Assesing the diversity and density of passerine birds in tam dao national park

In this study, density of four Passeriformes species which are Buff-breasted babbler Pellorneum tickelli, Grey-throated babbler Stachyris nigriceps, White-bellied yuhina Erpornis zanthol

ACKNOWLEDGEMENTS

This thesis was impossible without the support of various professors at Forestry University and Colorado State University I am grateful to my advisor Assoc Professor Vu Tien Thinh for giving me a constant support and enthusiasm guidance during the time of research and writing of this thesis

Thanks also go to Professor MacDonald for his support towards my thesis

Special thanks to Mr Thanh who actively helped and shared a lot of experience and skill in field survey

Finally, I would like to thank staffs in Tam Dao National Park and local people who provide useful information and kind support

Ha Noi, November 2015

TABLE OF CONTENTS

ACKNOWLEDGEMENTS

I INTRODUCTION 1

II GOALS AND OBJECTIVES 5

2.1 Goals 5

2.2 Objectives 5

III METHODS 6

3.1 Study area 6

3.2 Species descriptions 8

3.3 Data collection 11

3.3.1 Field survey 11

IV RESULT 17

4.1 Diversity of Passeriformes in TDNP 17

4.2 Density of species 21

4.2.1 Describing survey data 21

4.2.2 Modeling detection probability by distance method 25

4.2.3 Estimating of species density 29

V DISCUSSION 33

VI CONCLUSION 37

REFERENCES 39

LIST OF FIGURES

Figure 3.1 Location of TDNP 8

Figure 3.2 Buff-breasted babbler (Pellorneum tickelli) 9

Figure 3.3 Grey-throated babbler (Stachyris nigriceps) 9

Figure 3.4 White-bellied yuhina (Erpornis zantholeuca) 10

Figure 3.5 Grey-cheeked fulvetta (Alcippe morrisonia) 10

Figure 3.6 Simulating objects detected in line transects 11

Figure 3.7 Distance estimation/measurement along transects 12

Figure 3.8 Graph of four standard functions used in Distance method 14

Figure 4.1 Percentage of observation and hearing in Buff-breasted babbler group detection 23 Figure 4.2 Percentage of observation and hearing in Grey-throated babbler group detection24 Figure 4.3 Percentage of observation and hearing in White-bellied yuhina (erpornis) group detection 24

Figure 4.4 Percentage of observation and hearing in Grey-cheeked fulvetta group detection 25

Figure 4.5 Detection probability functions of Buff-breasted babbler 26

Figure 4.6 Detection probability functions of Grey-throated babbler 27

Figure 4.7 Detection probability functions of White-ballied yuhina 28

Figure 4.8 Grey-cheeked fulvetta_Uniform function 29

LIST OF TABLES

Table 3.1 Field data sheet used to collect information 13

Table 4.1 Passeriformes diversity in TDNP 17

Table 4.2 Distance group division 22

Table 4.3 Number and percentage of Observation and Hearing in detection species 22

Table 4.4 Buff-breasted babbler_Functions’ parameters 26

Table 4.5 Grey-throated babbler_Functions’ parameters 27

Table 4.6 White-ballied yuhina_Functions’ parameters 28

Table 4.7 Grey-cheeked fulvetta_Functions’ parameters 29

Table 4.8 Transect density of Buff-breasted babbler 30

Table 4.9 Transect density of Grey-throated babbler 30

Table 4.10 Transect density of White-bellied yuhina 31

Table 4.11 Transect density of Grey-cheeked fulvetta 32

Table 4.12 Minimum, maximum and average density of each data set 32

Table 5.1 Detection probability comparison of four Passeriformes 34

ABSTRACT

The density and diversity of wild animal including bird species always change, it is necessary to assess the number of these species Wildlife density estimation is an important field that useful for managing and conserving biodiversity However, there is not much research on wildlife density at current time In field survey, not all individuals are detected, especially the one far from transect Therefore detection probability should be concerned

before a survey is conducted In this study, density of four Passeriformes species which are Buff-breasted babbler (Pellorneum tickelli), Grey-throated babbler (Stachyris nigriceps), White-bellied yuhina (Erpornis zantholeuca), and Grey-cheeked fulvetta (Alcippe

morrisonia) were estimated using DISTANCE program The survey was conducted at Tam

