Status and distribution of khulan (Equus hemionus) in Mongolia

Abstract

The Asiatic wild ass Equus hemionus, or khulan, once ranged across much of Central Asia, but is now
globally threatened. The largest free-ranging populations are now restricted to a 250-km wide area (range
100±400 km) across the Gobi Desert region of southern Mongolia. Over the last 23 years the population
has moved further north and east into its former range. Surveys conducted in the 1970s and 1980s
estimated that the Mongolian population contained fewer than 15 000 animals and was declining as a
result of human exploitation and livestock competition. Aerial surveys (one in autumn 1994, two in spring
1997) were ¯own as line transects over portions of the khulan's range in Mongolia and ground surveys (®ve
in spring, summer, and autumn 1994±97) were conducted by vehicle and foot.

Full text

Status and distribution of khulan (Equus hemionus)in
Mongolia
Richard P. Reading
1
*, Henry M. Mix
2
, Badamjaviin Lhagvasuren
3
, Claudia Feh
4
, David P. Kane
1
, S. Dulamtseren
3
and Sumyain Enkhbold
5
1
Denver Zoological Foundation and University of Denver, 2900 East 23rd Avenue, Denver, CO 80205, U.S.A.
2
Naturschutz International, Schulzenweg 1, 15345 Mo
Èllensee, Germany
3
Mongolian Academy of Sciences, Institute of Biology, Ulaanbaatar - 51, Mongolia
4
Station Biologique de la Tour du Valat, Le Sambuc, 13200 Arles, France
5
Mongolian National University, Department of Zoology, Ulaanbaatar, Mongolia
(Accepted 4 September 2000)
Abstract
The Asiatic wild ass Equus hemionus, or khulan, once ranged across much of Central Asia, but is now
globally threatened. The largest free-ranging populations are now restricted to a 250-km wide area (range
100±400 km) across the Gobi Desert region of southern Mongolia. Over the last 23 years the population
has moved further north and east into its former range. Surveys conducted in the 1970s and 1980s
estimated that the Mongolian population contained fewer than 15 000 animals and was declining as a
result of human exploitation and livestock competition. Aerial surveys (one in autumn 1994, two in spring
1997) were ¯own as line transects over portions of the khulan's range in Mongolia and ground surveys (®ve
in spring, summer, and autumn 1994±97) were conducted by vehicle and foot. Sample sizes and areas
surveyed were larger than previous surveys, and our methods were often more systematic. Population size
was estimated at 33 000±63 000 wild asses in Mongolia. Animal density ranged from 4.2 1.3 to 19.1  3.2
per 100 km
2
. Mean group size ranged from four to 35 animals in the south-western Gobi, four to seven
animals in the southern Gobi, and three to 18 in the south-eastern Gobi. Our data suggest that Mongolia is
the most important stronghold for the conservation of E. hemionus. Conservation management continues
to be challenging because intensive studies on khulan biology and ecology are just beginning. As a free-
market economy continues to emerge in Mongolia, pressure from resource extraction interests and
nomadic livestock herders to remove the khulan's protected status, permit harvesting and halt population
growth and expansion, also makes implementation of research and conservation management programs
more imperative.
Key words: Gobi, Equus hemionus, Khulan, Mongolia, wild ass
INTRODUCTION
Mongolia represents one of the last strongholds for
Asian wild asses Equus hemionus, a wide ranging species
that inhabits the Middle East (E. h. onager), Central
Asia (E. h. kulan), parts of India (E. h. khur), and the
Gobi Desert of China and Mongolia. Taxonomic status
of the Gobi subspecies of wild ass, or khulan, remains
unclear, with some authors referring to it as E. h. luteus
(IUCN, 1996; Wang & Schaller, 1996) and others as
E. h. hemionus (Shagdarsuren et al., 1987; Reading,
Sumya et al., 1994; Shiirevdamba et al., 1997; Denzau
& Denzau, 1999; Feh, Munkhtuya et al., in press).
Asian wild asses in Mongolia are referred to as `khulan'
by Mongolians (not to be confused with the `kulan' of
the central Asian republics) and as `dziggetai' by
Russians. Khulan are listed as rare in the Mongolian
Red Book (Shiirevdamba et al., 1997) and protected
as rare animals under the Mongolian Hunting Law of
1995 (Wingard, 1996). A globally threatened species,
E. hemionus is also included in appendix I of the
Convention on the International Trade of Endangered
Species of Flora and Fauna (CITES) and listed as
`vulnerable' by the World Conservation Union (IUCN,
1996). The E. h. luteus subspecies is listed as `data
de®cient' in China and Mongolia (IUCN, 1996).
Similarly, the IUCN's Equid Specialist Group
records the khulan as `insuf®ciently known' (Duncan,
1992).
J. Zool., Lond. (2001) 254, 381±389 #2001 The Zoological Society of London Printed in the United Kingdom
*All correspondence to: R. P. Reading.
