نتایج جستجو برای: food web

تعداد نتایج: 481898  

2003
J. J. Vallino

Our inability to accurately model marine food webs severely limits the prognostic capabilities of current generationmarine biogeochemistrymodels. To address this problem we examine the use of data assimilation and mesocosm experiments to facilitate the development of food web models. The components of the data assimilation demonstrated include the constructionof measurement models, the adjoint ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Robert J Naiman J Richard Alldredge David A Beauchamp Peter A Bisson James Congleton Charles J Henny Nancy Huntly Roland Lamberson Colin Levings Erik N Merrill William G Pearcy Bruce E Rieman Gregory T Ruggerone Dennis Scarnecchia Peter E Smouse Chris C Wood

Well-functioning food webs are fundamental for sustaining rivers as ecosystems and maintaining associated aquatic and terrestrial communities. The current emphasis on restoring habitat structure--without explicitly considering food webs--has been less successful than hoped in terms of enhancing the status of targeted species and often overlooks important constraints on ecologically effective re...

2003
RICHARD J. WILLIAMS

While trophic levels have found broad application throughout ecology, they are also in much contention on analytical and empirical grounds. Here, we use a new generation of data and theory to examine long-standing questions about trophic-level limits and degrees of omnivory. The data include food webs of the Chesapeake Bay, USA, the island of St. Martin, a UK grassland, and a Florida seagrass c...

2011
Benjamin Baiser Roxanne S. Ardeshiri Aaron M. Ellison

Ecological communities show great variation in species richness, composition and food web structure across similar and diverse ecosystems. Knowledge of how this biodiversity relates to ecosystem functioning is important for understanding the maintenance of diversity and the potential effects of species losses and gains on ecosystems. While research often focuses on how variation in species rich...

Journal: :Conservation biology : the journal of the Society for Conservation Biology 2015
Sylvaine Giakoumi Benjamin S Halpern Loïc N Michel Sylvie Gobert Maria Sini Charles-François Boudouresque Maria-Cristina Gambi Stelios Katsanevakis Pierre Lejeune Monica Montefalcone Gerard Pergent Christine Pergent-Martini Pablo Sanchez-Jerez Branko Velimirov Salvatrice Vizzini Arnaud Abadie Marta Coll Paolo Guidetti Fiorenza Micheli Hugh P Possingham

Effective ecosystem-based management requires understanding ecosystem responses to multiple human threats, rather than focusing on single threats. To understand ecosystem responses to anthropogenic threats holistically, it is necessary to know how threats affect different components within ecosystems and ultimately alter ecosystem functioning. We used a case study of a Mediterranean seagrass (P...

Journal: :Philosophical Transactions of the Royal Society B: Biological Sciences 2009
Kevin D. Lafferty Armand M. Kuris

A robust food web is one in which few secondary extinctions occur after removing species. We investigated how parasites affected the robustness of the Carpinteria Salt Marsh food web by conducting random species removals and a hypothetical, but plausible, species invasion. Parasites were much more likely than free-living species to suffer secondary extinctions following the removal of a free-li...

Journal: :The Journal of animal ecology 2012
Jes Hines Mark O Gessner

1. Primary production and decomposition, two fundamental processes determining the functioning of ecosystems, may be sensitive to changes in biodiversity and food web interactions. 2. The impacts of food web interactions on ecosystem functioning are generally quantified by experimentally decoupling these linked processes and examining either primary production-based (green) or decomposition-bas...

Journal: :Science 1997
Brett Goldman

Models predict that food-web structure is regulated by both consumers and resources, and the strength of this control is dependent on trophic position and food-web length. To test these hypotheses, a meta-analysis was conducted of 11 fish (consumer)-by-nutrient (resource) factorial plankton community experiments. As predicted, zooplankton biomass was under strong consumer control but was weakly...

Journal: :Ecology letters 2007
David A Vasseur Jeremy W Fox

Natural food webs are species-rich, but classical theory suggests that they should be unstable and extinction-prone. Asynchronous fluctuations in the densities of competing consumers can stabilize food web dynamics in constant environments. However, environmental fluctuations often synchronize dynamics in nature. Using the same 'diamond-shape' food web model first used to demonstrate the stabil...

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