Subject: What is the difference between an 'invasive' and an 'evasive' species?

I understand the difference between invade and evade, and have seen many 
references to invasive species (which I also understand).  Recently I have seen 
some references to "evasive" species and in the context of the articles, it 
seems like the author is describing an "invasive" species.  My first conclusion 
was that the author was using "evasive" incorrectly, but while searching I 
discovered several articles that talk about "evasive" species.  I can't seem to 
figure out the difference.

Re: What is the difference between an 'invasive' and an 'evasive' species?