E-mail: zooresearch@denverzoo.org

Status and distribution of khulan
Until the mid-1800s, khulan were distributed across
most of Mongolia, small parts of Siberia and Man-
churia, western Inner Mongolia, and northern Xinjiang
(Harper, 1945). Reports from expeditions to the region
in the late 1800s and early 1900s suggest that the khulan
range was contracting, such that by 1938 wild asses
could no longer be found in north-eastern Mongolia,
where the holotype for the species was found (Harper,
1945). Andrews (1932) made expeditions to the Gobi in
1922 and 1925, reporting high densities near Lake
Tsagaan Nuur (45820'N, 101830'E) and no sightings east
of the Gurvan Saikhan Mountains (43830'N, 1048E)
(Fig. 1). Bannikov (1961) summarized the results of
Russian expeditions for the same period and estimated
that their range extended to 488N and 1088E. He
estimated a total population of `tens of thousands' of
khulan in the 1940s.
Today, khulan are distributed throughout the Gobi
region of southern Mongolia. This area includes the
s
outhern portions of Khovd, Gobi-Altai, Bayankhongo
r,
and Dundgobi Aimags, or provinces, as well as southern
and eastern Omnogobi Aimag and southern and western
Dornogobi Aimag (Figs 1 & 2). Relatively large
numbers of khulan have been located in this desert and
semi-desert region (Zhirnov & Ilyinsky, 1986; Mix,
Reading & Lhagvasuren 1995, 1997; Wang & Schaller,
1996; Feh, Munkhtuya et al., in press). Recent ®eld
research and surveys suggest that these populations
may, however, be increasing and expanding further
northward into the semi-desert steppe zones, especially
in the eastern portion of its range (Mix et al., 1995).
Khulan are rare in adjacent areas of China, especially
Inner Mongolia, where the population is probably
sustained only by migration from Mongolia (Wolfe,
1979; Gao & Gu, 1989; Wang & Schaller, 1996).
Most of the limited research on khulan has focused
on behavioural ecology or systematics (Bannikov, 1971,
1975; Wolfe, 1979; Munkhsaikhan et al., 1989; Feh,
Boldsukh & Tourenq, 1994). Fewer assessments of
khulan status and distribution have been conducted.
Previous researchers estimated variable numbers of
khulan in Mongolia (see Zhirnov & Ilyinsky, 1986),
including 4000±15000 in the 1970s (Sokolov et al., 1978;
Shiirevdamba et al., 1997) and 6000±15 000 in the 1980s
(Bannikov, 1981; Zhirnov & Ilyinsky, 1986). These
earlier estimates were based on surveys from relatively
limited portions of the range of khulan in Mongolia. In
particular, little to no research or surveys were con-
ducted in the south-eastern Gobi, a particularly
important portion of the range of the species.
Recently some surveys have been conducted to assess
the current population size and distribution of khulan in
Mongolia (Mix et al., 1995, 1997; Reading, Mix, Lhag-
vasuren & Blumer, 1999; Reading, Amgalanbaatar &
Lhagvasuren, 1999; Feh, Munkhtuya et al., in press).
From 1994 to 1997, three aerial surveys were conducted
over c. two-thirds of the range of khulan. In addition,
several ground surveys were performed for large ungu-
lates in portions of Gobi-Altai, Bayankhongor,
Omnogobi, Dundgobi, and Dornogobi Aimags.
R. P. Reading ET AL.382
90°92°94°96°98°100°102°104°
52°00’
106°108°110°112°114°116°118°50°40’
49°20’
46°40’
45°20’
44°00’
42°49’
41°20’
North
Capital city
Other cities
State & national boundaries
Rivers
Lakes
Aeriel survey areas:
1 Great Gobi
2 Gobi Gurvan Saikhan
3 south-eastern Gobi
88°
120°
48°00’
Altai
KHOVD
AIMAG
Mountains
Dzungarian
Gobi
Trans-Altai Mts
GOBI-
ALTI
AIMAG BAYAN-
KHONGOR
AIMAG
Uliastai
Sevrei
OMNOGOBI
AIMAG
Galbiin gobi
Dalanzadgad
Sainshand
DORNOGOBI
AIMAG
DUNDGOBI
AIMAG
Ulaanbaatar
Erdenet
Choibalsan
12
3
Fig. 1. Aerial survey areas for khulan Equus hemionus in Mongolia.

STUDY AREA
The study area included the portions of Khovd, Gobi-
Altai, Bayankhongor, Dundgobi, Omnogobi, and
Dornogobi Aimags and varies from true desert through
semi-desert to Gobi-steppe (Zhirnov & Ilyinsky, 1986;
Figs 1 & 2). The ¯ora and fauna are representative of
the arid regions of Central Asia. The region is character-
ized as a high upland (c. 1000 m) with dry streambeds
and hummocks, rocky outcrops, and mountain massifs
rising to > 2000 m above the surrounding landscape.
Springs and other water sources are rare. Climate is
strongly continental and arid, characterized by cold
winters (to 735 8C), dry, windy springs (to 5 m/s), and
relatively wet, hot summers (to 40 8C). Precipitation in
the Gobi is low, for example averaging 100 mm/year in
Great Gobi region B, 127.2 mm/ year in Omnogobi
Aimag and 116.7 mm/ year in Dornogobi Aimag.
