August 2007. A question was asked if basil and red amaranth were invasive species, presumably to Marshall Islands. It was also said that some people consider that some species are invasive by nature, even though it might take some time (a dormant period can be 1 to 80 years) for them to become so. According to this definition of ???invasive???, there???s no such thing as invasive to country A or B.
Definitions can be awkward at times, but it???s becoming clear among the “feral species community” of researchers that if a species is considered “invasive” then it is in the uppermost level of potential impacts with an ability to spread and naturalise.
If a species took 80 years to naturalise and then started spreading, it was doubtful that anyone could call that invasive unless its behaviour, after those 80 years, had radically changed. Only a few cases are known like this, and normally it is because of changes brought about by human activitiy.
Invasive is an overused and abused term in many respects. Perhaps the questions to ask are:
1. Could this species naturalise here?
2. Is it invasive elsewhere in similar climates, soils, landuses, etc?
The first picture looks like an ornamental variety of Coleus sp, (not Amaranthus). Coleus scutellarioides often escapes cultivation and locally become weedy in a number of Pacific Island countries.