An object-oriented model of the invasion and eradication of Poa annua L. on King George Island, Antarctica

Abstract

We implemented a custom object-oriented model to predict the spread of annual bluegrass population at Point Thomas Oasis and to evaluate potential eradication outcome at different eradication success rates. We modeled unobstructed population growth without eradication, sole elimination of plants and removal of plants together with soil within 10 cm around each specimen. Both eradication scenarios considered removal efficiency of 50–100 %. The population with no elimination campaign applied, was still in the exponential phase of growth after 45 simulated years and almost fulfilled the study area. The removal efficiency of 50 % sufficed to control the species, maintaining the population number at a stable and low level. Once the removal action ceased, the population number increased dramatically. 100 % elimination efficiency for 20 years did not guarantee eradication, as leaving even five or less seeds in the soil could initiate population reestablishment. Soil removal within 10 cm around each plant speeded up the elimination. The predicted duration of eradication process to reach 30 or less seeds in the soil, was around 20 years. The removal of annual bluegrass is obstructed by the soil seed bank. The most important parameter driving eradication success is eradication efficiency. Low removal efficiency simulation indicates that poor management, even for a few years, may be amended if the eradication efficiency increases. Our model is transferable for other potential invasive species at Point Thomas Oasis by changing dispersal and germination parameters. Its transferability for other locations would require changing the modeled space.