I worked on a research project last summer looking at native and invasive butterfly species in Colorado and comparing the data to records from the 50's (I actually did the plant surveys for the project, not the butterfly data). Invasive butterflies and climate change are indeed pushing native species into smaller and smaller ranges now, with many on the edge of extinction. Butterflies are well studied because they are a good indicator species of what is happening in the environment as they generally respond to the affects of change more quickly than most other species. Sadly, someday we simply won't have many of the species that we have now. We will be left with blank spaces in our beautiful ecosystems.
Andrea at Studio6or7