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clGrid * | mp_oSeedGrid |
| Pointer to the "Dispersed Seeds" grid created by disperse behaviors.
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clGrid * | mp_oPredatorGrid |
| Pointer to predator grid.
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std::string | m_sOutput |
| File to which to write intermediate output, if desired.
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float * | mp_fMaxInstantaneousDeclineRate |
| Max instantaneous rate at which predator abundance declines in the absense of food, number of predators per week - array index is 2 (# seasons)
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float * | mp_fDemographicEfficiency |
| Population's demographic efficiency - array size is 2 (# seasons)
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float * | mp_fDensityDependentCoefficient |
| Density-dependent coefficient - array size is 2 (# seasons)
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float * | mp_fForagingEfficiency |
| Foraging efficiency - array size is # behavior species.
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float | m_fPredatorInitialDensity |
| Predator initial density - number per square meter.
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float * | mp_fMaxIntakeRate |
| Maximum seed intake rate - number of seeds per predator per day - array size is # behavior species.
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float | m_fProportionGerminating |
| Proportion of seeds that germinate each week in the germination period - this must be a number between 0 and 1.
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float | m_fCellArea |
| Area of a seed grid grid cell in square meters - when multiplied by the density of predators, produces the number in the cell.
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float | m_fOfftake |
| Offtake rate - proportion of total seeds eaten, between 0 and 1.
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float * | mp_fTempSeeds |
| A place to stash the number of seeds, to allow easy collaborative access to this data between functions.
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float | m_fTempPredators |
| A place to stash the number of predators, to allow easy collaborative access to this data between functions.
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int | m_iNumWeeksToModel |
| Number of weeks to run the model.
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int | m_iNumWeeksSeedFall |
| Number of weeks of seed fall.
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int | m_iWeekGerminationStarts |
| Week in which germination begins.
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int | m_iWeekSeason2Starts |
| Week in which season 2 begins.
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short int * | mp_iSeedGridCode |
| Data member codes for seed grid for number of seeds.
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short int | m_iNumPredsCode |
| Data member in the predators grid.
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bool | m_bPreservePredatorDensities |
| Whether or not to carry over mouse population densities.
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bool | m_bIsLinked |
| Whether this is the linked (true) or standalone (false) version.
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short int | m_iNumSpeciesTypeCombos |
| How many type/species combos a behavior will act on.
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short int | m_iNumBehaviorSpecies |
| How many distinct species are in the combo list - important for filling species-specific values from parameter file.
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short int * | mp_iWhatSpecies |
| List of distinct species - for filling species-specific values from parameter file.
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stcSpeciesTypeCombo * | mp_whatSpeciesTypeCombos |
| Array of species/type combos that the behavior will act on.
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short int | m_iNewTreeInts |
| The number of new tree integer data members this behavior wants to add.
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short int | m_iNewTreeFloats |
| The number of new tree float data members this behavior wants to add.
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short int | m_iNewTreeChars |
| The number of new tree character data members this behavior wants to add.
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short int | m_iNewTreeBools |
| The number of new tree boolean data members this behavior wants to add.
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short int | m_iBehaviorListNumber |
| The number of this behavior in the behavior list, to differentiate between possible multiple copies of this behavior.
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float | m_fVersionNumber |
| Version number - this will be rounded to 2 digits after the decimal place.
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std::string | m_sXMLRoot |
| XML root that encloses the parameters for this behavior.
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float | m_fMinimumVersionNumber |
| Minimum version number - this behavior will run parameter data for a file marked between this number and the current version number, inclusive.
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std::string | m_sNameString |
| If a behavior has registered a command line command with the sim manager, this allows it to be called.
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clSimManager * | mp_oSimManager |
| Pointer to the simulation manager object.
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int * | mp_iAllowedFileTypes |
| List of the input file types this object can handle.
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int | m_iNumAllowedTypes |
| Number of input file types this object can handle.
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Models functional response seed predation.
This runs as a model-within-a-model, in weekly timesteps for a year. It doesn't matter if the length of the overall model timestep is longer than a year; the amount of seeds is treated as a one-year pool, which produces the same result.
This behavior reduces the number of seeds available in the "Dispersed Seeds" grid. In each cell of that grid, there are a certain number of predators (calculated from the initial density of predators) which have the number of seeds present in that cell as a food source. Each species to which this behavior is applied has its own parameters controlling how it is predated.
Seed rain is evenly divided over a set number of timesteps (weeks). The predator population has as a food source the number of seeds added during the current week's rain (if the rain is going on) plus any leftover seeds from previous weeks which have not been consumed. Beginning at a certain week in the spring, the number of seeds available to the mice is further reduced by a certain percentage each week to simulate germination. Once germination begins, it continues until the predator model finishes running. In order to correctly calculate mouse consumption and ensure that the seeds which germinate are actually available later, this keeps track of the seeds consumed; it is this number which is subtracted from total seeds at the end.
The predator population is updated each timestep as a response to number of seeds consumed. The response parameters can be divided into two seasons.
Seed offtake for each week is calculated as
O = Σ IRs * N
where
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0 = offtake
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IRs = per capita seed offtake for each species
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N = number of mice
Per capita seed offtake for each species is
IRs = cs(1 - e-(S*D)) * ps where
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cs = maximum seed intake rate per predator per day (a species-specific input parameter)
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S = number of seeds per predator per day
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D = foraging efficiency (a species-specific input parameter)
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ps = the proportion of the total seeds belonging to that species
The number of predators in each cell's population is calculated as
Nt = Nt-1 * ert-1
where
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Nt = number of predators for the current timestep
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Nt-1 = number of predators in the previous timestep
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rt-1 = instantaneous rate of change in predator abundance for the previous timestep.
The instantaneous rate of change, r, can use different parameters for two user-defined seasons. r is calculated as
r = (a + d(IR) + g(N))/12 where
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IR = sum of the IRs for each species
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a = the maximum instantaneous rate at which predator abundance delines in the absense of food (an input parameter, season 1 or 2)
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d = population's demographic efficiency (an input parameter, season 1 or 2)
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g = coefficient describing the effect that density-dependent factors have on r (an input parameter, season 1 or 2)
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N = number of predators per hectare
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divided by 12 - to take from per quarter to per week
This behavior must be used in conjunction with a disperse behavior. If such a behavior is not present (and thus the "Dispersed Seeds" grid is not present), a fatal error will be thrown during setup.
This behavior can be used as an independent behavior where seeds are removed, or it can be linked to another behavior (i.e. the neighborhood seed predation behavior, clNeighborhoodSeedPredation) and used to calculate a whole-plot offtake amount without actually removing any seeds. It's possible to use both in a single run so separate parameters are used for each.
The namestring and parameter file call string are "FunctionalResponseSeedPredation" when used alone, or "LinkedFunctionalResponseSeedPredation" when linked with another behavior.
Copyright 2011 Charles D. Canham.
- Author
- Lora E. Murphy
Edit history:
--------------—
October 20, 2011 - Wiped the slate clean for SORTIE 7.0 (LEM)