Tomtatluanan(Tienganh) nghiên cứu tình trạng, sinh thái và bảo tồn loài voọc quần Đùi trắng (trachypithecus delacouri (osgood, 1932)) tại khu bảo tồn thiên nhiên Đất ngập nước vân long, huyện gia viễn, tỉnh ninh bình

delacouri species to contribute to the management and conservation of the species in Van Long Wetland Nature Reserve - Ninh Binh, the doctoral student conducted a research thesis: “Rese

VIETNAM NATIONAL UNIVERSITY OF FORESTRY

-

LÂM NGHIỆP PHAM GIA THANH

RESEARCH ON THE STATUS, ECOLOGY AND CONSERVATION OF TRACHYPITHECUS DELACOURI (OSGOOD, 1932) IN VAN LONG WETSLAND NATURE RESERVE, GIA VIEN DISTRICT, NINH BINH

Supervisor: Assoc.Prof.Dr Dong Thanh Hai

Dr Nguyen Vinh Thanh

Reviewer 1: Reviewer 2: Reviewer 3:

The thesis will be defended at the Thesis Evaluation Council at the grassroots level at: Vietnam National University of Forestry

At hour day month year

The thesis can be found at:

- Library of Vietnam National University of Forestry

- National Library of Vietnam

INTRODUCTION

1 The necessity of the thesis

Trachypithecus delacouri is a primate endemic to Vietnam It is classified as a endangered, endemic to Vietnam, but is also listed as "critically endangered" on the IUCN Red List Trachypithecus delacouri is consistently ranked among the most threatened primates (Nadler et al., 2015; Schwitzer et

al., 2015) Van Long Wetland Nature Reserve in Gia Vien District, Ninh Binh Province was established

in 2001 with the main purpose of conserving the Trachypithecus delacouri population and other

biodiversity values The nature-created reserve is a limestone mountain area covered with vegetation and steep cliffs, surrounded by lagoons, creating an ideal terrain, ensuring the survival of this species [6, 7]

However, living in an isolated forest area and frequently impacted by humans, this rare primate population is threatened with extinction due to the risk of habitat being narrowed by the presence of humans and the increasing exploitation of natural resources and economic development Regarding the study of ecological characteristics and behavior of Trachypithecus delacouri, most previous studies were conducted in captivity [83, 89] Studies in the wild are few and mainly focus on the status, population structure or habitat use characteristics of the species Some studies on the behavior, group structure, and food ecology have been conducted by Nguyen Vinh Thanh, 2008 [48]; Workman, 2010 [116]; Agmen,

2014 [55], but there is limited mention of the social structure and habitat of T delacouri In Van Long

wetland nature reserve, most studies were conducted nearly a decade ago

In recent years, no in-depth research has been conducted on the population status, ecological characteristics and conservation of the species These are urgent issues today, because the ecological

characteristics and behavior of T delacouri in Van Long Wetland Nature Reserve are still incomplete, making it difficult to effectively conserve the species Meanwhile, the T delacouri species is still under

pressure from human activities such as illegal exploitation of natural resources, unsustainable land use, and limestone mining for cement production, … Based on the above reality, to update scientific

information on the current status, distribution area and impacts on the T delacouri species to contribute

to the management and conservation of the species in Van Long Wetland Nature Reserve - Ninh Binh,

the doctoral student conducted a research thesis: “Research on the status, ecology and conservation

of Trachypithecus delacouri (Osgood, 1932) in Van Long wetland nature reserve, Gia Vien district,

Ninh Binh province”

1) Update on population size, distribution and structure of T delacouri in the study area

2) Describe some social behaviors, habitat characteristics and food of species in the study area 3) Identify direct threats and assess their impact on species and their habitats

4) Propos management solutions to conserve and sustainably develop T delacouri population

in Van Long wetland nature reserve

3 Scope of the study

Field investigation was conducted within the boundary of Van Long National Park – Gia Vien District – Ninh Binh Province Interviews and consultations were conducted in communes within the core zone of the reserve

