Abstract
The presence and origin of plants listed in the Red Data Book (RDB) were examined in 240 home gardens in each of four villages in Nagasaki, Wakayama and Shizuoka Prefectures of Southwestern Japan in order to address three changes in biodiversity caused by the collection and relocation of plants mainly for ornamental use. Fifty-three RDB plant species belonging to 25 families were recognized, and more than one RDB species was maintained in 82% of the home gardens examined. Interviews of the inhabitants indicated that the primary origin of the RDB plants in the home gardens was collection from their original habitat (89 cases), followed by gifts from relatives or friends (45 cases), and purchase at gardening shops (12 cases). Species richness and the degree of diversity of the RDB plants present in a village were high in the mountainous villages engaging in agro-forestry and low in the seaside villages engaging in fishery. The escape from cultivation of RDB plants in home gardens and the intercrossing of inbred cultivars of RDB species with their natural populations may cause genetic contamination.
