نتایج جستجو برای: trophic level
تعداد نتایج: 1093170 فیلتر نتایج به سال:
Mean Trophic Rank (MTR), a new British biological macrophyte-based method for assessing trophic status of rivers was applied in Poland in 2000-2001. The occurrence and abundance of 86 aquatic plant species was recorded at 48 sites on 19 rivers in the lowland part of Poland. Forty-six of these species are MTR scoring taxa used in the British system, but another 40 species were recorded of which ...
The traditional trophic cascades model is based on consumer resource interactions at each link in a food chain. However, trophic-level interactions, such as mesocarnivore release resulting from intraguild predation, may also be important mediators of cascades. From September 2001 to August 2004, we used spatial and seasonal heterogeneity in wolf distribution and abundance in the southern Greate...
Predators have large effects on ecosystem properties by changing plant diversity, not plant biomass.
Cascading effects of predators on total plant trophic-level biomass tend to be weaker in terrestrial than in aquatic systems. Accordingly, it is hypothesized that top predator effects on terrestrial plant diversity and on ecosystem function should likewise be weak or unimportant. This report presents a test of this hypothesis using data from a long-term field experiment. The five-year experimen...
Organochlorine contaminants (OCs) were determined in liver and fat of seven species of seabirds (Alle alle, Uria lomvia, Cepphus grylle, Rissa tridactyla, Pagophila eburnea, Larus hyperboreus, and Fulmaris glacialis) collected in May/June 1998 from the Northwater Polynya in northern Baffin Bay. OC concentrations ranged over an order of magnitude between seabird species and OC groups, with PCBs ...
Article history: Received 5 April 2016 Received in revised form 4 September 2016 Accepted 14 October 2016 Available online 17 October 2016 While the effects of climate change on top predators are well documented, the role of predation on ecosystem level carbon production is poorly developed, despite it being a logical consequence of trophic dynamics. Trophic cascade effects have shown predator ...
A central goal of ecology is to understand the mechanisms behind variation in the abundance of species. Food web theory predicts higher biomass for animals at lower trophic levels. However, some high trophic level species may reach great abundance via highly efficient foraging behaviors. We evaluated ecological and behavioral traits of the giant tropical ant Dinoponera australis related to thes...
Species with a large adult-offspring size ratio and a preferred predator-prey mass ratio undergo ontogenetic trophic niche shift(s) throughout life. Trophic interactions between such species vary throughout life, resulting in different species-level interaction motifs depending on the maximum adult sizes and population size distributions. We explore the assembly and potential for coexistence of...
Food webs, networks of feeding relationships in an ecosystem, provide fundamental insights into mechanisms that determine ecosystem stability and persistence. A standard approach in food-web analysis, and network analysis in general, has been to identify compartments, or modules, defined by many links within compartments and few links between them. This approach can identify large habitat bound...
Ocean warming can modify the ecophysiology and distribution of marine organisms, and relationships between species, with nonlinear interactions between ecosystem components potentially resulting in trophic amplification. Trophic amplification (or attenuation) describe the propagation of a hydroclimatic signal up the food web, causing magnification (or depression) of biomass values along one or ...
Lee A. Dyer* and Deborah Letourneau Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA 70118, USA Department of Environmental Studies, University of California, Santa Cruz, CA 95064, USA *Correspondence: E-mail: [email protected] Abstract Apex predators and plant resources are both critical for maintaining diversity in biotic communities, but the indirect ( cascad...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید