ECOLOGY OF WILD-RICE PLANTED IN TAIWAN .1. SEQUENTIAL DISTRIBUTION OF SPECIES AND THEIR INTERACTIONS IN WEED COMMUNITIES

To learn about the conditions necessary for recovering the wild-rice (Oryza rufipogon) populations in Taiwan which became extinct around 1978, abandoned lowland fields selected at several locations were denuded and puddled, wild-rice seedlings were space-planted, and were observed without particular intervention for four years. The distribution of weed species developing in the field, including the wild rice, was exclusively lognormal, suggesting that species interactions are multiplicative. The component species of each community changed rapidly with secondary succession, and their interactions appeared to be diffused in general. But the fate of introduced wild-rice populations depended on the competition with a particular grass species, Leersia hexandra.