Invasive species and ecosystem services; good and bad?

Invasive Species: Not Always a Bad Thing? makes the case for the ecosystems service matrix which I began to explain in an earlier posting; Ecosystem services are nested hierarchical processes with two fundamental parts, one being the "natural" system services and the second nested higher level systems being the human, or artificial (artifice-cial) services. for more on this please link to: Sunday, February 15, 2009, Sustainability's Ecosystem Service Matrix

The two parts of ecosystem services are not exclusive from a human perspective, they are linked together as necessary for the continuation of the human species with a quality of life expectation assumed.