Reproductive Interference between the native and the alien dandelion (Taraxacum) in Izu, Japan

Abstract

Reproductive Interference is a negative interspecific interaction during reproductive processes, which may act a critical role in displacement of native species by its alien congeners. To understand the alien RI effect on distributional relationships of Japanese Taraxacum, we focused on a native species in Izu Peninsula, putatively T. platycalpum, and investigated the coexistence with the alien congener T. officinale and its vulnerability to the alien RI. Our field survey revealed strong negative correlations in the local density between the native and the alien, and reductions in seed-set of the native only when relative abundance of the alien was 80% or more. These results suggest considerable negative effects of the alien RI on the native in Izu only if the native is the small minority at a spatial scale within which RI works, but otherwise the native should be impervious to the alien.