Measures of ecosystem structure and function derived from analysis of flows.
TL;DR: Three simple ecosystem models are examined to demonstrate the utility of measures derived from the application of economic input-output analysis to ecosystem compartment models in explaining ecological phenomena.
About: This article is published in Journal of Theoretical Biology.The article was published on 1976-02-01. It has received 807 citations till now. The article focuses on the topics: Throughflow & Inflow.
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TL;DR: The paper summarizes the capabilities of the modeling system with respect to evaluating how fisheries and the environment impact ecosystems and presents an overview of the computational aspects of the Ecopath, Ecosim and Ecospace modules as they are implemented in the most recent software version.
1,648 citations
Cites background from "Measures of ecosystem structure and..."
...In overview form (see references below and the EwE Help system for more detailed descriptions) the following routines are among those included: • Cycling index: fraction of an ecosystem’s throughput that is recycled (Finn, 1976)....
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...• Cycling index: fraction of an ecosystem’s throughput that is recycled ( Finn, 1976)....
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TL;DR: The use of ECOPATH II is exemplified through presentation of a model of the Schlei Fjord ecosystem (Western Baltic) through the use of routines for balancing the flow in a steady-state ecosystem from estimation of a missing parameter.
1,120 citations
Cites methods from "Measures of ecosystem structure and..."
...The average path length (pL) is calculated from a steady-state version of the equation presented by Finn (1976)....
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...The average path length (pL) is calculated from a steady-state version of the equation presented by Finn (1976). We have...
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...This recycling index, developed by Finn (1976), is expressed as percentage of total throughput. It was originally intended to quantify one of Odum's (1969) properties of system maturity....
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...This recycling index, developed by Finn (1976), is expressed as percentage of total throughput....
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...This recycling index, developed by Finn (1976), is expressed as percentage of total throughput. It was originally intended to quantify one of Odum's (1969) properties of system maturity. However, its interpretation is apparently not as simple as E.P. Odum conceived, with recycling increasing as a system matures. Wulff and Ulanowicz (1989) suggest that the opposite may indeed be the case....
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TL;DR: The full suite of carbon exchanges among the 36 most important components of the Chesapeake Bay mesohaline ecosystem is estimated to examine the seasonal trends in energy flow and the trophic dynamics of the ecosystem.
Abstract: The full suite of carbon exchanges among the 36 most important components of the Chesapeake Bay mesohaline ecosystem is estimated to examine the seasonal trends in energy flow and the trophic dynamics of the ecosystem. The networks provide information on the rates of energy transfer between the trophic components in a system wherein autochthonous production is dominated by phytoplankton production. A key seasonal feature of the system is that the summer grazing of primary producers by zooplankton is greatly reduced due to top—down control of zooplankton by ctenophores and sea nettles. Some of the ungrazed phytoplankton is left to fuel the activities of the pelagic microbial community, and the remainder falls to the bottom where it augments the deposit—feeding assemblage of polychaetes, amphipods, and blue crabs. There is a dominant seasonal cycle in the activities of all subcommunities, which is greatest in the summer and least in the cold season. However, the overall topology of the ecosystem does not ap...
807 citations
TL;DR: A reliable estimate of throughfall nutrient flux demands a good forest hydrological budget because the transport of nutrients contained in throughfall and stemflow depends on the magnitude, timing, and form of the precipitation.
Abstract: Publisher Summary This chapter discusses a number of factors influencing the throughfall and stemflow quality and their variation. The effect of the canopy in altering the precipitation quality is also discussed. The annual nutrient return to the forest soil for the elements K, Na, and S is predominantly via throughfall and stemflow and little because of litterfall. Stemflow transfers only 5–20% of the total in precipitation-borne solutes, yet it is the major nutrient input to restricted areas of the forest floor. Because throughfall and stemflow are associated with precipitation events, the transport of nutrients contained in throughfall and stemflow depends on the magnitude, timing, and form of the precipitation. Thus, a reliable estimate of throughfall nutrient flux demands a good forest hydrological budget. The quantity and distribution of throughfall and stemflow depends on microscale features of canopy structure, such as crown density, closeness of the foliar elements, distance from the nearest bole, or open spaces in the canopy.
667 citations
TL;DR: A general model is presented describing ecosystem degradation to help decide when restoration, rehabilitation, or reallocation should be the preferred response, and 18 vital ecosystem attributes for evaluating stages of degradation and planning experiments in the restoration or rehabilitation of degraded ecosystems.
