David I. Theodoropoulos, Las Sombras Biological
Preserve, Box 337, La Honda, CA 94020-0337 USA
!INVASION OF THE ALIENS!
Science or Pseudoscience?
Paper presented at the 26th Annual Natural Areas Association Conference, Tucson, Arizona, October 1999.
The theory of harmful "alien invasions" is widely promoted. Examination of the origins of "natural" communities, ongoing natural movements and the plasticity of natural successional trajectories demonstrates that the concepts of "nativeness" and "alienness" on which invader theory rests are non-operational constructs dependent on arbitrary spatial and temporal scales, useless in the construction of a testable scientific theory. Following an Edenic mythos of coevolved equilibrium communities, nativists inappropriately impose an idealized European parkland on natural areas. Field work finds introductions ecologically integrated, stands of "invaders" disturbance indicators only, with high levels of diversity and beneficial effects, phenomena invisible to nativists due to confirmatory bias. Anti-invader literature is a deeply contaminated information-pool, with low standards of evidence, unsupported causal attributions, circular reasoning, data-mining, and other pseudoscientific characteristics. Field work among nativists found high resistance to contradictory evidence, faulty ingroup/outgroup categorizations, self-sealing arguments, defensive projection, conformation with the frustration-aggression-displacement theory of prejudice, and strong parallels with the conspiracy-theory psychologies of xenophobia and racism. The origins of the anti-exotics movement in the 1930s in National Socialist Germany confirm this. Through media sensationalism invader hysteria is promoted by the herbicide and regulatory industries. In furthering their economic interests dangerous and ill-advised extermination projects become widespread. We must decisively reject exotic-invader theory or find ourselves discredited. We must recognize the full spectrum, from functionalist rehabilitation through historical restorations, to the hyperdiverse compositionalist refuges of the future.