3. SPECIES DIVERSITY

3.1. Megadiversity

China is a vast country with complex topogeography and climate. It crosses frigid, temperate and tropical zones from north to south. The plateau and high mountains occupy over 50% of land. Biogeographically, China is situated in both the Palaearctic and Oriental Realms. Meanwhile, during the late Tertiary, most regions had not been effected by glaciation, thus the fauna and flora is 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 species, as a whole, make up about one tenth of the total number of species of the world.

Wild Yak (Bos grunniens) threatened in the wild in Qinghai-Xizang (Tibet) Plateau.	Tibetan Antelope (Pantholops hodgsoni), an endemic species of the Qinghai-Xizang ( Tibet) Plateau but threatened by poaching and habitat destruction.

Surveys of animals, plants and cryptogam revealed that some differences still exist in the studies of different populations. New taxa and new records are gradually being published. Through 1980-1986, the number of new species of insects and angiosperms have increased by 500 respectively. The invertebrates and cryptogams are only a little known which accounts for the difference between known and actually existing number of species. For example, insects account for 80% of the species known in the animal kingdom worldwide. However, insects in China account only for one tenth of the total number of the world. The number of species which had been named does not exceed 40,000, which is about one fourth of the total. Approximately 70% of insect species remain to be described. On the other hand, the number of species of mammals, birds, reptiles, amphibians and fishes, as well as mosses, ferns, gymnosperms and angiosperms are more or less better documented.

Numbers of Species in China and the World

Taxa	Spp.of China(SC)	Spp.of world(SW)	SC/SW(%)	Estimated Nos.in the world
Mammals	499	4,000	12.5	5,000
Birds	1,186	9,040	13.1	11,000
Reptiles	376	6,300	6.0
Amphibians	279	4,184	7.0
Fishes	2,804	19,056	12.1	28,000
Insects	40,000	751,000	5.3	1,500,000
Bryophytes	2,200	16,600	13.3
Pteridophytes	2,600	10,000	26.0
Gymnosperms	200	520	37.8
Angiosperms	25,000	220,000	11.4
Fungi	8,000	46,983	17.0	1,500,000
Bacteria	500	3,060	16.3	30,000
Algae	5,000	26,900	18.6	60,000

Cathaya argyrophylla, monotypis genus, endemic to China.

　

3.2. Endemism

A species distribution at certain limitation is known as specific phenomenon. For example. the monotypic genus of Cathaya argyrophylla only occurs in southern parts of China, the Yangtze River Dolphin (Lipotes vexillifer) only lives in lower reaches of the Yangtze River, the Giant Panda (Ailuropoda melanoleuca) is confined to the S.W. mountainous region, Sichuan, Gansu and Shaanxi. These are the endemic genera and species in China. In addition, some species, e.g. Cryptomeria found in China as well as in Japan, are regarded endemic taxa to east Asia. Therefore, the term endemism means a taxon with its distribution only in a specified region as compared with those taxa occurring throughout the world. Study of endemism is important in understanding the characteristics and formation of fauna and flora, and also in determining the priorities of conservation and sustainable use of biodiversity. A number of endemic taxa including higher ones are recognized and the main endemic taxa in China are shown in following table.

Number of Endemic Genera or Species in China

Taxa	Known gen. or spp.	Endemic gen. or spp.	%
Mammals	499 spp.	73 spp.	14.6
Birds	1,186 spp.	99 spp.	8.3
Reptiles	376 spp.	26 spp.	6.9
Amphibians	279 spp.	30 spp.	108
Fishes	2,804 spp.	440 spp.	15.7
Bryophytes	494 gen.	8 gen.	1.6
Pteridophytes	224 gen.	5 gen.	2.2
Gymnosperms	32 gen.	8 gen.	2.5
Angiosperms	3,116 gen.	232 gen.	7.4

Paphiopedilum armeriacum, an extremely rare and precious ornamental plant, found in 1980's.	Bretschneidera sinensis, monotypic genus, confined to China.
Camellia chrysantha, "Golden Hue", a rare species of the genus.
A diantum reniforme var. sinensis, discovered recently for the first time on the continent of Asia.	Golden Monkey (Rhinopithecus r. roxellanae) an unique monkey confined to China but also threatened by poaching and by habitat loss.

3.3. Status

In the process of evolution, the speciation and extinction of species were more or less kept on par. Today, however the extinction is greater than evolution of new species. Due to human interference as well as loss of natural habitat, biological resources are being exhausted at an alarming speed. It is reported that two species of birds become extinct every three years and, by the year 2000, this could reach the level of one species every year. It is estimated that by the end of this century, there will be 50 or 60 thousand plant species becoming threatened in various degrees, and at present the extinction of plant species goes at the rate of one species every day worldwide. In that case, half or one million species of animals and plants may become extinct within next two decades. The present few million species are the modern-day survivors of several billion species that have ever existed. All past extinction occurred by natural processes but today human interference is responsible for rapid extinction of species. Scientists have conducted a series of surveys on biotic and natural resources, accumulating valuable materials. A rough estimation shows that in China about 398 vertebrate species are endangered amounting to 7.7% of the total vertebrate. In plants, the rare and endangered species are as follows: Bryophytes 28, Pteridophytes 80, Gymnospermae 75, Angiospermae 836, in total 1,019 species, amounting to 3.5% of the higher plants.