4 New contributions of the thesis

The thesis updated data on the size, distribution and social structure of the T delacouri

population in the study area

The thesis has recorded some new habits of T delacouri species such as: drinking water habit, caring for young and mating habit of T delacouri species

The thesis has identified the main habitat types and described the silvicultural structure of the

habitat types of T delacouri in the study area

The thesis updated and analyzed the current threats to the T delacouri species and proposed

solutions to minimize those threats

Chapter 1 LITERATURE REVIEW

Based on an overview of research articles published internationally and domestically on the topics

(1) Population size and distribution of Trachypithecus delacouri, (2) Behavior and social structure, (3)

Food and feeding habits, (4) Habitat and habitat degradation, (5) Impacts threatening the population, (6) Studies on species conservation From the conclusions drawn during the overview research, the thesis identifies the following issues:

This species of langur is facing many threats such as: hunting for its body parts for medicine and the exploitation of limestone resources and indiscriminate forest exploitation "More than half of the langur subpopulations are seriously threatened by hunting", Tilo Nadler - Director of the Endangered

Primate Rescue Center (EPRC) founded 10 years ago to promote the conservation of T delacouri:

"Habitat loss and fragmentation of existing populations make them more vulnerable to extinction" [95]

In addition, a 2.7 million ton/year cement plant operates adjacent to the southeast of the reserve Blasting, breaking rocks to make roads, dust from factories to the conservation area covering forests, cliffs, water surfaces, causing environmental consequences affecting species that are very difficult to control At the same time, preventing the decline of forest area or habitat area, especially stone mining, encroachment for farming and livestock farming or planning ecological resort areas for tourism in Van Long - Ninh Binh is also very important in the species conservation plan

Summary of studies shows that in Vietnam's nature, it is estimated that there are only about

270-302 Trachypithecus delacouri individuals left [96, 97] Furthermore, they live very dispersed with

49-53 groups and that means there is very little opportunity for them to gather together to protect each other

and breed to maintain the species “Up to 60% of all T delacouri individuals live in isolated

subpopulations with a maximum of only about 20 individuals per subpopulation” [94], the possibility

of inbreeding can occur Therefore, in terms of genetics, the quality of the breed is also at risk of decline The situation of isolated subpopulations and strong hunting pressure are the most dangerous immediate threats to the survival of this species in nature Protecting forests, preventing hunting and strictly handling violators to limit negative impacts on the species are among the solutions set for government

units and organizations The T delacouri population is currently at a high level of alarm and is at risk

of extinction if not protected by appropriate measures Therefore, the participation of all levels, sectors and the entire population is needed to protect the biodiversity

Although there has been a long research process on the species Trachypithecus delacouri, the results of research on the current population status in the past few years have hardly appeared, and scientific data on the social behavior of this species is still very limited In particular, these studies have only begun in recent years with a short research period and not many scientific documents published systematically

From the above general arguments, it can be seen that the thesis “Research on the status, ecology

and conservation of T delacouri (Osgood, 1932) in Van Long wetland nature reserve, Gia Vien district,

Ninh Binh province” will have scientific and practical significance to overcome the scientific gaps cited

in the overview

Chapter 2 RESEARCH CONTENT AND METHODOLOGY 2.1 Research contents

2.1.1 To study the size, structure and distribution characteristics of T delacouri

2.1.2 To study budget activities and some social behaviors of T delacouri

2.1.3 To study food composition and habitat characteristics of Trachypithecus delacouri

2.1.4 To assess threats to Trachypithecus delacouri

2.1.5 To propose solutions for conservation and sustainable development of Trachypithecus delacouri

2.2 Methodology

2.2.1 Approaches

The thesis originates from the inheritance and collection of existing information and documents,

on the basis of interviews with relevant subjects, according to the results of research and field investigations and the collection of necessary data, the thesis determines the direction to solve the research problems summarized in Figure 3.1 (page 36 of the thesis)

