naturalization
process by which a non-native organism or species spreads into the wild and its reproduction is sufficient to maintain its population
en-US/ˈnæt͡ʃɹəlɪˈzeɪʃən/
en-GB/ˌnæt͡ʃɹəlaɪˈzeɪʃn/
process by which a non-native organism or species spreads into the wild and its reproduction is sufficient to maintain its population