The five species were selected in part because they represent the most problematic plants in the western U.S. The study authors created "bioclimatic envelope models," wherein the authors identified where the invasive plant species occurred, and identified critical climate variables such as precipitation patterns and temperature patterns that are associated with the presence of the invasive plants under investigation. The authors then determined what combined set of climate variables best described the distribution of these weeds, and mapped all of the places in the U.S. where these climate conditions occur.
Developing such models is important because scientists can use them to assess how changing climate conditions might affect the distributions of invasive plants. Maps of how invasion risk is likely to change with global warming are also important for land managers designing long-term protocols for fighting invasive plants.
The researchers employed 10 atmosphere-ocean general circulation models (AOGCMs) that predict what climatic conditions in the West are likely to be in 2100 if emissions are not limited, and matched those predicted conditions to the climate conditions associated with each of the invasive plant species. The projected invasive species distributions for each of the models were added together to create a map of invasion risk under future climate conditions.
"Just as native species are expected to shift in range and relative competiveness with climate change," the authors wrote, "the same should be expected of invasive species."
Specifically, the researchers concluded that climate change is likely to expand invasion risk from yellow starthistle in California and Nevada and lands currently occupied by invasive populations of the weed in California, Oregon and Washington are unlikely to become unsuitable for the species; hence, they have low
|Contact: Lucy Collister|