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Conservation of the Red-Shanked Douc Langur
(Pygathrix nemaeus nemaeus) in Bach Ma National Park,
Vietnam
Final Report
Prepared for
Peoples Trust for Endangered Species (PTES)
By Le Thi Dien
April, 2009
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Executive Summary:
The red-shanked douc langur (Pygathrix nemaeus nemaeus), is an endangered
monkey distributing in Vietnam, Lao, and Cambodia. Through this study, we
reported the total number of animals observed during the study is 22 animals
(estimate 26 animals). The survey area is 130 km2. Therefore, current population
density estimated was 0.17 individuals per km2. P. nemaeuswere mainly found at
elevation between 500 and 1.300m above sea level in Bach Ma National Park.
Groups of P. nemaues often distribute in restoration forest habitat or tropical
broadleaf evergreen rain forest habitat. A total of 41 belonging to 25 families were
observed eaten by P. nemaeus at Bach Ma National Park. One of the most
important finding is we add fifteen new tree species used by P. nemaeus to the
existing food list. P. nemaeus were observed feeding on variety of food items
including leaves, buds, flower buds, flowers, fruits, and bamboo shoots. We also
recognised that three main threats to P. nemaeuswere identified during the study,
including hunting, habitat destruction and tourism. Two senior students were
instructed to do research and three training courses were be organized to improve
conservation awareness of the BNP staffs, students of Hue University of Agriculture and
Forestry, and local people in endangered primate species survey and monitoring.
INTRODUCTION
The colobine monkeys of the genus Pygathrixare native to Indochina. Until only ten years
ago, just two distinct taxa were recognized: the red-shanked douc, Pygathrix nemaeus,
named by Linnaeus in 1771, in the northern part of Central Vietnam and Central Laos;
and the black-shanked douc, P. nigripes, from South Vietnam and east Cambodia,
described exactly a century later by Milne-Edwards. In Vietnam the douc langur is found
from Tay Ninh province to Nghe An province (Pham, 1993). Red-shanked douc langurs(Pygathrix nemaeus nemaeus) are found in Bach Ma National Park, and black-shanked
douc langurs (Pygathrix nemaeus nigripes) are found in Nam Cat Tien National Park in
Vietnam (Eames and Robson, 1993). Both the red and black-shanked douc langurs are
found in Kong Cha Rang, Kon Khi Kinh, and Mom Ray Nature Reserves (Lippold, 1995)1.
1 http://www.theprimata.com/pygathrix_nemaeus.html
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The beautiful red-shanked douc langur is only found in north and central Vietnam and
Laos. Its habitat is in the lowland to montane primary and secondary rainforest where it
lives in the mid to upper levels of the canopy2. They live in moist tropical rain forest but
have also adapted to dry (monsoon) forest (Camille Dorian, 2002).
The red-shanked douc langur has been listed as EN A1cd (IUCN Red List ver 2.3 (1994)),
Appendix I (CITES), Endangered (Red Book on Fauna of Vietnam, 2004), and category IB
(Decree 32/2006/ND-CP of Vietnam). However, their population sizes in the wild appear
to decline because of several conservation problems. Firstly, habitat loss and forest
fragmentation is one of the most important factors threatening this species. The loss of
natural forest by war, logging and the replacement of secondary natural forests by
commercial plantation forests in the area has reduced the quality and quantity of natural
habitat drastically. Secondly, it is currently known as one of the most popular primates inthe food and pet trade. They are considered a delicacy all over Southeast Asia. In
addition, it is also in danger of becoming medicinal products because some traditional
oriental medicines use douc langur body parts (Camille Dorian, 2002). Under pressure
from hunting and habitat loss, the number of this species is dwindling fast. Lastly, limiting
on skills of species monitoring and conserving of conservationists due to lacking the
specific information of species as well as non-participating of local communities on wildlife
conservation is another cause of the decline of this species in nature. Without immediate
and decisive conservation action, these species are likely to become extinct very soon 3.
