Assessing the diversity and density of birds at pine forest in tam dao national park

MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAM NATIONAL FORESTRY UNIVERSITY STUDENT THESIS Title ASSESSING THE DIVERSITY AND DENSITY OF BIRDS AT PINE FOREST IN TAM DAO NATIONAL PARK Major: Natural Resources Management Code: D850101 Faculty: Forest Resources and Environmental Management Student: Le Thi Hoa Student ID: 1253090010 Class: K57 Natural Resources Management Course: 2012 - 2016 Advanced Education Program Developed in collaboration with Colorado State University, USA Supervisor: Assoc Prof Dr Vu Tien Thinh HaNoi,November/2016 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 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 2016 ABSTRACT The density and diversity of wild animal especially bird species always change, it is necessary to assess the number and density 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 bird species at pine forest in Tam Dao national park was estimated using DISTANCE program The survey was conducted at pine forest in Tam Dao National Park (TDNP) from July 21 to August, 2016 During the survey 16 species belong to families with 954 groups were detected With the density of 1.59 birds/ha, Sooty-headed Bulbul (Pycnonotus aurigaster) is the most dominant species comparing with three remaining species The density of Red-whiskered bulbul (Pycnonotus jocosus), Red-vented bulbul (Pycnonotus cafer), Rufous-backed shrike (Lanius schach) respectively are 0.278, 0.495 and 0.22 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 TABLE OF CONTENTS ACKNOWLEDGEMENTS ABSTRACT TABLE OF CONTENTS LIST OF THE DATA TABLES LIST OF THE FIGURES INTRODUCTION GOALS AND (SPECIFIC) OBJECTIVES 2.1 GOALS 2.2 OBJECTIVES METHODS 3.1 STUDY AREA: 3.2 DATA COLLECTION: 3.2.1 COLLECTING DATA: 3.2.2 DATA ANALYSIS RESULTS 12 4.1 SPECIES DIVERSITY AT PINE FOREST IN TDNP 12 4.2 DENSITY OF BIRD SPECIES AT PINE FOREST: 14 4.2.1 DESCRIBING SURVEY DATA 14 4.2.2 MODELING DETECTION PROBABILITY BY DISTANCE METHOD 15 4.2.3 ESTIMATING DENSITY OF BIRD SPECIES 20 DISCUSSION 22 CONCLUSION 24 REFERENCES APPENDIX LIST OF THE DATA TABLES Table 3.1: Field data sheet used to collect information Table 4.1: Bird diversity at pine forest in TDNP 12 Table 4.2: Number and percentage of Observation and Hearing in detection species 13 Table 4.3: Distance group division 14 Table 4.4: Red-whiskered Bulbul’ parameters 16 Table 4.5: Red-vented bulbul’ parameters 17 Table 4.6: Sooty-headed Bulbul’ parameters 18 Table 4.7: Rufous-backed shrike’ parameters 20 Table 4.8: Density of each specie in each line transect 21 LIST OF THE FIGURES Figure 3.1: Location of pine forest in TDNP Figure 3.2: Line transect method Figure 3.3: Graph of four standard functions used in Distance method Figure 4.1: Detection probability functions for Red-whiskered Bulbul 15 Figure 4.2: Detection probability functions for Red-vented bulbul 17 Figure 4.3: Detection probability functions for Sooty-headed Bulbul 18 Figure 4.4: Detection probability functions for Rufous-backed shrike 19 INTRODUCTION Bird is very diverse group of animal Currently, there are over 10500 bird species, classified in 27 orders Bird play an important role in natural ecosystem Bird are excellent indicators of forest ecosystem health as their abundance and diversity are closely related to habitat disturbance It is an important chain in the food web Bird may be insectivores, frugivores, and nectarivores and it is also food of another animals Some nectar-feeding birds are important pollinators, and many frugivores play a key role in seed dispersal Plants and pollinating birds often co-evolve, and in some cases a flower's primary pollinator is the only species capable of reaching its nectar Bird are often important to island ecology Bird have frequently reached islands that mammals have not; on those islands, birds may fulfill ecological roles typically played by larger animals Birdlife international has ranked Vietnam as one of the leading countries of density and diversity of bird According to many statistic data, Vietnam’s bird population is over 870 species (Nguyen Cu, 1995) Tam Dao National Park is a protected area in North Vietnam It was established in 1996, succeeding from the Conservation Forest Tam Dao which was