“There is no such thing as a fixed ideal for an environment, no reef onto which nostalgia can anchor. The human imposition of borders on the world inevitably changes our perception of what ‘belongs’ where, but to look into deep time is to see only an ever-changing list of inhabitants of one ecosystem or another. That is not to say that native species do not exist, only that the concept of native that we so easily tie to a sense of place also applies to time.”