Cộng hoà xã hội chủ nghĩa việt nam

Cộng hoà xã hội chủ nghĩa Việt nam MINISTRY OF EDUCATION AND TRAINING MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAM NATIONAL UNIVERSITY OF FORESTRY VAN HUU NGUYEN STUDY ON THE STATUS AND DISTR[.]

MINISTRY OF EDUCATION AND TRAINING - MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAM NATIONAL UNIVERSITY OF FORESTRY VAN HUU NGUYEN STUDY ON THE STATUS AND DISTRIBUTION OF THE WHITECHEEKED GIBBON Nomascus leucogenys (Ogilby, 1840) IN VU QUANG NATIONAL PARK, HA TINH PROVINCE TO PROPOSE CONSERVATION SOLUTIONS Industry: Forest resource management Code: 62 02 11 SUMMARY REPORT OF THE FORESTRY DOCTORAL THESIS HANOI – 2022 THESIS IS COMPLETED AT VIETNAM NATIONAL UNIVERSITY OF FORESTRY MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT Science advisor: Prof Dr THINH TIEN VU Reviewer 1: Reviewer 2: Reviewer 3: The thesis will be defended at the State Thesis Evaluation Council according to Decision No: ………… date …… month ……year …… of the Rector of the Vietnam National University Forestry, meeting at the Vietnam National University Forestry on: …… hour… day… month …… …year……… HANOI - 2022 HEADING I QUESTION The white-cheeked gibbon (Nomascus leucogenys) is one of six gibbon species of the genus Nomascus recorded in Vietnam (Van Ngoc Thinh et al, 2010), (Nadler & Brockman, 2014) Apes are among the most endangered wildlife due to rapidly declining population size Specifically, there are species of gibbons classified as CR (Critically Endangered) and species classified as EN (Endangered) on the red list (IUCN, 2021) White-cheeked gibbon has a natural distribution in Vu Quang National Park, however, studies on White-cheeked gibbon in Vu Quang National Park so far have only focused on recording the presence and distribution, no research has been done any expertise on biological and ecological characteristics of the white-cheeked gibbon such as habitat, population structure, population size and threats to the population; Previously applied survey methods were point and line surveys, short investigation time, not yet applied automatic recording techniques in the investigation, no long-term investigation and monitoring plan for the survey was developed White-cheeked gibbon species in Vu Quang National Park In order to have complete data on the status and distribution of the white-cheeked gibbon population in Vu Quang National Park, this study conducted a survey by traditional method of points at 40 sites in 20 forest compartments during the period from February 21, 2020 to July 3, 2020; investigated by automatic recorder at 53 listening points distributed in 33 forest compartments during the period from July 22, 2019 to May 19, 2020, The data collected in the two survey methods above was processed to serve to evaluate the distribution, structure, size as well as biological and ecological characteristics of the white-cheeked gibbon population in Vu Quang National Park Proposing conservation plan, developing a monitoring plan for the white-cheeked gibbon in Vu Quang National Park, Ha Tinh province II RESEARCH OBJECTIVES, SUBJECTS AND SCOPE 2.1 Objectives 2.1.1 General objective Assess the current status, determine the distribution area as well as the threat factors to the population of the white-cheeked gibbon (Nomascus leucogenys) in Vu Quang National Park, Ha Tinh province, from which to develop a monitoring plan and make a decision Adaptation solutions to maintain and long-term conservation of the white-cheeked gibbon population in Vu Quang National Park 2.1.2 Detail objectives 2.1.2.1 Determining the population status and distribution of the white-cheeked gibbon in Vu Quang National Park: - Identification of the white-cheeked gibbon with data obtained from automatic recording devices - Determine the area and distribution area of the white-cheeked gibbon population with data obtained from automatic recording devices - Estimated distribution density (herds/km2) and population size of whitecheeked gibbon in Vu Quang National Park 2.1.2.2 Additional data on biological and ecological characteristics of the whitecheeked gibbon in Vu Quang National Park - Identify the preferred habitat of the white-cheeked gibbon in Vu Quang National Park - Evaluation of the population structure of the white-cheeked gibbon in Vu Quang National Park by age and sex through analysis of song recordings - Updating information on singing behavior (frequency, time by day/season) and results of sound spectrum analysis of white-cheeked gibbon in Vu Quang National Park - Assessing the influence of weather factors (rain, wind, fog) on the singing frequency of the white cheeked gibbon in Vu Quang National Park 2.1.2.3 Proposing some solutions to conserve the white-cheeked gibbon population in Vu Quang National Park - Assessing the threat factors to the white-cheeked gibbon in Vu Quang National Park - Proposing solutions to long-term conservation of the white-cheeked gibbon population in Vu Quang National Park - Developed a monitoring plan for the white-cheeked gibbon in Vu Quang National Park 2.2 Research subjects The subject of the study is the white-cheeked gibbon (Nomascus leucogenys) 2.3 Research scope - In terms of subjects, the study focuses on the white-cheeked gibbon (Nomascus leucogenys) - In terms of space, the topic focuses on the area of Vu Quang National Park, Ha Tinh province - The study conducted