Biodiversity in temperate steppe areas

Biodiversity in temperate steppe areas

1 The distribution of temperate steppe in China

3 Human activities threatening the biodiversity of temperate steppes

4 The conservation of steppe biodiversity

1 The distribution of temperate steppe in China

The steppe in China is mainly distributed in temperate regions, occupying vast areas of the Inner Mongolia Plateau and adjacent low mountain and hilly areas. The topography is broad and flat with an average altitude of between 1000～1200m. It joins the Mongolian steppe at its northern side, includes most of the Songliao Plain lying at a low altitude of between 120～500m, and encompasses a part of the Loess Plateau in the southwest, i.e., the east and middle part of Gansu Province, northern Shanxi Province, and northwestern Shanxi Province, climbing up to between 1500～2000 m in height. The plateau is characterized by scattered loess hills and low mountains. Some natural steppe features have been replaced by an agricultural landscape owing to the long history of cultivation.

The Steppe in China can be divided into three sub-zones from east to west: the forest, typical and desert steppes. The forest steppe is a transition sub-zone from the steppe to the forest and is characterized by a semi-moist climate with an annual precipitation of between 350～550 mm and a transitional, lush, rich vegetation, comprising meadow steppe and forest fringe meadow, blending in with island forests, Typical steppe is the major temperate steppe in China, consisting of bunch-grass steppe stretching, as a zone, from the northeast to the southwest. Annual precipitation is between 250(300)～350(450) mm, which enables trees to grow in sandy land and in gullies. Desert steppe is another transition sub-zone from the steppe to the desert. Climate becomes more arid with an annual precipitation of between 150(200)～250(450) mm. The dominant herb is a small species of Sinirnovia, with scattered dwarf grasses and often blending into desert communities. China also has mountain steppes in arid areas and high-cold steppe on the Qingzang Plateau.

2 Biodiversity of temperate steppe

(1) Plant species diversity

a. Plant species richness

According to preliminary statistics, the Chinese steppe zone has over 3,600 species of seed plants, belonging to 125 families. In the Inner Mongolia Steppe zone, 1,519 species of carpophytes have been collected, belonging to 94 families and 541 genera and making up 42.2% of the total of such species in the steppe zone of China. Of these, gymnosperms are represented by 3 families, 7 genera and 16 species, and angiosperms by 91 families, 534 genera and 1,503 species. Of the angiosperms, dicotyledons are represented by 75 families. 413 genera and 1,137 species, and monocotyledons by 16 families, 121 genera and 366 species. These make up 30% of the total families, 20% of the total genera and 6.5% of the total species of plants in China.

The biggest family is the Compositae, having 70 genera, 244 species and making up 16% of the total species of the steppe zone. The second is the Gramineae (62 genera and 192 species), and the third is the Leguminosae (25 genera and 123 species). Six other families each has between 31～50 species and 17 families each has between 11～30 species. The above 25 families totally have 407 genera, making up 73.7% of the number of total genera and 1,401 species, i. e., 92.9% of the total species. Another 35 families each has between 3~5 species while 18 families each has 1 species.

The genera Carex, Artemisia and Astragalus each has over 40 species, i. e., a total of 168 species and are the biggest enera in the Inner Mongolia steppe flora. Of other genera, 6 each has between 20~28 species, 16 genera each has between 10~17 species, and another 516 genera each has less than 10 species.

b. Rich diversity of edificator Stipa

The genus Stipa is distributed extensively in all grassland zones of the world, and often appears as an edificator. There are about 300 species of Stipa in the world. In China, there are 27 species, and of which 16 are editficators of steppe communities and have regular vicarious distributions in different parts of the steppe zone (Table 1).