There have been conservationists doing researches into distribution, population size and
diet of the species. Pham Nhat (1993) investigated into 49 floras of 22 fammilies used as
food by P.nemaeus. Some authors have identified the occurrence of the species in Bach
Ma Natonal Park such as Eames & Robson, 1993; Lippold, 1995; Matsumarra, 1997;
Huynh Van Keo and Van Ngoc Thinh, 1998. However, due to the high hunting pressure in
Bach Ma National Park, douc langur populations have considerably reduced (Vu Ngoc
Thanh, pers. comm.).
Therefore, data on biology, ecology, distribution, population abundance, and threats of thespecies is vital for long-term conservation and management recommendations. Training
courses and participating on project activities will provide local people, conservationists,
2 http://www.blueplanetbiomes.org/redshanked_douc_langur.htm
3 WWF
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young researchers, students, and others with the necessary skills for conserving this
species.
AIMS OF PROJECT
The overall aim of our project is to obtain information useful for the better monitoring and
conservation of the Red-Shanked Douc Langur (Pygathrix nemaeus nemaeus) in
particular and primate species in general in the central region of Vietnam. Hiring local
people and Bach Ma National Park staffs as field assistants within this project and training
courses will allow for the capacity development and conservation awareness of
stakeholder members.
Through the study, we intend:
(1) To identify the distribution and abundance of P. nemaeus;
(2) To study the ecology and behavior of P. nemaeus;
(3) To assess current and potential threats to P. nemaeus and its natural habitats and
propose possible solutions to the species conservation;
(4) To promote conservation awareness through employment and capacity development
of Bach Ma National Park staffs, students of Hue University of Agriculture and Forestry,
and local people in endangered primate species survey and monitoring;
(5) To make appropriate conservation and management recommendations for the species
and its habitats.
METHODS
1. Research site
Bach Ma National Park is located in the Central Truong Son, is a strip of forest connecting
the border between Lao and Vietnam with the East Sea. This National Park with high
biodiversity is the habitat of many rare plants and animals. Among those is P. nemaues.According to rangers experience, We have determined distribution sites of P.nemaeus in
sub-areas 207, 209, 210, 211, 214, 227, 229, 230, 231, 375, 384, 385, and 386 of the
National Park, the total scale of these areas is estimated to be 130km2. Thus, the
research areas are determined in the scale of 130km2 in these sub-areas.
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Study site was selected based on local informants and previous reports. Five transects
were established within the langurs known habitats:
(i) Transect 1: Bach Ma summit - Coldebay: two expeditions;
(ii) Transect 2: Km 14 Bach Ma - Tri Sao waterfall: one expedition;
(iii) Transect 3: Km 14 Bach Ma - Truoi lake: one expedition;
(iv) Transect 4: Bach Ma summit - Lien Chi slope: one expedition.
2. Research Time
The study was carried out from November, 2008 to May, 2009 in Bach Ma National Park.
In the first month we interwiewed rangers of Bach Ma National Park to collect data of the
times they encountered P.nemaues, the plants used as food by P. nemauesand threats
to the species, and identified line-transects.
In the rest months, we implemented field investigations in line-transects to collect data of
distribution, population size, food plants of the species and threats to it. Each expedition
was investigated in one day per month. The total number of days spent on field
investigation is 30.
3. Methodology
3.1. Interview
We carried out interviews with villagers, hunters, and experienced staffs of Bach Ma
National Park to determine the most likely places for encountering the species. These
interviews also provided information on the current and past distribution and population
size of the species, the list of food eaten by this species, as well as the threats to this
species in the study area.
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Figure 01. The Map of observed transects
3.2. Forest survey
(+) Investigation into the species distribution status and population size
Investigation in each line-transect was carried out to observe the occurrence of P.
nemaeus. The time for observation was from 6: am to 6: pm. In addition, all signs such as
tracks, faeces, feeding signs, vocalizations, etc. was noticed to determine distribution of
this species.
