A theory of seed plant invasiveness: The first sketch

Although biological invasions ale clearly one of the most important impacts humans have had on the Earth's ecosystems, we still do not have reliable tools which can help us to predict which species are potential invaders. At present, several limited generalizations are available for seed plants: (1) invasiveness of woody species in disturbed landscapes is significantly associated with small seed mass, short juvenile period, and short mean interval between large seed crops; (2) vertebrate dispersal is responsible for the success of many woody invaders in disturbed as well as 'undisturbed' habitats; (3) primary (native) latitudinal range of herbaceous Gramineae, Compositae, and Fabaceae seems to be the best predictor of their invasiveness, at least for species introduced from Eurasia to North America; (4) low nuclear DNA content (genome size) seems to be a result of selection for short minimum generation time and, therefore, may be associated with plant invasiveness in disturbed landscapes; (5) analysis of exotic Gramineae and Compositae introduced from Europe to California supports Darwin's suggestion that alien species belonging to exotic genera are move likely to be invasive than alien species from genera represented in the native flora. Fortunately, these seemingly disparate stories can be brought together and provide a foundation for building a general theory of seed plant invasiveness. Copyright (C) 1996 Elsevier Science Limited