Vegetation is sparse, especially in the southern regions,
and generally increases northward. Fine-leafed grasses
and onions dominate vegetation of the Gobi-steppe.
Dominant plants include Stipa klemenzii, S. gobica,
Salsola passerina, Thymus gobica, Cleistogenes squarrosa,
Ajania fructiculosia, Artemisia frigida, and A. rutifolia.
The semi-desert regions are characterized by semi-
shrubs, shrubs, and some grasses, including A. fructicu-
losa, S. gobica, S. glareosa, Caragana korshinskii,
C. pygmaea, Scorzonera capito, Lagochilus ilicifolius,
A. frigida, and Haloxylon ammodendron. The true Gobi
desert contains little vegetation. Semi-shrubs, shrubs,
and scrub vegetation dominate, including Zygophyllum
xanthoxylon, S. passerina, Anabasis brevifolia, Caragana
leucophloea,andH. ammodendron. Oases support the
greatest density of vegetation in the region, and are
dominated by Phragmites communis, Juncus spp. and
Achnatherum splendens. For more detail see Zhirnov &
Ilyinsky (1986).
METHODS
To assess the status of khulan throughout Mongolia
recently collected data from a variety of sources were
reviewed. We collected most of these data, some of
which are published elsewhere (Mix et al., 1995;
Reading, Amgalanbaatar & Lhagvasuren, 1999;
Reading, Mix, Lhagvasuren & Blumer, 1999; Feh,
Munkhtuya et al., in press). Other data are being pre-
sented here for the ®rst time, and still other researchers
collected additional data (Wang & Schaller, 1996).
We conducted 3 aerial surveys over portions of the
khulan's range in Mongolia in 1994 and 1997. We
followed the guidelines proposed by Burnham, An-
derson & Laake (1980) for conducting line transect
surveys as modi®ed by Reading, Amgalanbaatar, Mix &
Lhagvasuren (1997). Soviet AN-2 biplanes were ¯own
in straight, parallel transects at c. 100 m above the
ground. Navigation was conducted using a global posi-
tioning system (GPS), compass bearings, and landscape
features. One national biologist was responsible for
383Khulan in Mongolia
90°92°94°96°98°100°102°104°
52°00’
106°108°110°112°114°116°118°50°40’
49°20’
48°00
46°40’
45°20’
44°00’
42°49’
41°20’
North
Capital city
Other cities
State & national boundaries
Rivers
Lakes
Protected areas
Khulan range
Great Gobi region A
Great Gobi region B
1A
1B
2
3A
3B
Gobi Gurvan Saikhan
Little Gobi region A
Little Gobi region B
Ergliin Zoo
Suikhent
Zagiin Us
Ikh Nart
4
5
6
7
88°
120°
Choibalsan
Erdenet
Ulaanbaatar
Uliastai
Khovd
Dalanzadgad Sainshand
7
6
54
3B
3A
2
1A
1B
Fig. 2. Distribution of khulan Equus hemionus in Mongolia.

assisting the 2 pilots in accurate navigation. To compen-
sate for the relatively fast air speed (mean = 170 km/h),
2±4 observers were placed on either side of the plane. In
addition, the navigating expert often located animals.
One person took still and video camera photographs for
later data correction. Data collected included species,
group size, perpendicular distance from the transect
line, time of the sighting, weather, observer, and the
observer's location in the plane. Observers estimated
perpendicular distances by using markings on the wings
as guides. Sometimes animals moved before detection,
possibly introducing a source of bias into our estimate
(Burnham et al., 1980).
Survey 1 was conducted using 2 planes from 22 to 25
and 27 October (Mix et al., 1995). The survey included
the south-eastern third of Dundgobi Aimag, the central
and eastern parts of Omnogobi Aimag, and the southern
three-fourths of Dornogobi Aimag (Fig. 1). Data were
strati®ed by ecological zone and Aimag. Transects ran
north to south and were separated by c.40km
(although distance varied somewhat for logistic reasons,
such as refuelling). We ¯ew from 10:00±12:45 and then
14:00±16:30 on the ®rst day using 2 aircraft, 09:20±12:00
on the second day using 1 aircraft, 09:45±12:00 and then
14:00±17:00 on the third day using 2 aircraft,
10:00±14:00 on the fourth day using 2 aircraft in the
morning (1 plane until 11:30), and 09:00±11:45 on the
®fth day using 2 aircraft.
Survey 2 was conducted using 1 plane from 2 to 6
March 1997 over region A of Great Gobi Strict Pro-
tected Area (Reading, Mix, Lhagvasuren & Blumer,
1999; Fig. 1). Transects ran north to south and were
separated by c. 15 km. We conducted surveys from
09:12 to 11:40 and 14:16±18:24 on 2 March, 08:49±11:21
and 13:39±15:39 on 3 March, 08:46±11:15 on 4 March,
and 09:54±12:50 on 6 March.
