Biodiversity in temperate steppe areas

1 The distribution of temperate steppe in China

2 Biodiversity of temperate steppe

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 Some natural steppe features have been replaced by an agricultural landscape owing to the long history of cultivation.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
	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