(+) Food
All samples of food plants and potential food were collected from areas known to be in the
range of the monkeys.Representative samples of food eatenwere selected from trees in
which monkeys would be observed feeding. Additional samples were chosen from trees
judged to be common in the habitat.
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(+) Threats
Threats to the species are identified through interviewing rangers, field observation, and
the levels of threats are arranged according to the criteria: (+) range of impacts (total
impacts in the park or partly impact), (+) intensity of impacts (strongly impact or slightlyimpact).
Surveying in the field
3.3. Training and workshop:
- Three field training courses will be organized to improve conservation awareness of the
BNP staffs, students of Hue University of Agriculture and Forestry, and local people in
endangered primate species survey and monitoring.
- A workshop among the related stakeholders (Conservationists of Bach Ma National
Park, local authorities, local people, research team members, staffs of the Green Corridor
Project, Staffs of NGOs related to conservation in Thua Thien Hue Province, students of
Hue University of Agriculture and Forestry) by the end of the project will be organized to
present the research findings; have discussions; receive comments from participants to
finalize the research report; and create a network for research and primate conservation
among stakeholders.
RESULTS
1. Population status
Three groups and one solitary juvenile female of P. nemaeus were recorded based on
direct observations and informants during the study. The number of animals and age/sex
composition of 3 groups observed are presented in table 01.
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The highest count for a single group was 10 animals (estimated 12 animals) and the
lowest count for a single group was 5 animals (estimated 7 animals). Average group size
is 7 animals. The estimates were based on evidences such as branch movements and
vocalizations. Juveniles were seen in all three groups. An Infant clinging an adult female
was observed in group 3 in July 2008. The infants/adults ratio is 1: 2.75. It was difficult to
identify sexes of adults in the field since the groups observed traveled fast and
observations were made at distance. Further, animals appeared to be wary of observers
and they often fled away when detected observers.
Table 01. Population sizes ofRed-shanked douc langur in BMNP
No. Count EstimateAdult
Male
Adult
femaleJuveniles Infants
Solitary 1 1 1 (female)
Group 1 5 7 ? ? 2
Group 2 6 6 ?2 ?2 2
Group 3 10 12 ? ? 2 1
TOTAL 22 26 7 1
The solitary juvenile was rescued and released to the forest by forest rangers in July,
2007 when it was confined in a cage. Local people said that they had caught this Langur
in April, 2006. Meanwhile, the Langur was about 4-5 months old, it was in burned status
because it had been carried by his mother to near the field which was being burned for
afforestation. At the time being rescued, this Langur was about 20 months old and in good
health condition. When it is released, at first it only fed around the burnt-over land. Later, it
moved gradually to the top, it is currently seen at an altitude of 600-700m. Although living
close to the group of 5-7 langurs (2 km far from this group), the animal appeared not to
integrate with neighboring groups since she always traveled, fed and rested alone and
kept distance with neighboring groups.
The total number of animals observed during the study is 22 animals (estimate 26
animals). The survey area is 130 km2. Therefore, current population density estimated
was 0.17 individuals per km2.
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2. Distribution
The locations and elevations of 3 groups and a solitary female juvenile of Pygathrix
nemaeusare shown in table 2.1. P. nemaeuswere mainly found at elevation between 500
and 1.300m above sea level in Bach Ma National Park. According to local reports,Pygathryx nemaeus were often seen in CHO DEN (Prashorea stellata) forest and
surrouding areas. These groups sometimes shift from Truoi Pond to Morin for feeding.
Table 02. Distribution of 3 groups and a solitary juvenile female of
P. nemaeusat BMNP
No. Elevation (m) Locations Habitats
Solitary 18-678 N:16017,185
E:107010,126
N: 16013,125
E:107096,337
Burnt-over land, tropical
broadleaf evergreen rain forest
(poor forests)
Group 1 491-953 N:16016,231
E:107013,577
to N: 16012,156
E:107092,720
Tropical broadleaf evergreen
rain forest (secondary forest
after logging-young forests) and
sub-tropical broadleaf evergreen
rain forest (rich forests)
Group 3 1,375 N:16011,763
E:107051,755
Sub-tropical broadleaf evergreen
rain forest (poor and rich forests)
Group 4 1,150-1,336 From N: 16011,833
E:107050,729
to N: 160
11,856
E:107050,739
Sub-tropical broadleaf evergreen
rain forest (medium and rich
forests)
The distribution of the P. nemaeusare shown by Figure 02.
