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1 Animal
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season is
the wann
season is between May and September, warm and humid. Annual
average temperature is between - 0.1°C and -3.5°C. The coldest
monthly temperature is between -11.6°C and -16.5°C, occurred in
January and the wanmest monthly temperature is between 7.6°C and
9.8*C, in July. Average annual precipitation is 569 millimetres
(Regional Planning Committee et al 1990).
Grassland vegetation is zonal. Bare rock or tundra occurs over 4800-
5000 meters and grows sparse frigorideserta of cilia and spines, like
rhodiola rosea L.. Alpine meadow is between 3800 and 4300 meters,
pnmanly on north, northeast or northwest of slopes, and grows
kobresia capillifolia, kobresia graminifolia etc. Shrub meadow is
between 3800 and 4300 meters, on north, northeast or northwest of
slopes, and grows salix cupularis, potentilla fruticosa etc. Typical
alpine ineadow is on peaks and hummocks between 4300 and 4650
meters, and on south, southeast or southwest of slopes and valleys,
and grows kobresia pygmaea, poa spp., artemisia sp., ligularia sp.,
saxitraga stolonifera etc. Swamp meadow is on valley heads, valleys,
and low part of shaded slopes, over-wet, between 4000 and 4600
meters and. grows arteinisia spp., carex sp. etc. (Regional Planning
Comumittæ et al 1990).
Average population density is 1.25 persons/square kilometres.
Arumal husbandry is the economic mainstay. Raises include Tibetan
goat, yak, and horse.
3. GRASSLAND CLASSIFICATION SYSTEM
3.1. Principles
Type of grassland designate a range unit of similar natural and
economic characteristics at a certain place and a certain period
(Department of Animal Husbandry et al 1996) Grassland
classification of China evolved from two-level system represented
bv professor D. Wang(Wang 1955) in 1950s, to a three-level
phytoecological system bv. professor C. Jia (Jia. 1964, Jia 1980) in
1960s, and to a three-level steppe comprehensive sequential
classification system (Ren et al 1965, Ren et al 1980).
The basic principles taken into account in the definition of grassland
classification system include the following.
(1) Compatibility
The final classification scheme should be compatible, or of
inheritance trom the general grassland classification systems in
China. Climate is the detenmined factor for formation and
development of grassland (Department of Animal Husbandry et al
1996). Landform redistributes water and heat and grassland
vegetation is the core of study (Zhang & Qi 1992),
(2) Herbage and phytomass
The classification scheme should consider economic value,
management and grazing of grassland and phytomuss is also à
import factor witch is related to grazing capacity. Phytomass,
herbage, and vegetation coverage correlates to the degree of
grassland degradation (Li & Huang 1995, Wan & Wang 1990)
(3) Interpretability of remotely sensed unage and feasibility of
grassland mapping
Classified grassland units should be able to be drawn accurately onto
topographical maps (Department of Animal Husbandry et al 1996).
A key element which would be bore in mind for the definition of
grassland classification is the interpretability of cach category on
Landsat TM image, the experimental remotely sensed data, by visual
interpretation. Interpretation of vegetation coverage is of significance
since it is an important factor witch determines phytomass and can
be easily identified on remotely sensed images.
(4) Degenerated grassland
Degenerated grassland is one of the most unportant aspect the
project try to identify by means of remote sensing techniques, The
final classification system should represent some degree of
deteriorated grassland or its development stage.
32. Grassland Classification System
The final land/vegetation unit classification system include three-
level and 15 basic categories in total. Table 1 lists the categories.
e Table 1 Grassland classification system
First Level Second Level | Third Level
# | Name # | Name | # | Name
l | Alpıne 11 Typical alpine meadow
meadow 12 Alpine shrub meadow
13 Alpine swamp meadow
14 Alpine 141 | Severely
degenerated detenorated
grassland grassland
142 | Moderately
detenorated
| grassland
143 | Slightly
detenorated
grassland
15 Primary alpine meadow
2 | Thickets
3 | Settlements
4 | Water 41 River
42 Lake
[43 | Flood plain
| 5 | Burren rock
| 6 | Road [ol | Highway
| | 62 | Rural path
4 | IMAGE INTERPRETATION
4.1. Imagery and data
Two scenes of different time and season were acquired trom the
eng Receiving Station.
Scene |:
Time: December 13, 1996
Band combination: 4(R), KG) and 2(B)
Processing: segmental linear stretch, and geographical registered to
Gauss-Kruger projection.
Hardcopy scale: 1:100000
Sun elevation: 27.739°
Quality: cloud below 5%, snow about 10%, but most on bare peaks,
and no haze.
Scene 2:
Tume: Julv 20, 1995
Band combination: 4(R), 3(G) and 2(B)
Processing: segmental linear stretch, and geographical registered to
Crauss-Kruger projection.
Hardcopy scale: 1:100000
Sun elevation: 55.897?
Quality: cloud below 596, snow below 196, and no haze.
Intemational Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budavest, 1998 301
