Observations on Alpine Grazing in Bhutan
Tsering Gyaltsen and Sangay Dorji
Ministry of Agriculture; Royal Govt. of Bhutan, Thimpu, Bhutan
Introduction
Bhutan has a geographical area of 40,077 km2, which can be divided, into three distinct
physiographic zones: the southern foothills, the “inner” Himalayas, and the great Himalayas. The
southern foothills consist of the Siwalik hills adjacent to a narrow track of flat plains along the
Indian border and the altitude varies from 200 to 2000 metres above sea level (masl). The
“inner” Himalayas, made up of the main river valleys and steep hills, arise at elevations from
2000 to 4000 masl. The great Himalayas in the north along the Tibetan border consist of snowcapped peaks and alpine rangelands above 4000 m.
In Bhutan, the closest nomenclature which conforms to the definition of rangelands is ri which
literally means a range shed, when used in the context of a source of grazing, collection of
firewood and non-edible products, medicinal plants or incense plants. Rikha means on the range
and rikhaley means from the range. The term tsadok (also: tsadrog, tsamdo) is synonymous with
rangelands and means grazing land. Historically, in Bhutan as well as many other countries, the
definition is based on the kind of use, usually equated with grazing. Hence in official records or
in local lexicons, one comes across terms such as yari, guenri, sori; etc. for summer, winter, and
spring grazing ranges (Gyamtsho 1996).
In Bhutan, the latest land use figures indicate that the area of land registered as grazing land
(tsadok) is 413,622 ha (10.3 %) which can be loosely equated to rangelands as defined above
(LUPP/MoA, 1995). In general, current approaches to rangeland condition rely on comparisons
of species composition (relative biomass) of present vegetation compared to the ‘climax’ or
‘potential natural’ vegetation for the site. Vegetation is rated as poor, fair, good, excellent (or as
low seral, mid seral, high seral, potential natural) according to its similarity to the climax
(TGUCT, 1995). Departure from the climax, or retrogression, is generally attributed to livestock
grazing and occurs as a result of “years of overgrazing or of grazing intensity” (Stoddart et al.
1975). In Bhutan, livestock grazing is also considered as the main cause of rangeland denudation
although no quantitative data is yet available to support this statement. There is general
reluctance to admit that vegetation changes may occur as a result of many factors rather than
grazing, e.g. fire, lack of fire, extreme weather and natural events, climatic change, land use
change, invasion of exotic species, grazing by wild herbivores, and rodent activity (Gyamtsho,
1996). Only Gibson (1991) reported that rangeland degradation in western Bhutan might be
caused more by natural factors and grazing by herbivores other than domestic livestock.
50
Types of Alpine Rangeland
Gyamtsho (1996) reported that alpine rangelands are located at distances ranging from 15
minutes to 3 days journey with yak herds from the villages (1 day of herd journey = half day
journey without herd). The diversity in vegetation influenced by altitude, slope direction, and
slope gradient results in considerable variation both between and within range sites. Based on the
dominant vegetation cover, alpine range sites can be classified into the ecological types
described below, which are consistent with the descriptions provided by Rawat and Wangchuk
(1995).
Alpine Scree Slopes (AS): An area usually between 4800 and 5500-m covered with rock
outcrops and largely devoid of vegetation. Male yaks often get access to vegetative spots during
summer. Some rare species of plants are collected for medicinal or incense purpose.
Alpine Meadows (AM): The zone of herbaceous vegetation below the scree slopes between
