China is a vast country with complex geography and climate. It crosses cold, temperate and tropical zones from north to south. The plateaus and high mountains occupy ever 50% of the land surface. Meanwhile, since the late Tertiary, most regions have not been affected by glaciation, thus the fauna and flora are characterized by having many endemic and relic species. Therefore, it is considered internationally that China is one of the megadiversity countries in the world, where the number of specise, as whole, makes up about one tenth of the total species in the world. The ecosystems types arc very rich. The rapid growth rate of population and economic development are the main cause for the threatenedness of ecosystems.

Biotic diversity has been a hot topic internationally in recent years. Biotic diversity includes diversity at three different levels, namely ecosytem diversity, species diversity and genetic diversity. Issues of concern include the formation, current status and evaluation of biodiversity, causes for the loss of biodiversity and the far-reaching consequences of such loss, and the conservation and preservation of biodiversity. Among all these issues, genetic diversity, which includes diversity of microbes, plants, animals as well as human beings, is probably the central issue. This article will introduce some general concepts about the issue, and the application of these concepts by using some of our work as example.

China includes many different environments inhabited by insects, ranging from Palearctic to Oriental realms. More than 45 000 species of insects occur in China, but the status of knowledge varies widely among different groups. The status researches and conservation of insect diversity was introduced.
Insect studies as one of the project of biodiversity must synchronize with the research and protection of plants and animals. To coordinate the research of insect diversity in the Ecological Research Stations is necessary.
The priority sites and priority species of rare and endangered species are suggested. To strengthen biological and ecological studies of rare and endangered species and to edit the "Red List of Insect' are the urgent works in the coming years.

Compared with terrestial and marine ecosystems, freshwater ecosystems, including rivers and lakes, are relatively closed, with low feed-back capacity and stability. However, freshwaterness is one of the major resources that human beings live on. In the past decades, due to erosion caused by deforestation, reduction in lake area caused by drainage to creat arable land, damage to fish resources caused by over exploitation and interception of lakes from rivers, pollution caused by discharge of industrial waste water, and eutrophication caused by discharge of urban sewage, the natural freshwater biodiversity has been damaged to various extents, and reduction in biodiversity has cuased damage to the structure and fuctioning of the freshwater ecosystems, decreasing the availability of this renewable resource. This paper discusses some aspects of biological diversity in Chinese freshwater ecosystems that are of prime importance for research.

Some frontiers in marine biodiversity studies are introduced. Nano-and pico-planktons, primary productivity, some ecological porcesses and energy flow pathways, all of which are of crucial importance for
our understanding of ecological, eneviroimental and climatic problem, are discussed.

Since 1980's, China has made great progress in the construction of the Protected area. This paper briefly introduces its present situation and existing problems, indicates some necessary explicit recognization, Proposed priorites of next 10 years' works.

The botanic gardens of CAS (Chinese Academy of Sciences) have played an important role in the conservation and research of China's wild plant diversity since their establishment. About 13 000 species, or 45-50% of the China's flora, have been cultivated in the botanic gardens of China, in which over 200 species, occupying up to 55-60% of the total plant species that are listed as being rare, endangered and
endemic by the Chinese government, have been emphasized for special and prior conservation. In order to make the conservation more effective, some considerations including key objects and regions for prior conservation of plant diversity, and major fields of research are discussed in this paper.

One hundred steppe communities were investigated on climate gradients in the central Inner Mongolia. The main communities were dominanted by Stipa gobica, S. breviflora, S. krylovii, S. grandis, S.
baicalensis, Aneurole pidium chinense. Filifolium sibiruutn and Festuca dahurica, etc. . Their species diversity features were analyzed in relation to climate factors and grazing intensities. The results showed that species richness (S) in steppe communities was positively correlated with precipitation (S = — 5. 1 • e^0.00627P; r = 0. 85, p = 0. 001), but negatively with temperature (T) (S = 50. 9 • e ^-0.225T; r = 0. 92, p< 0. 001 ). The species richness decreased as climate aridity (A) increased (S = — 41. 81 + 48. 03 e^1/A, p< 0. 001). The communitie diversity had similar tendence of change with species richness along climate gradient. The highest diversity always appeared at moderate level of grazing intensity for a certain commuity. which was due to the prevention of exclusive competition of species by moderate grazing. An integrated schematic model on the relationship of community diversity with climate aridity and stocking rate was proposed.

Chemosystematics and genetic systematics of the practically important Actinomycetes are discussed. Use of new taxonomic techniques to recognize the diversity of Actionmycetes at molecular and gene level is also stated based on the current reaserch of Actionmycetes systematics.

Species diversity is closely related to forests. The major reason for the accelerated extinction of species is deforestation, especially in the tropics. We should attach great importance to reforestation and protection of habitats so as to regain and conserve species diversity. In this paper, we will discuss two methods of reforestation (natural recovery and artificial reconstruction) , and their effects on species diversity increment. We propose that artificial method can raise species diversity more effectively and rapidly than natural method. Meanwhile, based on the fact that high species diversity and ample biological resources exist in Dinghushan Biosphere Reserve, we suggest that more protected areas, even if they are not so big in size, should be established in China to conserve species diversity and protect more forest habitats.

This article described the natural status, and the status of the research and conversation on biodiversity in China.