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Distribution, Occupancy and Activity Patterns of Goral (Nemorhaedus goral)and Serow (Capricornis thar) in Khangchendzonga Biosphere Reserve, Sikkim,IndiaAuthor(s): Tapajit Bhattacharya, Tawqir Bashir, Kamal Poudyal, Sambandam Sathyakumar andGoutam Kumar SahaSource: Mammal Study, 37(3):173-181. 2012.Published By: Mammal Society of JapanDOI: http://dx.doi.org/10.3106/041.037.0302URL: http://www.bioone.org/doi/full/10.3106/041.037.0302
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Mammal Study 37: 173–181 (2012)
© The Mammal Society of Japan
Distribution, occupancy and activity patterns of goral (Nemorhaedus
goral) and serow (Capricornis thar) in Khangchendzonga Biosphere
Reserve, Sikkim, India
Tapajit Bhattacharya1,2
, Tawqir Bashir1
, Kamal Poudyal1,2
, Sambandam Sathyakumar1,
*
and Goutam Kumar Saha2
1
Wildlife Institute of India, P.O. Box 18, Chandrabani, Dehradun 248 001, Uttarakhand, India
2
Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India
Abstract. We assessed the distribution, occupancy, and activity patterns of two rupicaprids viz.,
Himalayan goral Nemorhaedus goral and Himalayan serow Capricornis thar in the western part of
the Khangchendzonga Biosphere Reserve, Sikkim, using camera traps during 2009–2010. Goral had
the highest photo-capture rate (# photo/100 days) of 6.37 ± 3.02 in temperate habitats (n = 169)
followed by 1.82 ± 1.27 in subalpine habitats (n = 41). Serow had the highest photo-capture rate of
1.65 ± 0.88 in subalpine habitats (n = 53) followed by 0.58 ± 0.34 in temperate habitats (n = 19). The
estimated detection probability was 0.57 for goral and 0.46 for serow. Detection probabilities were
negatively related to human presence. Occupancy of goral (0.27) was slightly lesser than serow
(0.30). Denser tree cover, warmer aspect and sites far away from tourist trails were the best predictors
for the occupancy of goral. Denser tree cover, higher elevation and warmer aspect were the best
predictors for the occupancy of serow. Spatial separation between these two species was not clear
although different activity peaks were observed. To ensure the survival of these species, protection
measures are required to keep their habitats free from anthropogenic activities.
Key words: activity patterns, eastern Himalaya, goral, occupancy, serow.
The Rupicaprids or goat-antelopes, a general name for
goral (Nemorhaedus spp.), serow (Capricornis spp.) and
takin (Budorcas taxicolor), hold an intermediate position
between ‘goats’ on the one side and ‘antelopes’ on the
other (Prater 1980; Sathyakumar 2002). These mountain
ungulates have a more or less goat-like build, goat-like
teeth, short tails and relatively small cylindrical horns
present in both sexes (Prater 1980). The goral is a cliff-
dwelling, sexually monomorphic mountain ungulate
with size 65–70 cm (shoulder high) and weighing about
25–30 kg (Prater 1980). The Himalayan goral is repre-
sented by two sub-species: the gray goral (N. goral
bedfordi) of the western Himalaya and the brown goral
(N. goral goral) inhabiting the eastern Himalaya
(Sathyakumar 2002). Goral in general are solitary
(Schaller 1977; Green 1987) but group size can vary
from 1 to 12 (Vinod and Sathyakumar 1999).
In appearance, the serow resembles a goral and is
generally a solitary animal (Schaller 1977; Prater 1980;
Nowak and Paradiso 1983). Both sexes are similar in
appearance and of about equal size (Schaller 1977). An
adult serow measures about 100 to 110 cm at its shoul-
ders and weighs about 91 kg on average (Prater 1980).
The Himalayan serow is found along the Himalayan
range of India, Nepal and Bhutan and also in Bangladesh
(Schaller 1977; Prater 1980; Nowak and Paradiso 1983;
Shackleton and Lovari 1997). It inhabits steep, rugged,
inaccessible and densely forested areas of the Himalaya.
Serow prefers damp and thickly wooded gorges and
occurs between 1,500–4,000 m (Schaller 1977; Prater
1980; Sathyakumar 2002). It is also seen on open cliffs
and rocky slopes.