In Bach Ma National park, groups of P. nemaues often distribute in restoration forest
habitat or tropical broadleaf evergreen rain forest habitat. However, the species has a
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wide range for feeding, from field habitat in the Park foot (in altitude of 18m) to sub-
tropical broadleaf evergreen rain forest (in altitude over 900m).
The Investigation and interviews show that the P. nemaues lives and feeds on many
different types of forests. However, it only occasionally feeds on poor forest habitat withforest structure is broken down completely, the cover is
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3. Organization and Behaviour of the P. nemaeusin research sites
3.1. Social system
The social system of P. nemaeusvaries between a unimale and a multimale-multifemale
system. The social system of the P. nemaeus depends on the roles played by each
individual in the group. In each group, there will be one adult male P. nemaeusby whom
the power of the group is held and most of the important activities of the group are
organized. In addition, male and female individuals of this species are also found living
alone in forests. A ratio of one male and one female is often found in each group of the P.
nemaeus. Females have a higher tendency to groom males in multimale groups than in
unimale groups.
In research sites, most of the time P. nemaeusis found living in groups with an adult male
P. nemaeus leading. When discovering strange sounds, they often inform others of
dangers by growling. Then, they begin their movements through the forest canopy to other
areas in the forests while carefully turning back to observe and growling. In each group,
mature individuals often get food for others, especially for younger individuals in the
group. Infants are often carried ventrally when they are foraging for food or making their
movement through forest canopy. Basing on the times of their occurrences that were
observed, this species can be said to live and move among branches of trees usually.
Sometimes, they also feed on the ground.
Thus, the social organization system of the P. nemaeushas common features with those
of other kinds of Primate living in groups on trees.
3.2. Behaviour
The P. nemaeus is one of the species of langurs lives on trees and carries out their
activities at day-time. They live in the mid to upper levels of the canopy.
* Daily activities:
Daily activities of this species consist of playing, climbing, jumping up
and down in one place, stooping, hanging, and swinging from
overhead supports. Contact between individuals during play consists
of touching, pulling, mouthing, wrestling, and chasing. in social play,
immature group members tend to play more than adults. The most
popular times for play are just after eating time and before resting at night.
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Figure 03. Percentage of time for daily activities of the P. nemaeus
Thus, most of the time in a day is used for feeding and resting. Resting time takes the
highest percentage with 13 hours and 55% of a day time. Feeding time is about 8.5 hours,
take 35% of a day time, and 2.5 hours left is play time, take 10% of a day time.
* Parental care and protection:
Movement of the group is led by the adult males with females and infants in the center
and juvenile males bringing up the rear (Lippold, 1998). Infants are often carried ventrally
by their mothers or adult members when the group is moving or feeding. Sometimes,
group members break off part of a branch with leaves and give it to another group
member (Kavanagh,1978).
* Hiding behaviour:
When hearing strange sounds, they often hide themselves behind canopies and huge
branches, adult or mature individuals growl to inform others of dangers and move to
another place (according to people who have encoutered the P. nemaeus in Bach MA
national Park).
4. Diet
4.1. Food composition
A total of 41 belonging to 25 families were observed eaten by P. nemaeusat Bach Ma
National Park (Table 04; figure 04). Euphorbiaceae, Moraceae, and Poaceae families
have largest number of tree species used by P. nemaeus(4 species). This was followed
55%10%
35%
n
Chi
Ngh
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by Sapindaceae (3 species). Anacardiaceae, Clusiaceae, Dilleniaceae, Fagaceae, and
Meliaceae families contributed two species to the food list. The rest was eaten only one
species by P. nemaeus.