formed in 1977 Tam Dao national park 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 a useful sources of medicinal Moreover, tourism in TDNP has been becoming a remarkable economic income 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 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 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 (Vo Quy and Nguyen Cu, 1995) From that biodiversity preservation in Vietnam started to develop and “Bird Vietnam” book published by Nguyen Cu, Le Trong Trai, Karen Phillips (2000) 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 Forest Inventory and Planning Institute (1990-1992), counted for 281 wild life species which include 58 mammals, 46 reptiles, 19 amphibians, and 158 bird species in Tam Dao national park Vo Quy and Nguyen Cu (1995), found 239 bird species in Tam Dao national park Tam Dao was recognized as one of the important bird areas in Vietnam, because region has the international importance in bird conservation The area has a large number of bird species restricted to a biogeographic unit In particular, the region recorded some species that have limited distribution are found only in a few areas in Vietnam such as: Blue-naped Pitta (Pitta nipalensis), Purple Cochoa (Cochoa purpurea), Chestnut-headed Tesia (Tesia castaneocoronata), Pale-footed Bush Warbler (Cettia pallidipes) and Rufous-headed Parrotbill (Paradoxornis ruficeps) (Tordoff 2002) 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 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 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 and in this survey, I used line transect method Distance sampling is a good method for both flora and fauna survey Although, up to now there are number of research about bird at pine forest in Tam Dao national park, 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 bird species at pine forest in Tam Dao national park are assessed using the distance sampling method GOALS AND (SPECIFIC) OBJECTIVES 2.1 Goals The goal of this research is to provide basic information on the diversity and density of bird which can contribute to the management and conservation of biodiversity at pine forest in Tam Dao national park 2.2 Objectives - To assess the diversity of bird of pine forest in Tam Dao national park - To estimate the density of bird of pine forest in Tam Dao national park Sooty-headed Bulbul: Figure 4.3: Detection probability functions for Sooty-headed Bulbul Table 4.6: Sooty-headed Bulbul’ parameters Detection Functional form AICValue Density CV (%) probability (Birds/ha) Half-normal 452.2 0.07 28.98 1.328 Uniform 447.13 0.08 29.11 1.325 467.7 0.1 29.5 1.41 446.61 0.09 29.3 1.59 Negative exponential Hazard-rate 18 With the smallest AIC value (446.61), Hazard- rate function is the best fit model which can well show the detection probability of Sooty-headed Bulbul (Pycnonotus aurigaster) density The next orders are Uniform, Half- normal and Negative expotential which have higher AIC values And, χ2 values, degree of freedom, and p-value are 3.59, and 0.36 (>0.05) These are also good parameters to model the fluctuation of detection probability by distance Rufous-backed shrike: Figure 4.4: Detection probability functions for Rufous-backed shrike 19 Table 4.7: Rufous-backed shrike’ parameters Density Detection Functional form AICValue CV (%) (Birds/ha) probability Half-normal 73.53 0.27 34.55 0.11 Uniform 73.49 0.19 32.74 0.112 73.06 0.47 40.5 0.22 75.1 0.86 79.3 0.155 Negative exponential Hazard-rate With the smallest AIC value (73.06), Negative expotential function is the best fit model which can well show the detection probability of Rufous-backed shrike (Lanius schach) density The next orders are Uniform, Half- normal and Hazard- rate which have higher AIC values And, χ2 values, degree of freedom, and p-value are 0.77, and 0.45 (>0.05) These are also good parameters to model the fluctuation of detection probability by distance 4.2.3 Estimating density of bird species The below tables show transects’ density of each data set of each specie (Table 4.8) 20 Table 4.8: Density of each specie in each line transect Transect/ Specie 10 11 12 Mean D Red-whiskered Bulbul 0.218 0.483 0 0.29 0.048 0.145 0.09 0.676 0.278 Red-vented bulbul 0.298 0.35 0.05 0.2 0.15 1.55 0.65 0.85 0.35 