技术与方法
基于红外相机的不可个体识别动物种群密度估算方法
- 1.东北虎豹国家公园保护生态学国家林业和草原局重点实验室, 北京 100875
2.生物多样性与生态工程教育部重点实验室, 北京 100875
3.北京师范大学生命科学学院, 北京 100875
4.天津师范大学生命科学学院天津市动物多样性保护与利用重点实验室, 天津 300387
收稿日期: 2022-07-22
录用日期: 2023-01-04
网络出版日期: 2023-03-20
基金资助
国家自然科学基金(31971539);国家科技基础资源调查专项(2019FY101700);国家科技基础资源调查专项(2021FY100702)
A practical guide for estimating the density of unmarked populations using camera traps
- 1 National Forestry and Grassland Administration Key Laboratory for Conservation Ecology of Northeast Tiger and Leopard National Park, Beijing 100875
2 Ministry of Education Key Laboratory for Biodiversity Science and Engineering, Beijing 100875
3 College of Life Sciences, Beijing Normal University, Beijing 100875
4 Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, College of Life Sciences, Tianjin Normal University, Tianjin 300387
Received date: 2022-07-22
Accepted date: 2023-01-04
Online published: 2023-03-20
摘要
种群密度估计对野生动物的保护和管理至关重要, 也是动物生态学和保护生物学备受关注的研究热点, 但对大中型兽类种群数量的准确估算一直面临挑战。红外相机是哺乳动物调查中普遍采用的工具, 也是克服这一挑战的一种经济有效的方法。目前国际上已有多种方法采用红外相机数据估算不可个体识别动物的种群密度, 但相关技术在我国的应用案例较少, 本文旨在为国内研究者应用红外相机数据估算动物种群密度提供参考。首先, 我们介绍了随机相遇模型(random encounter model, REM)、随机相遇与停留时间(random encounter and staying time, REST)模型、相机前停留时间(time in front of the camera, TIFC)模型以及红外相机距离取样(camera trap distance sampling, CTDS)这四种模型的基本原理和假设; 其次, 描述了这些模型在野外调查中的技术要点, 并给出数据处理与分析的建议; 最后, 总结了每个模型的数据需求、优点和缺点。虽然我国目前拥有估算种群密度的大量红外相机数据源, 但有很多物种的数量尚未知晓, 也没有一种方法对所有红外相机数据都是最优的, 所以我们建议研究者在了解所研究动物类群的生活史和生态需求基础上, 根据模型假设确定合理的采样和分析方案, 扩大这些方法的应用, 为我国重要物种的保护和保护地建设提供科学指导。
本文引用格式
李珍珍 , 杜梦甜 , 朱原辛 , 王大伟 , 李治霖 , 王天明 . 基于红外相机的不可个体识别动物种群密度估算方法[J]. 生物多样性, 2023 , 31(3) : 22422 . DOI: 10.17520/biods.2022422
Abstract
Background & Aim: Estimating population density is essential for wildlife management and conservation, but it is challenging to achieve. Camera trapping is a pervasive method used in mammal surveys and a cost-effective way to overcome this challenge, for which several methods have been described to estimate population density when individuals are indiscernible (i.e. unmarked populations). However, there are few examples of their use in China. We aim to provide a practical guide for conducting camera trap surveys to estimate the density of mammals applying the random encounter model (REM), random encounter and staying time (REST) model, time in front of the camera (TIFC) model and the camera trap distance sampling (CTDS).
Review Results: First, we provide a brief explanation about the structure and assumptions of the REM, REST, TIFC and CTDS models. Next, we describe essential steps in planning a field survey: determination of objectives, design of camera placement, and the layout of the camera station. We then develop detail-oriented instruction for conducting a field survey and analyzing the obtained visual data. Finally, for each analytical approach, we compiled the data requirements, advantages, and disadvantages of each to help practitioners navigate the landscape of abundance estimation methods.
Perspectives: Although multiple methods exist, no one method is optimal for every camera-trap data scenario. While there has been rapid improvement of camera traps in recent decades throughout China, we encourage researchers to evaluate the life history of the focal taxa, carefully define the area of the sampling frame, and enhance the use of camera trapping for estimating densities of unmarked populations.