Table 04. List of food plant and plant part eaten by P. nemaeusat BMNPTT Latin name Family Part eaten
1 Saurauia tristyla Actinidiaceae Leaves, fruits
2 Allospondias lakonensis Anacardiaceae Leaves, fruits
3 Dracontomelum duperreanum Anacardiaceae Leaves, fruits
4 Schefflera octophylla Araliaceae Leaves
5 Canarium album Burseraceae Leaves, fruits
6 Peltophorum tonkinense Caesalpiniaceae Fruits, flowers
7 Garcilinia mangostana Clusiaceae Leaves
8 Garcilinia oblongfolia Clusiaceae Leaves, buds
9 Ipomoea batatas Convolvulaceae Leaves
10 Trichosanthes kirilowii Cucurbitaceae Leaves, buds, fruits
11 Dillenia heterocephala Dilleniaceae Fruits
12 Dillenia indica Dilleniaceae Leaves, fruits
13 Prashorea stellata Dipterocapaceae Leaves, buds
14 Baccaurea ramiflora Euphorbiaceae Leaves, fruits
15 Bischofia javanica Euphorbiaceae Leaves, fruits
16 Endospermum chinense Euphorbiaceae Fruits
17 Macaranga denticulata Euphorbiaceae Leaves
18 Castanea mollisima Fagaceae Fruits
19 Castanop sisbosii Fagaceae Fruits
20 Gnetum montarum Gnetaceae Fruits
21 Engelhardtia spicata Juglandaceae Leaves
22 Aglaia korthalsii Meliaceae Leaves
23 Chisocheton paniculatus Meliaeae Leaves, fruits
24 Adenanthera microperma Mimosaceae Leaves, flowers
25 Artocarpus rigidus Moraceae Leaves, buds, fruits
26 Ficus glomerata Moraceae Leaves, fruits
27 Ficus hispida Moraceae Fruits, buds
28 Ficus vasculosa Moraceae Leaves, fruits
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TT Latin name Family Part eaten
29 Musa cocinea Musaceae Leaves, fruits
30 Eugenia brachiata Myrtaceae Fruits
31 Averrhoa carambola Oxalidaceae Fruits, Flowers
32 Bambusa spinosa Poaceae Bamboo shoot
33 Dendrocalmus pattelaris Poaceae Bamboo shoot
34 Neohouzean dullosa Poaceae Bamboo shoot
35 Thysanoloena maxima Poaceae Flower buds
36 Euphoria longana Sapindaceae Fruits
37 Mischocarpus sundaicus Sapindaceae Leaves
38 Nephelium chryseum Sapindaceae Fruits
39 Madhuca pasquieri Sapotaceae Fruits40 Scaphium macropodum Sterculiaceae Leaves
41 Grewia paniculata Tiliaceae Fruits
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
Euphorbiaceae
Moraceae
Poaceae
Sapindaceae
Anacardiaceae
Clusiaceae
Dilleniaceae
Fagaceae
Meliaceae
Actinidiaceae
Araliaceae
Burseraceae
Caesalpiniaceae
Convolvulaceae
Cucurbitaceae
Dipterocapaceae
Gnetaceae
Juglandaceae
Mimosaceae
Musaceae
Myrtaceae
Oxalidaceae
Sapotaceae
Sterculiaceae
Tiliaceae
Familyname
Species numbers
Figure 04. Tree families eaten by P. nemaeusin Bach Ma National Park
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4.2. Food items
P. nemaeus were observed feeding on variety of food items including leaves, buds,
flower buds, flowers, fruits, and bamboo shoots (Table 04). The proportion of tree species
used by P. nemaecus according to food items is shown in figure 05. Fruiting treesappeared to be preferred food trees of the langurs, contributing the largest proportion to
the total food list (26 species, 63.41%). This was followed by trees producing leaves (24
species, 58.54%); buds (5 species, 12.20%). Trees producing flowers and bamboo shoots
were made up an equal proportion of food trees in the food list (3 species, 7.32%). Only
one tree species producing flower buds used by the langurs (2.44%).
