XVI International Botanical Congess
Effects of isolation on a population growing in small islands were studied on a vulnerable species, Pinus armandii var. amamiana distributed in Japan. All populations in islands have diminished so quickly in their size because of excessive felling and insect damages that the population is fragmented into small pieces. Regeneration is very difficult and few seedlings can be observed. Number of seeds per cone is low and the seed fertility is very poor, but we could promote seed productivity and restore seed qualities by artificial cross-pollination. From those results, it is considered that isolation and fragmentation increase the frequency of self-pollination and prevent regeneration in this species.