Survey 3 was conducted using 1 plane from 12 to 15
March 1997 over Gobi Gurvan Saikhan National Park
and the surrounding area (Reading, Amgalanbaatar &
Lhagvasuren, 1999; Fig. 1). Transects ran east to west
and were separated by c. 15 km. Unfortunately, strong
winds forced the plane to deviate northward during a
portion of the survey. As a result, 2 portions of the
survey area were slightly under-sampled. Surveys were
conducted from 09:00 to 10:45 on 12 March,
09:15±12:45 and 13:30±14:40 on 13 March, and
09:30±10:40 on 15 March.
Large mammal density, group density, and popula-
tion size was estimated using the interactive computer
program Distance (Burnham et al., 1980). To obtain an
estimate that accurately modelled the data, we were
required to pool data into the following distance classes
based on the distribution of sightings by distance for
Survey 2: 0±100 m, 101±200 m, 201±500 m, 501±750 m,
751±1000, m 1001±2500 m. We allowed the program to
select among a variety of possible estimators, including
half normal, negative exponential, hazard-rate, and
uniform models based on minimum Akaike information
criterion (-2*ln-likelihood + 2m, where m= the number
of parameters). We selected estimators whose prob-
ability detection function model was not signi®cantly
different from the distribution of actual observations
using a w
2
goodness-of-®t test (Burnham et al., 1980).
The robustness of some of our density and population
estimates was examined by excluding large portions of
the survey area that did not have animal sightings
(primarily in the north) and remodelling our data.
Estimates using different survey areas and sampling
effort varied by < 0.5%. Results are presented as 
standard error of the mean (se).
Ground surveys were conducted in: (1) Great Gobi
region B of southern Gobi-Altai and Khovd Aimags
each year from 1994 to 1996 (Feh, Munkhtuya et al., in
press); (2) Omnogobi, Dornogobi, and Dundgobi
Aimags in August 1994; (3) Omnogobi Aimag in Sep-
tember and November 1995 (Reading, Amgalabaatar &
Lhagvasuren, 1999); (4) Omnogobi Aimag in May and
June 1996 (Reading, Amgalabaatar & Lhagvasuren,
1999); (5) Omnogobi, Dornogobi, and Dundgobi
Aimags in October 1997. For the ®rst ground survey,
total counts were made by travelling 318 km on 2±3
consecutive days each study period (June 1994, October
1995, and October 1996), stopping at the same locations
each study period, climbing hills, and scanning the
surrounding terrain with a spotting scope. The selected
locations permitted complete coverage of Great Gobi
region B, and it was often possible to count khulan and
recognize foals up to a distance of 10 km. All other
ground surveys were made by traversing large areas by
vehicle or on foot searching for khulan. Positive identi-
®cation of all khulan was made using binoculars and a
spotting scope and where possible adult±foal classi®ca-
tion of all animals observed was recorded. For the
second ground survey only, data were also collected on
the distance of khulan groups from the survey line for a
450 km section of the 1004 km survey route, permitting
population estimation using the Distance program.
The khulan's range in Mongolia was determined by
plotting all sightings made by our Mongolian colleagues
or by us during 1994±97. Sighting locations were re-
corded with a GPS or plotted on topographic maps.
Interviews with local people were used to validate our
®ndings. The probable distribution of khulan was
plotted based on locations and geographic features that
were considered barriers to dispersal (e.g. large moun-
tain ranges). Because we could not be sure that khulan
did not range beyond the distribution we plotted, our
distribution should be viewed as conservative.
RESULTS
South-western Gobi: Great Gobi Strictly Protected Area
and surrounding regions
The range of khulan in south-western Mongolia extends
from region A of Great Gobi Strictly Protected Area
across southern Mongolia to region B in the Dzun-
garian Gobi. Khulan in these areas are distributed south
of the Altai and Trans-Altai Mountains (Fig. 2).
R. P. Reading ET AL.384

Khulan are scattered throughout Great Gobi Strictly
Protected Area and surrounding regions, but are
densely distributed and slightly more numerous in
region B and the north of region A.
During the aerial survey of Great Gobi's region A in
winter 1997, 155 khulan were observed in 34 groups, for
a mean group size of 4.3  0.7 khulan/group (Table 1).
Group size ranged from one to 18 animals/group. Four
of these groups were observed while ¯ying to and from
the survey area (north of the survey area) and were
therefore not included during population size and
density estimation. The estimated density of khulan in
Great Gobi A was 4.2  1.3 animals/100 km
2
and
2.2  0.6 groups/100 km
2
(Table 2). The population
estimate for that section of the park was therefore
1674  506 animals (95% con®dence limit = 926±3025
khulan).
Ground surveys in Great Gobi's region B counted
1445 (74 groups), 1595 (47 groups), and 1506 (43
groups) khulan in 1994, 1995, and 1996, respectively
(Table 1). Therefore, an average of 1515.3  43.6 khulan
inhabited the 8810 km
2
of Great Gobi B in the mid-
1990s, yielding a mean density of 17.2  0.5 animals/100
km
2
(Table 2). Mean group size varied from
19.53  11.68 to 35.02  14.17 animals (range one to 850
animals).