These two near threatened (IUCN 2010) goat-antelopes
of Himalaya inhabit the heavily forested habitats
(Sathyakumar 1994; Mishra et al. 1994) or open habitats
at higher elevations, such as sub-alpine rhododendron
scrub, alpine meadow and grassland (Green 1985).
Complex terrain, steep topography and dense vegetation
*To whom correspondence should be addressed. E-mail: [email protected]
Mammal Study 37 (2012)174
impede field research and monitoring activities. Tradi-
tional field survey methods based on direct observation,
such as transect counts and behavioral observations, are
hence difficult to undertake due to the inaccessibility of
remote areas, lack of visibility in dense vegetation and
the species extreme sensitivity to human disturbance
(Sathyakumar 1994, 1997, 2002). In mountainous land-
scapes, a key factor that has limited quantitative habitat
modeling for forest antelope is the difficulty in estimat-
ing density or relative abundance (Bowkett et al. 2007).
This is because of low detection rates from methods
based on direct sightings (Feer 1995) and methodologi-
cal problems extrapolating from indirect signs such as
dung or tracks (Bowland and Perrin 1994; Struhsaker
1997; Lunt et al. 2007). However, camera-trapping has
shown excellent potential for studying elusive animals in
comparison with more traditional methods (Jácomo et al.
2004) and has proven useful for forest antelope in the
Udzungwa Mountains of Tanzania, where it has a high
detection efficiency and has recorded species otherwise
undetected (Rovero and Marshall 2004; Rovero et al.
2005; Bowkett et al. 2006). In this study, we used camera-
traps to detect goral and serow in dense, steep and very
moist eastern Himalayan forest. Previous studies on
these species in Indian and Nepal Himalaya (Green
1987; Lovari and Apollonio 1993, 1994; Cavallini
1992; Mishra et al. 1994; Sathyakumar 1994; Vinod
and Sathyakumar 1999; Aryal 2008; Bhattacharya and
Sathyakumar 2008) indicated that they can be present
in a wide range of elevation (1,000–4,000 m), and
depicted them as very shy, forest dwelling, steep slope
preferring animals which occasionally use the forest
openings (Mishra 1993; Pendharkar 1994; Sathyakumar
1994; Mishra and Johnsingh 1996; Aryal 2008). All the
above mentioned studies indicated that the geographical
factors such as terrain characteristics and ecological
factors such as forest type and vegetation cover and level
of anthropogenic activities may determine the abundance
of goral and serow. Resource-selection probability func-
tions and occupancy models are powerful methods of
identifying areas within a landscape that are highly used
by a species (MacKenzie 2005, 2006). In this study, we
modeled the essential habitat characters for occupancy
of goral and serow in an intricate valley of Eastern
Himalaya.
Apart from detection, camera traps have provided
detailed information on the occurrence and activity
patterns of relatively secretive mammals (Azlan and
Sharma 2006; Kawanishi and Sunquist 2008). As goral
and serow are reported to share similar type of habitats
(Sathyakumar 2002), assessment of their activity pat-
terns may elucidate about their likely differential strategy
of resource use. Studies on the behavioral patterns of
these ungulates indicated about their crepuscular and
probable nocturnal activity (Cavallini 1992; Lovari and
Apollonio 1994). In this study, using the camera-trap
data, we also observed their activity patterns and
assessed if any temporal difference was present.
Methods
Study area
Ecological information on rupicaprids in Indian
Himalaya, particularly from Eastern Himalaya is very
scanty (Sathyakumar et al. 2011). The geographical
position of Eastern Himalaya denotes the convergence
of three biogeographic realms, vis., Palaearctic, Africo-
tropical and Indo-Malayan (Mani 1974). This special
biogeographic position may have consequence the rec-
ognition of this area as one of the global biodiversity
hotspots (Myers et al. 2000) and also as one among the
important Global 200 Ecoregions (Olson and Dinerstein
1998). Sikkim, a tiny mountainous state of India is the
westernmost part of this biodiversity rich region. In spite
of being a biodiversity rich state, there has been only one
scientific study available on mammalian assemblage
from this state (Sathyakumar et al. 2011). Till date, only
the presence of these Rupicaprids has been reported
(Sharma and Lachungpa 2002) from Sikkim, whereas
almost all the ecological information about these impor-
tant prey species of large carnivores of subalpine and
temperate forests is still unknown.
