scholarly journals Distribution and drift dispersal dynamics of a caddisfly grazer in response to resource abundance and its ontogeny

2017 ◽  
Vol 4 (1) ◽  
pp. 160732 ◽  
Author(s):  
Izumi Katano ◽  
Hiromune Mitsuhashi ◽  
Hideyuki Doi ◽  
Yu Isobe ◽  
Tadashi Oishi
Keyword(s):  
Life Cycle ◽  
Food Source ◽  
Food Resource ◽  
Resource Scarcity ◽  
Fourth Instar ◽  
Late Winter ◽  
Food Web Structure ◽  
Resource Abundance ◽  
Larval Distribution ◽  
Web Structure

Stream grazers have a major impact on food web structure and the productivity of stream ecosystems; however, studies on the longitudinal (upstream versus downstream) and temporal changes in their drift dynamics and resulting distributions remain limited. Here, we investigated the longitudinal and temporal distributions and drift propensity of a trichopteran grazer, the caddisfly, Micrasema quadriloba , during its life cycle in a Japanese stream. The distribution of larvae significantly shifted downstream during the fifth instar larval stage during late winter; with periphyton abundance (i.e. their food source) showing similar shifts downstream. Therefore, our results show that the drift dispersal the caddisfly occurs in response to decline in available food resources (i.e. food-resource scarcity) and an increase in food requirements by growing individuals. Furthermore, our results show that this observed longitudinal shift in larval distribution varies through their life cycle, because the drift dispersal of fifth instar larvae was greater than that of immature larvae. The correlation between periphyton abundance and drift propensity of fourth instar larvae was not statistically significant, whereas that of fifth instar larvae was significantly negative. In conclusion, we detected an ontogenetic shift in drift propensity, which might explain the longitudinal and temporal distributions of this species.

Spatial and temporal patterns in the food web structure of a large floodplain river assessed using stable isotopes

2007 ◽  
Vol 64 (3) ◽  
pp. 495-508 ◽  
Author(s):  
Brian R Herwig ◽  
David H Wahl ◽  
John M Dettmers ◽  
Daniel A Soluk
Keyword(s):  
Food Web ◽  
Mississippi River ◽  
Food Resource ◽  
Large River ◽  
Food Resources ◽  
Integrative Approach ◽  
Spatial And Temporal Patterns ◽  
Food Web Structure ◽  
Web Structure

We assessed naturally occurring stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) for available food resources and consumers in the mainstream channel of the Mississippi River. Isotopic ratios were assessed for organic sources and organisms at two different sites during a fall, spring, and two summer seasons. Terrestrial C4 plants did not appear to be an important carbon source for consumers in the mainstream channel. A mixing model, IsoSource, indicated that terrestrial C3 vegetation, suspended algae, and epixylon were at times important food resources for large river consumers. Many consumer signatures fell outside the mixing polygon defined by these sources, indicating that there was a 13C-depleted food resource for which we did not account. We could not distinguish precisely whether downstream allochthonous and autochthonous carbon, or in situ production, was the dominant food resource supporting consumers in these systems. However, our data suggest that in situ organic matter sources can be important. Consumer δ13C and δ15N signatures intermediate between several sources indicated widespread omnivory in the river reaches that we studied. To fully understand food web structure and energy sources in complex large river ecosystems, an integrative approach that combines related empirical data sets is needed.

scholarly journals Circular Economy Strategies for Equipment Lifetime Extension: A Systematic Review

2021 ◽  
Vol 13 (3) ◽  
pp. 1117
Author(s):  
Alessandro Fontana ◽  
Andrea Barni ◽  
Deborah Leone ◽  
Maurizio Spirito ◽  
Agata Tringale ◽  
...  
Keyword(s):  
Life Cycle ◽  
Circular Economy ◽  
Resource Scarcity ◽  
Production Equipment ◽  
Environmental Standards ◽  
Multiple Strategies ◽  
Medium Enterprise ◽  
Equipment Lifetime ◽  
Selection Of ◽  
Lifetime Extension

Even if the economy nowadays is still locked into a linear model of production, tighter environmental standards, resource scarcity and changing consumer expectations are forcing organizations to find alternatives to lighten their impacts. The concept of Circular Economy (CE) is to an increasing extent treated as a solution to this series of challenges. That said, the multitude of approaches and definitions around CE and Life Cycle Extension Strategies (LCES) makes it difficult to provide (Small and Medium Enterprise) SMEs with a consistent understanding of the topic. This paper aims at bridging this gap by providing a systematic literature review of the most prominent papers related to the CE and lifetime extension, with a particular focus on the equipment and machinery sector. A taxonomy was used to define and cluster a subset of selected papers to build a homogeneous approach for understanding the multiple strategies used in the industry, and the standards in maintenance and remanufacturing strategies. As a final research step, we also propose a Strategy Characterization Framework (SCF) to build the ground for the selection of the best strategy to be applied for production equipment life cycle extension on several industrial use cases.

