US: Infestations of exotic plants negatively impact human health, the economy, native species and processes of the ecosystem. The article, Forecasting Weed Distributions using Climate Data: A GIS Early Warning Tool, in the October–December issue of the journal Invasive Plant Science and Management suggests a GIS-based solution to deal with this issue.
According to the article, such situation calls for an early warning system. The authors of this article present a GIS-based analysis to predict where weeds might strike next. This offers an important management tool of early detection. However, this is not meant to displace other, more accurate methods of detection, such as the use of point location data, but to offer a rapid response based on estimation.
Through GIS, an “environmental envelope” is created for each environmental variable for each species, establishing a range within which a species can survive. For example, in counties where an exotic species is found, the highest and lowest recorded temperatures are noted. This range is then compared to counties where the species is not found to determine if its temperature range might eliminate or justify a threat of invasion.
Once a many number of such climatic variables are examined, a species may be added to a watch list for a specific county. These watch lists can assist managers in making decisions about early warning, control prioritisation and targeting research to specific locations within counties assessed as vulnerable.
The GIS method was validated by a time series study of 66 species in counties in the Pacific Northwest and the Rocky Mountains. The analysis successfully selected counties that experienced exotic weed invasions in subsequent years.