参考文献
| [1] | Alexander JS, Zhang C, Shi K, Riordan P (2016) A granular view of a snow leopard population using camera traps in Central China. Biological Conservation, 197, 27-31. |
| [2] | Amburgey SM, Yackel Adams AA, Gardner B, Hostetter NJ, Siers SR, McClintock BT, Converse SJ (2021) Evaluation of camera trap-based abundance estimators for unmarked populations. Ecological Applications, 31, e02410. |
| [3] | Amin R, Klair H, Wacher T, Ndjassi C, Fowler A, Olson D, Bruce T (2022) Estimating forest antelope population densities using distance sampling with camera traps. Oryx, 56, 345-351. |
| [4] | Apps P, McNutt JW (2018) Are camera traps fit for purpose? A rigorous, reproducible and realistic test of camera trap performance. African Journal of Ecology, 56, 710-720. |
| [5] | Becker M, Huggard DJ, Dickie M, Warbington C, Schieck J, Herdman E, Serrouya R, Boutin S (2022) Applying and testing a novel method to estimate animal density from motion-triggered cameras. Ecosphere, 13, e4005. |
| [6] | Bessone M, Kühl HS, Hohmann G, Herbinger I, N’Goran KP, Asanzi P, Da Costa PB, Dérozier V, Fotsing EDB, Beka BI, Iyomi MD, Iyatshi IB, Kafando P, Kambere MA, Moundzoho DB, Wanzalire MLK, Fruth B (2020) Drawn out of the shadows: Surveying secretive forest species with camera trap distance sampling. Journal of Applied Ecology, 57, 963-974. |
| [7] | Broadley K, Burton AC, Avgar T, Boutin S (2019) Density- dependent space use affects interpretation of camera trap detection rates. Ecology and Evolution, 9, 14031-14041. |
| [8] | Brownlee MB, Warbington CH, Boyce MS (2022) Monitoring sitatunga (Tragelaphus spekii) populations using camera traps. African Journal of Ecology, 60, 377-385. |
| [9] | Buckland ST, Anderson DR, Burnham KP, Laake JL (1993) Distance Sampling: Estimating Abundance of Biological Populations. Chapman and Hall, London. |
| [10] | Buckland ST, Rexstad EA, Marques TA, Oedekoven CS (2015) Designing distance sampling experiments. In: Distance Sampling: Methods and Applications (eds Buckland ST, Rexstad EA, Marques TA, Oedekoven CS), pp. 29-34. Springer, New York. |
| [11] | Burgar JM, Stewart FEC, Volpe JP, Fisher JT, Burton AC (2018) Estimating density for species conservation: Comparing camera trap spatial count models to genetic spatial capture-recapture models. Global Ecology and Conservation, 15, e00411. |
| [12] | Burton AC, Neilson E, Moreira D, Ladle A, Steenweg R, Fisher JT, Bayne E, Boutin S (2015) Wildlife camera trapping: A review and recommendations for linking surveys to ecological processes. Journal of Applied Ecology, 52, 675-685. |
| [13] | Cappelle N, Després-Einspenner ML, Howe EJ, Boesch C, Kühl HS (2019) Validating camera trap distance sampling for chimpanzees. American Journal of Primatology, 81, e22962. |
| [14] | Cappelle N, Howe EJ, Boesch C, Kühl HS (2021) Estimating animal abundance and effort-precision relationship with camera trap distance sampling. Ecosphere, 12, e03299. |
| [15] | Caravaggi A (2017) remBoot: An R package for random encounter modelling. The Journal of Open Source Software, 2, 176. |
| [16] | Caravaggi A, Burton AC, Clark DA, Fisher JT, Grass A, Green S, Hobaiter C, Hofmeester TR, Kalan AK, Rabaiotti D, Rivet D (2020) A review of factors to consider when using camera traps to study animal behavior to inform wildlife ecology and conservation. Conservation Science and Practice, 2, e239 |
| [17] | Caravaggi A, Zaccaroni M, Riga F, Schai-Braun SC, Dick JTA, Montgomery WI, Reid N (2016) An invasive-native mammalian species replacement process captured by camera trap survey random encounter models. Remote Sensing in Ecology and Conservation, 2, 45-58. |
