Diana P. Zlatanova,
Elitsa D. Popova,

Reference to article

Zlatanova D.P., Popova E.D. 2018. Biodiversity estimates from different camera trap surveys: a case study from Osogovo Mt., Bulgaria.Nature Conservation Research 3(2). DOI: 10.24189/ncr.2018.026

Section Resarch articles

Inventorying mammal assemblages is vital for their conservation and management, especially when they include rare or endangered species. However, obtaining a correct estimation of the species diversity in a particular area can be challenging due to uncertainties regarding study design and duration. In this paper, we present the biodiversity estimates derived from three unrelated camera trap studies in Osogovo Mt., Bulgaria. They have different duration and positioning schemes of the camera trap locations: Study 1 – grid based, 34 days; Study 2 – random points based, 138 days; Study 3 – locations based on expert opinion, 1437 days. Utilising EstimateS, we compare a number of estimators (Shannon diversity index, Coleman rarefaction curve, ACE (Abundance-based Coverage Estimator), ICE (Incidence-based Coverage Estimator), Chao 1, Chao 2 and Jackknife estimators) to the number of present and confirmed and/or potentially present mammals (excluding bats) in the mountains. A total of 17 mammal species were registered in the three studies, which represents around 76% of the permanently present mammals in the mountain that inhabit its forested area and can be detected by a camera trap. The results point to some guidelines that can aid future camera trap research in temperate forested areas. A grid-based design works best for very short study periods (e.g. 10 days), while the opportunistic expert-based positioning scheme provides good results for longer studies (approx. a month). However, the grid-based design needs to be further tested for longer periods. Generally, the random points approach does not yield satisfactory results. In agreement with other studies, analysis based on the Jackknife procedure (Jack 2) appears to result in the best estimate of species richness. When performing camera trap studies, special care should be taken to minimise the number of unidentifiable photos and to take into account «trap-shy» individuals. The results from this study emphasise the need for careful preliminary planning of camera trap studies depending on aims, duration and target species.