Table 1 The distribution of the major species of Stipa in the temperate steppe zone

Species	Habitat type
Species	Meadow steppe	Typical steppe	Desert steppe	Mountains in desert area
Section Leostipa
Stipa baicalensis	+
Stipa grandis	+	+
Stipa krylovii	+	+		+
Stipa capillata				+
Stipa bungeana	+	+
Section Smirnovia
Stipa gobica			+
Stipa tianschanica var. klemenzii			+
Stipa glareosa			+
Stipa caucasica				+
Section Barbatae
Stipa breviflora		+	+
Stipa orintalis				+
Stipa purpurea				+
Section Pseudoptilagrostis
Stipa subsessiliflora				+

c. The steppe shrub Cargana has numerous species

Caragana (Leguminosae) is the most typical summer green shrub in central Asia. There are more than 80 species of Caragana in the world with 56 occurring in China Sixteen of these species are concentrated in the temperate steppe and its adjacent mountains, and form a complete ecological series from mesophytic small trees, to xerophytic, intensified-xerophytic and cold-xerophytic dwarf shrubs and cushion shrubs (Table 2).

Table 2 The distribution of species of Caragana in the steppe zone of China and adjacent areas

Species	Life form and ecological habit	Distribution/Habitat
C. sibirica	mesic, small arbor	Aestival-green, broad-leaved forest, in the west foothills of the Da Hinggan Ling
C. rosea	mesic, shrub	North China mountain forest and forest steppe zone
C. ahlbruckner	mesic, shrub	North China mountain forest and forest steppe zone
C. purdomii	xeric-mesic, shrub	Loess Plateau forest steppe zone
C. opulens	mesic-xeric, shrub	Loess Plateau forest steppe zone and western Tibet mountains
C. pruinosa	mesic-xeric, shrub	Vertical zone of mountain in desert area (Long Shou Mountain)
C. microphylla	xeric, shrub	Dry steppe sub-zone on the Inner Mongolia Plateau
C. davazamcii	xeric, shrub	Dry steppe on the Inner Mongolia Plateau; desert steppe, sandland
C. korshinskii	xeric, shrub	Dry steppe on the Inner Mongolia Plateau; desert steppe sub-zone
C. stenophylla	eury-xeric, shrub	Dry steppe on the Inner Mongolia Plateau; desert steppe sub-zone
C. pygmaea	eury-xeric, shrub	Dry steppe on the Inner Mongolia Plateau and steppe-desert sub-zone
C. brachypoda	ultra-xeric, shrub	Desert steppe on the Inner Mongolia Plateau and steppe desert sub-zone
C. leucophloea	ultra-xeric, shrub	Steppe desert sub-zone on the Inner Mongolia Plateau
C. tibetica	ultra-xeric, cushion shrub	Desert steppe on the Inner Mongolia Plateau and steppe desert sub-zone
C. jubata	eury-cold mesic, thorn shrub	North China forest, steppe and mountains in desert areas
C. roboroviskyo	ultra-xeric, thorn shrub	Mountain and dry riverbeds in the Alashan desert zone

d. No endemic families and genera, but some endemic species

There are no endemic families and genera in the Inner Mongolia steppe zone, but there are some endemic species. Plant species endemism is related to the differentiation of habitats in the interior of the plateau. It can be divided into: (1) steppe endemic species, e. g., Allium leucocephallum, A. mongolicum, Sibbaldia sericea and Gypsophila desertorum; (2) sandy land endemic species, e. g., Hedysarum fruticosum and (3) mountain endemic species, e. g., Prunus pedunculata. The endemism of steppe plants still needs to be further studied although documented endemic species are listed in Table 3.