| [18] | Carbone C, Christie S, Conforti K, Coulson T, Franklin N, Ginsberg JR, Griffiths M, Holden J, Kawanishi K, Kinnaird M, Laidlaw R, Lynam A, MacDonald DW, Martyr D, McDougal C, Nath L, O’Brien T, Seidensticker J, Smith DJL, Sunquist M, Tilson R, Shahruddin WN (2001) The use of photographic rates to estimate densities of tigers and other cryptic mammals. Animal Conservation, 4, 75-79. |
| [19] | Chandler RB, Royle JA (2013) Spatially explicit models for inference about density in unmarked or partially marked populations. The Annals of Applied Statistics, 7, 936-954. |
| [20] | Chen LJ, Xiao WH, Xiao ZS (2019) Limitations of relative abundance indices calculated from camera-trapping data. Biodiversity Science, 27, 243-248. (in Chinesse with English abstract) |
| [20] | [陈立军, 肖文宏, 肖治术 (2019) 物种相对多度指数在红外相机数据分析中的应用及局限. 生物多样性, 27, 243-248.] |
| [21] | Corlatti L, Sivieri S, Sudolska B, Giacomelli S, Pedrotti L (2020) A field test of unconventional camera trap distance sampling to estimate abundance of marmot populations. Wildlife Biology, (4), 1-11. |
| [22] | Cusack JJ, Swanson A, Coulson T, Packer C, Carbone C, Dickman AJ, Kosmala M, Lintott C, Rowcliffe JM (2015) Applying a random encounter model to estimate lion density from camera traps in Serengeti National Park, Tanzania. Journal of Wildlife Management, 79, 1014-1021. |
| [23] | Dénes FV, Silveira LF, Beissinger SR (2015) Estimating abundance of unmarked animal populations: Accounting for imperfect detection and other sources of zero inflation. Methods in Ecology and Evolution, 6, 543-556. |
| [24] | Fisher JT, Burgar JM, Dickie M, Burton AC, Serrouya R (2021) Density estimates of unmarked large mammals at camera traps vary among models, species, and years, signalling importance of model assumptions. Authorea, doi: 10.22541/au.163768980.02146968/v1. |
| [25] | Fleming P, Meek P, Ballard G, Banks P, Claridge A, Sanderson J, Swann D (2014) Camera Trapping:Wildlife Management and Research. CSIRO Publishing, Collingwood, Victoria. |
| [26] | Gilbert NA, Clare JDJ, Stenglein JL, Zuckerberg B (2021) Abundance estimation of unmarked animals based on camera-trap data. Conservation Biology, 35, 88-100. |
| [27] | Glen AS, Cockburn S, Nichols M, Ekanayake J, Warburton B (2013) Optimising camera traps for monitoring small mammals. PLoS ONE, 8, e67940. |
| [28] | Greenberg S (2021) Timelapse: An Image Analyser for Camera Traps. ) |
| [29] | Greenberg S, Godin T, Whittington J (2019) Design patterns for wildlife-related camera trap image analysis. Ecology and Evolution, 9, 13706-13730. |
| [30] | Gu WD, Swihart RK (2004) Absent or undetected? Effects of non-detection of species occurrence on wildlife-habitat models. Biological Conservation, 116, 195-203. |
| [31] | Gurarie E, Ovaskainen O (2013) Towards a general formalization of encounter rates in ecology. Theoretical Ecology, 6, 189-202. |
| [32] | Harris GM, Butler MJ, Stewart DR, Rominger EM, Ruhl CQ (2020) Accurate population estimation of Caprinae using camera traps and distance sampling. Scientific Reports, 10, 17729. |
| [33] | Haucke T, Kühl HS, Hoyer J, Steinhage V (2022) Overcoming the distance estimation bottleneck in estimating animal abundance with camera traps. Ecological Informatics, 68, 101536. |
| [34] | Henrich M, Hartig F, Dormann CF, Kühl HS, Peters W, Franke F, Peterka T, ?ustr P, Heurich M (2022) Deer behavior affects density estimates with camera traps, but is outweighed by spatial variability. Frontiers in Ecology and Evolution, 10, 881502. |
| [35] | Hofmeester TR, Cromsigt JPGM, Odden J, Andrén H, Kindberg J, Linnell JDC (2019) Framing pictures: A conceptual framework to identify and correct for biases in detection probability of camera traps enabling multi-species comparison. Ecology and Evolution, 9, 2320-2336. |
| [36] | Hongo S, Nakashima Y, Yajima G (2021) A practical guide for estimating animal density using camera traps: Focus on the REST model. bioRxiv, doi: 10.1101/2021.05.18.444583. |
