Species diversity of the genus Echinochloa (Poaceae), native to eastern Australia

a focus on their habitat and the threat of exotic species

Abstract

The natural habitat of the Echinochloa species growing in eastern Australia was investigated in May 2008. In this survey, four annual native species, E. dietrichiana, E. inundata, E. telmatophila, and E. turneriana, and three exotic species, E. colona, E. crus-galli, and E. polystachya, were observed. The native species clearly have separate habitats: permanent stagnant pools for E. dietrichiana, inland floodplains for E. inundata, in or beside streams for E. telmatophila, and inland watercourses for E. turneriana. While the habitat of the exotic species greatly overlap that of the natives, especially perennial E. polystachya, which forms monospecific stands in stagnant pools and in or beside flood rivers due to its remarkable productivity, and E. crus-galli, which has the potential to adapt to several moisture conditions. We predict that the invasive exotic Echinochloa species will become more and more threatening causing serious damage to the native species within the same genus.