3700 and 5000 m in the gentler slopes. Economically this is the most important ecological site
providing most of the grazing grounds for yaks. It is the main zone where yaks and other
herbivores compete for forage. Incense and medicinal plants are also collected.
Dry Alpine Scrub (DAS): An area between 3700 and 4200 m on dry south- and southeastfacing slopes with dominant scrub cover but intermixed with open-grazed meadows. Most of the
winter grazing areas are within this ecotype. Incense and medicinal plants are collected.
Moist Alpine Scrub (MAS): An area between 3800 and 4200-m covered with dense scrub
usually on north- and northwest-facing slopes largely inaccessible for grazing. The undergrowth
of bush plants, Forbes, and grasses are collected for making hay. Some incense, medicinal plants,
and mushrooms are collected from this ecological site.
Sub-Alpine Forest (SAF): The forest zone between 3300 and 3700 m, the south-facing slopes
of which are subject to grazing in winter while the steep north-facing slopes are covered with
relatively thick stands of fir trees. Firewood and timber are obtained from this area.
Riparian Forest (RF): This ecological site is found along the banks of streams. The vegetation
composition changes with elevation and other physical characteristics. Occasional grazing and
camping takes place in this area.
The physical features, including the proportion represented by each ecological type of selected
alpine range sites are presented in Table 1. The alpine range sites are predominantly located on
south-facing slopes varying in altitudes between 3300 m and 5100 m. Most of the areas are steep
to very steep with a mean gradient range from 26 to 55%. The proportion of area under each
ecological type varies considerably between sites. For example, the area under alpine meadows
varies between 20 to 100% with a mean of 55%.
The floral composition of the different ecological types is shown in Table 2. Delphinium and
Gentiana species can be found at altitudes up to 5000 m along with Carex, Poa, and Agrostis
51
species. The most common Forbes in the meadows between 3700 m and 4200 m are Aster,
Potentilla and Anemone species.
Table 1: Physical features and area proportions under different ecological types of selected
alpine range sites in Bhutan.
Range Site
Laya
1. Lungothang
2. Omtsa
3. Rodophu
4. Ngarithang
5. Chukarthang
6. Limethang
7. Shingja
8. Tsherijathang
Lunana
9. Ganglakachu
10.Tenchothang
11.Nyisharling
12.Pangtegang
13.Mendathang
Lingshi
14.Zumeri
15.Gopula
16. Jarila
Mean
Slope
Directio
n
Altitude
Range
(m.a.s.l.)
Slope
Angle
(%)
RF
(%)
SAF(
%)
MAS
(%)
DAS(
%)
S, SE
SE
S, SE
S, SW
SE, NW
S
SE, NW
SE, NE
3700-4100
3300-3800
3800-4600
4100-5200
3800-4500
3800-4300
4000-4500
3800-5100
15-45
20-60
15-60
20-45
10-60
05-45
30-50
05-60
0
10
10
0
10
10
15
10
5
40
5
0
5
10
15
0
0
0
30
10
30
30
0
0
30
20
15
20
20
20
30
20
55
30
30
60
20
30
40
60
10
0
10
10
15
0
0
10
SE
E
NE
E
E
4600-5100
3800-4500
4000-4300
4100-4350
4000-4100
45-60
30-60
40-60
40-70
0
0
10
0
0
0
0
20
0
0
0
0
20
0
0
0
0
30
10
10
0
40
20
90
90
100
60
0
0
0
0
E
S
SE,W
3900-4800
4100-4800
4300-5000
3430-4600
40-70
50-70
40-60
26-55
0
0
10
5
0
0
0
4
0
0
10
10
0
0
20
100
100
20
0
0
40
55
15
AM
(%)
AS
(%)
10
Key: RF = riparian forest; SAF = sub-alpine forest; MAS = moist alpine scrub; DAS = dry alpine scrub; AM = alpine meadow;
and AS = alpine scree slopes.
Table 2. Floral composition of ecological types of alpine rangeland in Bhutan
Ecological Site
Main
Genera
Tree Main Scrub Main
Genera
Genera
Alpine Scree slopes (AS) 4800-5500m
Alpine
Meadows (AM) 3700-5000 m
Dry Alpine (DAS) Juniperus,
3700-4200 m
Abies
Juniperus,
Ephedra,
Lonicera,
Rosa,
Forb Main
Grass
and
Sedge
Genera
Delphinium,
Carex,
Poa,
Gentiana,
Agrostis
Rhuem, Sedum,
Suasaria
Delphinium,
Festuca, Stipa,
Rhuem,
Poa, Agrostis,