| [37] | Houa NA, Cappelle N, Bitty EA, Normand E, Kablan YA, Boesch C (2022) Animal reactivity to camera traps and its effects on abundance estimate using distance sampling in the Ta? National Park, C?te d'Ivoire. PeerJ, 10, e13510. |
| [38] | Howe EJ, Buckland ST, Després-Einspenner ML, Kühl HS (2017) Distance sampling with camera traps. Methods in Ecology and Evolution, 8, 1558-1565. |
| [39] | Howe EJ, Buckland ST, Després-Einspenner ML, Kühl HS (2019) Model selection with overdispersed distance sampling data. Methods in Ecology and Evolution, 10, 38-47. |
| [40] | Hu XP, Huang B, Verones F, Cavalett O, Cherubini F (2021) Overview of recent land-cover changes in biodiversity hotspots. Frontiers in Ecology and the Environment, 19, 91-97. |
| [41] | Huggard D (2018) Animal density from camera data. Alberta Biodiversty Monitoring Institute. Edmonton, Canada. |
| [42] | Hutchinson JMC, Waser PM (2007) Use, misuse and extensions of “ideal gas” models of animal encounter. Biological Reviews, 82, 335-359. |
| [43] | Iijima H (2020) A review of wildlife abundance estimation models: Comparison of models for correct application. Mammal Study, 45, 177-188. |
| [44] | Jayasekara D, Mahaulpatha D, Miththapala S (2021) Population density estimation of meso-mammal carnivores using camera traps without the individual recognition in Maduru Oya National Park, Sri Lanka. Hystrix, 32, 137-146. |
| [45] | Johanns P, Haucke T, Steinhage V (2022) Automated distance estimation for wildlife camera trapping. Ecological Informatics, 70, 101734. |
| [46] | Jourdain NOAS, Cole DJ, Ridout MS, Rowcliffe JM (2020) Statistical development of animal density estimation using random encounter modelling. Journal of Agricultural, Biological and Environmental Statistics, 25, 148-167. |
| [47] | Kamgaing TOW, Bobo KS, Djekda D, Azobou KBV, Hamadjida BR, Balangounde MY, Simo KJ, Yasuoka H (2018) Population density estimates of forest duikers (Philantomba monticola & Cephalophus spp.) differ greatly between survey methods. African Journal of Ecology, 56, 908-916. |
| [48] | Kéry M, Royle JA (2016) Applied Hierarchical Modeling in Ecology: Analysis of Distribution, Abundance and Species Richness in R and BUGS (Vol. 1): Prelude and Static Models. Academic Press, London. |
| [49] | Li S, Wang DJ, Xiao ZS, Li XH, Wang TM, Feng LM, Wang Y (2014) Camera-trapping in wildlife research and conservation in China: Review and outlook. Biodiversity Science, 22, 685-695. (in Chinesse with English abstract) |
| [49] | [李晟, 王大军, 肖治术, 李欣海, 王天明, 冯利民, 王云 (2014) 红外相机技术在我国野生动物研究与保护中的应用与前景. 生物多样性, 22, 685-695.] |
| [50] | Li XH, Tian HD, Piao ZJ, Wang GM, Xiao ZS, Sun YH, Gao EH, Holyoak M (2022) cameratrapR: An R package for estimating animal density using camera trapping data. Ecological Informatics, 69, 101597. |
| [51] | Li YH (2021) A review on estimating population size of large and medium-sized mammals. Biodiversity Science, 29, 1700-1717. (in Chinese with English abstract) |
| [51] | [李月辉 (2021) 大中型兽类种群数量估算的研究进展. 生物多样性, 29, 1700-1717.] |
| [52] | Lu LL, Wang W, Li Y, Cai P, Shi YH, Yong J, Yin F (2020) Investigation and analysis of ungulate population size in Dulan, Qinghai Province. Forest Resources Management, (3), 63-66. (in Chinese with English abstract) |
| [52] | [卢琳琳, 王巍, 李叶, 蔡平, 石永红, 勇军, 尹峰 (2020) 青海都兰大型有蹄类种群数量调查与分析. 林业资源管理, (3), 63-66.] |
| [53] | Lucas TCD, Moorcroft EA, Freeman R, Rowcliffe JM, Jones KE (2015) A generalised random encounter model for estimating animal density with remote sensor data. Methods in Ecology and Evolution, 6, 500-509. |
| [54] | Luo G, Wei WD, Dai Q, Ran JH (2020) Density estimation of unmarked populations using camera traps in heterogeneous space. Wildlife Society Bulletin, 44, 173-181. |
| [55] | MacKenzie DI, Nichols JD, Lachman GB, Droege S, Andrew Royle J, Langtimm CA (2002) Estimating site occupancy rates when detection probabilities are less than one. Ecology, 83, 2248-2255. |
