A mathematical analysis of factors affecting the rate of spread of patches of annual weeds in an arable field

Abstract

A model is presented of the spread of a weed from a point source, with dispersal being both unaided and aided by a combine harvester. Four 'type' weeds were modeled, chosen to represent species of differing population and dispersal ecologies and based broadly on Avena spp. (wild oats), Raphanus raphanistrum (wild radish), Bromus spp. (bromegrass), and Fumaria spp. (fumitory). Wind-adapted species were excluded. The greatest rate of spread was predicted to be for R. raphanistrum and the least for Fumaria, regardless of whether dispersal by combine harvester was included. Rate of spread was more sensitive to dispersal parameters than to demographic parameters and increased up to 16-fold as soo..