Estimated Number of Endangered Species in China

Crested Ibis (Nipponia nippon) a critically endangered bird of the world with its distribution confined only in a small area of the Qingling Mountain and its population size estimated no more than few dozens.

Siberian Tiger (Panthera tigris altaica) critically endangered in China.

It is estimated, however, that there are 10% of plant species endangered or vulnerable in temperate zone, while in tropical and subtropical zones it is much higher. Owing to heavy deforestation, the estimated proportion of endangered or vulnerable plant species in China is about 15-20%, i.e. about 4,000 5,000 species of higher plants.

Based on the records of the extinction of plants and animals in Chinese history, animals species of Rhinoceros sp., Elaphurus davidianus, Saiga tatarica, Panthera tigris lecoqi, Pygathrix nemaeus, as well as plant species of Thuja sutchuensis, Ombrocharis dulcis, Machilus minutiloba etc. disappeared for decades or even centuries. It is believed that the Saiga (Saiga tatarica) extirpated in Xinjiang just after 1950's.

The species threatened at the brink of extinction are: Nipponia nippon, Panthera tigris allaica and P. t. amoyensis, Neofelis nebulosa brachyurus, Ailuropoda melanoleuca, Presbytis spp., Hylobates spp., Dugong dugung, Cervus eldi, Lipotes vexillifer, Archinecttia gaudissartii, Diplandrorchia sinica, Cycas hainanensis, Cepha.lotaxus mannii, Panax zingiberensis, P. ginseng, Gastrodia elata, Cistanche deserticola, Boschniakia rossica, Paeonia suffruticosa var. papaveracea, etc. Among these species, the Crested Ibis (Nipponia nippon) was still abundant in a rather wide range in the 1950's but only a small population was found in the late 1970's.

There are difficulties in estimating the endangered species of many groups such as insects, snails and other invertebrates, fungi and mosses, etc. Many of them are not described. There might be many more endangered species in lower plants, but at present even an estimate numbers are unavailable.

Chinese Monal (Lophophorus lhuysii), an endangered species and one of the 1st Catagory Protected Species in China.

3.4. Threats

3.4.1. Habitat Destruction

The main cause of extinction is destruction or loss of habitat, whether it is through land reclamation, an excessive forest felling or draining of fresh and salt marsh. For example, Hainan Island had 25% of natural forest in 1956, however it amounted to 7.2% in 1983. Large numbers of animals and plants become endangered and some extinct, such as Cephalotaxus mannii, Firmiana hainanensis, Paranephelium hainanensis, Sonneratia hainanensis. The coral reef in the South China Sea has been harvested excessively, resulting in disappearance of the coral reef fish through destruction of their habitat.

Destroyed tropical rainforest in S. Yunnan.

Fur trade, showing some endangered wildlife species traded in the market.

3.4.2. Over-exploitation

In 1950's, the macaque was captured in large numbers, and combined with habitat loss, the population declined on a large scale and have not yet recovered. Animal resources such as gazelles, deer, fur-bearing animals as well as freshwater fish have declined because of over-harvesting of fishing.

Poachers in a reserve in S. Yunnan.

3.4.3. Pollution

The freshwater in China is seriously polluted by industrial waste water causing major decline of aquatic fauna and flora. Serious pollution occurs in the sea and near the seashore from oil spillage. Some aquatic species are endangered while others became extinct such as Grass Carp, Silver Carp, Variegated Carp, Crucian Carp, Catfish, Pike, Black Carp and Triangular Bream, etc. in the Songhua River. Air pollution, acid rain and pesticides should be considered as important factors of species decline.

Besides, introduction of exotic species, the construction of new cities, dams and reservoirs, mining industries, as well as natural disasters such as earthquake and volcano eruptions, floods, forest fire, snowstorms, droughts, animal and plant diseases, insect pests, etc. are also threatening causes of plant and animal species reduction.

In conclusion, biological resources are renewable and will serve mankind forever only if they are properly conserved and rationally utilized.

NNP in China, one of the result concerning IGBP by Laboratory of Quantitative Vegetation, Institute of Botany, Chinese Academy of Sciences.

Previous Chapter		2. HABITAT AND ECOSYSTEM DIVERSITY
Next Chapter		4. GENETIC DIVERSITY
Content Page		Biodiversity Committee, CAS	中国科学院生物多样性委员会

Copyright (C) 1992 by Science Press