Food chain to food web: a natural progression?

1990 ◽  
Vol 24 (3) ◽  
pp. 187-190 ◽  
Author(s):  
Paul Webb ◽  
Gill Boltt
Keyword(s):  
Food Web ◽  
Food Chain ◽  
Natural Progression

scholarly journals Food Web Structure and Trophic Interactions Revealed by Stable Isotope Analysis in the Midstream of the Chishui River, a Tributary of the Yangtze River, China

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 195
Author(s):  
Qiang Qin ◽  
Fubin Zhang ◽  
Fei Liu ◽  
Chunling Wang ◽  
Huanzhang Liu
Keyword(s):  
Stable Isotope ◽  
Carbon Source ◽  
Food Web ◽  
Food Chain ◽  
Yangtze River ◽  
Trophic Niche ◽  
The Yangtze River ◽  
Food Chain Length ◽  
Trophic Pathways ◽  
Chishui River

Understanding energy flow and nutrient pathways is crucial to reveal the dynamics and functions of riverine ecosystems and develop appropriate conservation strategies. In this study, we utilized stable isotopes of δ13C and δ15N to examine the fundamental characteristics of trophic position, trophic niche, and carbon source for the food web in the midstream of the Chishui River, a tributary to the Yangtze River. Our results showed that stable isotope signatures among different sorts of basal resources and consumers were significantly distinguishable and that the food chain consisted of four trophic levels, indicating the multiple trophic pathways and long food chain length here. The trophic guilds of fish were classified into four categories, in which herbivorous and carnivorous fish showed greater trophic diversity and omnivorous fish had higher trophic redundancy, which meant that there was a stable trophic niche structure in the study area. Phytoplankton and periphyton presented the largest contributions to consumers, indicating that autochthonous productivity was the dominant carbon source in the midstream of the Chishui River. Since the Chishui River is still in a natural condition without any dam constructions, the autochthonous productivity, stable trophic niche structure, multiple trophic pathways and long food chain length found here demonstrate its high conservation value. Therefore, the strategy to refrain from damming on this river should persist into the future.

scholarly journals Food-web modification in the eastern Gulf of Finland after invasion of Marenzelleria arctia (Spionidae, Polychaeta)

NeoBiota ◽  
2021 ◽  
Vol 66 ◽  
pp. 75-94
Author(s):  
Sergey Golubkov ◽  
Alexei Tiunov ◽  
Mikhail Golubkov
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Food Chain ◽  
Native Species ◽  
Isotope Analysis ◽  
Marine Species ◽  
Trophic Levels ◽  
Benthivorous Fish ◽  
Neva Estuary ◽  
The Baltic

The paucity of data on non-indigenous marine species is a particular challenge for understanding the ecology of invasions and prioritising conservation and research efforts in marine ecosystems. Marenzelleria spp. are amongst the most successful non-native benthic species in the Baltic Sea during recent decades. We used stable isotope analysis (SIA) to test the hypothesis that the dominance of polychaete worm Marenzelleria arctia in the zoobenthos of the Neva Estuary after its invasion in the late 2000s is related to the position of this species in the benthic food webs. The trend towards a gradual decrease in the biomass of Marenzelleria worms was observed during 2014–2020, probably due to significant negative relationships between the biomass of oligochaetes and polychaetes, both of which, according to SIA, primarily use allochthonous organic carbon for their production. The biomass of benthic crustaceans practically did not change and remained very low. The SIA showed that, in contrast to the native crustacean Monoporeia affinis, polychates are practically not consumed either by the main invertebrate predator Saduria entomon, which preys on M. affinis, oligochaetes and larvae of chironomids or by benthivorous fish that prefer native benthic crustaceans. A hypothetical model for the position and functional role of M. arctia in the bottom food web is presented and discussed. According the model, the invasion of M. arctia has created an offshoot food chain in the Estuary food webs. The former dominant food webs, associated with native crustaceans, are now poorly developed. The lack of top-down control obviously contributes to the significant development of the Marenzelleria food chain, which, unlike native food chains, does not provide energy transfer from autochthonous and allochthonous organic matter to the upper trophic levels. The study showed that an alien species, without displacing native species, can significantly change the structure of food webs, creating blind offshoots of the food chain.

