by the uncertainty of the effects that may be manifested via indirect ...
Sabat Pablo - - 2009
One of the most controversial hypotheses that associate basal metabolic rate (BMR) with food habits and habitat productivity is the food habit hypothesis (FHH). Here we examined the relationship between BMR, diet, and climate among populations of the omnivorous passerine, Zonotrichia capensis (Emberizidae). We used nitrogen stable isotopes to estimate ...
Lindegren Martin - - 2009
Worldwide a number of fish stocks have collapsed because of overfishing and climate-induced ecosystem changes. Developing ecosystem-based fisheries management (EBFM) to prevent these catastrophic events in the future requires ecological models incorporating both internal food-web dynamics and external drivers such as fishing and climate. Using a stochastic food-web model for ...
Levin Lisa A LA Integrative Oceanography Division, Scripps Institution of Oceanography, La Jolla, CA 92093-0218, USA. - - 2009
Continental margins, where land becomes ocean and plunges to the deep sea, provide valuable food and energy resources, and perform essential functions such as carbon burial and nutrient cycling. They exhibit remarkably high species and habitat diversity, but this is threatened by our increasing reliance on the resources that margins ...
Wolkovich Elizabeth Mary - - 2009
Plant invasions have tremendous potential to alter food webs by changing basal resources. Recent studies document how plant invasions may contribute to increased arthropod abundances in detritus-based food webs. An obvious mechanism for this phenomenon-a bottom-up effect resulting from elevated levels of detritus from the invasive plant litter-has not been ...
Gross Thilo - - 2009
Insights into what stabilizes natural food webs have always been limited by a fundamental dilemma: Studies either need to make unwarranted simplifying assumptions, which undermines their relevance, or only examine few replicates of small food webs, which hampers the robustness of findings. We used generalized modeling to study several billion ...
O'Gorman Eoin J - - 2009
The pattern of predator-prey interactions is thought to be a key determinant of ecosystem processes and stability. Complex ecological networks are characterized by distributions of interaction strengths that are highly skewed, with many weak and few strong interactors present. Theory suggests that this pattern promotes stability as weak interactors dampen ...
Brown G E - - 2009
The effects of food ration and social context, as well as possible interactions, on the antipredator behaviour of juvenile rainbow trout Onchorhynchus mykiss were investigated in a pair of laboratory studies. In experiment 1, pairs of dominant and subordinate O. mykiss were exposed to conspecific alarm cues when maintained under ...
Gaonkar Chetan A - - 2010
Zooplankton abundance, biomass, and composition from the ports of Mumbai, India, were studied by selecting 14 stations in and around the area during three different periods between 2001 and 2002 (Nov 01, Apr 02, and Oct 02). The results are compared with the records available since the 1940s. Copepod species ...
O'Connor Mary I - - 2009
Climate change disrupts ecological systems in many ways. Many documented responses depend on species' life histories, contributing to the view that climate change effects are important but difficult to characterize generally. However, systematic variation in metabolic effects of temperature across trophic levels suggests that warming may lead to predictable shifts ...
Tófoli C F CF Departamento de Ecologia, Universidade Estadual Paulista, Rio Claro, SP, Brazil, 13506-900. - - 2009
Food habits of jaguarundi (Puma yagouaroundi) (Geoffroy, 1803) (Carnivora, Felidae) were studied between November 2000 and November 2001, in a 24.9 km(2) area of secondary Atlantic Rainforest and eucalypt plantation, in the Serra de Paranapiacaba, São Paulo State, Brazil. Analyses of 26 fecal and regurgitate samples, obtained over a stretch ...
Fröbisch Jörg - - 2009
Vertebrates have repeatedly filled and partitioned the terrestrial ecosystem, and have been able to occupy new, previously unexplored habitats throughout their history on land. The arboreal ecospace is particularly important in vertebrate evolution because it provides new food resources and protection from large ground-dwelling predators. We investigated the skeletal anatomy ...
Mayntz David - - 2009
Predator foraging may be affected by previous prey capture, but it is unknown how nutrient balance affects foraging behaviour. Here, we use a trap-building predator to test whether nutrients from previous prey captures affect foraging behaviour. We fed orb-weaving spiders (Zygiella x-notata) prey flies of different nutrient composition and in ...
Stiner Mary C - - 2009
Zooarchaeological research at Qesem Cave, Israel demonstrates that large-game hunting was a regular practice by the late Lower Paleolithic period. The 400- to 200,000-year-old fallow deer assemblages from this cave provide early examples of prime-age-focused ungulate hunting, a human predator-prey relationship that has persisted into recent times. The meat diet ...
Slos Stefanie - - 2009
Despite the potential impact on prey fitness and predator-prey interactions, most studies of predation risk ignore physiological responses and their dependence upon food level and sex. Therefore, we reared male and female larvae of the damselfly Lestes viridis under predator stress (dragonfly larvae) at high and low food levels, and ...
Lazzaro Xavier - - 2009
1. The structure and dynamics of prey populations are shaped by the foraging behaviours of their predators. Yet, there is still little documentation on how distinct predator foraging types control biodiversity, food-web architecture and ecosystem functioning. 2. We experimentally compared the effects of model fish species of two major foraging ...
Previtali M Andrea - - 2009
Precipitation plays an important role in the dynamics of species found in arid and semiarid environments. However, population fluctuations generally are driven by a combination of multiple factors whose relative contribution may vary through time and among species. We monitored fluctuations of species in three trophic levels for >17 years ...
Ingram Travis - - 2009
The features that govern the stability and persistence of species interaction networks, such as food webs, remain elusive, but recent work suggests that the distribution and strength of trophic links play an important role. Potential omnivory-stability relationships have been investigated and debated extensively, but we still have a relatively poor ...
Estes J A - - 2009
Populations of sea otters, seals and sea lions have collapsed across much of southwest Alaska over the past several decades. The sea otter decline set off a trophic cascade in which the coastal marine ecosystem underwent a phase shift from kelp forests to deforested sea urchin barrens. This interaction in ...
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