Gentiana,
Danthonia
Primula,
Cyanathus
Aster,
Stipa,
Anemone,
Danthonia,
Primula,
Elymus,
Polyonatum,
Festuca,
52
Rhododendron
Lepidotum,
Cotoneaster
Moist Alpine Scrub
(MAS) 3800-4500 m
Sub-Alpine Forest
(SAF) 3300-3700 m
Riparian Forest (RF)
varies with valley
floor
Onosma,
Thermopsis,
Calthus,
Pedicularis,
Potentilla
Juniper, Abies
Rhododendron, Primula,
Salix,
Calthus,
Myricaria,
Sausaria,
Sorbus
Potentilla,
Senecio,
Dandelion
Betula,
Rosa, Rhibes
Delphenium,
Rhododendron,
Primula,
Juniperus,
Calthus,
Abies, Larix,
Saxifrage,
Acer
Potentilla,
Gentiana
Betula, Larix, Salix,
Rosa, Primula,
Rhododendron Hippocacia
Calthus,
Potentilla
Agrostis,
Anthrox,
Carex, Juncus
Carex,
Poa,
Elymus, Stipa,
Danthonia
Festuca, Poa,
Carex,
Danthonia,
Elymus
Elymus,
Agrostis
Source : Gyamtsho (1996)
Livestock Populations in Alpine Rangelands
The official records for 1994 show that Bhutan has a yak population of 30,148 (Table 3).
However, it is generally understood that the official records compiled from livestock taxation
records, underestimate actual numbers. There are also other livestock like sheep and horse but
yaks are the main domestic animal in alpine region of the country.
Table 3. Population of Yak in Bhutan (LUPP 1995)
Dzongkhag
Thimphu
Haa
Paro
Gasa
Wangduephodrang
Bumthang
Lhuntse
Trashigang
Samdrup Jongkhar
TOTAL
No. of Geogs
with Yaks
6
3
9
2
5
4
1
4
1
35
Number of Yaks
Male
4,133
1,810
1,153
780
1,326
1,450
93
1,336
20
12,101
Female
6,016
2,709
1,882
1,334
1,809
1,805
202
2,257
33
18,047
Total
10,149
4,519
3,035
2,114
3,135
3,255
295
3,593
53
30,148
53
Farmers in general, and yak herders in particular, are prone to giving lower numbers to avoid
taxation; they know fully well the impracticality of making actual head counts of their animals
by revenue officials. Discrepancies of up to 30 percent or more between actual and census
figures have been reported by Gibson (1991). Therefore, a more realistic population lies closer to
40,000. The highest density is seen in Western Bhutan where average ownership per household
is more than five animals.
Grazing of Alpine Rangelands
Grazing Season and Grazing Pressure
There are no fixed patterns of seasonal grazing common to all areas of alpine rangelands in
Bhutan. Some sites are grazed in summer and winter, some only during one of the seasons, while
others are grazed continuously throughout the year. Apart from Ngarithang, Chukarthang,
Shingja in Laya, Nyisharling and Mendathang in Lunana and Jarila in Lingshi, it is difficult to
classify any given site as either summer or winter pasture as they are grazed in more than one
season in a year.
All native pastures accessible to domestic animals are generally overgrazed. The grazing
pressure is high to very high in Laya and Lingshi and moderate in Lunana (Table 4). It is clear
that most of the rangelands are overgrazed in Laya and Lingshi with the exception of Ngarithang
and Limethang. The most severely grazed areas are Lungothang and Rodophu in Laya,
Pangtegang and Mendathang in Lunana, and Gopula and Jarila in Lingshi, with a grazing
pressure of less than 2 ha per yak adult equivalent (YAE).
However, grazing by yaks is not the only reason for overgrazing. Large flocks of blue sheep
(more than 200 animals counted in each flock) were frequently sighted grazing on the rangelands
around Laya and Lingshi (Gyamtsho et al). The total population of blue sheep according to
estimates by local herders is over 5000 in both Laya and Lingshi.
The variance in grazing pressure calculated from registered areas and estimated areas indicates
that in winter pastures, generally, the area registered reflects only the camp site and not the actual
grazed area, as seen in the case of Omtsa in Laya and Mendathang in Lunana. A higher grazing
area per YAE obtained from the calculations for registered areas reflect a trend towards a