हिन्दू संस्कृति में पेड़-पौधों का धार्मिक, आध्यात्मिक एवं वैज्ञानिक महत्व

2018 ◽  
Vol 2 (01) ◽  
Author(s):  
रामलखन सिंह सि� Mishra
Keyword(s):  
Food Web ◽  
Food Chain ◽  
Anthropogenic Factors ◽  
Sustainable Utilization ◽  
Present Communication ◽  
Hindu Religion ◽  
Living Things ◽  
Entire Universe

The life of entire universe is governed by the five great elements (Panch Mahabhutas) which includes Earth, Water, Fire, Sky and Air which are existed in nature. All living things are composed from these five great elements. This fact is mentioned in various Hindu Holy Scriptures such as Vedas, Puranas, Ramayana, Mahabharat, Manusmrirti, Shrimad Bhagvat Gita etc. All living and non living things are existed in nature are entirely interconnected or interdependent to each other. Presence of sufficient living and non living things make sound and sustainable ecosystem. Therefore our ancient sages and hermits linked natures components such as plants, animals, rivers, mountains, forests etc to the worship in Hindu religion for sustainable utilization and conservation for generation to generation. The forests are regarded as 'Lungs of Earth' and 'Living Oxygen Cylinders' and provide fresh air, water, clean and green environment, maintain food chain and food web etc and also full fill all basic requirements such as food, medicine and shelter. But now due to the various anthropogenic factors, the forests are depleting fast from the nature, while importance of plants/forests has been described by ancient sages and hermits in various Holy Scriptures of Hindu religion. Importance of plants has been proved by modern research. In the present communication, the details are given.

scholarly journals Population dynamics of Indian sarus crane, Grus antigone antigone (Linnaeus, 1758) in and around alwara lake of Kaushambi district (Uttar Pradesh), India

2016 ◽  
Vol 4 (2) ◽  
pp. 206
Author(s):  
Ashok Kumar Verma ◽  
Shri Prakash
Keyword(s):  
Population Dynamics ◽  
Food Web ◽  
Aquatic Plants ◽  
Food Chain ◽  
Uttar Pradesh ◽  
Environmental Condition ◽  
Global Level ◽  
Wetland Ecosystem ◽  
Grass Land ◽  
Increasing Trends

Sarus crane is the only resident breeding crane in India. They prefer open habitat like marsh areas, irrigated paddy fields, grass land and river banks. These areas suit them for foraging, roosting and nesting. These cranes are omnivorous birds, feeding aquatic plants, seeds, roots, tubers, crustaceans, insects, molluscs, fishes, frogs, reptiles and avian eggs. These are not only involved in maintaining the food chain and food web but also providing strength to wetland ecosystem. Ecological and environmental condition of this lake is nicely supporting the survival of vulnerable Indian sarus crane, Grus antigone antigone. In general, the population of sarus crane is decreasing at global level but the authors recorded its increasing trends during their exploration from 2011 to 2014 in and around the Alwara lake of Kaushambi district of Uttar Pradesh (India).

scholarly journals Environmental Influences on Dietary Carbon and 14C Ages in Modern Rats and Other Species

Radiocarbon ◽  
2001 ◽  
Vol 43 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Nancy R Beavan-Athfield ◽  
Bruce G McFadgen ◽  
Rodger J Sparks
Keyword(s):  
New Zealand ◽  
Food Web ◽  
Aquatic Plants ◽  
Food Chain ◽  
Rattus Norvegicus ◽  
Volcanic Zone ◽  
Norway Rat ◽  
Radiocarbon Age ◽  
The North ◽  
Lake Waters

Diet can play a significant role in anomalous radiocarbon ages derived from bone and other tissues when the food web incorporates depleted 14C reservoirs, such as the marine environment. Dietary effects from a post-bomb carbon variation have also been found in modern invertebrates and populations of Rattus exulans (Beavan and Sparks 1998). We now present the effect on absolute percent modern (pMC) and the conventional radiocarbon age (CRA) of a modern aquatic/terrestrial food web in a volcanic zone of the North Island, New Zealand. At Lake Taupo, geothermal venting transfers 14C depleted carbon to lake waters, which aquatic plants fix into the food chain; depleted 14C is shown to then pass on to shellfish, waterfowl, and Norway rat (Rattus norvegicus). The geothermally induced 14C variations from modern atmospheric pMC and CRA can increase apparent 14C ages by >2000 years.

