The biodiversity of the high-cold Qingzang
plateau
3 Severe
threats to the biodiversity of the Qingzang Plateau
4 Urgent
measures to protect the biodiversity of the high-cold areas of the Qingzang
Plateau
The
Qingzang Plateau, with an average elevation of 4,500 m, towers over the west of
China. The length of the plateau from east to west is 2,500 km, the widest
place from the south to the north is 1,200 km, and the total area is 2 million
km2. It is the highest plateau on Earth, and known as “The roof of
the world”. The characteristics of the plateau are freezing weather, dry,
windy, low oxygen, strong solar radiation, great temperature differences
between day and night, and a unique biodiversity.
(1) Species abundance
According
to the results of several dozen biological surveys, over 12,000 species in
1,500 genera of vascular plants, i. e., 40% of the total of the country, have
been found in the plateau, including the Himalayas and the Hengduan Mountains.
Of the lower animals, it is known that there are 458 species of aquatic
protozoans, 208 species of rotifer, and 59 species of Crustacea, in addition to
2,340 species in 1,160 genera, 173 families and 20 orders of insects in the
Tibetan part of the plateau, Of the vertebrates, there are 152 species in 45
genera, 5 families and 3 orders of fish in the plateau, and there are 1,047
species in 343 genera of terrestrial vertebrates which is 43.7% of the total in
China. (Table 1).
Table 1 Species abundance of terrestrial
vertebrates in the Qingzang Platean.
|
Class |
Family
|
Genus
|
Species |
Percentage
of the country |
|
Mammalia |
28 |
102 |
206 |
41.3 |
|
Aves |
63 |
263 |
678 |
54.5 |
|
Reptilia |
8 |
43 |
83 |
22.1 |
|
Amphibia |
9 |
21 |
80 |
28.7 |
|
Total |
108 |
434 |
1047 |
43.7 |
In
the high-cold areas above 4,000 metres, there are 955 species of vascular
plants, making up 8% of this kind of plant in the plateau and 3.2% in the
country. Corresponding figures for terrestrial vertebrates are 215, 20.5% and
9.2%, respectively (table 2).
Table 2 Species abundance of vertebrates in the
high-cold Qingzang Plateau
|
Class |
Species
in the high cold area |
Percentage
of the total species in the Qingzang Plateau |
Percentage
of the total species in China |
|
Mammalia |
53 |
25.7 |
10.6 |
|
Aves |
150 |
22.1 |
12.6 |
|
Reptilia |
5 |
6.0 |
1.3 |
|
Amphibia |
7 |
8.9 |
2.5 |
|
Total |
215 |
20.5 |
9.2 |
(2) Endemic species
Based on a
preliminary survey, there are about 60 endemic genera of vascular plants on the
plateau. The exact number of species is not, however, clear. Some endemic
species are: Ajaniopsis penicillifomis, Bolocephalus saussureoides, Parapteropyrum tibeticum, Lomatogoiopsis alpia, Cortilla hookeri, Sinoleontopodium lingianum and Xizangia
serrata.
By comparing
the original endemic species in the high-cold areas (mainly distributed in
high-cold meadows, steppes and deserts) with the endemic species of the
surrounding mountains, it is known that: (a), the numbers of high-cold endemic
mammals and birds are more than in the surrounding mountains. In a sense, the
higher the elevation and the more specific the ecological conditions, the more
endemic species; (b), in contrast, there are more mountain-specific endemic
species of reptiles and amphibians in the surrounding areas below 4,000 m where
the mild and humid weather is more favorable for their survival (Table 3).
Table 3 The endemic
terrestrial vertebrates of the Qingzang Plateau,
as compared with the
surrounding mountains*
|
Class |
Mammalia |
Aves
|
Reptilia |
Amphibia |
||||
|
Endemic species |
Species |
% |
Species |
% |
Species |
% |
Species |
% |
|
Plateau |
25 |
12.10 |
33 |
6.13 |
8 |
9.60 |
5 |
6.40 |
|
Hengduan Mountains |
19 |
9.20 |
10 |
1.87 |
7 |
8.40 |
23 |
29.50 |
|
Himalayas |
7 |
3.40 |
15 |
2.80 |
17 |
20.50 |
17 |
22.00 |
|
Hengduan-Himalayas |
8 |
3.90 |
83 |
15.50 |
— |
— |
4 |
5.00 |
|
Total |
59 |
28.60 |
141 |
26.30 |
32 |
38.5 |
49 |
62.90 |
*percentage=endemic
species/total species in Qingzang Plateau (×%).