0.69 0.299 0.495 Sooty-headed Bulbul 2.23 3.06 1.87 2.32 3.53 0.55 1.87 0.09 0.19 0.29 1.59 Rufous-backed shrike 0.146 0.22 0.37 0.37 0.37 0.07 0.146 0 0.07 0.22 According to table 4.8, we see that there are big differences between density of transects of all four species That means all four species are not evenly distribution over study region The considered reasons are position and natural condition of transect lines such as human activities, food And, mean density of Sooty-headed Bulbul is biggest so Sooty-headed Bulbul is more abundant than the other three species 21 DISCUSSION The change of distance can lead to the changes in detection probability and observation or hearing proportion as well The number of detected groups goes down when the distance go up It makes the detection probability decrease gradually However, this trend is not always true Due to the small body length of all four bird species (11-15cm), and the high density of tree (primary forests), surveyors cannot see the birds at far distances It means the proportion of bird groups discovered by observation decreases when the distance increases, and bird groups tend to be detected by their sound at far distances Because the song of the species is not loud, only small numbers of groups were detected by acoustic signal at far distances The density of Red-whiskered Bulbul (Pycnonotus jocosus), Red-vented bulbul (Pycnonotus cafer), Sooty-headed Bulbul (Pycnonotus aurigaster) and Rufous-backed shrike (Lanius schach) respectively are 0.278, 0.495, 1.59 and 0.22 birds/ hectare So, Sooty-headed Bulbul is more abundant than the other three species A common point for all four species is uneven distribution This is evidenced by the big different between transects’ density (Table 4.8) A good example is the differences between minimum and maximum transects’ density of Red-whiskered Bulbul is 14 times The considered reasons are position and natural condition of transect lines If the transect lines are established near human residents and be affected by human activities, the number of detected groups could be smaller than transect lines in restricted regions In addition, a transect line which has thin tree density can help surveyor more easily in detection Additionally, there will be more detection in a transect that has good condition for bird living (food, shelter,…) 22 The effect of volume of bird sound on detection probability is quite obvious Most of Red-vented bulbul birds were detected by their songs/calls (59.6%) (Table 4.2) In addition, Uniform function model (Figure 4.2) shows the gradual decrease of detection probability with respect to increase in distance That means their calls are easy to recognize and loud enough to be heard at far distances In contrast, the calls of Redwhiskered Bulbul (Pycnonotus jocosus) , Sooty-headed Bulbul (Pycnonotus aurigaster) and Rufous-backed shrike (Lanius schach) are quite weak and hard to hear This limits ability of surveyor to recognize at far distances and causes low detection probability An advantage of distance sampling surveys is that they can be performed at any time during the year because they are not dependent on the variation of vision Comparing with distance sampling method, density result estimated by traditional method is always lower It increase when the width of transect decrease In other word, when apply distance sampling method, to approach more exactly result surveyor should survey in only small areas However, it wastes time and costs Therefore, distance sampling should be popular use instead of traditional method Although distance sampling method is a great way to estimate detection probability and density of bird, bias are still occurred Therefore, in order to avoid significant bias and get high accurate data, when field investigations are conducted, surveyor should be more careful in counting and distance estimating 23 CONCLUSION In a total of 954 groups, there were 16 species belonging bird families that were detected The number of detected groups decrease when the distance increase, it make the detection probability decline At far distance, groups are found out by acoustic signal instead of observation It is the reason why proportion of observation decrease and proportion of hearing increases with the rise of