Invasion biology: searching for predictions and prevention, and avoiding lost causes.

Abstract

Abstract The introduction and establishment of alien species is one of the many profound influences of ongoing anthropogenic global environmental change. Invasion biology has emerged as the interdisciplinary study of the patterns, processes and consequences of the redistribution of biodiversity across all environments and spatio-temporal scales. The modern discipline hinges on the knowledge that biological invasions cannot be defined and studied solely by their final outcome of establishing alien species but rather as a sequential series of stages, or barriers, that all alien species transit: the 'invasion pathway'. Some of the most important influences for a species transiting these sequential stages (i.e. transport, introduction, establishment and spread) are event-level effects, which vary independently of species and location, such as the number of individuals released in any given location (propagule pressure). The number of studies of biological invasions has increased exponentially over the past two decades, and we now have a significant body of research on different aspects of the invasion process. In particular, the hierarchical nature of the invasion pathway has lent itself strongly to modern statistical methods in hierarchical modelling. Now, the science behind invasive species management must continue to develop innovative ways of using this accumulated knowledge for delivering actionable management procedures.