نتایج جستجو برای: trophic levels

تعداد نتایج: 930571  

Journal: :Ecological applications : a publication of the Ecological Society of America 2018
Tessa N Hempson Nicholas A J Graham M Aaron MacNeil Andrew S Hoey Shaun K Wilson

Regime shifts between alternative stable ecosystem states are becoming commonplace due to the combined effects of local stressors and global climate change. Alternative states are characterized as substantially different in form and function from pre-disturbance states, disrupting the delivery of ecosystem services and functions. On coral reefs, regime shifts are typically characterized by a ch...

Journal: :The American naturalist 2015
John P DeLong Benjamin Gilbert Jonathan B Shurin Van M Savage Brandon T Barton Christopher F Clements Anthony I Dell Hamish S Greig Christopher D G Harley Pavel Kratina Kevin S McCann Tyler D Tunney David A Vasseur Mary I O'Connor

Trophic cascades are indirect positive effects of predators on resources via control of intermediate consumers. Larger-bodied predators appear to induce stronger trophic cascades (a greater rebound of resource density toward carrying capacity), but how this happens is unknown because we lack a clear depiction of how the strength of trophic cascades is determined. Using consumer resource models,...

Journal: :Proceedings. Biological sciences 2005
Yves Cherel Keith A Hobson

Cephalopods play a key role in the marine environment but knowledge of their feeding habits is limited by lack of data. Here, we have developed a new tool to investigate their feeding ecology by combining the use of their predators as biological samplers together with measurements of the stable isotopic signature of their beaks. Cephalopod beaks are chitinous hard structures that resist digesti...

2008
John F Bruno Bradley J Cardinale

www.frontiersinecology.org W know that predators play a vital role in maintaining the structure and stability of communities and that their removal can have a variety of cascading, indirect effects (Terborgh et al. 2001; Duffy 2003; Figure 1). But how important is predator richness? Are the numbers of predator genotypes, species, and functional groups ecologically important properties of predat...

2012
Catarina Magalhães Mark I. Stevens S. Craig Cary Becky A. Ball Bryan C. Storey Diana H. Wall Roman Türk Ulrike Ruprecht

Multitrophic communities that maintain the functionality of the extreme Antarctic terrestrial ecosystems, while the simplest of any natural community, are still challenging our knowledge about the limits to life on earth. In this study, we describe and interpret the linkage between the diversity of different trophic level communities to the geological morphology and soil geochemistry in the rem...

Journal: :The American naturalist 2001
A Persson L A Hansson C Brönmark P Lundberg L B Pettersson L Greenberg P A Nilsson P Nyström P Romare L Tranvik

Simple models, based on Lotka-Volterra types of interactions between predator and prey, predict that enrichment will have a destabilizing effect on populations and that equilibrium population densities will change at the top trophic level and every second level below. We experimentally tested these predictions in three aquatic food web configurations subjected to either high or low nutrient add...

2006
Stacy M. Philpott Jorge Maldonado John Vandermeer Ivette Perfecto

Trophic cascades exist in numerous terrestrial systems, including many systems with ants as the top predator. Many studies show how behavioral modifications of herbivores are especially important in mediating species interactions and trophic cascades. Although most studies of trophic cascades focus on predator-herbivore-plant links, the trophic cascades concept could be applied to almost any le...

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