This is a beautifully simple ecological network model that can simulate predator-prey and competitive multispecies dynamics. This is the B model of the paper 1, I read it long ago and for many years I wanted to make a version of it, finally, I did it.
You can find the source code here https://github.com/lsaravia/snim, to install it you need to clone it using git clone or download and compile it, following the instructions in the README will be enough.
SNIM This is a C++11 implementation of a stochastic multispecies model. The model has multiple applications to investigate the relationship between ecological interactions (competition, predation) and diversity. It involves a discrete definition of individuals belonging to a given set of species. The dynamics are essentially probabilistic at the microscopic scale, but it leads to recognizable macroscopic patterns both in space and time. The model in is actual version is spatially implicit but a spatially explicit version is planned (never did it).