decrease in grazeable areas due to shrub invasion, erosion, or steep topography. The stocking
rates shown in Table 4 were obtained by dividing the total registered area and estimated area
respectively by the number of YAE multiplied by the period of time grazed. The mean grazing
pressure was 5.6 per YAE and ranges from 2.5 ha to 25 ha per YAE.
Calculation of yak adult equivalent (YAE):
Yak numbers were converted to adult equivalent (YAE) by multiplying the total number of yaks
in the herd by a factor of 0.7 as was used by Miller (1987a) and Gibson (1991). The value of 0.7
is derived from the average herd composition for Laya. Male yaks above 4 years old were
regarded as one YAE, female yaks above 4 years old as 0.8 YAE and young male and female
yaks below 4 years as 0.35 and 0.3 YAE respectively.
54
Table 4: Area of alpine rangelands, grazing season, stocking rate, and grazing pressure from yak
herds in Bhutan (Gyamtsho 1996).
Area
Range Site
Registered
Estimated
as Tsadok1
by author
(ha)
(ha)
Grazing Pressure 3
Grazing Season and Stocking Rate
Summer
Autumn
Winter
Spring
No.
No.2
No.
No.
No.
Herds
YAE
Herds
YAE
Herds YAE
Herds YAE
No.
No.
No.
Tsadok
Estimated
area
area
(ha/YAE)
(ha/YAE)
Laya
1. Lungothang
2. Omtsa
3. Rodophu
4. Ngarithang
5. Chukarthang
6. Limethang
7. Shingja
8. Tsherijathang
NA
1
175
424
NA
245
132
1022
150
150
75
600
120
200
30
2000
8
0
3
5
1
0
1
5
72
0
59
153
43
0
27
489
10
0
0
0
0
1
0
5
146
0
0
0
0
69
0
419
8
11
3
0
0
0
0
19
72
125
59
0
0
0
0
784
10
0
0
0
0
1
0
5
146
0
0
0
0
69
0
419
3.6
6.7
22.2
12
1.7
1.8
2.9
1.5
9.5
6.7
18.1
2.7
3.4
NA
50
177
21
222
50
50
300
30
150
0
1
0
4
0
0
14
0
20
0
0
0
0
4
0
0
0
0
20
0
0
1
12
4
44
0
14
50
0
141
0
0
0
4
0
0
0
0
20
0
0
4.1
14.7
1
3.8
0
4.1
25
1.4
2.6
NA
NA
NA
NA
400
500
250
316
0
0
14
2.6
0
0
407
80
4
14
0
2.6
147
407
0
76
4
14
0
7
147
407
0
112
0
0
0
1.3
0
0
0
41
NA
NA
NA
NA
5.5
2.5
1.8
5.6
Lunana
9. Ganaglakachu
10.Tenchothang
11.Nyisharling
12.Pangtegang
13.Mendathang
Lingshi
14.Zumeri
15.Gopula
16.Jarila
Mean
1
Tsadok areas obtained from Thram (Landholding Handbook) of individual herders;
of yaks obtained from herders and converted to yak adult equivalents (YAE);
3 Grazing pressure obtained by dividing the registered or estimated areas by the average daily number of YAE grazing the site on
an annual basis, i.e. (YAE x 150) + (YAE x 30) + YAE x 35)/365. For the purpose of this calculations seasonal lengths are taken
as follows: summer = 150 days; autumn = 30 days; winter = 150 days and spring = 35 days based on the grazing duration’s
reported by the herders.
NA = not available/applicable.
2 Number
Effects of Grazing
From table 4 it follows that most alpine pastures are overgrazed, yet the grazing pressures
calculated are comparable to other estimates. FAO (1981) estimated 10 ha of native alpine and
sub-alpine pastures per yak adult equivalent (YAE) per year; AHD (1986) allows 10 ha of
unimproved alpine pasture per YAE while MPW (1986) allows 4.2 ha per year YAE in the
alpine regions. Only Gibson (1991) obtained lower grazing pressure of 69 ha/YAE/year in
summer pastures and 29 ha/YAE/year in winter pasture in the Soi Yaksa study, which he
attributed to the use of actual tsadok area inclusive of steep, rocky, and brush-covered areas.
55
The stocking rates on the rangelands in Gyamtsho’s study are very variable. The uncertainties in
the data include: the actual boundaries of the rangelands; grazing by yaks belonging to other
herders; grazing by animals other than yaks; the proportion of rangelands that is in valley
meadows and rock outcrops; the amount of unpalatable shrubs; and social customs which permit
animals and grazing site exchange to balance out production. Any attempt at defining stocking
rates with these unknowns is meaningless and should only be taken as indications of actual