0
4
8
12
16
20
24
28
32
Items
Species eaten
Series1 24 5 1 3 26 3
Leaves Buds Flower buds Flowers FruitsBamboo
shoots
Figure 05. Percent of tree species eaten by P. nemaeus
according to plant parts
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Faeces, feeding signs of P. nemaeusin research sites
4. Some charecteristics of forests where the P. nemaeusdistributes:
At each site where Red-shanked douc langur distributes, we made investigation in 2
sample plots with the same forest status, each sample plot covers an area of 1,000m2, the
total area investigated is 0.8ha. In each sample plot, trees with diameter 6cm were
measured and counted. The results are indicated in the table below:
Table 05. Charecteristic of forest status where Red-shanked douc langur distributes
Forest status Sample plotN/a sample
plot (tree)N/ha(tree) D1.3 (cm) Hvn (m)
1 27 270 15.77 18.70
2 28 280 15.00 17.75IIIA1
TB 27.5 275 15.39 18.23
3 20 200 17.77 19.65
4 32 320 18.58 19.75IIIA2
TB 26 260 18.18 19.70
5 30 300 21.19 20.60
6 28 280 20.75 20.15IIIA3
TB 29 290 20.97 20.38
7 34 340 31.79 22.13
8 32 320 32.00 24.10IIIB
TB 33 330 31.90 23.12
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Percentage of plant species in divisions is indicated clearer in figure 06:
12%10%
76%
2%
Thng t (Lycopodiophyta)
Dng X(Polypodiophyta)
Thng (Pinophyta)
Ngc lan (Magnoliophyta)
Figure 06: percentage of plant divisions
It can be realized that plant species composition in areas where the P. nemaeus
distributes mainly belongs to Ngoc lan division (39 species, 76% of the total species of
divisions). Magnoliophyta takes the highest percentage in number of familia and species
in these areas since this is a division with huge range of favorite trees used for food by the
P. nemaeus.
6. Threats
Three main threats to P. nemaeus were identified during the study. They are hunting,
habitat destruction and tourism.
Hunting:
Traps are considered the most currently serious threat to the primates and other wildlife in
the areas surveyed. A variety of traps were widely seen during the surveys, especially in
CHO DEN (Prashorea stellata) forests. The most common traps used by local people are
string traps that are able to capture birds, small and large mammals, especially primate
species. Guns and hunting dogs did not be seen during the surveys.
Habitat destruction:
- Non-Timber Forest Products collection (NTFPs): Local people living in buffer zone often
go to the forests to collect NTFPs such as woodfire, (Livistona bracteata) for roof,
weaving, or sale, Rattan (Calamus spp.) for household use, making handcraft items, or
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sale, Wild broom (Thysanoloena maxima) forhousehold use and sale . These activities
directly affect P. nemaeus behavior. For example, the langurs often seen feeding on
flower buds of Thysanoloena maxima, but this species was widely exploited by local
people for household use and sale.
- Illegal logging: In general, illegal logging has been successfully controlled by forest
rangers and is not considered as a major threat to the langurs in the areas surveyed.
However, there are still some local people living in buffer zone are seen exploiting a
certain kind of tree species for selling such as Hopea siamensis, Prashorea stellata,
Afzelia xylocarpa during non-crop season. This may partly influence on the langurs
habitat integrity.
Tourism:
Tourist activities have recently been paid attention and developed in Bach Ma National
Park. Infrustructures such as roads, hotels, guest houses are often contructed within the
langurs known habitats. These activities may influence on normal behavior of populations
of P. nemaecussuch as noises from tourists. However, based on recent observations, the
langurs appeared to be familiar with the presence of tourists and the noises. For example,
the groups of P. nemaeuswere seen at close distance to the hotels and tourist roads.