The study was carried out in Khangchendzonga
Biosphere Reserve (BR) in Sikkim, India (Fig. 1), from
February 2008 to August 2010. The Khangchendzonga
BR is one of the most significant biodiversity hotspots of
India, having varying ecozones from temperate to arctic
(1,220–8,586 m). The varying elevation within an aerial
distance of just 42 km makes this park a unique natural
heritage hotspot in the world. The Khangchendzonga
BR encompasses temperate, subalpine and alpine habi-
tats (1,000 to 5,000 m) as well as rocky slopes, glacial
moraines and permafrost areas (> 5,000 m) with diverse
slope and aspect categories, along with a range of wild-
life use. The area of Khangchendzonga BR has been
divided into seven watersheds (Fig. 1) or river sub-
systems, namely, Lhonak (15%), Zemu (23%), Lachen
(5%), Rangyong (36%), Rangit (6%), Prek (8%) and
Bhattacharya et al., Goral and serow in Khangchendzonga 175
Churong (7%). The Prek Chu valley (27°37'N, 88°12'E–
27°21'N, 88°17'E) opens up in the upper reaches with a
total area of 182 km2
. The highest elevation and the low-
est elevation of the Prek Chu are 6,691 m (summit of
Pandim) and 1,200 m respectively, with a mean of 3,562
m (Tambe 2007). The following elevation classes are
observed: 1,200–2,000 m (5%), 2,001–3,000 m (13%),
3,001–4,000 m (25%), 4,001–5,000 m (44%) and 5,001–
6,991 m (13%) in the study area. The annual rainfall
ranges from 1,750 mm to 2,250 mm, with the mean
being around 2,230 mm (Tambe 2007). The Prek Chu
has a typical monsoon climate and can be divided into
the following habitat classes-mixed sub-tropical and
mixed temperate (17%), subalpine and krummholtz
(36%), alpine meadows (5%), rocky area and snow cover
(41%) and water bodies (1%) (Fig. 2).
Camera trapping
Based on the knowledge acquired through reconnais-
sance surveys and trail walks (n = 22, 1.5 to 7 km) for
ungulate evidences carried out in 2008 (Bhattacharya et
al. 2010; Sathyakumar et al. 2011), intensive camera
trapping was carried out in Prek Chu from February
2009 to August 2010. Prek Chu was divided into 1 km2
blocks using Geographic Information System (GIS)
tools. For simplicity, the area was categorized into three
different survey zones according to the elevation, vis.,
temperate (1,200–3,000 m), sub-alpine (3,000–4,000 m)
and alpine (above 4,000 m) and the camera traps were
deployed corresponding to the area coverage of the sur-
vey zones and their accessibility (13 blocks in temperate,
18 blocks in subalpine and 13 blocks in alpine). One
camera unit was placed in each block for at least 1
month, and was then moved to a different block of differ-
ent habitat. Due to difficult navigation in the field, more
than one camera units were occasionally placed in one
block (15 blocks). Within each survey zone, cameras
were placed in likely animal-use areas and > 500 m from
other cameras. Twenty seven cameras were deployed at
71 sites in 44 blocks (Fig. 3). The camera trapping was
done continuously in all the seasons (winter: January–
March; spring: April–May; summer: June–September;
Fig. 1. Location of the study area: Khangchendzonga Biosphere
Reserve in Sikkim, India showing the different watersheds including
Prek Chu catchment.
Fig. 2. Major habitat categories in Prek Chu Catchment,
Khangchendzonga Biosphere Reserve, Sikkim, India.
Mammal Study 37 (2012)176
autumn: October–December); however, similar intensity
of camera trapping could not be maintained in alpine
zone during winter and in temperate zone during peak
monsoon (July–August). Four models of infrared-
triggered camera units: two DeerCam (Deercam Scout-
ing Camera, Non Typical, Inc., Park Falls, WI, USA),
two Wild-view (wildview xtreme2, Grand Prairie, Texas,
USA), 18 Stealthcam (Stealthcam, LLC, Grand Prairie,
Texas, USA) and five Moultrie (Moultrie Feeders, Ala-
baster, Alabama, USA) were used. Head-on, oblique
and side-view camera configurations were used to obtain
photographs at varying body orientations (Blomqvist
and Nystrom 1980; Jackson et al. 2006). Since the study
species were rare and the area being vast, the strategy
was to survey more sampling units less intensively rather
than less sampling units more intensively (MacKenzie
and Royle 2005). All the camera units were set with a
1 min delay between photographs, and set for 24-h
monitoring. Camera units were attached to trees 15–30
cm above the ground and 3–5 m from a trail or point
where animal movement might be expected. A time/date
stamp accompanied each photograph and at each sample
site we recorded GPS location, elevation, slope, aspect
and habitat, including forest type and percentage of
vegetation cover (ground cover along with understorey
and canopy cover). The number of camera trap-days
was calculated from the date of deployment till the date
of retrieval (if the memory card was not full) or till the
date of the final photo.