Dao National Park (TDNP) from August 26 to September 15, 2015 During the survey 71 Buff-breasted babbler, 53 Grey-throated babbler, 49 White-bellied yuhina and 125 Grey-cheeked fulvetta individuals were detected With the density of 11.68 birds/ha, Grey-cheeked fulvetta is the most dominant species comparing with three remaining species The density of Buff-breasted babbler, Grey-throated babbler, and White-bellied yuhina respectively are 1.00, 2.25 and 5.23 birds/ha The detection probability and number of bird groups which are detected by observation decrease with the increase of distance, but in some case this trend is not satisfied By density comparison between distances sampling and traditional methods, distance sampling method which use detecting probability indicate its higher accuracy result Therefore adjusting the density by using the detection probability is an effective method in wildlife survey and monitoring

I INTRODUCTION

Passeriformes which is also called passerine or perching bird is the largest order of bird and the dominant avian group on Earth today With 5,300 species, the order Passeriformes is divided into two suborders: Tyranni and Passeri The first suborder contains about 1,250 species which is considered more primitive and is often grouped informally as the “suboscines” The other suborder’s birds are often grouped as the “oscines” or

“songbirds” This group is made up of about 4,500 species (Jonsson et al, 2006) Passeriformes has a worldwide distribution, with representative on all continents except Antarctica The highest density of perching bird is in the tropics Because of high diversity, perching bird is a wide field for researching and studying

Passeriformes and all other wildlife density always change under the impact of natural and human pressure So, to reach the best control and management, it is important to estimate the density and diversity of these species However, the importance of wildlife survey was not early recognized This is the reason why the quantitative methods in wildlife survey were introduced later than in flora survey Most of the quantitative methods in surveys and monitoring wildlife were created in the recent four decades (Gilbert et al 1976) Therefore, the number of research or study about wildlife density is still limited

In field survey, the density and diversity estimation of fauna is much difficult than flora The biggest challenge is detect the entire individual in study area, almost object far from transect is missed For this reason, ecologists generally have to depend on some kind of estimate of abundance or density There exists a variety of method exist to do this job Each kind of wildlife is best suitable with one survey method For example, insects, aquatic organisms, soil organisms can be surveyed by using point, plot survey methods; number of fishes or small mammals are detected by mark and recapture method; etc In case of bird, the best method used is line transect survey method However, it is still impossible to obtain a

complete count or census of a natural bird population It mean that the density estimated is smaller than reality and detection probability is smaller than 1 There are two ways to deal with this error The first way is survey in narrow transects, but this way is not efficient in term of time and economic And the rest way is using the data collected from objects in far transect to estimate the detection probability, and then use this number to adjust the density estimate

The term “distance sampling” refers to a suite of method that will estimate the absolute density of biological population, based on accurate distance measurements of all objects near a line or point (Buckland et al 1993) The main methods are line-transect sampling and point-transect sampling In both methods, each object detected is recorded the distance from the line or point to this object Not all objects can be observed, but a fundamental assumption of the basic methods is that all the objects on the line or point are detected, and the “detection probability” equal 1 Detection probability is the probability of detecting an object, given that it is at any distance from the random line or point With increasing distance from the line or point, the objects become harder to detect So, the key to distance sampling method is to fit a suitable detection function to the observed distances, and use this function to estimate the proportion of missed objects By this proportion, we can obtain point and interval estimates for the density and diversity of objects in study area Distance sampling is a good method for both flora and fauna survey, but it has not popular applied in Vietnam yet