We estimate that between 3500 and 5000 khulan
inhabit the desert and semi-desert areas of Mongolia
west of, and including, Great Gobi A.
Southern Gobi: Gobi Gurvan Saikhan National
Conservation Park and surrounding areas
Few khulan were sighted in the southern Gobi in and
around Gobi Gurvan Saikhan National Conservation
Park. We conducted two ground surveys and one aerial
survey in this region. Nine groups (0.5 herd/100 km)
with 61 animals (3.7 animals/100 km) were sighted
during roadside count surveys in 1995 and 18 khulan
(1.2 animals/100 km) in four groups (0.3 groups/
100 km) were sighted in 1996. During an aerial survey
in winter 1997, 35 khulan were sighted in ®ve groups.
Mean khulan group size was 6.8  2 animals/group in
1995, 4.5  1.2 animals/group in 1996, and 7  2.5
animals/group in 1997 (Table 1). During all of these
surveys, only two groups (six animals and one animal)
were sighted within park boundaries, both in 1996, in
the mouth of a valley in the north-central Zoolongiin
Mountains. The remainder were sighted outside park
boundaries in the desert±steppe area south of the Zool-
ongiin Mountains. According to local people, khulan
use areas of the park near Sevrei during the summer.
The area south of Gobi Gurvan Saikhan Park to the
Chinese border and west of the park to Great Gobi is
the area least surveyed for large ungulates. We have
¯own and driven only a small portion of this region.
These surveys, on the edges of the khulan range, suggest
that khulan densities are relatively low in the southern
Gobi, perhaps on the order of that found in Great Gobi
A (~ 4 khulan/100 km
2
; Table 2). We therefore roughly
extrapolated using these densities to estimate that
1000±2500 khulan inhabit the South Gobi from the
eastern boundary of Gobi Gurvan Saikhan to the
eastern boundary of Great Gobi. Khulan in this region
range from the southern portion of Gobi Gurvan
Saikhan to the Mongolian border with China (Fig. 2).
South-eastern Gobi
Our most rigorous and reliable population estimates for
khulan come from the south-eastern Gobi where two
ground surveys were conducted. In August 1994 we
surveyed the Galbiin Gobi of southern Omnogobi and
Dornogobi Aimags. This depression is an important
khulan foaling area. During 1004 km of driving 287
animals, or 28.6 khulan/100 km, were observed in 84
groups. Mean group size was 3.4  0.6 (range = one to
47; Table 1). The Distance program was used to
385Khulan in Mongolia
Table 1. Number of khulan Equus hemionus, groups, mean ( se) group sizes, and animals/100 km observed in different regions
of the Gobi Desert of Mongolia
Survey Mean group size No. of khulan
Type Date No. of animals No. of groups  se (median) seen/100 km
Great Gobi's region A
Air Mar 1997 155 34 4.32  0.66 (3) 9.1
Great Gobi's region B
Ground Jun 1994 1397 74 19.53  11.68 (3) 4.5
Ground Oct 1995 1486 47 33.94  8.72 (8) 5.0
Ground Oct 1996 1506 43 35.02  14.17 (8) 4.7
Gobi Gurvan Saikhan
Ground Sep±Nov 1995 61 9 6.78  1.99 (4) 3.7
Ground May±Jun 1996 18 4 4.50  1.19 (5.5) 1.2
Air Mar 1997 35 5 7.00  2.49 (6) 3.4
South-eastern Gobi
Ground Aug 1994 287 84 3.41  0.64 (2) 28.6
Air Oct 1994 2530 139 18.20  5.36
a
(6) 55.6
Ground Oct 1997 1744 125 13.95  1.86 (6) 122.1
a
Mean group size drops to 13.3 2.09 khulan/group if a single group of 700 animals is excluded.

estimate khulan densities for the 450-km portion of the
survey during which data were collected on the distance
of khulan groups from the survey line (n= 61 groups).
Estimated densities were 17.9  4.1 khulan/100 km
2
and
8.2  1.6 groups/100 km
2
(Table 2). In October, 1997 we
surveyed portions of the Borzongiin, Galbiin, Ooshiin,
and Dolooddin regions of the Gobi, and adjacent areas
to the north in Omnogobi, Dornogobi, and Dundgobi
Aimags. We sighted 1744 khulan in 125 groups during
1428 km of survey work, or 122.1 khulan/100 km (Table
1). Mean group size was 13.9  1.9 (range one to 140;
Table 1). The number of young were counted for 50
groups. These groups averaged 8.9  1.3 adults (444
total) and 2.4  0.3 young (118 total) per group, or
21.0% young. We were unable to distinguish between
males and females for most animals sighted.
In August 1994, Wang & Schaller (1996) conducted a
ground survey of large ungulates in Dundgobi,
Omnogobi, and Dornogobi Aimags of the south-eastern
Gobi. They sighted 1400 khulan (including one group of
400+ animals) during 2700 km of driving, or 51.9
khulan/100 km. The frequency of sighting drops to 37
khulan/100 km if the herd of 400 is excluded; a sighting
frequency similar to that found during our ®rst ground
survey.
