Collateral damage: military invasions beget biological invasions

Biological invasions are frequently and closely associated with armed conf lict. As a key element of human history, war involves the invasion of (often distant) enemy territories, during which time species can be translocated, intentionally or unintentionally. Large-scale conf licts such as World War I and II, in which thousands of soldiers and supplies (including foodstuffs) were trans-ported within and between continents, resulted in the spread of non-native taxa. However, smaller scale military actions may also involve rapid movements of troops between geographical areas, potentially facilitating the accidental introduction of species into previously unoccupied areas. Furthermore, invasive pests have occasionally been used by armies as weapons to weaken and dis-rupt opposing forces or nations. The introduction of invasive species during war could be considered relatively minor collateral damage, but many biological invasions in conf lict zones have long-lasting effects. Regulation of military practices to minimize or prevent biological invasions through existing international conventions has so far been unsuccessful, necessitating the develop-ment of additional measures.