distance The detection probability of Red-whiskered Bulbul (Pycnonotus jocosus), Redvented bulbul (Pycnonotus cafer), Sooty-headed Bulbul (Pycnonotus aurigaster) and Rufous-backed shrike (Lanius schach) respectively are 0.123, 0.08, 0.09 and 0.47 These values are affected by distance and the call volume of birds By using distance sampling method, best fit models for each species data are determined With the best fit model is Half-normal, the density of Red-whiskered Bulbul estimated is 0.278 (CI: 0.156- 0.31) and with the best fit model is Uniform, the density of Red-vented bulbul estimated is 0.495 (CI: 0.42- 0.58) In case of Sooty-headed Bulbul, the best fit function is Hazard- rate, and density respectively are 1.59 (CI: 1.35- 1.89) and with the best fit model is Negative expotential, the density of Rufous-backed shrike estimated is 0.22 (CI: 0.125- 0.388) Because of highest density, Sooty-headed Bulbul is the most abundant species compared to the remaining three species With the big difference in density among transect lines, all four studied species are concluded as having uneven distribution of species This is caused by the differences in position and natural conditions of each transect line Because of higher density estimated results, distance sampling method shows its higher accuracy than traditional method This is the reason why distance sampling should be applied more in bird and other fauna surveys 24 The results from density survey of bird species positively contributes to bird conservation in Tam Dao national park Birds’ abundance data allow us to measure changes in population size and hence gauge the impact of habitat loss, pollution or harvesting and to assess whether or not isolated populations are viable However, there are not many specific studies on bird species at pine forest in Tam Dao national park currently In conclusion, more research should be conducted at pine forest in Tam Dao national park to assess the diversity and density of specific bird species and all other avian species in general 25 REFERENCES Rachel E McCaffrey, 2005 Using Citizen Science in Urban Bird Studies In Urban habitats: An electronic journal on the biology of urban areas around the world (Center for Urban Restoration Ecology), Arizona, US J M Marzluff, R Bowman, and R Donelly, eds., 2001 Avian Ecology and Conservation in an Urbanizing World 1st edition, Springer Science and Business Media New York, New York, 585 pages Krizler C Tanalgo; JohnArislynPineda; MaricelAgrvante&AmerolZabide, 2015 Bird Diversity and Structure in Different Land-use types in Lowland south Central Mindanao, Philippines Tropical life sciences research 26( 2): 85-103 Buckland, S.T , 2016 Point transect surveys for songbirds : Robust Methodologies The Auk 123: 345- 357 Nguyen Hai Tuat, Tran Quang Bao ,Vu Tien Thinh, 2011 Ứng dụng số phương pháp định lượng nghiên cứu sinh thái rừng Nhà xuất Nông nghiệp, Hà Nội Thomas, L., S.T Buckland, E.A Rexstad, J.L Laake, S Strindberg, S.L Hedley, J.R.B Bishop & T.A Marques, 2009 Distance software: design and analysis of distance sampling surveys for estimating population size In Journal of Applied Ecology (Marc Cadotte, Jos Barlow, Nathalie Pettorelli and Philip Stephens and Martin Nuñez), UK, pp 5-14 Tordoff, A W et al, 2003 Directory of important bird areas in Vietnam: key sites for conservation BirdLife International in Indochina and the Institute of Ecology and Biological Resources, Hà Nội, 233 pages Nguyen Cu, Le Trong Trai, Karen Phillips, 2000 Bird Vietnam Nhà xuất lao độngxã hội, Hà Nội, 250 pages Anderson, D R., K P Burnham, G C White, and D L Otis, 1983 Density estimation of small-mammal populations using a trapping web and distance sampling methods In Ecology Ecological society of America, USA, pp 674-680 10 Buckland S.T, Anderson D.R, Burnham K.P, Laake J.L, Borchers D.L and Thomas L, 2001: Introduction to Distance Sampling: Estimating Abundance of Biological Populations 1st edition, Oxford University Press, Oxford, UK, 448 pages 11 Craig Robson, 2005 Birds of Southeast Asia Princeton University Press, Princeton, New Jersey, 304 pages 12 Vo Quy, 1981 Chim Viet Nam: hình thái phân loại Nhà xuất khoa học kỹ thuật, Hà Nội 13 Vo Quy and Nguyen Cu, 1995 Danh luc chim Viet Nam Nhà xuất nông nghiệp, Hà Nội 14 Vo Quy, 1993 A