European emigrants and their descendants are all over the place, which requires explanation

Alfred Crosby, Ecological Imperialism, 1986.

And some other quotations that appear in the book:

Yet, if we wield the sword of extermination as we advance, we have no reason to repine the havoc committed.

Charles Lyell, Principles of Ecology, 1832.

When civilized nations come into contact with barbarians the struggle is short, except where a deadly climate gives its aid to the native race.

Charles Darwin, The Descent of Man, 1871.

and my favourite:

We have the apparent double anomaly, that Australia is better suited to some English plants than England is, and that some English plants are better suited to Australia than those Australian plants were which have given way before English intruders

Joseph Dalton Hooker, 1853.