The "non-spatial" in non-spatial disperse refers to the fact that this behavior ignores the location of parent trees and scatters seeds uniformly across the plot. Non-spatial disperse has two components: basal-area-dependent seed rain and non-density-dependent (bath) seed rain, the two of which are independent and can be used together or separately. For basal-area-dependent seed rain, the number of seeds added is in direct proportion to the amount of basal area of parent trees of a given species. Bath seed rain adds a constant number of seeds each timestep, even if there are no parent trees of that species in the plot.
Parameter name | Description |
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Intercept of Mean Non-Spatial Seed Rain, seeds/m2/yr | The intercept of the non-spatial seed rain function. This is the bath seed rain term. Set this value to zero to turn off bath non-spatial seed rain. |
Slope Mean Non-Spatial Seed Rain, seeds/m2/ha of BA/yr | The slope of the non-spatial seed rain function. This is the basal-area-dependent seed rain term. Set this value to zero to turn off basal-area-dependent non-spatial seed rain. |
Minimum DBH for Reproduction, in cm | The minimum DBH at which a tree can reproduce. This value does not have to match the Minimum adult DBH. |
Seed Distribution | The distribution method to be applied to seeds (randomization). The forms for these functions can be found here. Choices are:
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Seed Dist. Clumping Parameter (Neg. Binomial) | If you have chosen the negative binomial probability distribution function for "Seed distribution", this is the clumping parameter of the function, in seeds per m2. If you have not chosen that PDFs, then this parameter is not required. |
Seed Dist. Std. Deviation (Normal or Lognormal) | If you have chosen the normal or lognormal probability distribution functions for "Seed distribution", this is the standard deviation of the function, in seeds per m2. If you have not chosen these PDFs, then this parameter is not required. |
Non-spatial disperse calculates how many seeds to distribute as:
In the equation above, μ is the basal-area-dependent seed rain term. Setting this value to zero turns off density-dependent seed rain. κ is the bath seed rain term. Setting this value to zero turns off bath seed rain.
Apply this behavior to adults of the species you wish to use non-spatial disperse.