نتایج جستجو برای: trophic indices

تعداد نتایج: 97826  

2013
Laura McKinnon Erica Nol Cédric Juillet

A climate-induced phenological mismatch between the timing of reproduction and the timing of food resource peaks is one of the key hypothesized effects of climate change on wildlife. Though supported as a mechanism of population decline in birds, few studies have investigated whether the same temperature increases that drive this mismatch have the potential to decrease energetic costs of growth...

2016
Ning Hu Hui Li Zheng Tang Zhongfang Li Jing Tian Yilai Lou Jianwei Li Guichun Li Xiaomin Hu

We examined community diversity, structure and carbon footprint of nematode food web along a chronosequence of T. Sinensis reforestation on degraded Karst. In general, after the reforestation: a serious of diversity parameters and community indices (Shannon-Weinier index (H'), structure index (SI), etc.) were elevated; biomass ratio of fungivores to bacterivores (FFC/BFC), and fungi to bacteria...

2015
German A. Soler Graham J. Edgar Russell J. Thomson Stuart Kininmonth Stuart J. Campbell Terence P. Dawson Neville S. Barrett Anthony T. F. Bernard David E. Galván Trevor J. Willis Timothy J. Alexander Rick D. Stuart-Smith Dennis M. Higgs

Marine Protected Areas (MPAs) offer a unique opportunity to test the assumption that fishing pressure affects some trophic groups more than others. Removal of larger predators through fishing is often suggested to have positive flow-on effects for some lower trophic groups, in which case protection from fishing should result in suppression of lower trophic groups as predator populations recover...

2016
Sean M. Naman Correigh M. Greene Casimir A. Rice Joshua Chamberlin Letitia Conway‐Cranos Jeffery R. Cordell Jason E. Hall Linda D. Rhodes

Identifying causes of structural ecosystem shifts often requires understanding trophic structure, an important determinant of energy flow in ecological communities. In coastal pelagic ecosystems worldwide, increasing jellyfish (Cnidaria and Ctenophora) at the expense of small fish has been linked to anthropogenic alteration of basal trophic pathways. However, this hypothesis remains untested in...

2004
Owen L. Petchey Amy L. Downing Gary G. Mittelbach Lennart Persson Christopher F. Steiner Philip H. Warren Guy Woodward

Experiments and theory in single trophic level systems dominate biodiversity and ecosystem functioning research and recent debates. All natural ecosystems contain communities with multiple trophic levels, however, and this can have important effects on ecosystem structure and functioning. Furthermore, many experiments compare assembled communities, rather than examining loss of species directly...

2009
Francesc Maynou

Recent studies have shown that the population dynamics of deep-sea organisms are affected by coupling between surface oceanic processes and energy, or trophic resources, reaching the sea floor. I analysed the correlation between the landings of a deep-sea shrimp (Aristeus antennatus) in Catalonia (NW Mediterranean) and the climatic indices of the annual North Atlantic Oscillation (NAO) and wint...

Journal: :Marine pollution bulletin 2010
Mariéva Denoyelle Frans J Jorissen Daniel Martin François Galgani Jacques Miné

We compare foraminifera and macrofauna as bio-indicators of oil-based drill mud disposal site off Congo. The most polluted sites are characterized by poor faunas, dominated by some very tolerant taxa. Slightly further from the disposal site, there is an area with strongly increased densities, heavily dominated by opportunistic taxa. Still further, macrofauna appears to be similar to that at the...

2004

The ecological impacts of anthropogenic activities on aquatic environments have led to the development of new methods of environmental monitoring (Cohen et al 1993, Kelly and Whitton 1995). Benthic algae represent a ubiquitous group of photosynthetic organisms that play a pivotal role in stream food webs but may also be used for observing long-term trends in community changes that can occur bec...

Journal: :Advances in entomology 2022

Crop pests are a permanent threat to horticultural production. Several control methods recommended for their control, including biological control. This method based on the use of natural enemies is not well established. The objective this study was assess diversity and abundance crop pests. A survey crops associated with carried out 144 fields in southern Senegal measure various pests, determi...

Journal: :Proceedings. Biological sciences 2010
K H Andersen M Pedersen

The largest perturbation on upper trophic levels of many marine ecosystems stems from fishing. The reaction of the ecosystem goes beyond the trophic levels directly targeted by the fishery. This reaction has been described either as a change in slope of the overall size spectrum or as a trophic cascade triggered by the removal of top predators. Here we use a novel size- and trait-based model to...

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