Ground survey results compare favourably with
results from an aerial survey conducted in 1994. In
autumn 1994, an aerial survey was made over the entire
south-eastern Gobi (from east of Gobi Gurvan Saikhan
National Conservation Park). During the aerial survey,
2530 khulan were seen in 139 groups during 4552.5 km
of ¯ying over 20.9 million ha. Mean group size was
18.20  5.36 khulan/group (range one to 700), although
it drops to 13.26  2.09 khulan/group (range one to 200)
if we exclude the large group of 700 (Table 1).
Khulan densities were estimated by modelling the
aerial survey data, but without using the group of 700
khulan (which were added to the results of the model-
ling). We found 19.1  3.2 animals/100 km
2
and 1.6  0.2
groups/100 km
2
for the entire south-eastern Gobi (Table
2). Since most khulan were concentrated in the southern
portion of their range, data were also examined for the
southern 11.6 million km
2
of the survey area. As
expected, densities were greater in the south: 30.6  5.7
animals/100 km
2
and 2.4  0.3 groups/100 km
2
. Our
population estimate for the south-eastern Gobi is there-
fore 39 991  6697 animals (95% CL = 28 867±55 402
khulan), with the majority (35 666  6627 khulan) in the
southern half. Khulan in this region range from the
eastern boundary of Dornogobi Aimag westward across
the southern portion of Mongolia. Their distribution
includes most of the area north of the Chinese border to
a line running approximately south of Sainshand to just
west-northwest of Sainshand to just south of Dalan-
zadgad (Fig. 2).
Overall
The overall estimate for Mongolia therefore includes:
(1) 3500±5000 khulan in the south-western Gobi; (2)
1000±2500 khulan in the southern Gobi; (3) 28 867±55
402 khulan in the south-eastern Gobi, for a total of 33
367±62 902 animals in Mongolia. The species ranges
across the southern one-quarter to one-®fth of the
nation from Dornogobi Aimag to Khovd Aimag,an
area that corresponds to the extent of the Gobi Desert
in Mongolia. The south-eastern Gobi Desert (southern
and western Dornogobi, southern Dundgobi, and
south-eastern Omnogobi Aimags) seems to be the
stronghold for khulan in Mongolia, although a healthy
population also apparently inhabits Great Gobi B (Feh,
Munkhtuya et al., in press). Recent surveys suggest that
the species may be expanding into its former range in
this region of Mongolia (Schaller, 1994; Mix et al.,
1995; Feh, Munkhtuya et al., in press).
R. P. Reading ET AL.386
Table 2. Khulan Equus hemionus population size and density estimates ( se) in the Gobi Desert of Mongolia
South-eastern Gobi
Variable Great Gobi A Great Gobi B Ground survey Aerial survey
Year 1997 1994±96 1994 1994
Area surveyed (km
2
) 39 865 8810 6000 209 000
Distance travelled (km) 1700 318 450 4552.5
Number of groups 32 43±74 61 139
Animal density/100 km
2
4.20  1.27 17.20  0.49 17.94  4.14 19.13  3.20
Group density/100 km
2
2.18  0.57 0.62  0.11 8.23  1.62 1.64  0.17
Population estimate 1674  506 1515  44 1076  248 39991  6697
Estimation method Distance
a
Total count Distance
a
Distance
a
Model
b
Negative exponential N/A Negative exponential Hazard rate
Signi®cance
a
P= 0.92 N/A P= 0.66±0.79 P= 0.15±0.23
a
Survey data modelled using the Distance program to estimate densities and numbers (see Burnham et al., 1980).
b
Sightings models selected by the Distance program included the hazard rate key model: k(y) = 1 - exp(-(y/A(1))**-A(2)), where
k= no. of samples, y= distance, and A(i) = the i-th parameter in the estimated probability density function; and the negative
exponential model: k(y) = exp(-y/A(1)), where k,y, and A(i) are as above.
c
Signi®cance measurements are for w
2
tests of actual data vs the Distance program's modelled curve. Better models have lower
w
2
values, and thus higher P-values (i.e. actual data and modelled curves are not signi®cantly different). Ranges of P-values are
provided for models that permitted data to be grouped into several different categories.

DISCUSSION
Status and distribution of khulan
Before the 1990s, there were few published surveys of
khulan in Mongolia. Zhirnov & Ilyinsky (1986) con-
ducted aerial surveys of Great Gobi in the early 1980s
and estimated that 800 khulan inhabited Great Gobi
Strictly Protected Area region A and another 1500
inhabited region B, but found high ¯uctuations of
khulan numbers. Duncan (1992) suggested that 2500
khulan inhabited both regions A and B of Great Gobi.
Unfortunately, methods and descriptive statistics from
these earlier studies in the Great Gobi were lacking;
however, if comparable with our results, they indicated
that the khulan population in region B has remained
remarkably stable at about 1500 animals, while the
population in region A has been increasing from about
500 in the mid-1970s to 1674  506 animals in the mid-
1990s.
