Habitat gradient and reproductive habits of the sevenStellaria species in Japan

Abstract

The author studied the habitat preference, life form, life cycle and reproductive characteristics of the seven species of the genusStellaria along a valley in the northeastern part of Kyoto City. Along the valley 150 quadrats were set from the village up to the hills. The quadrats were sorted into 15 quadrat groups by their affinity in the environment. The quadrat groups were ordinated by the quotients of community and the Bray-Curtis method in order to reveal the complex gradient in the environment. The complex gradient could be best understood by the degree of human disturbance. The seven species showed a continuous distribution along the complex gradient. There existed three patterns in their habitat preference and reproductive characteristics: (1)S. media andS. neglecta grew as annuals in the habitat of severe human disturbance. (2)S. tomentella, S. sessiliflora, andS. diversiflora grew as perennials in the habitat of slight human disturbance. (3)S. aquatica andS. alsine grew as facultative annuals either in the habitat of severe or slight human disturbance.