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features have been replaced by an agricultural landscape owing to the long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 |