Fig 1.
Simplified forrester diagram representing the relationships between parameters and main variables of the Human-Plant Coevolution (using R notation; see Tables 1 and 2).
Populations are shown in yellow, their change in red, type-wise vector or array variables in blue, aggregate population variables in orange, and parameters in white.
Fig 2.
A successful case of coupled mutualism and coevolution, as defined in the Human-Plant Coevolution model.
As the interaction between populations (coloured arrows) becomes stronger, carrying capacities increase and populations grow (number of organisms) and stronger mutualism types (stronger colour shades) become more frequent.
Table 1.
Parameters.
Table 2.
Variables.
Table 3.
Variables (output only).
Table 4.
Assumptions on ecological relationships and population dynamics.
Table 5.
Assumptions on population diversity and coevolution.
Fig 3.
Examples of trajectories and end-states produced by the Human-Plant Coevolution model.
A: no coevolution; B: only plant population changes (domestication without cultivation); C: only human population changes (cultivation without domestication); D: some change happens in both populations (diverse populations); E: strong change in both populations (domestication and cultivation). More details on the timing of changes are given in the following sections.
Fig 4.
Example of a simulation run producing a trajectory without coevolution.
The dynamics is reduced to the changes required for the initial populations to adjust their levels and type distribution to the least mutualistic stable state under the given conditions.
Fig 5.
Example of a simulation run with a case of successful coevolution where human and plant populations change roughly at the same time.
Vertical dashed lines mark the timing of change for humans (cyan) and plants (pink). This parameter setting was taken as the default in the R implementation of the model.
Fig 6.
Example of a simulation run with a case of partial oscillatory coevolution where only the human population fully transits to a majority of stronger mutualism types.
The timing of this change is marked by the vertical cyan dashed line.
Table 6.
Parameter classification.
Fig 7.
The importance of parameters measured as a percentage of mean squared error increase (%IncMSE) and total decrease in node impurities (IncNodePurity) obtained by fitting Random Forest Regression models where parameters are inputted as predictors of the human (left) and plant (right) coevolution coefficients; for similar applications, see [69, 70].
The number of trees and number of sampled variables were optimized by a standard 10-fold cross-validation procedure [71].
Fig 8.
The coevolution coefficients and tend resulting from a four-parameter exploration of ,
, UbH1, and UbHn.
The plot depicts examples of facilitators ( and
; values of large grid), and obstructors (UbH1 and UbHn; values of small grids).