Zhirnov & Ilyinsky (1986) found mean densities of
0.8±5.1 khulan/100 km
2
and mean group sizes of 1.7±7.0
animals/group in the Great Gobi. Our numbers fell
within those ranges; we found a density of 4.20 animals/
100 km
2
and mean group size of 4.32 animals/group in
region A of Great Gobi.
In the last few decades, khulan were reported as
declining, being forced into more marginal habitats as a
result of poaching and competition for forage and water
(Zhirnov & Ilyinsky, 1986). Our data suggest that
khulan populations have been expanding in recent years
and that 33 367±62 902 khulan inhabit Mongolia; a
population estimate much higher than estimates made
over the past 25 years (Table 3). Bannikov suggested
that about 15 000 khulan inhabited Mongolia in both
1974 and 1980 (Bannikov, 1981). Similarly, an unsyste-
matic aerial survey in the mid-1980s yielded an estimate
of 14 000 animals (S. Dulamtseren, pers. comm.; see
also Shiirevdamba et al., 1997). These estimates contrast
with Sokolov et al. (1978), whose surveys in the
mid-1970s led to a population estimate of 4000 or less,
and with Zhirnov & Ilyinsky (1986), who estimated
6000±7000 khulan in Mongolia in the mid-1980s.
Unfortunately, the methods used to determine these
estimates were not provided, making comparisons with
our data dif®cult. If our numbers are correct, most or
all of these earlier population estimates were probably
too low, although some may have been correct if there
has been a recent and substantial population increase.
Mongolia harbours the world's largest population of
Asian wild ass, of any subspecies, with numbers several
times higher than that found in other countries (Table
3).
Our results are probably more reliable than previous
estimates because they are based on a much larger
sample size than previous studies, covering a far greater
percentage of the territory occupied by khulan. In
addition, our surveys of Great Gobi A (Reading, Mix,
Lhagvasuren & Blumer, 1999), Great Gobi B (Feh,
Munkhtuya et al., in press), the southern Gobi
(Reading, Amgalabaatar & Lhagvasuren, 1999), and the
south-eastern Gobi (Mix et al., 1995) were the only
studies that systematically surveyed sample areas using
standardized methods.
Conservation implications and recommendations
A substantially higher population of khulan was found
than previously estimated, and all indications suggest
that the population continues to grow and expand its
range. As such, Mongolia represents an important
stronghold for the conservation of the khulan sub-
species, as well as Asian wild ass species in general.
Several factors, however, threaten to change this situa-
tion. Increases in poaching, grazing pressure, and
natural resources exploitation coupled with reduced law
enforcement and major social changes (Valdez, Frisina
& Buyandelger, 1995; Reading, Amgalanbaatar & Mix,
1998) could easily reverse what seems to be an
increasing khulan population.
The expanding khulan population has resulted in an
increase in the number of con¯icts with local, nomadic
herders who view khulan as competitors for livestock
forage. One result has been increased pressure to
remove the protected status from khulan, at least in
some areas, and to permit recreational and even com-
mercial harvests. In addition, poaching of khulan for
387Khulan in Mongolia
Table 3. Population estimates for different geographically isolated population of Asian wild asses Equus hemionus
Country Subspecies Year Population estimate Source
India E. h. khur 1993 750 Shah (1993)
Iran E. h. onager 1997 500 B. Dareshori & L. Tatin (pers. comm.)
Turkenistan E. h. kulan 1995 5000 P. Duncan (pers. comm.)
Kazakhstan E. h. kulan 1997 300 Salathe
Â(pers. comm.)
Mongolia E. h. hemionus 1974 15 000 Bannikov (1981)
1976 ~ 4000 Sokolov et al. (1978)
1980 15 000 Bannikov (1981)
1984 14 000 S. Dulamtseren (pers. comm.)
1985 6000±7000 Zhirnov & Ilyinsky (1986)
1994 10 000 A. Avirmed (pers. comm.)
1990s 33 367±62 902 This study
China E. h. hemionus 1996 250 Wang & Schaller (1996)

meat and hides seems to be increasing (Duncan, 1992).
Greater competition between livestock and khulan may
indeed be occurring (Shiirevdamba et al., 1997), but it is
unclear if this is a result of increased khulan numbers,
expanding livestock herds (Mueller & Janzen, 1997), or
both. We believe it is the latter. Finally, pressure to
extract Mongolia's rich reserves of natural resources
from khulan habitat is growing (Dondog, Lhagva &
Hasbaatar, 1996), especially in the face of the recent,
large-scale socio-political changes that have accompa-
nied Mongolia's shift to democracy and a free market
system (see UNDP, 1997). These factors and pressures
are creating signi®cant challenges to wildlife managers
who have little money to address such issues. Given how
little is really known about khulan biology and ecology
in Mongolia, we recommend that managers proceed
cautiously and only after additional research has been
conducted to permit more informed, scienti®cally based
management.
