This is a very philosophical issue, and one that I enjoy immensely. I don't necessarily consider these alien invasions to be unnatural. Sure, humans caused them, but then humans are part of the natural environment too. Don't get me wrong. I think these alien invasions can be tragic, and I applaud efforts to contain, control, and prevent them. But I choose not to think of them in terms of humans versus nature. These are all natural processes. Species have been wiping each other out for ages. Humans are probably the first species with the capacity to understand their impact on the planet and likewise be equipped to regret & learn from (and consequently modify) their actions! This Massachusetts ban is certainly intriguing. Banning the import of aggressive plants is a good first step, but now eliminating them from the landscape is the bigger challenge! Dennis in Cincinnati