Difference between native, nonnative, invasive, and exotic species?

Non-native speciesspread by natural process or human activities ... When anexotic species becomes harmful to the ecosystem, it is called an invasive species. The maindifference between exotic andinvasive species is that exotic species is harmless to the ecosystem whereasinvasive species is harmful to the ecosystem.

Answer: Native species can be the hardest to explain. Simply put, natives are species that are from a particular place without human intervention-humans didn't put them there directly or indirectly. Digging into that a bit means that "native" can vary a lot based on what scale one is considering, and whether or not there are records of pre-settlement organisms (think fossils). As with anything, there are lots of other names for native, like "indigenous." Non-native species spread by natural process or human activities ... When an exotic species becomes harmful to the ecosystem, it is called an invasive species. The main difference between exotic and invasive species is that exotic species is harmless to the ecosystem whereas invasive species is harmful to the ecosystem.