TDNP is a protected area in North Vietnam It was established in 1996, succeeding from the Conservation Forest Tam Dao which was formed in 1977 TDNP is a precious natural resource, where keep high biological diversity with many rare and endemic plants and animals Tam Dao forest also has many species of rare medicinal plants as an useful sources of medicinal Moreover, tourism in TDNP has been becoming a remarkable economic income

Birdlife international has ranked Vietnam as one of the leading countries of density and diversity of birds According to many statistic data, Vietnam’s bird population is over

870 species (Nguyen Cu, 1995) Particularly, in TDNP, it has discovered 239 bird species which belong to 140 genus, 50 families The highest species diversity in TDNP is Passeriformes, include 147 species belonging to 73 genus and 26 families In the total 239 bird species, there are 9 endemic species to the North of Vietnam and 5 endemic species to the country

In Vietnam, study on bird species is a major field from past to current time Before

1945, almost of bird research project were done by foreign scientist In this period, the most famous is two French scientists are Delacour and Jabuille From 1945 to 1954, because of war, all researches were interrupted After that, bird research was started again in 1957 The most remarkable projects belong to authors like Vo Quy (1962-1966), Tran Gia Huan (1960-1961), Do Ngoc Quang (1965), Vo Quy and Anorova N.C (1967) Generally, scientist had focused on classification In 1971, professor Vo Quy had summarized his research from 7

year before and published the book: “Biology of common bird in Vietnam” Then, when Vietnam formally became independent, “Bird Vietnam” and “Morphology and classification”

were introduced and these books also were the first books about bird morphology and classification in Vietnam Then, in the years after that, the area of forest was reduced rapidly because of increasing of population and economic development As the result, plant and animal decreased seriously in term of number, bird species is one To deal with this problem, Vietnam Government has established a system which includes 87 forest areas (Area is about

1690 km2) But almost these areas did not promote efficiently At that moment, the book “The

list of Vietnam bird” of Vo Quy –Nguyen Cu (1995) was published The list contains 19

orders, 81 families and 828 species of Vietnam bird The book focuses much on status and distribution of each species In recent years, there are many biodiversity preservation projects

of foreign Government invest to Vietnam such as Netherlands, Germany, Australia, NGOs, Bird Life International, IUCN, WWF, etc From that biodiversity preservation in Vietnam

started to develop and “Bird Vietnam” book published by Nguyen Cu, Le Trong Trai, Karen

Phillips (2000) This book introduces about over 500 species in 850 recorded species in term

of description, distribution, status and color picture attached

Fauna which includes birds in Tam Dao was studied by some French professor like J.Delacouri (1931), Osgood (1932), Bourret (1943),… Investigation in Tam Dao has strongly developed from 1954, include projections of University students From 1990-1992, Forest Inventory and Planning Institute has conducted researches on fauna in this area They counted for 281 wild life species which include 58 mammals, 46 reptiles, 19 amphibians, and 158 birds species In 1995, base on Vo Quy and Nguyen Cu research, Tam Dao had 239 bird species

Although, up to now there are number of research about birds in TDNP, most of them are general study, and there is not much study which point out the density and diversity of a particular order Therefore, in this study, the density and diversity of some species in the highest diversity order – Passeriformes are assessed using the distance sampling method

II GOALS AND OBJECTIVES

2.1 Goals

The goal of this research is to provide basic information on the diversity and density

of Passerine birds which can contribute to the management and conservation of biodiversity

in TDNP

2.2 Objectives

- To assess the diversity of Passeriformes in TDNP

- To estimate the detection probability of four Passeriformes in TDNP by using

Distance sampling method

- To estimate the density of four Passeriformes in TDNP

III METHODS

3.1 Study area

Data was collected from August to September, 2015 in Tam Dao National Park with coordinate 21°21’- 21°42’ degrees north latitude, 105°23’- 105°44’ degrees east longitude The current area of TDNP is 34.995 hectares belonging to 3 provinces are Vinh Phuc, Thai Nguyen and Tuyen Quang Entire TDNP border lie on Tam Dao mountain range, stretching over 80 kilometers, runs northwest – Southeast from Son Duong District (Tuyen Quang) to Phuc Yen Town (Vinh Phuc) Tam Dao mountain range includes many mountains over 1,300 meters, the highest peak is Tam Dao Bac (1,592 meters) Due to human activities such as harvesting, cultivation or forest fire, current forest areas are mainly on 700 meter altitude Below this elevation, forest has been cleared and replaced by secondary shrubs, grass-shrubs, and pine plantation forest

