COINS (COntrol of INvasive Species)

The routine implements a modelling approach for the optimal spatiotemporal control of invasive species in natural protected areas of high conservation value. The model is based on diffusion equations, is spatially explicit, and includes a functional response (Holling type II) which models the control rate as a function of the state variable, i.e. the invasive species density. The control variable is represented by the effort needed to eradicate the invasive species. Furthermore a budget constraint is imposed to the amount of effort made available. The growth of the species is modulated by a habitat suitability function internally computed by using the land cover map of the study area and the map of the initial density of the invasive species. The habitat suitability is evaluated through the frequency of occurrence of each land cover class in a neighborhood of the species points of presence. The routine solves a constrained otpimal control problem by searching for the optimal allocation of effort which minimizes the density of the invasive species in both time and space. In the current version the model is applied to the Ailanthus altissima plant species populating a National Park in the South of Italy (Murgia Alta)