Table 3 Rare and endangered plants of China’s steppes

Species	Endemicity	Life form	Protection rank
Atraphaxis tortuosa	endemic	shrub	1
Aconitum yinschanicum	endemic	herb	1
A. bailangense	endemic	herb	1
Oxtropis yinschanica	endemic	herb	1
Dracocephalum rigidulum	endemic	herb	1
Pinus sylvestris var. mongolica	－	herb	2
Arabis alaschanica	－	tree	2
Prunus pedunculata	－	shrub	2
Oxytropis neimonggolica	－	herb	2
Spongiocarpella grubovii	endemic	semishrub	2
Astragalus hoantchy	－	herb	2
Seseli intramongolicum	－	herb	2
Panzeria alaschanica	－	herb	2
Tugarinovia mongolica	endemic	herb	2
Ophioglossum thermale	－	herb	3
Pulstailla sukaczewii	－	herb	3
Gentiana mandshrica	－	herb	3
Adenophora biformifolia	－	herb	3
Codonopsis pilosus	－	vine	3
Platycodon grandiflorus	－	herb	3
Jurinea mongolica	－	herb	3
Tulipa uniflora	－	ultrashort life	3
Glycine soja	－	herb	3

(2) Animal species diversity on the Inner Mongolia steppe

Inner Mongolia constitutes the main area of temperate steppe in China. Five hundred and fifty-one species of vertebrate animals are recorded from Inner Mongolia steppes. Of these, 65 species are mammals, 295 are birds, 21 are reptiles, 8 are amphibians and 82 are fish.

A unique fauna characterizes the broad and level steppe environment. Representative animals are fast running and ruminating ungulates, and burrowing rodents. Many of these live in high density groups and make long migrations. Some rodents hibernate and store food for winter.

a. Ungulata. Procapra gutturosa is the most dominant and typical ungulate. Its small and light body is extremely good for running. They congregate in large groups before foaling in spring and mating in early winter, and long distance seasonal migrations. The distribution of Procapra gutturosa has been decreased to a narrow strip along the border between Mongolia and China, because of intensive hunting and isolation by traffic routes.

b. Rodentia. Unlike the decrease in the Procapra gutturosa population, the species of Rodentia and Lagomorpha are prospering. There are about 50 species of Rodentia in the steppe, the biggest species being Marmota sibirica. Other common species are Citellus dauricus, Microtus brandti, Meriones unguiculatus, Myospalax aspalax, Allactaga sibirica and some species of Cricetulus, Phodopus and Microtus. Lepus tolei and Ochotona daurica (Lagomorpha) are also widespread on the steppe.

c. Carnivora. The carnivore species are Canis lupus, Vulpes vulpes, V. Corsae and some species of Mustela.

d. Birds. There are few endemic species of birds on the steppes. The main species of birds on the Mongolia steppe are Melanocorypha mongolica and Syrrhaptes paraoloxus. Other widespreaded species are Alaucla arvensis and Eremophila alpestris. Nevertheless, birds of prey are relatively abundant. Common species are Milvus korschum, Aquila repax, A. chrysaetos, Accipiter nisus, A. gentilis, Buteo hemilasius, B. Lagopus and some species of Falco. The large Egyptian vulture, Aegypius monachus, is an important scavenger of dead ungulates.

There are many wetlands distributed in the eastern part of the steppe zone and are used as habitats by migratory birds. Thousands of Grus vipio, Cygnus and Ciconia spp. appear around these waters during autumn. Dalinor, in Chifeng, is the western boundary of the breeding area in China of the Red-crowned crane, while the Ordos Plateau is the eastern boundary of the breeding ground of Larus relictus. Large flocks of Fulica atra are dominant in summers.

e. Insects. Insects are abundant not only in terms of species, but also in terms of biomass. Locusts are the major herbivorous insects, there being about one hundred species, such as Chorthippus spp., Bryodema spp., Dasyhippus barbipos and Calliptamus italicus. The common species of Coleoptera is Holotrichia obilita, which is called the scavenger of the steppes. Butterflies and moths are important insects on the steppe, there being over 150 species of moths in Xilinhot alone.

Further studies are necessary to identify steppe endemics. Nevertheless, among the national protected key animals, 14 species of steppe animals are listed in Class I and 48 species are listed in Class II.