There have been few studies of khulan in Mongolia
(Bannikov, 1971, 1975; Wolfe, 1979; Munkhsaikhan et
al., 1989; Feh, Boldsukh & Tourenq, 1994; Enkhbold,
1997; Feh, Munkhtuya et al., in press). Most of this
research has focused on behavioural ecology or systema-
tics, although some data were collected on khulan
numbers and distribution during these and other studies
(e.g. Zhirnov & Ilyinsky, 1986). Only recently have
surveys been conducted to assess the current population
size and distribution of khulan in Mongolia (Mix et al.,
1995, 1997; Wang & Schaller, 1996; Reading, Mix,
Lhagvasuren & Blumer, 1999).
Several protected areas have been created within the
khulan's range in Mongolia, and we found populations
of animals in all of them (Johnstad, Reading &
Wingard, 1996; MNE, 1996b; Shiirevdamba et al., 1997;
Fig. 2). The largest of these is the two-section,
53 117 km
2
Great Gobi Strictly Protected Area in the
Dzungarian and south-western Gobi. Gobi Gurvan
Saikhan National Conservation Park protects 21 717 km
2
in the South Gobi, but only a small portion of the
park's area (in the south) includes khulan. Gobi Gurvan
Saikhan should investigate the possibility of expanding
its boundaries to the south to include important khulan
habitat. Khulan habitat seems to be available, yet
unused within the Park and studies should attempt to
understand why this exists. Two new protected areas
were created primarily for khulan conservation in 1996.
Baga Gobi Strictly Protected Area covers 18 391 km
2
in
a two-section reserve on the Chinese border in the
south-eastern Gobi, and Zagiin Us Nature Reserve
protects 2763 km
2
further north. Khulan also inhabit
three smaller protected areas: Ergeliin Zoo Nature
Reserve (609 km
2
), Ikh Nartiin Khad Nature Reserve
(437 km
2
), and Suikhent Natural Monument (48 km
2
).
Creation of these protected areas was an important ®rst
step, but now the hard work of initiating and imple-
menting conservation management programmes begins.
Effecting such programmes will require substantial com-
mitment by the Mongolian government and assistance
from the international community (Reading, Johnstad
et al., 1999).
Although khulan are expanding their range in south-
eastern Mongolia, the south-western population seems
to be relatively stable. The reasons for the difference in
population dynamics between the two regions are
unknown, but deserve attention. Khulan inhabited the
Great Lakes Basin in west-central Mongolia as recently
as the 1950s (Bannikov, 1954), and conservationists
might consider attempting to encourage re-establish-
ment of a population in this area.
The khulan's range in southern Mongolia extends to
the Chinese border (Fig. 2); however, only two small,
fragmented khulan populations remain in China, one in
the Junggar Basin of northern Xinjiang and the other in
western Inner Mongolia (Zhang et al., 1997). Wang &
Schaller (1996) suggest that khulan, and several other
species inhabiting the Gobi Desert, are sustained in
China only by migration from Mongolia (e.g. Reading,
Mix, Lhagvasuren & Blumer, 1999). For khulan, their
suggestion is corroborated by our ®nding that the
khulan population in Mongolia's south-eastern Gobi
seems to be expanding.
Thousands of khulan inhabit large expanses of avail-
able habitat throughout the Mongolian Gobi. Although
Mongolia's livestock and human populations are
growing (Mueller & Janzen, 1997), both remain well
below densities found throughout most of the rest of the
Asian wild ass' range, providing conservationists with
the opportunity to initiate proactive wild ass conserva-
tion in Mongolia.
Acknowledgements
Funding for this research was provided by the Denver
Zoological Foundation, Nature Conservation Inter-
national, the Mongolian Academy of Sciences, the
Mongolian Ministry for Nature and the Environment
(MNE), the Mongolian Society for the Conservation of
the Mongolian Gazelle, Brandenburg Ministry for
Nature and the Environment, the Mongolian Hunting
Association, the Chicago Zoological Society, WWF-
Germany, the Mongolian Forestry and Hunting Insti-
tute, National Geographic, Balser Stiftung fu
Èr
Biologische Forschung, the Wilds, the UNDP-MNE
Global Environment Facility's Mongolia Biodiversity
Project, and the German Agency for Technical
Co-operation. We thank L. Amgalan, S. Amgalanbaatar,
A. Avirmed, J. Batbold, O. Batbold, Z. Batjargal,
E. Blumer, B. Boldgev, U. Buyandelger, Choijun,
M. Dolek, D. Enkhbileg, T. Galbaatar, J. Grif®n,
M. Johnstad, L. Lhagvasuren, A. Liegl, B. Mijiddorj,
P. Moehlman, B. Munkhtsog, Z. Namshir, M. Otgon-
jargal, M. Rowen, K. Sakeen, Sangdesuren, S. Schmidt,
Tomar, G. Wingard, and J. Wingard for their assistance
with various portions of this study. Comments from
C. Groves and P. Duncan contributed greatly to the
manuscript.
R. P. Reading ET AL.388

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389Khulan in Mongolia