field data collection from July 2019 to July 2020 Chapter OVERVIEW OF RESEARCH ISSUES AND NATURAL ECONOMICAL SOCIAL CONDITIONS OF THE RESEARCH AREA 1.1 Overall study results - Vietnam has a total of 06 gibbon species, all of which belong to the crested gibbon (Nomascus); There are differences between species in terms of morphology and genotype The distribution of these species stretches from North to South, all gibbon species have a very high conservation level, of which 02 species are endangered (EN), 04 species are critically endangered (CR) The habitat of gibbons is severely reduced, the special-use forests are fragmented, some populations have a small number of individuals but cannot connect with other populations, so they are of little significance in conservation - In the past, surveys of apes usually used manual methods, line or point surveys, in recent years, in addition to human surveys, recording devices or automatic recording software have been used, in order to reduce costs and increase the efficiency of the investigation, with the recording of the appearance of gibbons by singing in the recording files, after analyzing and comparing with the standard sound spectrums - Using the "Distance" method with extended functions and series to simulate the fluctuation of the probability of detecting the investigated object according to the distance, thereby calculating the probability of detecting the investigated object, this result is calculated used to correct population density estimates - The boundary of Vu Quang National Park belongs to the natural distribution area of the white-cheeked gibbon (Nomascus leucogenys), this species has been recorded in a number of surveys and scientific projects in the National Park; However, data on the white-cheeked gibbon in Vu Quang National Park is still sketchy and has not been updated in terms of distribution area, herd structure, population size the monitoring of this species in the National Park still encounters many problems and difficulties Therefore, it is necessary to have a study and assessment of the current status of the white-cheeked gibbon in Vu Quang National Park in order to develop a conservation plan and monitoring plan for this species in the future Chapter RESEARCH CONTENTS AND METHODS 2.1 Research content The study focuses on three main research topics, specifically as follows: 2.1.1 Determining the current status and distribution of the white-cheeked gibbon population in Vu Quang National Park - Identification of the white-cheeked gibbon with data obtained from automatic recording devices - Determining the area and distribution area of the white-cheeked gibbon population with data obtained from automatic recording devices - Estimate the probability of singing daily; Estimated distribution density and size of the white-cheeked gibbon population in Vu Quang National Park 2.1.2 Research on biological and ecological characteristics of white-cheeked gibbon (Nomascus leucogenys) in Vu Quang National Park, Ha Tinh province - Determining the preferred habitat of the white-cheeked gibbon in Vu Quang National Park - Analyze the sound spectrum and determine the population structure of the white-cheeked gibbon by age and sex through analysis of song recording files - Analysis of singing frequency by time of day, time of singing start and end, length of time of day - Evaluation of the influence of some weather factors on the singing frequency of the white-cheeked gibbon during the investigation in the study area 2.1.3 Proposing some solutions to conserve the population of the white-cheeked gibbon (Nomascus leucogenys) in Vu Quang National Park, Ha Tinh province - Assessment of threats to the white-cheeked gibbon population in Vu Quang National Park - Evaluation of the organizational structure of the management apparatus and the status of conservation work in Vu Quang National Park - Proposing solutions to preserve the white-cheeked gibbon in Vu Quang National Park - Proposing a monitoring plan for the white-cheeked gibbon in Vu Quang National Park 2.2 Research Methods 2.2.1 Inheritance method 2.2.2 Methods of surveying the white-cheeked gibbon in the field 2.2.2.1 Method of investigation by automatic recorder Purpose: Data obtained from the method of investigation by automatic recorders are recording files, these recording files are processed by Raven Pro 16.1 software to create audio spectrums and compare audio spectrums obtained with the standard sound spectrum to determine the presence of the white-cheeked gibbon in the study area, in addition, the analysis of the sound spectrum also determined the structure of the gibbons group, the location of the recorders distributed by areas and habitats with the white-cheeked gibbon - Time to place the machine: From July 2019 to the end of May 2020, recording times; Phase from July 22, 2019 to August 31, 2019; phase from December 7, 2019 to January 31, 2020; Phase from February 4, 2020 to the end of May, 2020 2.2.2.2 Traditional method Purpose: The data obtained from the traditional survey method are the coordinates of listening points, the azimuth from the listening points to the gibbon group's position, the estimated distance from the listening point to the gibbon group's position, present Forest status at listening points, start and end times of gibbon groups, weather conditions at listening points, from this data, this data