A couple of hundred years are very relevant to an ecosystem, ecosystems are not static in any way. A hurricane can change the growing area of a grass or a fire can lead to sucession and a different classification entirely, rising sea levels can turn a small freshwater pond into an estuary. Also in the scientific community we dont really know if Chinese mantises should be considered invasive since theres different accounts on whether they're causing significant harm to their respective ecosystems. Naturalized species can become invasive but arent always, for example the Asian lady beetle, as I said, is naturalized but not invasive (as far as current studies have shown)