Monitoring of camera traps was done at least twice
a month which included changing the batteries and
memory card. Due to the topography and remoteness
of the area all field activities were carried out in the
form of field expeditions i.e., camping in different areas
of the Prek Chu.
Analytical methods
Photographic encounter rates were calculated for each
species for each habitat zone. Photographic encounter
rate was calculated as the number of photo captures of
a species divided by the number of trap-days per site.
Trap-days were computed as the number of 24-h periods
from deployment of camera until the film/memory card
was used up or the camera was retrieved. Instances
where the same species were captured by the same
camera more than once within 1 hour were excluded
from trap rate calculation (Bowkett et al. 2007). This
was a compromise between scoring the same individual
multiple times and missing individuals (Rovero et al.
2005) and is more conservative than other published
studies (e.g., Kinnaird et al. 2003). All detections for
each species were summed for each camera site, multi-
plied by 100, and divided by the total sampling effort
for that sample point (number of camera-days). We
used this photographic rate to compare detection of each
species in different habitats and tested the significance
using Mann-Whitney U test.
The sampling record at each site was divided into five
consecutive 5-day segments based on the date stamp on
the photographs. A detection matrix of each species
was established following the approach proposed by
MacKenzie et al. (2002). We excluded sites where the
sampling was less than five 5-day segment (41 sites were
included). An occupancy model (program PRESENCE,
v. 2.2; Hines 2006; MacKenzie et al. 2006) was used to
estimate the site occupancy rate (ψ) and detection prob-
Fig. 3. Map of study area showing locations of camera traps in
1 km × 1 km grids in different habitats of Prek Chu Catchment,
Khangchendzonga Biosphere Reserve, Sikkim, India.
Bhattacharya et al., Goral and serow in Khangchendzonga 177
ability (p) relative to seven sampling variables and two
detection variables (Table 1). Geographical orientation
of mountain ranges are in north-south direction in
Sikkim Himalaya (Tambe 2007); hence, only the eastern
aspects get exposed to the sun in the forenoon and regu-
lar cloudy weather in afternoon prevent the western
aspects to get the warmth of the afternoon sun. This
typical orientation of mountain ranges and the cloudy
weather have resulted the categorization of eastern
aspects as warmer and western aspects as cooler. The
detection variable ‘human signs’ included every possible
indirect evidence of human such as plastics, discarded
shoes or clothes or any other such objects and direct
evidence such as photo capture. Akaike Information
Criterion (AIC; Akaike 1973) values were used to rank
the occupancy models and all the models whose ΔAIC
< 2 were considered as equivalent models. The summed
model weight of each covariate in these models was used
to determine the most influential variables for each
species. The sign of logistic coefficient of each variable
(positive or negative) was used to determine the direction
of influence of the variable. The time and date printed
on the photographs has been used to determine the daily
activity pattern of individual species (Pei 1998). We
used a Daily Activity Index (DAI) of 2-hour durations to
examine the daily activity level:
DAI = No. of photographs within a duration
× 100/Total no. of photographs
Rayleigh uniformity test and Watson U2
test (Mardia
and Jupp 2000) using Oriana 3.13 (1994–2010 Kovach
Computing Services) was applied to determine unifor-
mity and the significance of differences in the daily
activity patterns between species.
Results
A sampling effort of 6,278 camera-days across 71
sample sites was achieved in the three survey zones
(1,407 camera-days in temperate, 3,061 camera-days in
subalpine, 1,810 camera-days in alpine), resulting in
4,517 photo captures (2,668 wild animal, 1,849 domestic
animals and human) 284 of which contained goat-
antelopes. During the 2-year survey, 42 mammal species
were recorded (Sathyakumar et al. 2011), seven of which
were ungulates (n = 468 photo captures). Brown goral
and Himalayan serow were the most frequently detected
ungulates for both temperate and subalpine habitats
within the low and mid-elevation range (1,200–3,700 m).