| [56] | Mason SS, Hill RA, Whittingham MJ, Cokill J, Smith GC, Stephens PA (2022) Camera trap distance sampling for terrestrial mammal population monitoring: Lessons learnt from a UK case study. Remote Sensing in Ecology and Conservation, 8, 717-730. |
| [57] | Meek PD, Ballard GA, Fleming PJS, Schaefer M, Williams W, Falzon G (2014) Camera traps can be heard and seen by animals. PLoS ONE, 9, e110832. |
| [58] | Miller DL (2021) Package ‘Distance’, Version 1.0.7. https://cran.r-project.org/web/packages/Distance/index.html. (accessed on 2022-11-15) |
| [59] | Moeller AK, Lukacs PM, Horne JS (2018) Three novel methods to estimate abundance of unmarked animals using remote cameras. Ecosphere, 9, e02331. |
| [60] | Mysterud A, Ims RA (1998) Functional responses in habitat use: Availability influences relative use in trade-off situations. Ecology, 79, 1435-1441. |
| [61] | Nakashima Y, Fukasawa K, Samejima H (2018) Estimating animal density without individual recognition using information derivable exclusively from camera traps. Journal of Applied Ecology, 55, 735-744. |
| [62] | Nakashima Y, Hongo S, Akomo-Okoue EF (2020) Landscape- scale estimation of forest ungulate density and biomass using camera traps: Applying the REST model. Biological Conservation, 241, 108381. |
| [63] | Nathan R, Getz WM, Revilla E, Holyoak M, Kadmon R, Saltz D, Smouse PE (2008) A movement ecology paradigm for unifying organismal movement research. Proceedings of the National Academy of Sciences, USA, 105, 19052-19059. |
| [64] | Nichols JD, Williams BK (2006) Monitoring for conservation. Trends in Ecology & Evolution, 21, 668-673. |
| [65] | Norouzzadeh MS, Nguyen A, Kosmala M, Swanson A, Palmer MS, Packer C, Clune J (2018) Automatically identifying, counting, and describing wild animals in camera-trap images with deep learning. Proceedings of the National Academy of Sciences, USA, 115, E5716-E5725. |
| [66] | O’Brien TG (2011) Abundance, density and relative abundance:A conceptual framework. In: Camera Traps in Animal Ecology: Methods and Analyses (eds O’Connell AF, Nichols JD, Karanth KU), pp. 71-96. Springer, New York. |
| [67] | O’Connell AF, Nichols JD, Karanth KU (2011) Camera Traps in Animal Ecology: Methods and Analyses. Springer, New York. |
| [68] | Pal R, Bhattacharya T, Qureshi Q, Buckland ST, Sathyakumar S (2021) Using distance sampling with camera traps to estimate the density of group-living and solitary mountain ungulates. Oryx, 55, 668-676. |
| [69] | Palencia P, Rowcliffe JM, Vicente J, Acevedo P (2021) Assessing the camera trap methodologies used to estimate density of unmarked populations. Journal of Applied Ecology, 58, 1583-1592. |
| [70] | Palencia P, Vicente J, Barroso P, Barasona Já, Soriguer RC, Acevedo P (2019) Estimating day range from camera-trap data: The animals’ behaviour as a key parameter. Journal of Zoology, 309, 182-190. |
| [71] | Pettigrew P, Sigouin D, St-Laurent MH (2021) Testing the precision and sensitivity of density estimates obtained with a camera-trap method revealed limitations and opportunities. Ecology and Evolution, 11, 7879-7889. |
| [72] | Rich LN, Miller DAW, Mu?oz DJ, Robinson HS, McNutt JW, Kelly MJ (2019) Sampling design and analytical advances allow for simultaneous density estimation of seven sympa- tric carnivore species from camera trap data. Biological Conservation, 233, 12-20. |
| [73] | Rovero F, Marshall AR (2009) Camera trapping photographic rate as an index of density in forest ungulates. Journal of Applied Ecology, 46, 1011-1017. |
| [74] | Rovero F, Zimmermann F, Berzi D, Meek P (2013) Which camera trap type and how many do I need? A review of camera features and study designs for a range of wildlife research applications. Hystrix, 24, 148-156. |