2.2.2 Methods

The thesis used methods including: (1) Data inheritance; (2) Interview method; (3) Line transects; (4) Botanical plots; and Threats Reduction Assessment to collect data on population size, group size, social behavior, diet, habitat characteristics and threats

(6) Methods for assessing threats

Following the method of Margoluis and Salafsky (2001), based on ranking and scoring from 1 to n, then arranging in descending order of the impact of the threats according to 3 criteria: (1) Area, (2) intensity and (3) urgency of the threat

(7) Data analysis

Data analysis and processing are based on the application of common software: Mapinfo 15.5 and ArcGIS 10.1 for analysis, processing and displaying Langur recording points on digital maps, Statistical analysis is applied and processed through SPSS 20.0 software and other software applications

such as Word, Excel, …

Chapter 4 RESULTS AND DISCUSSIONS 4.1 Size, structure and distribution

4.1.1 Population size

The study recorded a total of 25 herds with 212 T delacouri individuals in the study area Herd

size ranged from 4 to 22 individuals The average size was 8.5 individuals/herd The ratio of adult males

to adult females was 1:1.4 The ratio of juveniles to adult females was 1:3.1 The ratio of adults to juveniles was 6.1:1 (Table 4.1)

Table 4.1 Size and structure of Trachypithecus delacouri herds in the study area

Herd structure ratio

Adult

Male

Adult Femal

Total number

of individua

ls observed

Adult Male:

Adult Fema

le

Immatur e: Adult female

Adult:Im mature

Herd structure ratio

Adult

Male

Adult Femal

Total number

of individua

ls observed

Adult Male:

Adult Fema

le

Immatur e: Adult female

Adult:Im mature

Notes: (*) Interview Information; (**) The herd gathers to observe; TT – Adult; CXĐGT – Gender

unknown; QS – Observation; ĐTT – Adult Male; CTT – Adult Female

Compared the number of Trachypithecus delacouri individuals in this study with the results

recorded in the years 2000 - 2008 - 2010 - 2011 - 2018 [70] showed that the number of individuals has changed in an increasing direction, from 53 individuals in 2000, to 100 individuals in 2010, to 184 individuals in 2018 and up to now is 212 individuals Of which, 184/212 individuals were directly observed with 158 adults, 26 immature individuals (of which 19 were juveniles and 7 were newborns)

Table 4.2 Comparison of the number of herds and individuals of Trachypithecus delacouri in

Van Long with some other conservation areas

Cuc Phuong National Park

Pu Luong Nature Reserve

Van Long Nature Reserve

Survey Results

2002 [89]

Number of herds 4-5 8-9 7-10 Number of individuals 20-25 40-45 52-67 Survey Results

2011 [92]

Number of herds 2 6-7 14 Number of individuals 8-11 31-38 137-147

In this study

(2022)

Number of herds No reports No reports 25 Number of individuals 184-212

The above comparison results show that: Only the Trachypithecus delacouri population in Van

Long is showing a tendency to develop and expand its population in both the number of herds and individuals over the years Over the past 20 years, the number of herds has increased 2-3 times and the number of individuals has increased 3-4 times This partly reflects that the protection and conservation

activities of the species in the area are showing good results

4.1.2 Population structure

4.1.2.1 Population structure

The results of observation and recording of Trachypithecus delacouri activities in the research

area identified a total of 212 individuals of Langurs of different ages and genders, specifically 57 adult males, 80 adult females, 21 adults of undetermined gender, 19 juveniles (juveniles were recorded in all

12 months of the year, easily seen from January to March), 7 newborns still attached to their mothers (Newborns were seen in most months of the year)

Figure 4.2 Diagram of the population structure of Trachypithecus delacouri by gender and age

Compared with the research results of Nguyen Vinh Thanh (2008) [48], the number of herds identified in Van Long in this study (2022) is 25 herds, 14 more than in the 2008 study, in which the herd with the largest number is 15 individuals and the lowest is 3 individuals compared to the results in

this study where the largest herd is 22 individuals and the smallest is 4 individuals

