Conservation for regional populations of endangered plant species growing in seminatural ecosystems

对北海道3个地方种群的生境、繁殖特征和种群结构进行了调查。这种林下草本植物是日本最典型的春季短命植物之一，其栖息地受到土地利用变化的威胁。研究地点是该物种分布范围最东端附近的Tanno镇，朝日市的tosho -zan和Shintotsukawa镇的Pin-neshiri。田野镇生长季节的温度条件比托索赞和平内什里更恶劣。虽然在本州岛的日本菊似乎是异交种，但传粉实验表明，日本菊种群不仅具有自交亲和性，而且具有自动自交传粉能力。旭川人略微具备这两种能力，但pinneshiri人没有。以叶面积鉴定的最大个体大小从pinneshiri、Tosshozan到Tanno依次递减。这两种能力的程度似乎与研究地点的栖息地条件有关。采用Leslie矩阵模型对tosho -zan和Tanno种群进行了种群动态模拟。无论种群的初始生长率如何，无论是在土正赞种群还是在天野种群中，灭绝的可能性都很低。综上所述，三个种群处于稳定状态，灭绝概率较低。需要进一步研究种群的遗传多样性，以及由于自亲和性而导致近亲繁殖枯竭的存在。

We investigated habitat condition, reproductive characteristics and population structure in three local populations of Erythronium japonicum in Hokkaido. This understory herb is one of the most typical spring ephemerals in Japan, and the habitat of the species has been threatened by land use changes. The study sites are Tanno town near the easternmost part of the distribution range of the species, Tossho-zan in Asahikawa City, and Pin-neshiri in Shintotsukawa town.The temperature condition of growing season was harsher in Tanno town than in Tosshozan and Pin-neshiri.Although E. japonicum seems to be an outcross species in the Honshu island, pollination experiments showed that the Tanno population has not only self compativility but also automatic self pollination ability. The Asahikawa population slightly has both abilities, but the Pin-neshiri population does not. Maximum individual size identified by leaf area was decreasing order from the Pin-neshiri, the Tosshozan, to the Tanno populations. The extent of both abilities seems to be accompanied with the habitat conditions of the study sites.Population dynamics was simulated by Leslie matrix model for the Tossho-zan and the Tanno populations. Regardless to initial growth rates of population, the probabilities of extinction were low not only in the Tossho-zan population but also in the Tanno population.Based on the results mentioned above, it is concluded that the three populations studied are in stable conditions, and have low probabilities of extinction. Further studies will be needed for genetic diversities of the populations, and for the presence of inbreeding depletion as a consequence of self compatibility.