The main
ecosystems of the plateau comprise forest, high-cold bush and meadow, high-cold
steppe and high-cold desert. The first of these has been discussed in Chapter
3.3 and will be omitted here. The other ecosystems occupy a vast area which
makes up more than three fourths of the whole plateau and are spread in a zonal
pattern from the southeast to the northwest. The environmental conditions of
the ecosystems are high altitude, drought, low temperature, low oxygen, very
windy and strong solar radiation. The composition, structure and feature of
these ecosystems are unique, due to the high-cold conditions.
(1) The high-cold bush and meadow ecosystem
This is
distributed in the northeast of the plateau with an average elevation of 4,000
m and an annual rainfall of between 300~700 mm. The annual mean temperature is
3 to –4℃,
the mean temperature of the hottest month is 5~13℃, and the maximum highest
temperature is 20~28℃. The mean temperature in the coldest
month is -7 to -17℃ and the minimum lowest temperature is -30
to -40℃.
Solar radiation is very strong. It is very windy in winter and storms and hail
are frequent in summer.
The principal
part of the ecosystem is elevated-cold meadow with Kobresia pygmaea, K. pusilla, K.
prainii, K. royleana and K. littledalei as
dominant species; the elevated-cold plateau bushes are distributed as patches
in areas with mild environmental conditions, or as scattered individuals in
grassy marshlands where the dominant species are Rhododendron trichostomum, R.
nivale, R. setosum, R.
laudandum, Potentilla glabra,
P. fruticosa, Salix oritrepha and Caragana jubata.
There are 7
species of Amphibia in the high-cold bush and meadow ecosystems, such as Batrachuperus tibetanus,
Scutiger boulengeri, S.
mammatus and Andrias davidianus.
The first two species are endemic to Tibet and the latter two are Chinese
endemics. In addition, there are Rana
temporaria and Nanorana.
There are only 3 species of reptiles: Phrynocephalus
vlangalii, Leiolopisma tsinlingensis and
Agkistrodon strauchi.
These are endemic to the plateau, except the second. The common species of
birds is bush niches are Perdix
hodgsoniae, Phasianus colchicus,
Anthus hodgsoni, A. roseatus, Turdus ruficollis,
Phylloscopus affinis and Carpodacus
pulcherrimusm, while the dominant species of birds in
the meadows are Calandrella rufescens and
Melanocorypha maxima. Of the mammals, fur animals such as Martes foina, Vulpes ferrilate,
V. vulpes and Felis manul and endemic species such as Cervus albirostris,
Moschus sifanicus, Myospalax baileyi and Ochotona thibetana used to inhabit the
bush environment.
The species
number and representatives of the dominant species in the ecosystem are listed
in Table 4.
Table 4 Species
numbers and representative species in the high-cold bush
and meadow ecosystems
of the Qingzang Plateau
|
|
Class |
Family |
Genera |
Species |
Typical species |
|
Higher plants |
Seed plants |
43 |
140 |
500 |
Dominated by Kobresia with shrubs, Rhododendron
spp., Caragana spp., Salix spp. |
|
Vertebrates |
Amphibia |
4 |
5 |
7 |
Batrachupperalus
tibetanus,
Andrias davidianus, Satiger spp.,
Rana temporaria |
|
|
Reptilia |
3 |
3 |
3 |
Phrynocephalus
valangalii,
Leiolopisma tsingensis, Agkistrodon
strauchi |
|
|
Aves |
29 |
70 |
103 |
Perdix
hodgsoniae,
Calandrella rufescens, Anthus
roseatus, A. hodgsonii, Turdus ruficollis,
Carpodacus pulcherrimus, Phasianus
colchicus |
|
|
Mammalia |
14 |
31 |
45 |
Martes
foina,
Vulpes ferrilata, V. Vulpes, Cervus albirostris,
Moschus sifanicus, Myospalox
baileyi, Ochotoma thibetana |
|
|
Total |
930 |
249 |
648 |
|
Compared
with the mountain bush meadows at the upper limit of the forest in the Henduan
Mountains and the Himalayas, many typical mountain forest and bush species such
as Lerwa lerwa, Tetraophasis obscursu,
Crossoptilon crossoption, Certhia
himalayana, Alcippe striaticollis, Moschus fuscus, Hemitragus jemlahicus,
Ochotona royle and O. Himalayana, are not foumd in the former. The large Artiodactyla which inhabit
the open gentle high-cold meadows, such as Procapra
picticaudata, are also not found
on the mountain bush meadows.