grazing pressure.
The very short height of the swards proves that yaks are highly adapted to grazing short swards.
In the case of winter pastures which are not grazed in summer like Omtsa and Limethang in
Laya, sward height at the end of the growing season was observed to be well over 10 cm. The
swards are, however, cut for hay making before introducing the animals for grazing. Gibson
(1991) reported that the herbage available in the most fertile areas of the high limestone river
valleys (at Pege) was palatable accessible herbage at a height greater than 5-cm. Generally
palatable herbage was not taller than 3 cm. Harris (1987) also found yak pastures in Soi Yaksa
to be less than 5 cm in height.
By contrast, palatable herbage in protected sites or semi-inaccessible sites contained a large
amount (> 1000 kg DM/ha ?) of dead herbage to a height of more than 15 cm from the previous
year’s growth. This observation suggests that all herbage in accessible areas is grazed short as
soon as it grows. There are no experimental results available from controlled/fenced areas to
quantitatively assess the effects of grazing. The dominant climax species observed in completely
protected areas in the alpine grasslands is Carex norvegia. Danthonia schneideri was observed in
areas, which are inaccessible to grazing. Intermediate species consists of Trisetum, Helictrichon,
Bromus, Elymus, and Stipa grass species and Potentilla, Bistorta, Primula, and Ranunculus forb
species. Unpalatable shrubs of Juniper, Rhododendron, Cotoneaster, and Berberis species are
widespread in most areas. In the heavily grazed areas Festuca, Agrostis, and Poa grasses are
common, with also an abundance of sedge and rush species.
Grazing Competition between Wild and Domestic Animals
Competition for grazing resources from wildlife was not very obvious in the sub-alpine forested
areas but was very obvious in the alpine zones (Gibson,1991). Extensive blue sheep (Pseudois
nayaur) dung was seen in many alpine meadows. Pastoralists have started to complain about the
increasing numbers of blue sheep that are competing with yaks for forage. Yak herders contend
that blue sheep numbers have more than doubled since the last wild dog (Cuon alpinus) pack was
wiped out from the area about a decade ago. However, to date, there is no official blue sheep
population figure and many authors (Miller, Harris et al) have reported several mobs of blue
sheep being sighted, some numbering from 60 to 200 heads. It is likely that many mobs were
unseen by these authors, as the sheep were always at a distance and well camouflaged in the
surroundings.
Wangchuk (1995) conducted a study (Lingshi) to determine the amount of dietary overlap
between the two species (yak and blue sheep). Table 5 lists the percent occurrence of plant
56
species before and after grazing by yaks, while Table 6 lists the percent occurrence of plant
species before and after grazing by blue sheep.
Table 5. Percent occurrence of plant species before and after grazing by yak.
Species
Occurrence
before (%)
(Ratsa 19.2
Cyperus sp.
Poray)
Carex sp.
Bistorta macrophylla
Schoenopteetus sp.
Juncus himalensis
Potentilla microphylla
Cassiope selagineides
25.0
23.1
49.9
27.2
43.1
2.5
Occurrence
after (%)
4.9
P value
3.8
2.5
1.4
2.7
0.8
22.0
<0.005
<0.003
<0.040
<0.030
<0.030
<0.005
<0.002
Table 6. Percent occurrence of plant species before and after grazing by blue sheep (Wangchuk
1993).
Species
Occurrence
before (%)
Cyperus sp. (Ratsa Poray)
Carex sp.
Bistrota macrophylla
Schoenopleetus sp.
Potentilla microphylla
Gueldenstaedtia himalaica
39.5
30.0
32.0
34.2
32.5
43.0
Occurrenc
e
after (%)
10
4.9
6.1
11.0
3.1
1.0
P value
<0.002
<0.020
<0.030
<0.020
<0.005
<0.010
The species significantly grazed by yaks were Cyperus sp. (Bhutanese name: Ratsa Poray),
