Changes between Version 1 and Version 2 of EwEugPredictingConsumption


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Timestamp:
2010-01-28 16:14:27 (9 years ago)
Author:
varunr
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  • EwEugPredictingConsumption

    v1 v2  
    33Ecosim bases the crucial assumption for prediction of consumption rates on a simple Lotka-Volterra or ‘mass action’ assumption, modified to consider ‘foraging arena’ properties. Following this, prey can be states that are or are not vulnerable to predation, for instance by hiding, (e.g., in crevices of coral reefs or inside a school) when not feeding, and only being subject to predation when having left their shelter to feed, (see Figure 3.3 in [[Vulnerabilities in Ecosim.htm|Vulnerabilities in Ecosim]]). In the original Ecosim formulations (Walters et al 1997, 2000) the consumption rate for a given predator ''i'' feeding on a prey ''j'' was thus predicted from, 
    44 
    5 ../Resources/Images/08000026.png''' Eq. 51''' 
     5[[Image(wiki:EwEugImages:08000026.png)]] ''' Eq. 51''' 
    66 
    77where, ''a'',,''ij'',, is the effective search rate for predator ''i'' feeding on a prey ''j'', ''v'',,''ij'',, base vulnerability expressing the rate with which prey move between being vulnerable and not vulnerable, ''B,,i,,'' prey biomass, ''P,,j,,'' predator abundance (''N,,j,,'' for split pool groups discussed later, and ''B,,j,,'' for other groups). 
     
    1111Early experience with Ecosim has led to a more elaborate expression to describe the consumption: 
    1212 
    13 ../Resources/Images/08000027.png''' Eq. 52''' 
     13[[Image(wiki:EwEugImages:08000027.png)]] ''' Eq. 52''' 
    1414 
    1515where, ''T,,i,,'' represents prey relative feeding time, ''T,,j,,'' predator relative feeding time, ''S'',,''ij'',, user-defined seasonal or long term forcing effects, ''M'',,''ij'',, mediation forcing effects, and'' D,,j,,'' represents effects of handling time as a limit to consumption rate, 
    1616 
    17 ../Resources/Images/08000028.png'''Eq. 53''' 
     17[[Image(wiki:EwEugImages:08000028.png)]] '''Eq. 53''' 
    1818 
    1919where ''h,,j,,'' is the predator handling time. The feeding time factors are discussed further in ''Foraging time and predation risk'' (see [[Foraging time and predation.htm|Eq. 65]]). A vulnerability setting of 1 will result in consumption being estimated using bottom-up conditions only through 
    2020 
    21 ../Resources/Images/08000029.png 
     21[[Image(wiki:EwEugImages:08000029.png)]]