Changes between Version 1 and Version 2 of EwEugGroupInfo


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Timestamp:
2010-02-07 18:00:21 (10 years ago)
Author:
varunr
Comment:

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  • EwEugGroupInfo

    v1 v2  
    1010'''Maximum relative feeding time''' 
    1111 
    12 If prey becomes more scarce, (e.g., because predator abundance increases), their predators will have to spend more time feeding (and hence be at a greater risk to predation themselves). Use this variable to limit how much the feeding time may increase. The default is that the feeding time may at the most double, i.e., a value of 2.0. There is empirical evidence showing limits to how great a predation risk organisms are willing to take. Juveniles may for instance be found hiding at food-deprived shorelines even though suitable prey is more abundant in the pelagic zone close by. Going out to there for prey would however place the juveniles at a considerable risk of predation, and they may choose not to do so, or at least to lower the risk by limiting the time spent feeding. For more information see [wiki:EwEugForagingTimeAndPredation Foraging time and predation risk]. 
     12If prey becomes more scarce, (e.g., because predator abundance increases), their predators will have to spend more time feeding (and hence be at a greater risk to predation themselves). Use this variable to limit how much the feeding time may increase. The default is that the feeding time may at the most double, i.e., a value of 2.0. There is empirical evidence showing limits to how great a predation risk organisms are willing to take. Juveniles may for instance be found hiding at food-deprived shorelines even though suitable prey is more abundant in the pelagic zone close by. Going out to there for prey would however place the juveniles at a considerable risk of predation, and they may choose not to do so, or at least to lower the risk by limiting the time spent feeding. For more information see [wiki:EwEugForagingTimeAndPredation Foraging time and predation risk]. 
    1313 
    1414'''Feeding time adjustment rate (Range: ![0,1])''' 
    1515 
    16 This factor determines how fast organisms adjust feeding times so as to stabilize consumption rate per biomass (see [wiki:EwEugForagingTimeAndPredation Foraging time and predation risk]).  Setting the value to 0.0 causes feeding time (and hence time exposed to predation risk) to remain constant, all changes in consumption per biomass then result in growth rate changes.  Setting this parameter to zero also results in simulation of compensatory growth rate responses (see [wiki:EwEugCompensatoryGrowth Compensatory growth]). Setting it to 1.0 results in fast time response, which causes reduction in vulnerability to predation rather than increased growth rate when/if food density increases. See [wiki:EwEugUsingEcosimToStudyCompensation Compensatory recruitment] for recommendations for using this parameter to create the effects of compensation in recruitment in models with multi-stanza groups. See [wiki:EwEugCompensatoryNaturalMortality Compensatory natural mortality] for recommendations for using this parameter to create the effects of compensation in natural mortality. 
     16This factor determines how fast organisms adjust feeding times so as to stabilize consumption rate per biomass (see [wiki:EwEugForagingTimeAndPredation Foraging time and predation risk]).  Setting the value to 0.0 causes feeding time (and hence time exposed to predation risk) to remain constant, all changes in consumption per biomass then result in growth rate changes.  Setting this parameter to zero also results in simulation of compensatory growth rate responses (see [wiki:EwEugCompensatoryGrowth Compensatory growth]). Setting it to 1.0 results in fast time response, which causes reduction in vulnerability to predation rather than increased growth rate when/if food density increases. See [wiki:EwEugUsingEcosimToStudyCompensation Compensatory recruitment] for recommendations for using this parameter to create the effects of compensation in recruitment in models with multi-stanza groups. See [wiki:EwEugCompensatoryNaturalMortality Compensatory natural mortality] for recommendations for using this parameter to create the effects of compensation in natural mortality. 
    1717 
    1818In general we recommend that you set the feeding time to 0 for all groups, apart from, e.g., marine mammals where a value of 0.5 often seems reasonable. Explore the consequences of changing this factor. 
     
    2020'''Fraction of other mortality sensitive to changes in feeding time ![0-1]''' 
    2121 
    22 This is the proportion of the unexplained natural mortality rate (M0, 1-EE x total mortality rate) that is assumed to be sensitive to changes in feeding time.  Setting it to 0.0 causes M0 to remain constant. Setting it to a higher value causes that proportion of M0 to vary in proportion to relative time spent feeding (see feeding time factor above).  Setting nonzero value along with nonzero feeding time factor generally results in density-dependent M: as density increases, feeding time usually has to increase to maintain food consumption rate, and this increased feeding time leads to higher mortality rate. See [wiki:EwEugUsingEcosimToStudyCompensation Compensatory recruitment] for recommendations for using this parameter to create the effects of compensation in recruitment in models with multi-stanza groups. 
     22This is the proportion of the unexplained natural mortality rate (M0, 1-EE x total mortality rate) that is assumed to be sensitive to changes in feeding time.  Setting it to 0.0 causes M0 to remain constant. Setting it to a higher value causes that proportion of M0 to vary in proportion to relative time spent feeding (see feeding time factor above).  Setting nonzero value along with nonzero feeding time factor generally results in density-dependent M: as density increases, feeding time usually has to increase to maintain food consumption rate, and this increased feeding time leads to higher mortality rate. See [wiki:EwEugUsingEcosimToStudyCompensation Compensatory recruitment] for recommendations for using this parameter to create the effects of compensation in recruitment in models with multi-stanza groups. 
    2323 
    2424'''Predator effect on feeding time ![0-1]''' 
     
    2828'''Density-dependent catchability (>=1)''' 
    2929 
    30 See introductory material on [wiki:EwEugDensityDependentChangesInCatchability Density-dependent changes in catchability], also in Chapter 3 of the User Guide. 
     30See introductory material on [wiki:EwEugDensityDependentChangesInCatchability Density-dependent changes in catchability], also in Chapter 3 of the User Guide. 
    3131 
    3232'''QBmax/QBo (handling time) [>1]''' 
    3333 
    34 See introductory material on [wiki:EwEugPredatorSatiationAndHandlingTimeEffects Predator satiation and handling time effects], also in Chapter 3 of the User Guide. 
     34See introductory material on [wiki:EwEugPredatorSatiationAndHandlingTimeEffects Predator satiation and handling time effects], also in Chapter 3 of the User Guide. 
    3535 
    3636'''Switching power parameter ![0-2]''' 
    3737 
    38 Default 0 is no switching. See introductory material on [wiki:EwEugModellingSwitchingBehaviour Modelling switching behaviour], also in Chapter 3 of the User Guide. 
     38Default 0 is no switching. See introductory material on [wiki:EwEugModellingSwitchingBehaviourInEcosim Modelling switching behaviour], also in Chapter 3 of the User Guide.