Abstract: A general model is presented describing ecosystem degradation to help decide when restoration, rehabilitation, or reallocation should be the preferred response. The latter two pathways are suggested when one or more “thresholds of irreversibility” have been crossed in the course of ecosystem degradation, and when “passive” restoration to a presumed predisturbance condition is deemed impossible. The young but burgeoning field of ecological restoration, and the older field of rehabilitation and sustainable range management of arid and semiarid lands (ASAL), are found to have much in common, especially compared with the reallocation of lands, which is often carried out without reference to pre-existing ecosystems. After clarifying some basic terminology, we present 18 vital ecosystem attributes for evaluating stages of degradation and planning experiments in the restoration or rehabilitation of degraded ecosystems. Finally, we offer 10 hypotheses concerning ecological restoration and rehabilitation as they apply to ASAL and perhaps to all terrestrial ecosystems.
494 citations
References
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TL;DR: Input-output theory is developed for an ecosystem in terms of production and respiration energy flows and the structure is determined for two examples and a perturbation technique for the energy flow is suggested.
559 citations
TL;DR: In this paper, the authors present a system analysis and simulation framework for ecology and natural resource management systems analysis with examples in csmp and fortran link, and provide a free e-book for the same purpose.
Abstract: systems analysis and simulation in ecology volume 3 systems analysis and simulation in ecology volume 3 systems analysis and simulation in ecology volume 3 systems analysis and simulation in ecology volume iii free ebooks systems analysis and simulation in ecology systems analysis and simulation in ecology volume i ecology and natural resource management systems analysis systems analysis and simulation i theory and foundations ecology and natural resource management systems analysis with examples in csmp and fortran link.springer research & reviews journal of ecology and environmental systems analysis and simulation in ecology volume 3 ecology and natural resource management systems analysis fantastic adventures september 1947pulp magazine ebook write you a song ucretsizbot how to woo a spinster ricuk systems analysis and simulation in ecology volume 3 men in white coats probos st lfelt 39 s plant ecology plants the soil and man by st downloads/the ecology diet pdf download now references to multimedia, multipathway, and multireceptor making his move sqlman halliday 5th edition physics volume 3 solutions arcbc agro-environmental systems and agent-based simulation handbook of scaling methods in aquatic ecology measurement stormwater management in western washington rebekah all the bible teaches about ebook | imchasingplaces a systems approach framework for ecology and society introduction to the special issue “systems ecology: a encyclopedia of physics volume 52 astrophysics 3 the a simulation tool for industrial ecology: creating a board water resources news, volume 3, no. 6, summer issue 1971 studies in viral ecology volume 2 animal host systems
477 citations
TL;DR: Quantities of suspended matter removed by oysters and deposited as feces or pseudofeces varied seasonally, reaching maxima in September, and biodeposits of filter feeders such as barnacles, tunicates, and other lamelli-branchs were similar to those of oysters.
Abstract: Quantities of suspended matter removed by oysters (Crassostrea virginica) and deposited as feces or pseudofeces varied seasonally, reaching maxima in September. Below 2.8C, measurable quantities were not produced. At certain seasons, levels of suspended solids influenced quantities of biodeposits. Laboratory studies indicated that the oysters on 0.405 hectare of an estuarine bottom may produce up to 981 kg of feces and pseudofeces weekly. Of the particles, 95% were under 3 µ in diameter. all types of algal cells present in the surrounding water were represented. The deposits contained 77–91% inorganic matter, mostly illite, chlorite, and mixed-layer clays, 4–12% organic carbon, and 1.0 g/kg phosphorus. biodeposits of filter feeders such as barnacles, tunicates, and other lamelli-branchs were similar to those of oysters. Filter feeders may influence deposition, transport, and the composition of suspended sediments in estuaries. A possible relationship between the removal from suspension and the subsequent deposition of radionuclides associated with particles of clay, silt, or planktonic algae and feces or pseudofeces is suggested.
257 citations
172 citations
TL;DR: Fecal ingestion rates were positively correlated with carbon and nitrogen contents of the pellets, and the effect of coprophagy on the overall energy transFer efficiency of marinc food chains was discussed.
Abstract: Rates of coprophagy were dctcrmined in 38 feeding studies. The animals consumed from 0 to 83% of their body weight in fecal pellets during 48 hr. The fecal pellets used included those of the polychaetc Onuphis microcephala, a prosobranch gastropod (family IIydrobiidae), the pclecypod Crassos~~ea uirginica, the crustaceans Cdianassa major and Penueus setiferus, and the telcost Mugil cephalus. The animals offered these pellets included three polychaetes, four gastropods, three pelecypods, seven crustaceans, and three telcosts. Coprophagy rates are compared with calculated maintenance food requirements of the test animals. Fecal ingestion rates were positively correlated with carbon and nitrogen contents of the pellets. The potential effects of coprophagy in marinc ecosystems arc discussed emphasizing the effect of coprophagy on the overall energy transFer efficiency OF marinc food chains.
153 citations