| [75] | Rowcliffe JM, Field J, Turvey ST, Carbone C (2008) Estimating animal density using camera traps without the need for individual recognition. Journal of Applied Ecology, 45, 1228-1236. |
| [76] | Rowcliffe JM, Carbone C, Jansen PA, Kays R, Kranstauber B (2011) Quantifying the sensitivity of camera traps: An adapted distance sampling approach. Methods in Ecology and Evolution, 2, 464-476. |
| [77] | Rowcliffe JM, Kays R, Kranstauber B, Carbone C, Jansen PA (2014) Quantifying levels of animal activity using camera trap data. Methods in Ecology and Evolution, 5, 1170-1179. |
| [78] | Royle JA (2004) N-mixture models for estimating population size from spatially replicated counts. Biometrics, 60, 108-115. |
| [79] | Sollmann R, Mohamed A, Samejima H, Wilting A (2013) Risky business or simple solution—Relative abundance indices from camera-trapping. Biological Conservation, 159, 405-412. |
| [80] | Steenweg R, Hebblewhite M, Kays R, Ahumada J, Fisher JT, Burton C, Townsend SE, Carbone C, Rowcliffe JM, Whittington J, Brodie J, Royle JA, Switalski A, Clevenger AP, Heim N, Rich LN (2017) Scaling-up camera traps: Monitoring the planet’s biodiversity with networks of remote sensors. Frontiers in Ecology and the Environment, 15, 26-34. |
| [81] | Sun P, Huang SM, Su Y, Meng DH, Zhang ZR, Teng LW, Liu ZS (2021) Red deer population size and structure on Helan Mountain, Inner Mongolia, China. Chinese Journal of Wildlife, 42, 341-347. (in Chinese with English abstract) |
| [81] | [孙萍, 黄师梅, 苏云, 孟德怀, 张致荣, 滕丽微, 刘振生 (2021) 内蒙古贺兰山马鹿的种群数量及种群结构. 野生动物学报, 42, 341-347.] |
| [82] | Wang TM, Andrew Royle J, Smith JLD, Zou L, Lü XY, Li T, Yang HT, Li ZL, Feng RN, Bian YJ, Feng LM, Ge JP (2018) Living on the edge: Opportunities for Amur tiger recovery in China. Biological Conservation, 217, 269-279. |
| [83] | Warbington CH, Boyce MS (2020) Population density of sitatunga in riverine wetland habitats. Global Ecology and Conservation, 24, e01212. |
| [84] | Wearn OR, Bell TEM, Bolitho A, Durrant J, Haysom JK, Nijhawan S, Thorley J, Rowcliffe JM (2022) Estimating animal density for a community of species using information obtained only from camera-traps. Methods in Ecology and Evolution, 13, 2248-2261. |
| [85] | Wearn OR, Glover-Kapfer P (2019) Snap happy: Camera traps are an effective sampling tool when compared with alternative methods. Royal Society Open Science, 6, 181748. |
| [86] | Whittington J, Hebblewhite M, Chandler RB (2018) Generalized spatial mark-resight models with an application to grizzly bears. Journal of Applied Ecology, 55, 157-168. |
| [87] | Willi M, Pitman RT, Cardoso AW, Locke C, Swanson A, Boyer A, Veldthuis M, Fortson L (2019) Identifying animal species in camera trap images using deep learning and citizen science. Methods in Ecology and Evolution, 10, 80-91. |
| [88] | Williams BK, Nichols JD, Conroy MJ (2002) Analysis and Management of Animal Populations: Modeling, Estimation, and Decision Making. Academic Press, San Diego. |
| [89] | Xiao WH, Feng LM, Mou P, Miquelle DG, Hebblewhite M, Goldberg JF, Robinson HS, Zhao XD, Zhou B, Wang TM, Ge JP (2016) Estimating abundance and density of Amur tigers along the Sino-Russian border. Integrative Zoology, 11, 322-332. |
| [90] | Xie JC, Meng DH, Li ZZ, Zhang ZR, Liu ZS, Teng LW (2022) Population size and structure of blue sheep in Helan Mountains National Nature Reserve, Ningxia. Acta Ecologica Sinica, 42, 4189-4196. (in Chinese with English abstract) |
| [90] | [谢建冲, 孟德怀, 李宗智, 张致荣, 刘振生, 滕丽微 (2022) 宁夏贺兰山国家级自然保护区岩羊(Pseudois nayaur)种群数量及结构. 生态学报, 42, 4189-4196.] |
| [91] | Yu LH (2021) Surveys on the resource actualities of the wild boar population in Huangshan City. Anhui Forestry Science and Technology, 47(3), 46-54. (in Chinese with English abstract) |
| [91] | [余立华 (2021) 黄山市野猪种群资源现状调查. 安徽林业科技, 47(3), 46-54.] |
Options