(2) The high-cold steppe ecosystem
The
high-cold steppe ecosystem spreads to the west of the high-cold bush meadow
ecosystem and the middle Qingzang Plateau. The elevation here is about
4,500~5,000m with a typically continental plateau climate characterized by
freezes, drought, and average annual temperature from 0℃ to -5℃, a lowest temperature of -40℃, and an annual rainfall of
between 100~400 mm. In winter, it is very windy, clear and dry, with extremely
strong evaporation and very strong solar radiation.
Stipa purpurea is the most important,
widespread, and typical species in the high-cold steppe, followed by S.
basiplumosa, S. glareosa, S. roborowskyi and S.
subsessiflora. Other species are Carex moorcroftii, Artemisia younghushandii, A. wellbyi and A. stracheyi.
A few
common species of reptiles in the high-cold steppe ecosystem are Phrynocephalus vlangalii, P.
theobaldi and Agkistrodon stauchi. Dominant species of birds are Calandrella acutirostris, Alauda gulgula, Eremophila alpestris,
Pseudopodoces humilis,
Mongtifringilla adamis, M. tazanowskii, M. blanfordi, Syrrhaptes tibetanus and Tetraogallus tibetanus. All the above species, except Calandrella and Alauda, are endemic to
the Qingzang Plateau. Species of mammals, such as Marmota himalayana and Pitymys
leucurus, Ochotona curzoniae, Lepus oiostolus, Procapra piticaudatea,
Pantholops hodgsoni and Bos mutus, are not only representative of the
high-cold steppes, but are also endemic to the Qingzang Plateau.
The
ecosystem was formed during the uplifting of the plateau in the Caenozoic Era.
Species diversity is thus much lower than on long-standing temperate steppes.
In addition, the harsh ecological condition also decreases its species
abundance which is even lower than that of the high-cold bush meadow ecosystem,
e. g., there are no amphibians (Table 5).
Table 5 Species numbers and representative
species in the high-cold steppe ecosystem
|
Class |
Family |
Genus |
Species |
Typical
species |
|
|
Higher plants |
Seed plants |
40 |
133 |
＞300 |
Stipa
purpurea, S.
basiplumosa, S.
glareosa, S. roborowskyi, S. subsessiliflora, Carex moorcroftii Artemisia
younghusbandii, A.
wellbyi, A. stracheyi |
|
Vertebrates |
Reptilia |
2 |
2 |
3 |
Phrynocephalid
vlangalii, P.
theobaldi, Agkistrodon stauchi |
|
|
Aves |
33 |
79 |
118 |
Calandrella
acutirostris, Alauda gulgula,
Eremophila.
Alpestris, Pseudopodoces humilis, Mongtifringilla adamis, M. traogallus tibetanus |
|
|
Mammalia |
15 |
28 |
35 |
Marmota
himalayana, Pitymys leucurus,
Ochotona curzoniae,
Lepus oiostolus, Procapra
piticaudata,
Pantholops hodgsoni |
|
|
Total |
90 |
242 |
＞456 |
|
In
the high-cold steppes, in comparison with the temperate steppes of northern
China, there is a striking lack of those species which inhabited forest
steppes, bushes at the forest fringe, and bushes such as Crossoptilon auritum,
Petaurista xanthotis, Tamiops spp.,
Cervus elaphus and Felis bengalensis.
(3) The high-cold desert ecosystem
This kind
of ecosystems spreads to the west and northwest of the Qingzang Plateau, where
the elevation is between 4,200~4,500 m with freezing conditions and extraordinary
droughts. The main features of the climate are: an average annual temperature
from –3 to –10℃; 9~10 months with a monthly mean
temperature of below 0℃; minimum lowest temperature of below -40℃; an annual precipitation of
less than 20~100 mm and mostly in the form of snow; strong solar radiation;
windy winters; and extremely strong evaporation. The plants of the area are
more sparse (the cover is less than 10%) than that in the high-cold steppes,
and the species are extremely monotonous, dominated by xerophytes and cushion
plants. There are no amphibians and reptiles. Species diversity is simple.
The principal plants of the ecosystem are cushiony Ceratiodes compacta, Ajania tibetica and Artemisia rhodantha. The representative bird species are Syrrhaptes paradoxus, Prune