Blue sheep Pseudois nayaur and musk deer Moschus
sp. only occurred over 3,700 m in alpine meadows and
sub-alpine shrub habitats respectively. Barking deer
Muntiacus muntjak and wild pig Sus scrofa occurred
only < 2,500 m in lower temperate habitat. Himalayan
tahr Hemitragus jemlahicus was detected very rarely
(n = 6 photo captures) in subalpine and alpine habitats.
Between the goat-antelopes, aggregation behaviour was
recorded only in case of goral as twenty five photo cap-
tures contained two adult individuals and three photo-
graphs contained a group of three adults. Only one
photograph of serow contained two individuals.
Goral was detected over the broadest elevation range
(1,730–3,670 m), with the highest photo-capture rate
6.37 ± 3.02 (SE) in temperate (n = 169 captures) fol-
lowed by 1.82 ± 1.27 in subalpine (n = 41 captures).
Serow was detected over the elevation range 2,310–
3,700 m, and had the highest photo-capture rate 1.65 ±
0.88 in subalpine (n = 53) followed by 0.58 ± 0.34 at
temperate habitat (n = 19). Mann-Whitney U test showed
that there was no significant difference in photo-capture
rates between subalpine and temperate habitats in case of
both goral (P = 0.68) and serow (P = 0.07).
Goat-antelopes were detected at 12 sites (9 sites each
for goral and serow). The estimated site occupancy rates
of both species were slightly higher than the naive esti-
mates (i.e., the proportion of sites where the species was
detected at least once, 0.24 for both goral and serow),
although the estimated detection probabilities of both
Table 1. Variables used to estimate the site occupancy rates and
detection probabilities of goral and serow in the occupancy model
Abbreviation Name Description
Sampling variables
V Vegetation cover (%) Numeric (Range 0–80%)
E Elevation Numeric (Range 1,830–4,520 m)
A Aspect Categorical (Warm – NE, E,
SE, S (denoted as 0); Cold – N,
NW, W, SW (denoted as 1))
T Trekking trail Categorical (present, absent)
C Conifer forest Categorical (present, absent)
B Broadleaved forest Categorical (present, absent)
S Slope Categorical (steep > 30°
denoted as 0, gentle ≤ 30°
denoted as 1)
Detection variables
H Human presence Human sign (including direct
and indirect evidences) present
or absent
R Season Rainy (May–September) or
dry (October–April)
Mammal Study 37 (2012)178
species were greater than 0.40 (Table 2), suggesting that
our sampling duration (at least 30 days) was long enough
to detect the species at each site when they were present.
Results of occupancy modeling showed that detection
probability of both serow and goral were negatively
related with human presence at camera site (Table 3).
The estimation of occupancy rate of goral (0.27) was
slightly lesser than that of serow (0.30). Denser tree
cover, warmer aspect and distant sites from regularly
used tourist trails were the best predictors for the occu-
pancy of goral. Denser tree cover, higher elevation and
warmer aspect were determined as the best predictors for
the occupancy of serow (Table 3).
The DAI for goral and serow (182 and 60 photo-
graphs, respectively) confirmed that both species can be
found during daytime as well as at night, however, the
activity peaks differed. Goral showed an early morning
activity peak at 0400–0600 h (Rayleigh Z = 3.73, P =
0.02; indicating that the data was not uniformly distrib-
uted). Serow was active during the daytime with a peak
at morning (0600–0800 h), during afternoon, evening
and throughout the night; from 1600 h to 2200 h the
DAI of serow were same and highest (13.33). Rayleigh
Z test showed that the data was more or less uniformly
distributed (Rayleigh Z = 1.02, P = 0.36). The difference
between DAI of goral and serow (Fig. 4) was significant
(Watson’s U2
= 0.196, P < 0.05).
