Background/Question/Methods: By 1600 astute observers around busy settlements and port cities recognized the advents of foreign (sometimes unrecognizable) species of plants and animals that could only have arrived accidentally along with domestic animals, nursery stock, seedstock, discarded ship's ballast (rocks and soil), or trade goods. In the mid-1800s, despite (and perhaps because of) the fact that these populations were often clearly “fit,” thriving and expanding in new locations, such adventive biota were considered interesting at best and deplorable at worst; but all were relegated to the "unnatural" status of known but undomesticated associates of humans. How (if at all) did practitioners of the new science of ecology engage with the prevailing view that the human animal and its commensals were unnatural, and therefore qualitatively different from all others? The answer emerges from a parallel examination of historical findings about scientists' reactions to adventive populations, and maps suggesting how the expansion of human activities and adventive populations of biota gradually rendered most of the biosphere "unnatural."

Results/Conclusions: Despite ecology's view that human populations are ecological entities, few scientists have been willing to argue aloud for admitting the human animal and its "portmanteau biota" of "camp followers," "inquilines", "invaders" or plain old commensals into the company of properly natural objects or phenomena. The model for ecology's conception began to emerge among English botanists in the early 1830s, while Darwin was still aboard the Beagle. The native/alien dichotomy was applied to biota by the early 1840s, and several elaborate taxonomies of nativeness (which I call anekeitaxonomies, from the Greek for "belonging") were proposed and mostly forgotten. Even as the ecological influence of humans and human commensals become increasingly systemic, pervasive and irreversible, ecological discourse persistently stigmatized the biota involved as unnatural, unbelonging, and unqualified for consideration except as aberrations. In the face of this wholesale reconfiguration, ecology still practices a centuries-old tradition of rationalizing hopeful boundaries dividing culture from nature, and belonging from unbelonging, rejecting the present and likely future worlds in favor of a lost and mostly legendary past.