Using invasion process theory to enhance the understanding and management of introduced species: a case study reconstructing the invasion sequence of the common myna (Acridotheres tristis).

Research indicates that invasion is a multi-step process, where each stage is contingent on the stage that precedes it. Numerous hypotheses addressing the factors that influence each stage of the invasion process have been formulated, but how well does this theory match what occurs in the natural world? We created a general conceptual model for the invasion process based on invasion theory. Using a composite 41-year data set, we then reconstructed the invasion sequence of the common myna (Acridotheres tristis) to investigate the similarities between invasion theory and this observed invasion. We observed a lag period before population growth of 2.7 (±0.3) years, a maximum rate of population growth of 24.1 (±6.4) birds per km(2) per year, a lag period before spreading of six years and an average spreading rate of 0.4 km per year. The length and duration of these stages correspond closely with what invasion process theory would anticipate. We suggest that a conceptual model, coupled with basic species, environment and event information, could be a useful tool to enhance the understanding and management of invasions.