Discussion
During reconnaissance survey and trail sampling in
2008, we got only eight and four visual encounters of
goral and serow respectively, and the dung densities
calculated for different seasons were also very low
Table 2. The top models for predicting site occupancy (Est. ψ) and detection probability (Est. p) of goral and serow in Prek Chu watershed of
Khangchendzonga Biosphere Reserve
Models ΔAIC AIC weight No. Par. (–2LL) Est. ψ (± 1 se) Est. p (± 1 se) Est. of c-hat
Goral
ψ (VA), p (H) 0 0.2634 5 80.11 0.2671 ± 0.0492 0.5474 ± 0.0191 0.68
ψ (VAT), p (H) 0.21 0.2372 6 78.32 0.2544 ± 0.0491 0.5682 ± 0.0178 0.78
ψ (V), p (H) 0.78 0.1783 4 82.89 0.2585 ± 0.0439 0.5599 ± 0.0184 0.75
ψ (VATB), p (H) 1.72 0.1115 7 77.83 0.2551 ± 0.0491 0.5689 ± 0.0178 0.79
ψ (EVAT), p (H) 1.89 0.1024 7 78 0.2555 ± 0.0492 0.5678 ± 0.0178 0.72
ψ (VAT), p (HR) 1.99 0.0974 7 78.1 0.2557 ± 0.0493 0.5552 ± 0.0175 0.71
Serow
ψ (EVAC), p (H) 0 0.284 7 59.87 0.3046 ± 0.0667 0.4452 ± 0.0237 0.91
ψ (EVAC), p (HR) 0.08 0.2729 8 57.95 0.3151 ± 0.0660 0.4496 ± 0.0253 0.67
ψ (EVTA), p (HR) 0.28 0.2469 8 58.15 0.2661 ± 0.0591 0.4706 ± 0.0242 0.83
ψ (EVTA), p (H) 1.5 0.1342 7 61.37 0.2690 ± 0.0594 0.4668 ± 0.0233 0.93
Table 3. Summed model weight (Σ), Average β value with standard error (SE) and sign [positive (+), negative (–) and (*
) if significant] of each
sampling variable in the equivalent models listed in Table 2
Variables (Abbreviation)
Goral Serow
Σ model weight Average β value (SE) Σ model weight Average β value (SE)
Sampling variables
Tree % (V) 0.99 +2.1 (0.91)* 0.94 +14.38 (4.51)*
Elevation (E) 0.1 +0.56 (1.02) 0.94 +11.08 (3.74)*
Aspect (A) 0.81 –1.89 (0.7)* 0.94 –5.83 (2.53)*
Trekking trail (T) 0.55 –1.74 (0.62)* 0.38 –4.82 (2.15)*
Conifer forest (C) NA NA 0.56 +4.97 (2.39)*
Broadleaved forest (B) 0.11 –0.94 (1.32) NA NA
Detection variables
Human presence (H) 0.99 –1.61 (0.55)* 0.94 –2.77 (1.01)*
Season (R) 0.10 –0.19 (0.42) 0.52 0.74 (2.13)
NA = Not appeared in top models.
Bhattacharya et al., Goral and serow in Khangchendzonga 179
(Bhattacharya et al. 2010). Visual encounters of goat-
antelopes were very rare due to dense cover and steep
terrain (Bhattacharya et al. 2010; Sathyakumar et al.
2011). Our result showed that these species are active at
night also, thus camera trapping proved to be the most
efficient method to detect these mountain ungulates in
Khangchendzonga BR. Of the seven ungulate species
recorded, goral and serow showed the coverage of
broadest elevation range. Other studies on the ecology
and distribution of these goat-antelopes also indicated
broad elevation range for goral (Green 1985; Cavallini
1992; Mishra 1993; Sathyakumar 1994; Vinod and
Sathyakumar 1999) in western Himalaya. All of these
studies indicated that goral can be found from very low
elevation (500 m) to the tree line (4,000 m), similarly
during this study, goral photographs had been captured
from the lowermost part of the study area (1,730 m) to
the subalpine forests (3,700 m). Aryal (2008) showed
that serow preferred 2,500–3,500 m altitude range in
central Himalaya of Nepal. Similarly, in this study most
of the serow photographs were captured in this elevation
range. No significant difference between photo-capture
rates of goral in subalpine and temperate habitats indi-
cated the similar level of presence (or use) of the species
in both habitats. Photo-capture rates of serow indicated
no significant difference between subalpine and temper-
ate habitats but the significance level (P = 0.07 at 95%
level of significance) may also hint for its presence more
in subalpine (53 captures) than in temperate habitats
(19 captures).
