Changes between Version 5 and Version 6 of EwEugSpatialOptimizationProcedures


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Timestamp:
2010-01-31 16:09:48 (9 years ago)
Author:
varunr
Comment:

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  • EwEugSpatialOptimizationProcedures

    v5 v6  
    3434[[Image(wiki:EwEugImages:03000010.png)]] 
    3535 
    36 where ../Resources/Images/03000011.png  is baseline Ecopath biomass for group (../Resources/Images/03000005.png), and ../Resources/Images/03000012.png equals the group biomass ../Resources/Images/03000007.png if ../Resources/Images/03000013.pngis lower than the mandated biomass, ../Resources/Images/03000014.png for the group, and ../Resources/Images/03000014.png if it is not. 
     36where [[Image(wiki:EwEugImages:03000011.png)]]  is baseline Ecopath biomass for group ([[Image(wiki:EwEugImages:03000005.png)]]), and [[Image(wiki:EwEugImages:03000012.png)]] equals the group biomass [[Image(wiki:EwEugImages:03000007.png)]] if [[Image(wiki:EwEugImages:03000013.png)]] is lower than the mandated biomass, [[Image(wiki:EwEugImages:03000014.png)]] for the group, and [[Image(wiki:EwEugImages:03000014.png)]] if it is not. 
    3737 
    38 The mandated rebuilding objective can be used to set ‘minimum biological acceptable levels’ (or MBAL as commonly used). By setting high mandated biomasses (../Resources/Images/03000014.png) for a group it can also be used to capture ‘existence values,’ e.g., of marine mammals of interest for a whale watching industry. We do not discount the mandated rebuilding structure over time. 
     38The mandated rebuilding objective can be used to set ‘minimum biological acceptable levels’ (or MBAL as commonly used). By setting high mandated biomasses ([[Image(wiki:EwEugImages:03000014.png)]]) for a group it can also be used to capture ‘existence values,’ e.g., of marine mammals of interest for a whale watching industry. We do not discount the mandated rebuilding structure over time. 
    3939 
    40 The ecosystem structure objective is meant to capture that mature (K-type) ecosystems tend to be dominated by long-lived species and individuals (Odum, 1969). We seek to capture this characteristic through the inverse production/biomass ratio, estimating for each time step (../Resources/Images/03000001.png) 
     40The ecosystem structure objective is meant to capture that mature (K-type) ecosystems tend to be dominated by long-lived species and individuals (Odum, 1969). We seek to capture this characteristic through the inverse production/biomass ratio, estimating for each time step ([[Image(wiki:EwEugImages:03000001.png)]]) 
    4141 
    42 ../Resources/Images/03000015.png 
     42[[Image(wiki:EwEugImages:03000015.png)]] 
    4343 
    44 where ../Resources/Images/03000016.png is the overall ecosystem structure measure, and ../Resources/Images/03000017.pngthe ecosystem structure factor for (../Resources/Images/03000005.png). We provide default values for ../Resources/Images/03000018.png in form of the inverse ../Resources/Images/03000019.pngratios (unit year), supplied as part of the basic parameterization of the Ecopath model. To avoid unduly influence by very short-lived species we have (arbitrarily) set ../Resources/Images/03000017.pngto 0 for groups with an average lifespan of less than a year, (i.e. groups whose ../Resources/Images/0300001A.png is less than 1 year-1). 
     44where [[Image(wiki:EwEugImages:03000016.png)]] is the overall ecosystem structure measure, and [[Image(wiki:EwEugImages:03000017.png)]] the ecosystem structure factor for ([[Image(wiki:EwEugImages:03000005.png)]]). We provide default values for [[Image(wiki:EwEugImages:03000018.png)]] in form of the inverse [[Image(wiki:EwEugImages:03000019.png)]] ratios (unit year), supplied as part of the basic parameterization of the Ecopath model. To avoid unduly influence by very short-lived species we have (arbitrarily) set [[Image(wiki:EwEugImages:03000017.png)]] to 0 for groups with an average lifespan of less than a year, (i.e. groups whose [[Image(wiki:EwEugImages:0300001A.png)]] is less than 1 year^-1^). 
    4545 
    4646The ecosystem structure objective is not discounted over time; having long-lived species in the future being deemed as important as having them now. 
    4747 
    48 As a measure of biomass diversity, we used a modified version of Kempton’s Q75 index, originally was developed to describe species diversity (Kempton, 2002). We here used a biomass diversity indicator following Ainsworth and Pitcher (2006), albeit slightly modified. We estimate the biomass diversity index (../Resources/Images/0300001B.png from 
     48As a measure of biomass diversity, we used a modified version of Kempton’s Q75 index, originally was developed to describe species diversity (Kempton, 2002). We here used a biomass diversity indicator following Ainsworth and Pitcher (2006), albeit slightly modified. We estimate the biomass diversity index ([[Image(wiki:EwEugImages:0300001B.png)]] from 
    4949 
    50 ../Resources/Images/0300001C.png 
     50[[Image(wiki:EwEugImages:0300001C.png)]] 
    5151 
    52 here ../Resources/Images/0300001D.png is the number of functional groups, and ../Resources/Images/0300001E.png is the biomass of the (../Resources/Images/0300001F.png)th most common group, using a weighted average of the two closest group if (../Resources/Images/0300001F.png) is not an integer. The biomass diversity index describes the slope of a cumulative group abundance curve. As a sample with high diversity (evenness) will have a low slope, we reverse the index and express it relative to index value from the Ecopath base run (../Resources/Images/03000020.png) 
     52here .[[Image(wiki:EwEugImages:0300001D.png)]] is the number of functional groups, and [[Image(wiki:EwEugImages:0300001E.png)]] is the biomass of the ([[Image(wiki:EwEugImages:0300001F.png)]])^th^ most common group, using a weighted average of the two closest group if ([[Image(wiki:EwEugImages:0300001F.png)]]) is not an integer. The biomass diversity index describes the slope of a cumulative group abundance curve. As a sample with high diversity (evenness) will have a low slope, we reverse the index and express it relative to index value from the Ecopath base run ([[Image(wiki:EwEugImages:03000020.png)]]) 
    5353 
    54 ../Resources/Images/03000021.png 
     54[[Image(wiki:EwEugImages:03000021.png)]] 
    5555 
    5656We truncate the index in the extreme and unlikely case that ../Resources/Images/03000022.png would more than double from the base run. We only include higher trophic level groups (TL>3) in the calculation of the biomass diversity index – should this, for models with only few functional groups, lead to less than 10 groups being included in the calculations, we, however, base the calculations on all living groups. As for the other ecological indicators we do not discount future index values.