catalogue of the birds of Vietnam Thanh Pho publishing house Ha Noi 15 Vu Tien Thinh, Paul F Doherty and Kathryn P Huyvaert, 2012 Avian conservation value of pine plantation forests in northern Vietnam Bird Conservation International 22(2): 193-204 APPENDIX Table : List of bird species recorded at each line transect at pine forest Transect Common name Latin name Number Streak-breasted Scimitar Babbler Pomatorhinus ruficollis Red-whiskered Bulbul Pycnonotus jocosus Rufous-backed shrike Lanius schach Striped tit-babbler Macronous gularis Gray Treepie Dendrocitta formosae Common tailorbird Orthotomus sutorius Red-vented bulbul Pycnonotus cafer Sooty-headed Bulbul Pycnonotus aurigaster 24 Ashy Drongo Dicrurus leucophaeus 11 Common tailorbird Orthotomus sutorius 15 Sooty-headed Bulbul Pycnonotus aurigaster 33 Streak-breasted Scimitar Babbler Pomatorhinus ruficollis Puff-throated Bulbul Alophoixus pallidus Rufous-backed shrike Lanius schach Ashy Drongo Dicrurus leucophaeus 31 Red-vented bulbul Pycnonotus cafer Puff-throated babbler Pellorneum ruficeps Red-whiskered Bulbul Pycnonotus jocosus Striped tit-babbler Macronous gularis Ashy Drongo Dicrurus leucophaeus 44 Sooty-headed Bulbul Pycnonotus aurigaster 20 Rufous-backed shrike Lanius schach Striped tit-babbler Macronous gularis Puff-throated Bulbul Alophoixus pallidus Red-vented bulbul Pycnonotus cafer Common tailorbird Orthotomus sutorius Sooty-headed Bulbul Pycnonotus aurigaster 25 Ashy Drongo Dicrurus leucophaeus 20 Common tailorbird Orthotomus sutorius Red-vented bulbul Pycnonotus cafer Puff-throated Bulbul Alophoixus pallidus Rufous-backed shrike Lanius schach Streak-breasted Scimitar Babbler Pomatorhinus ruficollis Common tailorbird Orthotomus sutorius 12 Ashy Drongo Dicrurus leucophaeus 23 Rufous-backed shrike Lanius schach Red-whiskered Bulbul Pycnonotus jocosus Sooty-headed Bulbul Pycnonotus aurigaster 38 Red-vented bulbul Pycnonotus cafer Puff-throated babbler Pellorneum ruficeps Puff-throated Bulbul Alophoixus pallidus Streak-breasted Scimitar Babbler Pomatorhinus ruficollis Puff-throated babbler Pellorneum ruficeps Sooty-headed Bulbul Pycnonotus aurigaster Rufous-backed shrike Lanius schach Common tailorbird Orthotomus sutorius 18 Ashy Drongo Dicrurus leucophaeus Gray Treepie Dendrocitta formosae 11 13 15 17 Red-vented bulbul Pycnonotus cafer 31 Buff-breasted babbler Pellorneum tickelli Striped tit-babbler Macronous gularis Puff-throated Bulbul Alophoixus pallidus Streak-breasted Scimitar Babbler Pomatorhinus ruficollis Puff-throated Bulbul Alophoixus pallidus 13 Common tailorbird Orthotomus sutorius Red-whiskered Bulbul Pycnonotus jocosus Puff-throated babbler Pellorneum ruficeps Rufous-backed shrike Lanius schach Common tailorbird Orthotomus sutorius Red-vented bulbul Pycnonotus cafer 13 Ashy Drongo Dicrurus leucophaeus Common tailorbird Orthotomus sutorius 17 Streak-breasted Scimitar Babbler Pomatorhinus ruficollis Sooty-headed Bulbul Pycnonotus aurigaster 20 Puff-throated Bulbul Alophoixus pallidus 12 Buff-breasted babbler Pellorneum tickelli 12 Striped tit-babbler Macronous gularis 25 Red-vented bulbul Pycnonotus cafer 17 Striped tit-babbler Macronous gularis Common tailorbird Orthotomus sutorius 20 Streak-breasted Scimitar Babbler Pomatorhinus ruficollis Buff-breasted babbler Pellorneum tickelli 14 Sooty-headed Bulbul Pycnonotus aurigaster 19 21 23 Puff-throated Bulbul Alophoixus pallidus Red-whiskered Bulbul Pycnonotus jocosus Puff-throated Bulbul Alophoixus pallidus Striped tit-babbler Macronous gularis Buff-breasted babbler Pellorneum tickelli Red-vented bulbul Pycnonotus cafer Common tailorbird Orthotomus sutorius 13 Sooty-headed Bulbul Pycnonotus aurigaster Streak-breasted Scimitar Babbler Pomatorhinus ruficollis Red-whiskered Bulbul Pycnonotus jocosus Common tailorbird Orthotomus sutorius 12 Red-vented bulbul Pycnonotus cafer 14 Ashy Drongo Dicrurus leucophaeus Rufous-backed shrike Lanius schach Puff-throated Bulbul Alophoixus pallidus 13 Sooty-headed Bulbul Pycnonotus aurigaster Red-vented bulbul Pycnonotus cafer Common tailorbird Orthotomus sutorius 15 Streak-breasted Scimitar Babbler Pomatorhinus ruficollis Puff-throated Bulbul Alophoixus pallidus Buff-breasted babbler Pellorneum tickelli Red-whiskered Bulbul Pycnonotus jocosus 14 Ashy Drongo Dicrurus leucophaeus