Carex sp., Bistorta macrophylla, Schoenopleetus sp., Tuncus himalensis, and Potentilla
microphylla. Yak did not graze on Cassiope selagineides since the species increased in plots
which were grazed. The following species did not increase or decrease after grazing by yak:
Arenari bryophylla, Aster flaccidus, Anaphalis trilinervis var. monocephala, Juniperus
squamata, and Cotoneaster microphylla. However, visual observations indicated that they had
been grazed on.
The following species were reported significantly grazed by blue sheep: Cyperus sp., Carex sp.,
Bistorta macrophylla, Schoenopleetus sp., Potentilla microphylla, and Gueldenstaedtia
himalaica. Blue sheep did not eat Cassiope selagineides since it increased in the plots grazed by
blue sheep. The following species did not increase or decrease after grazing by blue sheep:
Arenari bryophylla, Potentilla peduncularis, Phlomis ratata, and Juniperus squamata. However,
visual observations indicate that they had been grazed on.
Wangchuk (1995) concluded that that there is significant dietary overlap between blue sheep and
yak. Visual observations of plant parts indicated that yak and blue sheep also ate the same plant
57
parts. Although no measurements were made, both animals seemed to prefer leafy foliage and
avoided woody parts. Furthermore, the author concluded that whether there is competition
between blue sheep and yak for forage or not, an inescapable fact is that signs of overgrazing
such as bare and eroded pastures are becoming increasingly visible in his study area.
Migration Patterns and Herding Systems:
In general yak herding involves transhumance from winter pastures lying between 3000m and
3500m to summer pastures between 3500 - 5000m. Summer pastures are usually grazed from
June to September and winter pastures from November through March. In spring and autumn
there are pastures lying along the path of movement which serve as transitional grazing and
camping grounds between summer and winter pastures. The animals are moved from one grazing
site to another usually between 4-6 weeks depending on the number of sites and situation of
fodder availability. While travelling, yak herds use individual tsadok belonging to others,
without payment, for 1-2 days, then move on. We were told that tsadok boundaries were well
respected and no animals (cattle or yaks) grazed outside their proper boundaries except while
travelling. Most of the herders are closely related and digressions are no doubt tolerated, unless
they are extreme, to maintain harmony amongst the herders. As well, it is apparently custom that
if a herder has excess feed on his tsadok that herder will allow another with less feed to graze
some of his yaks on the first herder’s tsadok. Also some herders may temporarily care for yaks
belonging to others if the other has insufficient grazing.
Some of yak winter pastures have dual ownership, a yak herder in winter-spring and cattle in
summer autumn. This type of tsadok is continuously grazed and it is common in Naro area.
Recommendations:
Most of the high altitude regions in Bhutan are declared as protected areas and given the status
of national parks and wildlife sanctuaries. Therefore, recommendation of socio-economic
development must account for this special status and should not isolate the local people and must
reflect a high degree of sensitivity to their basic needs and their aspirations for better quality of
life. Based on the findings of Gyamtsho (1996) and keeping with the national policy objectives
of achieving socio-economic progress on the principle of self-reliance, sustainability and
environmental conservation, the following strategic recommendations could be made for alpine
rangelands management/improvement.
1. Improve soil fertility and soil conservation through improved nutrient cycling
and management by:

