Diana P. Zlatanova, Associate Professor, Sofia University «St. Kliment Ohridski», Faculty of Biology, Department of Zoology and Anthropology (8 Dragan Tsankov blvd.,1164 Sofia, Bulgaria); e-mail:
Elitsa D. Popova, Sofia University «St. Kliment Ohridski», Faculty of Biology, Department of Zoology and Anthropology (8 Dragan Tsankov blvd.,1164 Sofia, Bulgaria); e-mail:

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): 13–25.

Section Research 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

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Received: 31.01.2018

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