Food Chains and Omnivory

2011 ◽  
Author(s):  
Kevin S. McCann
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Empirical Evidence ◽  
Food Chain ◽  
Stage Structure ◽  
Food Chains ◽  
Dependent Manner ◽  
Food Web Structure ◽  
Web Structure ◽  
Consumer Resource

This chapter extends the consumer–resource theory to include simple but common three-species modules behind the construction of whole food webs, with particular emphasis on food chains and omnivory. It first considers some common simple modular food web structures and whether the dynamics of subsystems can be seen using the framework laid out in previous chapters. Specifically, it asks when common food web structure increases or weakens the relative interaction strengths and/or when a food web structure modifies flux between consumers and resources in a density-dependent manner such that the food web tends to increase flux rates in some situations and decrease the coupling in other situations. The chapter also explores how stage structure can influence food chain stability before concluding with a review of empirical evidence on the dynamical implications of omnivory for food webs.

Organochlorine transfer in the food web of subalpine Bow Lake, Banff National Park

2000 ◽  
Vol 57 (6) ◽  
pp. 1258-1269 ◽  
Author(s):  
Linda M Campbell ◽  
David W Schindler ◽  
Derek CG Muir ◽  
David B Donald ◽  
Karen A Kidd
Keyword(s):  
Food Web ◽  
Food Chain ◽  
National Park ◽  
Lake Trout ◽  
Stable Carbon Isotope ◽  
Nitrogen Isotope ◽  
Stable Carbon ◽  
Pelagic Copepod ◽  
Banff National Park ◽  
Highly Correlated

Lake trout (Salvelinus namaycush) from subalpine Bow Lake, near the Continental Divide in Banff National Park, have been reported to have higher concentrations of toxaphene than other lake trout populations of the Rocky Mountains. Our original hypothesis was that unusually high biomagnification via a long food chain was responsible for elevated levels of toxaphene and other persistent organochlorines in the lake trout. This hypothesis was refuted by the analyses of stable carbon (δ13C) and nitrogen (δ15N) isotope ratios in lake biota. Stable nitrogen isotope analyses demonstrated that the food chain length in Bow Lake was short. The sources of carbon (pelagic or benthic), as indicated by stable carbon isotope values, were highly correlated with organochlorine concentrations in the food web. Lake trout with more pelagic carbon signatures had higher organochlorine concentrations than littoral-feeding mountain whitefish (Prosopium williamsoni) and lake trout. The pelagic copepod Hesperodiaptomus arcticus had higher organochlorine concentrations (wet weight basis) than any other organism, including the fish. This was attributed to the high lipid content of copepods and possibly their ingestion of suspended solids, including glacial silt or direct absorption from solution in glacial inflows.

scholarly journals δ13C values of wood and Charcoal Reveal Broad Isotopic ranges at the base of the Food Web

Radiocarbon ◽  
2019 ◽  
Vol 61 (6) ◽  
pp. 2003-2017 ◽  
Author(s):  
Bente Philippsen ◽  
Jesper Olsen ◽  
Søren A Sørensen ◽  
Bjørnar Måge
Keyword(s):  
Time Dependence ◽  
Food Web ◽  
Food Chain ◽  
Species Range ◽  
Small Study ◽  
Individual Species ◽  
Δ13c Values ◽  
The Mean ◽  
High Degree

ABSTRACTThe aim of this study is to investigate the range, the degree of variability, and a possible time or species dependence of wood and charcoal δ13C values within one small study area. To achieve this, we used δ13C and 14C determinations of more than 400 archaeological samples from a ca. 300 ha area in Denmark, spanning 5000 years and covering several different species. The δ13C values of the wood and charcoal range from −32.8‰ to −21.2‰. We found no time-dependence of wood and charcoal δ13C values, neither in general nor within one species. The mean δ13C of all wood samples is −28.5‰, while the means of individual species range from −30.6‰ to −26.3‰. The mean of all charcoal samples is −25.7‰, with the means of individual species ranging from −28.1‰ to −24.3‰. The wood δ13C values can be used to infer the possible range of plant δ13C values, which otherwise are not available. They imply that a high degree of variability can be expected at the base of the food chain. This is relevant for palaeodietary studies that rely on the measurement of baseline isotope values.

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