I work for my state Department of Natural Resources and one of my duties is pulling out invasive (non-native) plants, and birds. (Tree of Heaven, Garlic Mustard, and House Sparrows mostly) You can speculate on the need for controlling an invasive without seing its impact on the native species, but it is a hole nother matter once you see the impact first hand. non-native species compete with native species for limited resources, and the non-natives often win due to a lack of biological controls. There is a moral question when controllin invasives, especialy when you have not seen the damage they can cause. Did you know that non-native House Sparrows kill native Blue Birds for thier nests? Did you know that non-native Brown Tree Snakes have nearly eradicated all the native birds in Gaum? Some things to think about before you condem "richy rich" countries for controling invasive exotics.
Although the report talks about the iguana problem from a human impact perapective, however the real problem is their impact on the environment. This is especialy true for an island ecosystem with limited resources.