serves to calculate the singing probability for gibbon groups, calculate density of gibbon groups gibbon, from which to calculate and estimate the size of the gibbon population in the study area; forest status data used to calibrate the distribution map of gibbon populations, weather data used to determine the influence of weather factors on gibbon singing frequency in the study area The method of investigating song by listening points (Brockelman & Ali, 1987) was used to assess the population size, density and status of the white-cheeked gibbon in the study area The total number of human survey sites is designed to be 40 points, in 20 forest compartments; The time of field investigation by humans was carried out from February 21, 2020 to July 3, 2020 The method of investigating song according to listening points (Brockelman & Ali, 1987) was used to assess the population size, density and status of the whitecheeked gibbon in the study area 2.2.2.3 Methods of investigation and survey of threatening factors to the whitecheeked gibbon population a Survey identifies threats to the white-cheeked gibbon while conducting tape recorders and investigations on line, listening point: b Through data analysis from recording files: c Interviews with forest protection officers and people living near the forest: 2.2.3 Data processing methods 2.2.3.1 Determining the current status and distribution of the white-cheeked gibbon population in Vu Quang National Park a Determination of the presence and structure of the white-cheeked gibbon with data from automatic recording devices Acoustic data obtained from an automatic recorder, analyzed using Raven software (Cornell Lab of Onithology; Version: Raven Pro 1.6) to generate the sound spectrum of the songs of the gibbons; song gibbons data are recorded in the table Compare the results of the analysis of the obtained sound spectrum with the model song sound spectrum of (Konrad, R; Geissmann, T, 2006) b Determining the area and distribution area of the white-cheeked gibbon population with data obtained from automatic recording devices c Estimate the probability of singing daily; Estimated distribution density and size of the white-cheeked gibbon population in Vu Quang National Park * Location of gibbon herds from human census data * Estimation of singing probability and correction factor Singing probability and correction factor were performed according to the guidance of (Vu Tien Thinh & Rawson, B M, 2011) * Estimation of gibbon population size by distance method Distance software (Thomas et al, 2010) was used to estimate the gibbon population using the distance method The topic uses four functions to simulate the effect of detection probability by distance (Buckland et al, 2001) 2.2.3.2 Methods of studying biological and ecological characteristics of the whitecheeked gibbon (Nomascus leucogenys) in Vu Quang National Park, Ha Tinh province a Determining the preferred habitat of the white-cheeked gibbon in Vu Quang National Park b Analysis of singing frequency by time of day, time of singing start and end, length of time of day b1 Analysis of singing frequency by time of day b2 Calculate seasonally how often gibbons start singing b3 Determine how often the length of time gibbons sing during the day c Evaluation of the influence of some weather factors on the singing frequency of the white-cheeked gibbon during the investigation in the study area - Effects of rain at the time of investigation: - The effect of the rain the night before: - The influence of the wind: - The effect of fog: Using Chi-squared criterion to test the influence of weather factors on the singing frequency of gibbons: 2.2.4 Proposing some solutions to preserve the white-cheeked gibbon in Vu Quang National Park - Synthesis, assessment and analysis of threats to the white-cheeked gibbon population in Vu Quang National Park by scoring method; thereby identifying major/minor threats to the white-cheeked gibbon population: 12 - The area of the white-cheeked gibbon distributed in Vu Quang National Park is calculated to be 32,432.26 ha; - The population density of gibbon in the distribution area is estimated at 0.42104 herds/km2 (0.16930-1.0471); - The data from the processing of determining the structure of the whitecheeked gibbon population at Vu Quang National Park shows that the average number of individuals in a herd is about 1.97 individuals.; Calculation results: - Population size of the white cheeked gibbon in Vu Quang National Park is: (0.42104 herds/km2 x 32,432.26 ha)/100 = 137 herds; - The number of white-cheeked gibbon in Vu Quang National Park is about 1.97 x 137 = 270 individuals These data not include juveniles that have not been recorded in the recording of the white-cheeked gibbon's song 3.2 Biological and ecological characteristics of the white-cheeked gibbon (Nomascus leucogenys) in Vu Quang National Park, Ha Tinh province 3.2.1 Preferred habitat of white-cheeked gibbon in Vu Quang National Park The results of the forest status survey at the listening points, combined with the data layer on the current status of forests and forest land of Vu Quang National Park in 2019 are processed using Mapinfo 10.5 software; The results show that the areas recorded with the white-cheeked gibbon distributed in Vu Quang National Park have rich forest status accounting for 22.33% of the area, average forest status accounting