The area of TDNP is 34,995 hectares, including 26,163 hectares of forest, mostly natural moist evergreen forest with 70% coverage of the entire area Also, in TDNP exist some other forest types such as evergreen subtropical moist low mountain, pygmy forest, bamboo forest, restoration forest after mining, plantation, scrub, grass land, etc

TDNP is known as one of the areas with high biodiversity value in Vietnam, there are many species which has significant conservation value for country, region, especially rare and endemic species threatened with extinction in the different levels Firstly, about flora resource, initial survey results (in 2000) have listed 1282 species belonged to 660 genus and

179 family of vascular plants In this total number, there are 42 endemic species and 64 rare species which need to be protected of Vietnam and global Secondly, fauna in TDNP is also diverse in both species composition and number of individual TDNP has long been famous

for the presence of Paramesotriton deloustali Up to now, TDNP is also a home of a huge

number of reptiles, amphibians in the system of nature reserve and national park in Vietnam

TDNP has been recognized as one of the 63 important bird areas of Vietnam (Tordoff et al 2002) It has a significant number of bird species which are distribution limited in a biogeography unit In addition, TDNP is also noted the presences of two species which are

threatened at global level are Eastern imperial eagle (Aquila heliacal) and Red-bellied pitta (Pitta nympha) These two species are globally Vulnerable (VU) (Birdlife International

2004) According to Nguyen Xuan Dang et al, 2005, TDNP has been recorded 77 mammal species, with 29 species are priority conservation Moreover, almost research has showed that TDNP is considered as a national park with highest diversity of insects in Vietnam Vu Van Lien, 2005, have listed 360 species of butterfly, including 9 species of concerned conservation, and Dang Thi Dap, 2000, have listed 122 species of leaf-eating insects, in which many species have high value always hunted for trading

Beside of biodiversity value, TDNP has important role in water regulation, soil protection and contribute to conservation and sustainable development of Red River watershed TDNP also contributes a big proportion to Tam Dao economic by give a great tourism potential

Figure 3.1 Location of TDNP

3.2 Species descriptions

This project focuses on estimating the density of four Passerine birds which are

Buff-breasted babbler (Pellorneum tickelli), Grey-throated babbler (Stachyris nigriceps), White-bellied erpornis (Erpornis zantholeuca), and Grey-cheeked fulvetta (Alcippe morrisonia) These four

species are most abundant species that can generate enough sample size for the analysis

Pellorneum tickelli (Sibey and Monroe 1990, 1993) has been split into tickelli and

buettikoferi and both are included in the genus Trichastoma following Wells et al (2001) Buff-breasted babbler’s body size is 13-15cm (Figure 3.2) Squarish-tipped long tail; forehead feathers seem slightly scaled with pale shaft-streaks; warm brown above; warm duff

bellow; with whitish belly and no grey on face This species distribute from Northeast India and Bangladesh over Burma and south China to Thailand, Laos, India, Myanmar and Vietnam Habitat is tropical and subtropical forest This species population is suspected to be stable in the absence of evidence for any current decline or substantial threats

Figure 3.2 Buff-breasted babbler (Pellorneum tickelli)

Source: Orientalbirdimages.org Grey-throated babbler (Stachyris nigriceps) is a species of bird in the Timallidae

family It is 12-15cm long (Figure 3.3) The forehead, top of the head and nape are alternate black and white; white around eyes; yellow or red face; brown or light black upper beak, gray under beak; dull brown above and buff-brown below This species is found in Bangladesh, Bhutan, China, India, Indonesia, Lao, Malaysia, Myamar, Nepal, Thailand and Vietnam Its habitats are subtropical

or tropical most lowland forests and subtropical or tropical montane forests

Figure 3.3 Grey-throated babbler (Stachyris nigriceps)