3 Human activities threatening the biodiversity of temperate steppes

(1) Overgrazing and rangeland degradation

Although the area of rangeland is vast in China and has not been fully used, overgrazing and degradation is common. For example, in the Inner Mongolia Autonomous Region, the area of degraded grassland makes up about 50% of the total available while, seriously degraded grassland comprises nearly 20%. In the famous Hulunbeir and Xilinguole Steppes, the areas of degraded and seriously degraded rangeland makes up 23% and 41%, respectively. The most serious degradation (68%) occurs in the rangeland of the Ordos Plateau.

(2) Excessive mowing and indiscriminate harvesting for medicinal herbs

Intensive mowing, year after year, has made the natural productivity of rangelands decline, species richness fall, and reduced the excellent Leguminosae forage, while poor quality Compositae and Chenopodiaceae forms have increased. Medicinal herbs have also been illegally uprooted and collected. The numbers of many natural medicinal herbs that used to be widely distributed in the steppes, such as Ephedra, Glycyrrhiza uralensis, Astragalus membranaceus, Saposhnikovia divarication, Bupleurum chinese, polygala tenuifolia, Cistanche deserticola and Cynomorium songaricum, have been dramatically reduced and some are even facing extinction.

(3) Grassland reclamation and farmland sandification

There are some multi-suitable land resources in the Chernozem and dark Chestnut soil areas of the forest steppe. Most of these, however, have been opened up and become an agriculture base for food production and a diversified economy. With population growth, however, the demand for food has increased and steep slopes, sandy land, and even fixed sand-dunes have been opened up. Rangelands have been destroyed and farmlands sandified. These have drastically decreased the biodiversity and value of the steppes.

(4) Coal and oil exploitation and the pollution of the steppe environment

Mineral resources, especially the reserves of coal, oil and natural gas, are abundant in the steppe regions of China. Economic development needs, have led to the exploitation of these underground resources on a large scale. This will inevitably result in the destruction of the grassland ecosystem structure and its ecological processes.

(5) Indiscriminate killing of wildlife

Few Mongolian gazelle, which wandered the Inner Mongolia steppes in large herds in the 1960s, are only just surviving today because of indiscriminate killing. Based on the latest data, as many as between 70,000~80,000 Mongolian gazelle have been killed each year in this area since 1980. This has resulted in a dramatic decrease in the Mongolian gazelle, Birds of prey which were once common on the steppes, such as Accipiter nisus, Milvus korschum and Buteo hemilasius, have become rare. In contrast, the reduction in natural enemies has resulted on the increase of some kinds of graminivorous mouse, such as Microtus brandri. It reaches disastrous numbers during the breeding seasons.

Under the influence of the above human activities, the Chinese temperate steppe is rapidly degrading. An accurate analysis of biodiversity losses is not known because detailed studies and monitoring data are not available. Nevertheless, the rapidly decreasing species should be listed as now rare and/or endangered. Special attention must be paid to endemic species.

4 The conservation of steppe biodiversity

Some measures should be taken to protect Chinese steppe biodiversity, as follows:

(1) To strictly implement the “Grassland Law of the People’s Republic of China”

The enforcement of the law and the legal management of rangeland are fundamental to the maintenance of steppe biodiversity.

(2) To strengthen the steppe natural conservation region system and improve the management of steppe biodiversity conservation.

Since 1980, various grassland conservation regions have been established on the steppes, and a network of steppe conservation regions has also been formulated. Nevertheless, the low management level in most conservation regions, research weaknesses, low technological abilities, simple, crude, equipment, and insufficient funds, should all be improved.

(3) To enhance scientific research and formulate action plans

Based on the requirements of the overall objective for biodiversity protection in China, and considering the increasing intensity of steppe resource utilization and ecological deterioration, new policies for animal husbandry adapted to the special local social structure and new systems for resources management must be formulated in order to protect steppe biodiversity and facilitate the sustainable use of rangeland.