DISCUSSION
1. Population status
Arcording to Nadler (2003), in the observations in areas previous to the spraying of Agent
Orange, Osgood (1932) reported groups of 30 to 50 individuals of Red-shanked douc
langur in Bach Ma National Park. In contrast, Lippold (1995b) found group-sizes of no
more than 20 at Bach Ma. One group of 3 to 4 Red-shanked douc langurs was seen by
Eames & Robson (1993) in January 1990 in secondary forest during a primate survey in
southern Vietnam. The same team observed one single male in February 1990 in primary
forest at an altitude of 700 m. Lippold (1995a) reported sightings of three groups of 5, 15
and 20 individuals in primary and secondary forest during surveys conducted in 1994 and
1995. In "Preliminaly study on ecology and behaviour of the Red shanked douc langur in
Bach Ma National Park", Huynh Van Keo and Van Ngoc Thinh (1998) reported two
sightings by park forest guards before September 1994 and in August 1996 of groups with
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about 5 and 10-15 animals. In May 1997, Matsumura discovered a group of about 5 to 7
individuals (Huynh Van Keo & Van Ngoc Thinh, 1998).
The current population is not comparable to previous reports (table 07). In comparison
with the population of the species before the war, the population of P. nemaues in BachMa National Park decreased remarkable (estimated to decline a half compared to the
report of Osgood (1932). However, in comparison with investigation of Lippold and
(1995a) and Huynh Van Keo and Van Ngoc Thinh (1998), the population of the P.
nenameusdoes not have much change along with the time. In this research, we found out
an animal which was rescued and released to the forest by rangers in 2007. Nevertheless,
if comparing in population sizes, we could recognize that from 1995 till now, the
population sizes has declined from 40 animals (1995) to 30 animals (1998) and only 26
animals now. Moreover, we also realized that in the group of 10-12 animals, there was amother Langur carried an infant. This showed that, the number of individuals decreasing is
more than that because there had been adults replaced by infants.
Table 07. Comparision of current population size of P. nemaeus
with previous reports
No Sites Population sizeNumber of
groupsobserved
References
1 Bach Ma 30-50 ? Osgood, 1932
2 Bach Ma 3-4
1
1
1
Eames & Robson, 1993
3 Bach Ma 40 3 Lippold, 1995a
4 Bach Ma 20 ? Lippold, 1995b
5 Bach Ma 5-7 1 Matsumura, 1997
6 Bach Ma 30 3 Huynh Van Keo and Van
Ngoc Thinh, 1998
7 Bach Ma 22-26 4 This study
2. Distribution
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The beautiful red-shanked douc langur is only found in north and central Vietnam and
Laos. Its habitat is in the lowland to montane primary and secondary rainforest where it
lives in the mid to upper levels of the canopy (Camille Dorian, 2002). In Vietnam the douc
langur occurs primarily below 1500 meters (Eames and Robson, 1993).
In Bach Ma National Park, P. nemaeus is often found in primary and secondary tropical
broadleaf evergreen rain forest habitats below 1.500 m above sea level. This supports
Eames and Robson (1993)s findings. A possible explanation for these similarities is that
most langurs feeding trees are widely distributed below 1.500 m above sea level. They
include Parasorea stellata, Garcilinia oblongfolia, Bischofia javanica, Endospermum
chinense, Peltophorum tonkinense, Canarium album, Nephelium chryseum, Schefflera
octophylla, Dendrocalmus patellaris, Neohouzean dullosa, Ficus hispida. Further,
populations of P. nemaeus are frequently seen in Prashorea stellata forests that havebeen reported by Huynh Van Keo and Van Ngoc Thinh (1998).
3. Diet
Table 08. Comparision of tree species and families eaten by P. nemaeusbetween
current study and previous reports
Refferences No. of family (%) No. Of species (%)
Pham (1993) 22 100 49 100
This study 25 95.45 41 65.31
The current food list recorded is less than Pham (1993)s finding in terms of number of
tree species and families eaten by P. nemaeus (table 07). The possibility for this
difference is Pham (1993) appeared to report food list for the whole Vietnam populations
of P. nemaeuswhereas this study just focuses on Bach Ma National Park site.