4.1.2.2 Social structure

The social structure of Trachypithecus delacouri recorded in the study area was single male and

multiple females, multiple males and multiple females and all-male groups Specifically as follows:

(1) Herds consisting of multiple males and multiple females: Because it was not possible to

distinguish between adult males and immature males, a total of 16 herds of Trachypithecus delacouri

were recorded as multiple males and multiple females, consisting of 2-7 males, 2-6 females, and 0-3 juveniles (Figure 4.3) Size ranged from 4-22 individuals The average size of multiple males and multiple females was 10.1 individuals/herd

(2) Herds consisting of 01 male and many females: A total of 5 herds of Trachypithecus delacouri were recorded as one male and many females, including 01 male, 2 - 5 females and 0 - 4

young and newborns (Figures 4.4 - 4.5) Size ranged from 4 - 8 individuals The average size of a herd

of one male and many females was 5.8 individuals/herd These are smaller herds than herds with many males and many females

(3) All-Male Groups: Small groups of 4-5 individuals, all adult and male, with 3-4 adult males feeding and engaging in social activities together, with no evidence of all-female groups

Đực TT Cái TT Con non Con sơ sinh Con TT

of individuals and herds is the Dong Quyen mountain range area with 12 herds and 111-117 individuals,

the Hang Tranh area has 6 herds and an estimated 46-48 individuals

Table 4.5 Distribution of Trachypithecus delacouri

in Van Long Wetland Nature Reserve

area (ha)

Total number of individuals

Total number

of herds

Average area (ha/herd)

1 Kem Tram – Tra Lai 75 4-11 2 35,5

2 Dong Quyen mountain 250 111-117 12 20,8

4 Hang Tranh 105 46-48 6 17,5

5 Ba Non - Thung Gieng 830 23-36 5 207,5

The reasons for the uneven distribution of herds according to habitat areas can be considered in the following aspects:

+ Currently, Dong Quyen and Hang Tranh mountain areas are the areas with the highest

concentration of Trachypithecus delacouri subpopulations These are two areas with vegetation

consisting of low-lying vine shrubs, surrounded by natural and artificial water channels separating them from the foot of the mountain, ensuring a safe area with little impact from the outside environment on the life activities of the species

+ In Kem Cham - Doi Soi area: This is the area adjacent to the Vissai cement factory where the food source of the species is affected by dust and smoke and the habitat of the species is greatly affected

by noise, because next to the raw material area of the Vissai factory, rocks are often broken and mined, causing loud noises that shake and affect the surrounding area;

+ In Meo Cao area: This is an isolated area, completely surrounded by lagoons and canals with residential dykes, the habitat here is poor, mostly bare mountains and very little vegetation exists, so there is not enough food for the species to survive

- Gia Hung area: Bordering Xich Tho commune, Nho Quan district and Dong Tam commune, Lac Thuy district, Hoa Binh province, because it is a border area, the administrative boundaries in the field are not yet clear Inside Gia Hung commune, local people cultivate crops in (Do Ngo area), affecting the living environment of the langurs, the habitat is narrowed, this is the reason why the langurs move to the Northwest In particular, the entire forest area of Gia Hung commune according to the planning until 2020 with nearly 50 hectares is mainly planted forest with the main tree species being Acacia, Chukrasia tabularis, Dalbergia tonkinensis Prain, which are not the preferred food of the Langur

4.1.3.2 Distribution of herds according to habitat types

(1) Habitat (1): Secondary forest on heavily impacted limestone

This type of habitat is mainly located in the northwest of the reserve and a small part in the south

of the reserve with a total area of about 565.11 ha The investigation and interview process determined

that in the habitat, there are 03 Trachypithecus delacouri herds with an estimated 16-21 individuals

living in the area of the research area and 04 herds with 35-38 individuals living in the border area of Dong Tam commune, Hoa Binh province