Selective application of fertilizers on extremely impoverished soil to restore P levels to stable
states;

Reducing collection of dung from pastures for manuring crops and for fuel, and
58

Introducing selected local and exotic legumes which are adopted to low levels of fertility and
acidic conditions which do not spread beyond control; example lotus and local vetch.
2.
Improve grazing management by:

Establishing User Group Association (UGA) for each rangeland to over see proper utilization
through monitoring of stock numbers, grazing and grazing time, nutrient management, shrub
and weed control;

Sub-dividing rangelands into extensive and intensive management units;

Establishing hay meadows with high yielding fodder legumes(Red clover, Lotus etc.) and
grasses ( Cocksfoot, Tallfescue, Italian ryegrass and local species) under high nutrient
supply conditions to reduce pressure on winter pastures;
Manipulating grazing pressure from livestock and wildlife by introducing livestock species
with less habitat competition with wildlife; e.g., cattle in Lay and Sheep in Luann;

3.
Improve rangeland vegetation through:

Prescribed burning, mechanical clearing of shrubs followed by reseeding with selected
species and protection from grazing;

Reseeding with selected local and introduced legume and grass species and discriminated use
of mineral phosphorus;

Collecting seeds from species with high forage and soil conservation values, and preferably
with other Ethan botanical values for seed multiplication under a co-operative scheme
involving local people.
4. Conduct further surveys and research on :

Taxonomic identification and distribution of plant species;

Appropriate agronomic practices on selected rangeland plants;

The extent of grazing competition between yaks, blue sheep and marmot and their effects on
plant communities and general conditions of the rangelands;

Quantification of nutrients in different pools of the nutrient cycle ( soil, plant, animals,
products) and amount and rate of exchanges between the pools;

Optimum requirements of N and P for reaching stable states under intensive and extensive
use of ranges;
59

Sustainable stocking rate of rangelands under different grazing systems, i.e.; continuous,
seasonal and deferred grazing system under single or multiple species grazing situations;

The potential of prescribed burning as a rangeland improvement and management tool in
combination with various methods of reseeding;

The potential of local and introduced species of plants for reseeding of degraded rangelands;

The growth pattern, growth rate, nutritive values and seed production potential of native
herbage plants; and

The causes and rates of soil erosion and sedimentation of streams and
References
Gibson T. 1991. Forest management and conservation: Bhutan. Forest grazing study. Working
Document No. 26, FO: DP/BHU/85/016, Dept. of Forestry, Thimphu.
Gyamtsho P. 1996. Assessment of the condition and potential for improvement of high altitude
rangelands of Bhutan (PhD thesis submitted to SFIT, Zurich).
Harris P.S. 1987 Grassland Survey and Integrated Pasture Development in High Mountain
Region of Bhutan [TCP/BHU/4505(A)] AHD/FAO, Thimphu, Bhutan.
Miller D.J. 1987 Yaks and Grasses: Introductory notes on pastoralism in Himalayan Kingdom of
Bhutan and potential for development. Bhutan Journal of Animal Husbandry 9: 54-59.
Wangchuk T. 1995. Competition for forage between Blue sheep and domestic Yak in Jigme
Dorji National Park: Tseden 5(1): 15-21. Thimphu.
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