Our findings from the occupancy based models
(summed model weights) for serow indicated that dense
conifer forests in upper elevation zone of Prek Chu may
be occupied more by the species. The summed model
weight of elevation (Table 3) was low and depicted that
dense broadleaved forests of the temperate zone may be
occupied more by goral. Thus, findings from both photo
captures and occupancy based models indicated a ten-
dency for spatial separation between goral and serow
(altitudinal) in terms of forest type specific distribution
although the distinction was not very prominent.
Absence of other ungulates in the subalpine and upper
temperate region; as blue sheep and musk deer inhabited
the alpine and alpine-subalpine edge and barking deer
and wild pig confined to the lower temperate zones,
goral and serow may co-occur in the above mentioned
unoccupied zones. Being goat-antelopes, goral and
serow may have similar food and covers requirements
(Green 1985, 1987; Sathyakumar 1994, 2002; Awasthi et
al. 2003) as they were detected in the same temperate
and subalpine forests of the study area. Although the
spatial separation between these two species was not
clear from our findings but the different activity peaks
(goral was active at dawn and morning and serow was
active at afternoon and night) and a significant difference
in daily activity indices may indicate probable temporal
separation between these rupicaprids. Detailed studies
on behavior using intensive camera trapping in specific
locations and on the food habits through fecal pellet anal-
ysis of these goat-antelopes in eastern Himalayan region
may be helpful to properly understand the complex eco-
logical perspectives of these least studied goat-antelopes.
Studies on habitat use patterns of goral in western
Himalaya (Sathyakumar 1994; Mishra and Johnsingh
1996; Vinod and Sathyakumar 1999; Bhattacharya and
Sathyakumar 2008) described its preference for open
patches, but unlike the western Himalayan light wooded
or open habitats such as scattered trees and scrub
(Sathyakumar 1994), the eastern Himalayan habitats are
denser and thus in our findings dense forest cover was
one of the best predictors as depicted by the occupancy
models. Both goral and serow preferred warmer eastern
aspects of the study area but the specific reason for this
preference was not clear from the results of this study.
As depicted by the studies in western Himalaya, both
the species showed preference for steep slopes and we
considered steepness of slope as a site covariate in the
occupancy model (Table 1), but more or less uniform
steepness (> 30°) of the study area may result the omis-
sion of slope as a variable from best predictor models of
occupancy of goat-antelopes though presence of cliffs
and/or steep slope is important determinant of these rupi-
caprids habitat preference (Bhattacharya et al. 2010).
Fig. 4. Daily activity patterns of goral and serow in Prek Chu catch-
ment area of Khangchendzonga Biosphere Reserve.
Mammal Study 37 (2012)180
According to the result of occupancy modeling, dis-
tant sites from the regularly used trekking trails were best
occupied by goral and same was true for the occupancy
of serow. Presence of human at the camera sites clearly
affected the detection probability of both species nega-
tively. Both species are shy and mostly solitary in nature
(Sathyakumar 2002) thus avoidance of human presence
was quite normal. But at the same time, presence of
human inside the National Park either for tourism or for
livestock grazing was frequently observed during the
study period. In the temperate zone, proximity to the
villages resulted in presence of more livestock (pack
animals such as horse, dzo and cattle) and human inside
the dense broadleaved forest (dominated by Quercus
spp. and Castanopsis spp.) and in some cases at potential
goral habitats. In the subalpine conifer forests (domi-
nated by Abies spp. and Rhdodendron spp.), only anthro-
pogenic activity recorded was tourism and its impact was
probably confined only along the trekking trails. Regu-
lation of human and livestock entry inside the temperate
zone of the Biosphere Reserve may be helpful in protect-
ing the goral habitat. Strict vigil is also necessary to
keep the subalpine habitats intact and free from the
adverse impacts of tourism for the survival of serow.
Acknowledgments: We are grateful to the Department
of Forests, Environment and Wildlife Management,
Government of Sikkim for granting us permission to
work in Sikkim. We thank the Wildlife Institute of
India, Dehradun for providing us the grants and support.
We thank Mr. Sukbahadur and Mr. Sukraj for their help
during field work. We thank the reviewers for their
comments on the manuscript.
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Received 22 December 2011. Accepted 23 March 2012.