for 75.19% of the area, total area the area of rich and medium forest accounts for 97.52%, the status of poor and poor forests accounts for only 2.49%; Gibbons are not recorded in the status of restored forest, mixed forest, planted forest, unforested land and bare land While at places where the white-cheeked gibbon is not recorded, the percentage of current status by area is as follows: rich forest occupies 8.08% of the area, medium forest occupies 58.18% of the area, and poor forest occupies 27 .83 % of the area, the remaining states accounted for 5.9 % of the area Thus, the preferred habitat of the white-cheeked gibbon in Vu Quang National Park is evergreen broad-leaved natural forests with medium to rich reserves, this result is also consistent with the ecological data of this species The species of white- 13 cheeked gibbon has been reported previously (Pham Nhat, 2002), but in this study, the proportion of natural broad-leaved evergreen forest with medium to rich reserves accounted for 97.52 was quantified in this study % area 3.2.2 Sound spectrum and structure determination of white-cheeked gibbons through analysis of sound spectrum From the analysis results of 32 audio files, the basic structure of the whitecheeked gibbon in the study area has been determined, including the following types: (1) herd of only male gibbons (5 herds); (2) herd has adult male and adult female (23 herds); (3) herd has male, adult and semi-adult (3 herds); (4) herd has adult male gibbons, adult female gibbon (1 herd) 3.2.3 Frequency of singing by time of day, time of singing start and end, length of time of day The time of singing by day of the white-cheeked gibbon was counted for 32 times of detecting the song The analysis results show that, 100% of the flocks start singing after 5:00 p.m., of which 11 flocks start singing between 5:00 a.m and 6:00 p.m., accounting for 34.38%; 16 flocks start singing between 6:00 and 7:00, accounting for 50%; groups started singing from 7:00 am to 8:00 pm, accounting for 12.50% and only one group started singing at 8:00 am - 9:00 am, accounting for 3.13%, figure 3.8 In addition, the survey results show that when the weather is better, the gibbons go to feed earlier and also sing earlier Thus, during the investigation process, it is advisable to start the investigation at 5:00 am and finish the investigation before 9:30 am In the summer, gibbons sing earlier than other seasons of the year, most of the gibbon groups start singing between 5:00 and 5:30, accounting for about 75% In the spring, gibbons sing later, starting to sing between 5:30 and 6:00, and most of the herds begin to sing around 5:30 to 6:30, accounting for about 72.22% Then some flocks continued to sing, but not many In winter, gibbons sing much later than in summer, which is also consistent with the behavior of other primates and mammals that are active during the day No gibbons have been recorded singing before a.m in winter Most of the gibbon groups (83.33%) start singing between 6:00am - 14 7:00am, 16.67% of the remaining gibbons start singing later, between 7:00am 7:30am The results show that 100% of the gibbons have a singing time of less than 35 minutes, of which the most concentration is in the period from minutes to under 25 minutes, accounting for 90.70% of the songs; The number of songs with duration of less than minutes and over 35 minutes only accounts for 9.30% of the total number of songs 3.2.4 Effects of some weather factors on the singing frequency of the whitecheeked gibbon during the investigation in the study area a Effects of rain at the time of investigation Research results show that the white-cheeked gibbon sings on both rainy and non-rainy days, however, the frequency of singing on a rainy day is 40.26%, while on a rainy day, the singing frequency is only 13.64%; Similarly, the frequency of gibbons not singing on rainy days is 59.74% and the frequency of gibbons not singing on rainy days is 86.36% Using Chi-square test to test the influence of rain on the singing frequency of gibbons: Ho Hypothesis: Singing frequency of gibbons is not affected by rain Ha Hypothesis: Singing frequency of gibbons is influenced by rain Calculation results have: 2 = 9.35; df=1 and sig=0.00223 Look up the distribution table 2 with degrees of freedom df=1, the critical value =0.05 is 3.84 2 calculations >3.84 reject the Ho hypothesis and accept the hypothesis that Ha or rain when investigating has an effect on the singing frequency of the whitecheeked gibbon, when the weather does not rain, the white-cheeked gibbon sings more often with rain, this result is similar to the study of (Dena et al, 2020) b Effect of wind on the singing frequency of the white-cheeked gibbon Research results show that the frequency of singing of the white-cheeked gibbon on windless days is 26.83%, while the frequency of singing on windy days is 32.5%; similarly, gibbons that don't sing on windless days are 73.17% and gibbons that don't sing on windy days are 67.5% 15 Using Chi-square test to test the influence of wind on the singing frequency of gibbons: Ho Hypothesis: The frequency of singing of gibbons is not affected by wind Ha Hypothesis: Singing frequency of gibbons is influenced by wind Calculation results have: 2 = 0.41; df=1 and sig=0.52165 Look up the distribution table 2 with degrees of freedom df=1, the critical value =0.05 is 3.84 2 calculations