camera trap, grid, mammals, random points, rare species

Artice information

Received: 31.01.2018

The full text of the article

Bengsen A.J., Leung, L.K.P., Lapidge S.J., Gordon I.J. 2011. Using a general index approach to analyze camera-trap abundance indices. Journal of Wildlife Management 75(5): 1222–1227. DOI: 10.1002/jwmg.132
Birds Protection Directive, 79/409/EEC. Available from:
Bischof R., Hameed S., Ali H., Kabir, M., Younas M., Shah K.A., Din J.U., Nawaz M.A. 2014. Using time-to-event analysis to complement hierarchical methods when assessing determinants of photographic detectability during camera trapping. Methods in Ecology and Evolution 5(1): 44–53. DOI: 10.1111/2041-210X.12115
Caravaggi A., Banks P.B., Burton A.C., Finlay C.M.V., Haswell P.M., Hayward M.W., Rowcliffe M.J., Wood M.D. 2017. A review of camera trapping for conservation behaviour research. Remote Sensing in Ecology and Conservation 3(3): 109–122. DOI: 10.1002/rse2.48
Carvalho W.D., Adania C.H., Esbérard C.E.L. 2013. Comparison of two mammalian surveys made with camera traps in southeastern Brazil, focusing the abundance of wild mammals and domestic dogs. Brazilian Journal of Biology 73(1): 29–36. DOI: 10.1590/S1519-69842013000100005
Chao A., Chiu C. 2016. Species Richness: Estimation and Comparison. Statistics Reference Online Online: 1–26. DOI: 10.1002/9780470015902.a0026329
Coleman B.D., Mares M.A., Willig M.R., Hsieh Y.H. 1982. Randomness, area, and species richness. Ecology 63(4): 1121–1133. DOI: 10.2307/1937249
Colwell R.K. 2013. EstimateS: Statistical estimation of species richness and shared species from samples. Version 8.2. User's Guide and application.
Cusack J.J., Dickman A.J., Rowcliffe J.M., Carbone C. 2015. Random versus Game Trail-Based Camera Trap Placement Strategy for Monitoring Terrestrial Mammal Communities. PLoS ONE 10(5): e0126373. DOI: 10.1371/journal.pone.0126373
Foster R.J., Harmsen B.J. 2012. A critique of density estimation from camera-trap data. Journal of Wildlife Management 76(2): 224–236. DOI: 10.1002/jwmg.275
Gaston K.J. 1994. Rarity. 1st ed. Springer Netherlands. 205 p. DOI: 10.1007/978-94-011-0701-3
Glen A.S., Cockburn S., Nichols, M., Ekanayake J., Warburton B. 2013. Optimising Camera Traps for Monitoring Small Mammals. PLoS ONE 8(6): 1–7. DOI: 10.1371/journal.pone.0067940.
Gotelli N., Colwell R. 2010. Estimating species richness. In: A.E. Magurran, B.J. McGill (Eds.): Biological Diversity: Frontiers In Measurement And Assessment. Oxford: Oxford University Press. P. 39–54.
Habitats Directive, 92/43/EEC. Available from:
Heltshe J.F., Forrester N.E. 1983. Estimating Species Richness Using the Jackknife Procedure Published. Biometrics 39(1): 1–11.
Hubancheva A. 2009. Bats (Mammalia: Chiroptera) of the osogovska planina mountain-results from a survey carried in 2008. Biotechnology and Biotechnological Equipment 23: 72–76. DOI: 10.1080/13102818.2009.10818368
Kauffman M.J., Sanjayan M., Lowenstein J., Nelson A., Jeo R.M., Crooks K.R. 2007. Remote camera-trap methods and analyses reveal impacts of rangeland management on Namibian carnivore communities. Oryx 41(1): 70. DOI: 10.1017/S0030605306001414
Kolowski J.M., Forrester T.D. 2017. Camera trap placement and the potential for bias due to trails and other features. PLoS ONE 12(10): 1–20. DOI: 10.1371/journal.pone.0186679
McCleery R.A., Zweig C.L., Desa M.A., Hunt R., Kitchens W.M., Percival H.F. 2014. A novel method for camera‐trapping small mammals. Wildlife Society Bulletin 38: 887–891. DOI: 10.1002/wsb.447
Michaux J.R., Libois R., Filippucci M.G. 2005. So close and so different: Comparative phylogeography of two small mammal species, the Yellow-necked fieldmouse (Apodemus flavicollis) and the Woodmouse (Apodemus sylvaticus) in the Western Palearctic region. Heredity 94(1): 52–63. DOI: 10.1038/sj.hdy.6800561
O'Brien T.G. 2008. On the use of automated cameras to estimate species richness for large- and medium-sized rainforest mammals. Animal Conservation 11(3): 179–181. DOI: 10.1111/j.1469-1795.2008.00178.x
O'Connell A.F., Nichols J.D., Karanth K.U. (Eds.). 2011. Camera Traps in Animal Ecology: Methods and Analyses. Springer Japan. 271 p. DOI: 10.1007/978-4-431-99495-4
Petrov P., Popova E., Zlatanova D. 2015. Summer food niche comparison between the red fox and genus Мartes in mountain habitats. Annuaire de l'Université de Sofia «St. Kliment Ohridski» Faculte de Biologie 100(4): 291–303.
