| Biological diversity or biodiversity is the complexity of living organisms, as well as all relevant ecological processes. Biodiversity is the fundamental feature of all life systems. Biodiversity exists at a variety of biological levels such as genes, cells, tissues, organs, populations, species, communities, ecosystems and landscapes. Most of biodiversity studies have been carried out on the three levels genetic diversity (gene diversity), species diversity and ecosystem diversity.Conservation biology is a synthetic branch of science, studying biodiversity conservation. One objective of conservation biology is to understand the effect of human activities on species, communities and ecosystems, the other is to develop practical methods to keep species from extinction, and to recover the normal functions of endangering species in the ecosystem. The key research field of conservation biology is to study the mechanisms of species endangering and extinct. China Plant Red Data Book (Vol.1) classified the threatened species as endangered, rare and vulnerable ones. The conservation biology for endangered plant species aims to clarify the internal mechanism and external factors of plant species' endangerment to develop ways and measures to keep the species from endangerment.Sorbus amabilis Cheng ex Yii belongs to Rosaceae and Sorbus, and an endemic species of East China, being an ornamental or used as architecture and pharmacy material. Its distribution area and amounts are declining, which was listed in the third class of the national protection plant species in 1984.This paper studied the biological and ecological aspects of S. amabilis, including geographical distribution, biological characteristics, ecology, propagation biology and genetic diversity. The threatening factors have been analyzed and several measures for effective preserving the species have also been proposed. The results are as follows:1. S. amabilis distributes in Anhui, Hubei, Zhejiang and Fujian provinces. The natural distribution area of S. amabilis is very narrow, fragmentary andclumped. It is confined to mountainous region, with an altitude of 900-2000m, 晈ith Mount Huangshan and Mount Dabieshan as its distributing center.2. S. amabilis is suitable to cool, moist, misty and humid habitat, with humus-riched dark yellow-brown acidic soil well-drained and strict demands for light, temperature and humidity.3. S. amabilis propagated mainly by seeds, occasionally by forming clones. Seeds germinated into seedlings in suitable habitat, with the two cotyledons coming up out of soil.4. Most of the S. amabilis populations are small or rather small. As S. amabilis has a high demand for light, it lives at the edge or the gap of the forest. As an accompany species in its communities, S. amabilis does not have a strong competition predominance against other species.5. In most of the S. amabilis populations, the young individuals are few, the adult ones are in an inferior position in community succession, and the population size is tending to decline.6. The flowering and fruiting dates varied in different years and in different habitats (especially light and temperature conditions). The flowering characteristics had a distinct correlation with the factor of light. Mean number of inflorescence per plant, and flowers per inflorescence were different from each other with the change of altitude and light.7. The seed quality of S. amabilis was very poor, and percentage of seeds with vitality was low, which restricts the spreading of populations of S. amabilis.8. Seed germination biology of S. amabilis was studied. The results showed: (1) The freshly harvested seeds were in dormancy during winter; (2) In the different natural habitats, the germination rates of the seeds were very low (around 8.92%); (3) Under 60% natural light conditions, the percentage of germination was highest. The germination rates of the seeds showed different from one another under different light conditions; (4) The temperature rang...
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