A simple framework for an invasive species early warning system for counties

The number of non-native species establishing in the United States is continuing to rise. After prevention fails at the national level and a species becomes established, reproduces, continues to spread, and becomes invasive, the most successful action at a local level is early detection followed by eradication.  It has become increasingly important to have tools and technologies to predict where species may appear.  We have developed a simple early warning modeling tool for non-native plants that uses readily available species distribution and environmental data that could aid in prediction when more detailed species abundance and distribution data are lacking.  We demonstrate the utility of habitat matching models for ten species with various levels of current county level distributions for the continental United States and with differing historically documented distributions from a time series of Pacific Northwest county level data.  For species with currently limited distributions, the predicted maps of the United States limited the search area, and the time series analysis indicated that this method could be useful in limiting the counties that need to monitor for a particular non-native species or group of invaders.