I've seen various articles about how the arbitrary herbiciding of GMO crops has reduced milkweed from 100 Million Acres of land. Google loss of milkweed/habitat and numerous information comes up concerning the peril of monarchs as a result of GMO crops.
If you want to help prevent additional habitat loss, write your politicians and ask that they remove support from Monsanto and of GMO crops. If one can afford it, shop at specialty stores that have a policy that no products they sell carry GMO ingredients (Whole Foods enacted this). Reduction in meat eating will also lend towards lack of support of GMO crops since these crops assist as animal feed for ultimate human consumption. Lastly, support of your local, organic farmer will redirect your money away from GMO crops. We can make a difference in this area with our personal choices and with our collective voice.