Petrov P.R., Popova E.D., Zlatanova D.P. 2016. Niche partitioning among the red fox Vulpes vulpes (L.), stone marten Martes foina (Erxleben) and pine marten Martes martes (L.) in two mountains in Bulgaria. Acta Zoologica Bulgarica 68(3): 375–390.
Popova E.D. 2017. Behavioural ecology of mammals studied with camera traps. PhD Thesis. Sofia: Sofia University «St. Kliment Ohridski». 150 p. [In Bulgarian]
Racheva V., Zlatanova D., Peshev D., Markova E. 2012. Camera traps recorded use of sett sites by badgers (Meles meles L., mammalia) in different habitats. Acta Zoologica Bulgarica 64(2): 145–150.
Rovero F., Martin E., Rosa M., Ahumada J.A., Spitale D. 2014. Estimating species richness and modelling habitat preferences of tropical forest mammals from camera trap data. PLoS ONE 9(7). DOI: 10.1371/journal.pone.0103300
Rovero F., Rathbun G.B., Perkin A., Jones T., Ribble D.O., Leonard C., Mwakisoma R.R., Doggart N. 2008. A new species of giant sengi or elephant-shrew (genus Rhynchocyon) highlights the exceptional biodiversity of the Udzungwa Mountains of Tanzania. Journal of Zoology 274(2): 126–133. DOI: 10.1111/j.1469-7998.2007.00363.x
Rovero F., Tobler M., Sanderson J. 2010. Camera trapping for inventorying terrestrial vertebrates. In: J. Eymann, J. Degreef, C. Häuser, J. Monje, Y. Samyn, D. VandenSpiegel (Eds.): Manual on Field Recording Techniques and Protocols for All Taxa Biodiversity Inventories. Brussels: Belgian National Focal Point to the Global Taxonomy Initiative. P. 100–128.
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(2): 148–156. DOI: 10.4404/hystrix-24.2-6316
Séquin E.S., Jaeger M.M., Brussard P.F., Barrett R.H. 2003. Wariness of coyotes to camera traps relative to social status and territory boundaries. Canadian Journal of Zoology 81(12): 2015–2025. DOI: 10.1139/z03-204
Shannon C.E.E. 1948. A Mathematical Theory of Communication. Bell System Technical Journal 27(3): 379–423. DOI: 10.1002/j.1538-7305.1948.tb01338.x
Si X., Kays R., Ding P. 2014. How long is enough to detect terrestrial animals? Estimating the minimum trapping effort on camera traps. PeerJ 2: e374. DOI: 10.7717/peerj.374
Silveira L., Jácomo A.T.A., Diniz-Filho J.A.F. 2003. Camera trap, line transect census and track surveys: A comparative evaluation. Biological Conservation 114(3): 351–355. DOI: 10.1016/S0006-3207(03)00063-6
Smith E.P., Van Belle G. 2010. Nonparametric Estimation of Species Richness. Biometrics 40(1): 119–129. DOI: 10.2307/2530750
Soininen E.M., Jensvoll I., Killengreen S.T., Ims R.A. 2015. Under the snow: a new camera trap opens the white box of subnivean ecology. Remote Sensing in Ecology and Conservation 1(1): 29–38. DOI: 10.1002/rse2.2
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. DOI: 10.1016/j.biocon.2012.12.025
Tobler M.W. 2013. Camera Base 1.6. Available from:
Tobler M.W., Carrillo-Percastegui S.E., Leite Pitman R., Mares R., Powell G. 2008. An evaluation of camera traps for inventorying large- and medium-sized terrestrial rainforest mammals. Animal Conservation 11(3): 169–178. DOI: 10.1111/j.1469-1795.2008.00169.x
Trolliet F., Huynen M., Vermeulen C., Hambuckers A. 2014. Use of camera traps for wildlife studies. A review. Biotechnologie, Agronomie, Société et Environnement 18(3): 446–454.
Vasileva S., Zlatanova D., Racheva V.V. 2005. The food of the Red fox (Vulpes vulpes L.) and the Marten (Martes foina, Erxl) in the spring-summer period in Osogovo mountain. In: B. Gruev, M. Nikolova, A. Donev (Eds.): Proceedings of the Balkan Scientific Conference of Biology in Plovdiv (Bulgaria) (19–21 May 2005). Plovdiv. P. 481–488.
Wegge P., Pokheral C.P., Jnawali S.R. 2004. Effects of trapping effort and trap shyness on estimates of tiger abundance from camera trap studies. Animal Conservation 7(3): 251–256. DOI: 10.1017/S1367943004001441
Zlatanova D., Genov P., Purov V. 2005. Mammalian fauna of Osogovo mountain. In: B. Gruev, M. Nikolova, A. Donev (Eds.): Proceedings of the Balkan Scientific Conference of Biology in Plovdiv (Bulgaria) (19–21 May 2005). Plovdiv. P. 473–480.
Zlatanova D., Racheva V., Peshev D., Gavrilov G. 2009. First hard evidence of Lynx (Lynx lynx L.) presence in Bulgaria. Biotechnology & Biotechnological Equipment 23(sup.1): 184–187. DOI: 10.1080/13102818.2009.10818396.