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  • 1
    Publikationsdatum: 2013-02-01
    Beschreibung: Arising from S. Pawar, A. I. Dell & V. M. Savage 486, 485-489 10.1038/nature11131(2012)A recent paper by Pawar and colleagues has provided important insights into the consequences of foraging behaviour for food-web dynamics. One notable pattern predicted by their analysis is that consumption rate (c) scales superlinearly (cm(1.16)) with consumer body mass (m) in three-dimensional (3D), but not two-dimensional (2D), foraging spaces. Although we feel that the authors should be applauded for this interesting contribution, we argue that their result is not consistent with established life-history theory. To resolve this contradiction, progress in both fields is probably required, including new empirical studies in which consumption rate, metabolism and dimensionality are examined directly under natural conditions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Giacomini, Henrique C -- Shuter, Brian J -- de Kerckhove, Derrick T -- Abrams, Peter A -- England -- Nature. 2013 Jan 31;493(7434):E1-2; discussion E2-3. doi: 10.1038/nature11829.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord St., Toronto, Ontario M5S 3G5, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23364748" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; *Ecosystem ; Feeding Behavior/*physiology ; *Food Chain ; *Models, Biological
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 72 (1987), S. 248-258 
    ISSN: 1432-1939
    Schlagwort(e): Pagurus ; Competition ; Resource partitioning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Resource partitioning was quantified for 6 species of intertidal hermit crabs in the genus Pagurus, that occur on the outer coast of Washington. This, together with field evidence of shell shortage and with laboratory experiments to quantify the mechanism of interactions for shells, allowed estimation of the relative intensities of inter-and intraspecific competition between these species. The findings were that: (1) the magnitude of intraspecific competition was greater than any single interspecific competitive effect for all of the species; and (2) the relative proportion of intraspecific competition was greater for the middle and upper intertidal species than for the lower intertidal species. Studies at several outer coast sites supported these generalizations. Both of these findings are consistent with the hypothesis that competitive divergence has occurred in the past. The structure of the outer coast hermit crab assemblage is compared with that of the San Juan Archipelago hermit crab assemblage. Differences between the two do not seem to be the result of adaptive responses to the presence of more competing species in the former group.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 72 (1987), S. 233-247 
    ISSN: 1432-1939
    Schlagwort(e): Pagurus ; Competition ; Resource partioning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Competition for empty gastropod shells in a group of three sympatric hermit crabs (Pagurus hirsutiusculus, Pagurus granosimanus, and Pagurus beringanus) was studied in the San Juan Archipelago, Washington State. Estimates of the competitive effects of each species on the others' shell supplies were derived using field data on shell utilization and the results of laboratory experiments to determine rates of acquisition and exchange of shells and preferences for different shell species. Each species experienced approximately an order of magnitude more intraspecific competition than interspecific competition for empty shells. This resulted from differences in preference for shell shapes, shell size use, and habitat use between P. hirsutiusculus and P. granosimanus, and largely from differences in habitat use between P. beringanus and the other two species. Experiments involving the release and recensusing of marked empty shells were used to estimate competitive effects more directly for the interaction between P. hirsutiusculus and P. granosimanus. Results were consistent with the estimates derived from data on resource partitioning. Possible causes of the low levels of interspecific competition are discussed, and results are compared with studies of other organisms that estimated both inter- and intra-specific competition.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 73 (1987), S. 272-281 
    ISSN: 1432-1939
    Schlagwort(e): Competition ; Interaction ; Mutualism ; Predation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The classification of interspecific interactions can have an important impact on ecologists' world views. Previous classifications have often been incomplete, have suffered from ambiguously defined categories, and/or have wrongly equated categories of population level effects with particular mechanisms of interaction. I use several simple mathematical models to argue that effects on short-term population growth rate, long term population size, and short term relative fitness of interactants may differ qualitatively. Equating all (--) effects with competition and all (+-) effects with predation may have caused ecologists to ignore a variety of potentially important interaction mechanisms. Failure to define the type of effect used in classifying interactions has led to confusion about the nature of interactions; several controversies regarding competition have apparently been caused or exaccerbated by problems with definition or clasification. In applying classification schemes, ecologists should realize that the classification of an interaction between two populations may change with the sizes of those populations or of other populations with which they interact.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2015-07-09
    Beschreibung: Movement is a fundamental aspect of the population and community ecology of many organisms, yet, until recently, it has been difficult to measure in the wild. Consequently, simple assumptions are often used to represent movement; a key assumption found in many classic theoretical ecological models (e.g., predator–prey interactions) is that organisms move like ideal gas particles. Here, we test whether this assumption adequately describes the movement of the Cisco ( Coregonus artedi ) and its schools using fisheries acoustic surveys and mathematical models. We find that several of the individual components of an ideal gas model (IGM) have some inconsistencies with Cisco behavior, yet overall patterns of school formation are close to IGM expectations. For both individual fish and schools: 1) the spatial distributions were random or slightly clumped; 2) the swimming speed distributions were unimodal but significantly different from normal; 3) horizontal movement was more frequent than depth changes; and 4) movement trajectories across the acoustic beam sometimes deviated from straight lines. However, including the average individual and school swimming speeds and known nighttime densities in an IGM generated values that were similar to the observed values for: 1) the time required for schools to form in the morning and 2) school encounter rates.
    Print ISSN: 1045-2249
    Digitale ISSN: 1465-7279
    Thema: Biologie
    Publiziert von Oxford University Press
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Publikationsdatum: 1987-05-01
    Print ISSN: 0029-8549
    Digitale ISSN: 1432-1939
    Thema: Biologie
    Publiziert von Springer
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 1987-05-01
    Print ISSN: 0029-8549
    Digitale ISSN: 1432-1939
    Thema: Biologie
    Publiziert von Springer
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Publikationsdatum: 1987-01-01
    Print ISSN: 0029-8549
    Digitale ISSN: 1432-1939
    Thema: Biologie
    Publiziert von Springer
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2007-06-01
    Print ISSN: 0269-8463
    Digitale ISSN: 1365-2435
    Thema: Biologie
    Publiziert von Wiley im Namen von British Ecological Society.
    Standort Signatur Erwartet Verfügbarkeit
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