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features have been replaced by an agricultural landscape owing to the long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