(2) Habitat (2): Secondary forest on limestone mountain recovering from exploitation

Through the investigation, 04 herds living in the distribution area of this habitat (herds

5-14-16-17 with about 26 individuals) The total estimated area for the entire area is about 423.93 ha The vegetation of this habitat accounts for about 22% of the total natural forest area of Van Long Nature Reserve

(3) Habitat (3): Grasslands, shrubs and scattered secondary trees on limestone

With an area of about 740.6 hectares distributed on large limestone mountains Trachypithecus delacouri is scattered here with a total of 07 herds with an estimated number of 52-60 individuals This

is the largest habitat among the 5 habitat types where Trachypithecus delacouri lives, with abundant

food sources and diverse species composition

4) Habitat (4): Shrublands and secondary grasslands in arid valleys

With a total area of about 233.15 ha The research team has identified 09 Trachypithecus delacouri herds living in this habitat, estimated at about 89 - 105 individuals, the highest among the

habitats The sparse tree layer, not creating a continuous canopy, so there are many gaps in the habitat, creating favorable conditions for Langurs to observe, the proportion of tree species that are food for Langurs is very high, the low shrub layer is suitable and easy for the species to move around to find food sources every day, not adjacent to other provinces, close to the Hoa Lu - Van Long Special-use Forest Management Board and the forest protection stations of the area

(5) Habitat (5): Treeless rocky land

With an area of about 17.2 ha, this habitat is mainly bare rocky mountains, with almost no or negligible trees, with slow-growing tree species, so the ability to create biomass of the plant community

is not large During the field investigation, the research team observed and identified 1 herd (Herd No 1) with 04 individuals in the Mieu Mountain area

(6) Distribution map of Trachypithecus delacouri by habitat

The results of this study show that only Trachypithecus delacouri appears and performs all life

activities in the 05 listed habitats In the forms of aquatic ecosystems, planted forest land or bare land and residential land, the research team has not yet determined the distribution of the species

Trachypithecus delacouri

Figure 4.10 Distribution of Trachypithecus delacouri by habitat

in Van Long Wetland Nature Reserve

4.1.3.3 Elevational distribution

Based on the terrain characteristics and distribution areas of T delacouri herds, the thesis

divides the study area into four main terrain groups, in which the low mountainous area is where the largest number of herds are concentrated with 19 herds This is a terrain type that plays an important

role in the conservation of T delacouri in the Van Long area, because in addition to having a large area,

this terrain type is also evenly distributed, surrounded by high mountain ranges that are natural obstacles

for T delacouri to move, forage and shelter safely

Table 4.10 Topographical characteristics of the distribution of Trachypithecus delacouri herds

in the study area

1

High mountainous

2

Intermediate mountainous region

Sim Mountain (233m), Dong Quyen Mountain slopes - foothills (226m), Meo Cao Mountain (206m)

50-150m

Herd number 5-6-7-8-9-10-11-12-13-14-15-16-18-19-20-23

Trachypithecus delacouri spent the most time resting at 33.16%, followed by eating at 20.37%,

social activities at only 16.3% and moving at 12.74% and observing at 4.09%, drinking water at 143 observations at 3.75%, which is also the lowest time budget in the main activities of the species and the remaining 9.59% for other activities

Most species of langurs in the genus Trachypithecus have similar activity schedules, spending more time feeding than most other activities, while other langurs spend more time resting (51-61%)

Table 4.11 Comparison of activity time budgets of Trachypithecus genus species

Eat Rest Drink

water

Obser vation

Social Move Others

T.delacouri 20,37 33,16 3,75 4,09 16,30 12,74 9,59 This study (2022)

the support during the movement of Trachypithecus delacouri showed that the most used support was

limestone ground, accounting for 50%

4.2.2.2 Feeding activity

The foraging time of T delacouri varies significantly during the day He langurs begins to be

active during the day from around 05:15 am, moving away from the nighttime roost to look for food The foraging time also varies according to the season (Figure 4.14) In winter and spring, the weather is