One of the most important finding is we add fifteen new tree species used by P. nemaeus
to the existing food list. They are Saurauia tristyla, Schefflera octophylla, Ipomoea
batatas, Trichosanthes kirilowii, Dillenia indica, Prashorea stellata, Baccaurea ramiflora,Bischofia javanica, Macaranga denticulate, Engelhardtia spicata, Aglaia korthalsii,
Artocarpus rigidus, Thysanoloena maxima, Mischocarpus sundaicus, and Scaphium
macropodum. Thysanoloena maximaappeared to be heavily exploited by the langurs in
April coincide with when this tree flowering.
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P. nemaeusin Bach Ma appeared to exploit the same food items as in other areas. They
ate leaves, buds, flowers and flower buds, fruits, young stems, and bamboo shoots
(Pham, 1993; Wisconsin, 2002). However, the proportion of food items in the diet of P.
nemaeus in Bach Ma is different from that in previous reports. Wisconsin (2002) reported
that Douc langurs diet comprises mainly leaves (82%) while populations of P. nemaeusat
Bach Ma consumed more fruits than any other types of food. The difference may be a
result of differences in methodology and study season. Long-term phenological monitoring
in the study area may be an answer for the difference.
4. Threats
Hunting and habitat destruction have been recognized as the major threats to the wild
populations of P. nemaeus(Nadler et al., 2004; Timmins and Duckworth, 1999). In Bach
Ma, although illegal logging and NTFPs collection are going on (Gilmour and Nguyen Van
San, 1999), these activities just operate at small scales and are widely controlled by
National Park staffs, indicating that habitat destruction may have little impact on the
populations of P. nemaeusat Bach Ma. Currently, traps and tourist activities are identified
as the major threat to the langurs in Bach Ma. The degree of impact of these activities on
the populations of P. nemaeushas not been assessed yet, future research should look at
how impact of tourist activities on the langurs are and what types of traps do the local
people use to capture primates as well as wildlife in general.
TRAINING AND EDUCATIONAL ACCOMPLISHMENTS
We instructed a senior student to do research with the topic "Distribution, population
status and ecology of P. nemaeus in Bach Ma national Park" and he greatly got the best
mark (10/10).
Three field training courses were be organized to improve conservation awareness of the
BNP staffs, students of Hue University of Agriculture and Forestry, and local people in
endangered primate species survey and monitoring.
Currently,we are guiding a senior student to do research on "Distribution, population
status, ecology and conservation of P. nemaeus in Bach Ma national Park" with the
research area expanded wider in comparison to previous research areas.
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Training for students in the field
Training for local people
RECOMMENDATIONS
1) Strengthening protection of the species and habitat
- Plan for tightly monitoring of the areas where the P. nemaeusdistributes, especially the
areas inside and around CHO DEN (Prashorea stellata) forest.
- Strengthen investigation, preventing local people in the buffer zone from trapping in the
forest. Penalize local people who break the law. Remove traps set in the forest.
- Monitor tightly activities of local people to exploit NTFPs; limit local people exploit NTFPs
for food in the distribution sites of the P. nemaeus.
- Manage tightly eco-tourism activities; forbid tourists make noises that impact on the
species.
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2) Doing more researches in the species
- Extend the research scale to supplement data of distribution and population sizes of the
species in different points of time in a year.
- Carry out more researches in food plants in different seasons of a year.
3) Improve communities' awareness
- Propagandize law of forest protection and wildlife protection for local people.
- Organize courses about the important role of the species as well as the need to protect
the species for local people.
ACKNOWLEDGMENT
I would like to thank to Bach Ma National Park for the support and permission. Special
thanks to forest rangers for their dedicated participation and assistance. Thanks to Hue
University of Agriculture and Forestry for giving time and supporting field equipment to
conduct this study.
We also thank to Vietnam Forestry University for sending experts to conduct this study.
Thanks to People's Trust for Endangered Species for financial support.
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