scholarly journals Life Cycle Assessment of Households in Santiago, Chile: Environmental Hotspots and Policy Analysis

2021 ◽  
Vol 13 (5) ◽  
pp. 2525
Author(s):  
Camila López-Eccher ◽  
Elizabeth Garrido-Ramírez ◽  
Iván Franchi-Arzola ◽  
Edmundo Muñoz
Keyword(s):  
Global Warming ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Impacts ◽  
Food Consumption ◽  
Household Income ◽  
Resource Scarcity ◽  
Life Cycles ◽  
The Impact ◽  
Freshwater Eutrophication

The aim of this study is to assess the environmental impacts of household life cycles in Santiago, Chile, by household income level. The assessment considered scenarios associated with environmental policies. The life cycle assessment was cradle-to-grave, and the functional unit considered all the materials and energy required to meet an inhabitant’s needs for one year (1 inh/year). Using SimaPro 9.1 software, the Recipe Midpoint (H) methodology was used. The impact categories selected were global warming, fine particulate matter formation, terrestrial acidification, freshwater eutrophication, freshwater ecotoxicity, mineral resource scarcity, and fossil resource scarcity. The inventory was carried out through the application of 300 household surveys and secondary information. The main environmental sources of households were determined to be food consumption, transport, and electricity. Food consumption is the main source, responsible for 33% of the environmental impacts on global warming, 69% on terrestrial acidification, and 29% on freshwater eutrophication. The second most crucial environmental hotspot is private transport, whose contribution to environmental impact increases as household income rises, while public transport impact increases in the opposite direction. In this sense, both positive and negative environmental effects can be generated by policies. Therefore, life-cycle environmental impacts, the synergy between policies, and households’ socio-economic characteristics must be considered in public policy planning and consumer decisions.

Invasive rodents have multiple indirect effects on seabird island invertebrate food web structure

2017 ◽  
Vol 27 (4) ◽  
pp. 1190-1198 ◽  
Author(s):  
Joshua J. Thoresen ◽  
David Towns ◽  
Sebastian Leuzinger ◽  
Mel Durrett ◽  
Christa P. H. Mulder ◽  
...  
Keyword(s):  
Food Web ◽  
Indirect Effects ◽  
Food Web Structure ◽  
Web Structure ◽  
Invasive Rodents

scholarly journals Hydrodynamics drive pelagic communities and food web structure in a tidal environment

2020 ◽  
Vol 106 (2) ◽  
pp. 69-85
Author(s):  
Matthew J. Young ◽  
Frederick Feyrer ◽  
Paul R. Stumpner ◽  
Veronica Larwood ◽  
Oliver Patton ◽  
...  
Keyword(s):  
Food Web ◽  
Food Web Structure ◽  
Web Structure ◽  
Pelagic Communities

scholarly journals The more food webs change, the more they stay the same

2009 ◽  
Vol 364 (1524) ◽  
pp. 1789-1801 ◽  
Author(s):  
Kevin Shear McCann ◽  
Neil Rooney
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Scale Invariant ◽  
Food Web Structure ◽  
Behavioural Responses ◽  
Web Structure ◽  
Food Web Ecology ◽  
Food Web Theory

Here, we synthesize a number of recent empirical and theoretical papers to argue that food-web dynamics are characterized by high amounts of spatial and temporal variability and that organisms respond predictably, via behaviour, to these changing conditions. Such behavioural responses on the landscape drive a highly adaptive food-web structure in space and time. Empirical evidence suggests that underlying attributes of food webs are potentially scale-invariant such that food webs are characterized by hump-shaped trophic structures with fast and slow pathways that repeat at different resolutions within the food web. We place these empirical patterns within the context of recent food-web theory to show that adaptable food-web structure confers stability to an assemblage of interacting organisms in a variable world. Finally, we show that recent food-web analyses agree with two of the major predictions of this theory. We argue that the next major frontier in food-web theory and applied food-web ecology must consider the influence of variability on food-web structure.

Environmental warming alters food-web structure and ecosystem function

Nature ◽  
10.1038/47023 ◽  
1999 ◽  
Vol 402 (6757) ◽  
pp. 69-72 ◽  
Author(s):  
Owen L. Petchey ◽  
P. Timon McPhearson ◽  
Timothy M. Casey ◽  
Peter J. Morin
Keyword(s):  
Food Web ◽  
Ecosystem Function ◽  
Food Web Structure ◽  
Web Structure ◽  
Environmental Warming
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