Source: Orientalbirdimages.org

White-bellied yuhina (Erpornis zantholeuca) is the only member of the genus

Erpornis The morphology of this bird is nearly similar to yuhina, yellowish-green above and grayish-white with yellow vent below; with short crest, squared-off tail And, body size is 11-13cm (Figure 3.4) This bird distribute in a large range: Bangladesh, Bhutan, Brunei, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Singapore, Taiwan, Thailand and Vietnam Its natural habitats are subtropical of tropical moist montane forests

Figure 3.4 White-bellied yuhina (Erpornis zantholeuca)

Source: Orientalbirdimages.org Grey-cheeked fulvetta (Alcippe morrisonia) is another Passeriformes belonging to

Alcippe gunus, Pellorneidae family This 12.5-14cm long bird (Figure 3.5) has a grey head with a white eye ring; long black eye stripe running from the bill down the side of the neck; olive above and yellow below Grey-cheeked fulvetta is found in Taiwan, Laos, China, Myanmar, Thailand and Vietnam It inhabits in subtropical of tropical moist montane forests

Figure 3.5 Grey-cheeked fulvetta (Alcippe morrisonia)

Source: Orientalbirdimages.org

Because of the large distribution range and great population, the populations of all four species do not approach the thresholds for Vulnerable at current time

3.3 Data collection

3.3.1 Field survey

Base on the interview results, the survey was conduct in Tay Thien and Dao Tru communes where Passeriformes are most observed was defined, the study area is narrowed

a Prepare for investigation site

Before collecting data, a survey was conducted to verify the information on maps (topographic map, administrative map, forest status), if there is any change or difference, supplement the information collected

12 lines transects are distributed

evenly in secondary forest which are from the

elevation of 200m-600m Each transect’s

length is 500 meters The selected transects

were located away from the status boundary

at least 75m to minimize edge effects and

impact of the status change on the detecting

probability Transects were arranged at least

100 m apart to make sure independence

(Figure 3.6)

Figure 3.6 Simulating objects detected in line transects

Equipments for survey are binoculars, cameras, data sheet, and map Document used for bird identification and classification are “Bird of Southeast Asia” (Craig Robson, 2005) and “Birds of Viet Nam” (Nguyen Cu et al.2000)

b Collecting data

All transect are surveyed from early morning to mid-noon (11:00 to 12:00) and from 15:00 to 18:00 Because these periods of time are operation and food searching time of birds, convenient for observing

Observers go along transects with the speed is around 0.5km/40 minutes, observe and record the presence, number of bird by observing and singing And, observers also estimate the distance from object to transect Each transect is surveyed in three times

There are two ways of estimating the distance: 1) make a direct estimate of the distance between the bird and the line (the perpendicular distance (yi) from transect line to object of interest is estimated/measured) or 2) estimate the distance between the observer and the bird and the angle of the sighting away from the line (yi is calculated using ri and the sighting angle θi These methods are illustrated in Figure 3.7:

Figure 3.7 Distance estimation/measurement along transects

L = transect line

Z = position of observer

X = position of object

W = strip width (1/2)

ri = sighting distance (flushing distance)

θi (theta) = sighting angle

yi = perpendicular distance (note: y = ri sin θi )

The collected data is recorded in data sheet as table below:

Table 3.1 Field data sheet used to collect information

 Estimating detection probability

In order to estimate the density of objectives, surveyors need to estimate detection probability by using the investigate data Detection probability is estimated base on frequency distribution at different distance to transect or the observer And, the software which is popular used to analyze detection probability is DISTANCE 6.0 (Thomas et al, 2010)

Before estimating detection probability, surveyors must define detection probability function Four basic functions which are used to estimate detection probability by distance are:

