POTENTIAL AND LIMITATIONS OF PREDICTING INVASION RATES

Invasions by two species are analyzed, that of the collared dove (Streptopelia decaocto Privaldszky) invading Europe, and that of the African bee (Apis mellifera scutellata Ruttner) invading tropical South America, Central America and the southern part of North America. The analysis is made in terms of population growth and dispersal. After this analysis, the observed parameter values are altered to investigate the sensitivity of the expected velocity to small changes in life history and long-distance dispersal. This gives an impression of how likely it is that species, once confined to a certain geographical region, expand their range, invading virgin regions beyond their former range limit. The results of this approach are compared with the common theory concerning invasion-proneness of species and biotypes. The present theory seems to offer a more parsimonious explanation of invasions than does the common theory based on static properties.