 Uniform: ( )

 Half-normal: ( )

 Negative exponential: ( )

With: g(y) is the detection probability of an object with distance to line transect is y

(length unit); w, , b are the estimated parameters;

Beside of these four functions, there are three expansion series which can be used to change the shape of detection probability curves and simulate better the variation of detection probability These three expansion series are Cosince, Simple polynomials, and Hermite polynomials series The combination of standard functions and expansion series is show in

the function: g(y) = basic function(y) + expansion series(y)

In some cases, this combination can indicate the relationships between detection probability and distance better

Figure 3.8 Graph of four standard functions used in Distance method

Aikaike’ Information Criterion (AIC) (Anderson, 2007) is used to determine which function is the best for estimating detection probability ) This standard is based on the principle of balance between the standard deviation and variance Function which has lowest AIC value will be used In addition, Distance method also provides χ2 values to check the

suitability of function with the distribution of empirical frequency When the best function is determined, detection probability (Pa) is calculated by divide the area of upper function curve part by rectangle area and time with transect wide, function:

∫ ( )

 Estimating density of species

The estimation of density with distance sampling cannot exactly unless five fundamental assumptions have to be satisfied:

 Objects on the line are detected with certainty Objects directly on the line are 100% detected g (0) =1 and the probability of detection substantially decreases with the increase of distance (Buckland et al 2001)

 Objects do not move All measurements are made from the objects’ initial location, before it was affected by the observer (Buckland et al 2001)

 Measurements are accurate All angles, distance, objects, sex and other necessary measurements are measured with accuracy without any errors (Buckland et al 2001)

 For animal species that occur in clusters (groups), cluster sizes are recorded without error In some circumstances, cluster sizes may be accurately estimated close to the line or point, but poorly estimated at larger distance Bias from this source can be avoided by using the regression correction for size-biased sampling that is the default for clustered data

in the software Distance (Buckland et al 2001)

 The sampled plots (circles or strips) are representative of the entire survey region This is not usually listed as an assumption, because if an appropriately randomized design is used, the assumption holds by design However, non-random plots are often covered, in which case this assumption becomes important

Although other assumptions are made, generally only the above five have any practical significance

With each transect whose length is L meters, there is (are) n object(s) detected The perpendicular distance of each object to the transect line is also recorded When all objects located on the line are detected with certainty, the density of objects in the survey are (D) is estimated as:

̂ ̂ (Buckland et al, 2001)

With: n – Total objects is detected in the surveys

̂ - Detection probability ≤ 1

a = 2Lw (w – width of line transect, L – total line length)

Variance of density estimation is calculated by the formula:

̂ ( ̂) = ̂² { ̂( )

+ ̂( ̂ )( ̂̂ ) + ̂ ̂( ) ( ) } Variance of density estimation show fluctuations the number of individuals detected

in transect (E(s) is group size)

The total number of individual in each species (population size) is calculated by time density ( )̂ with area (A): ̂ ̂

The variance of population size is: ̂ ( ̂) ̂ ( ̂)

IV RESULT

4.1 Diversity of Passeriformes in TDNP

There were 68 species belonging to 41 genus and 19 families Passerine birds were

detected (Table 4.1) There are 227 groups of Puff-throated bulbul (Alophoixus pallidus) were

found out, that means this is most abundance Passerine species in TDNP All Passerine

species are ranked at Least Concerned group in IUCN red list

Table 4.1 Passeriformes diversity in TDNP

Detection quantity (Groups)

Conservati

on status (IUCN)

1 Campephagidae Pericrocotus Scarlet minivet Pericrocotus

3 Cisticolidae Orthotomus Common

tailorbird

Orthotomus sutorius

Dark-necked tailorbird

Orthotomus atrogularis

4 Corvidae Cissa Indochinese

green magpie/

breasted magpie

yellow-Cissa hypoleuca 4 LC

5 Dicaeidae Dicaeum Nilgiri

flowerpecker

Dicaeum concolor