Abundance, Density and Relative Abundance: A Conceptual Framework

  • Timothy G. O’Brien


In the early 1990s, biologists began experimenting with camera traps to estimate the abundance of tigers Panthera tigra in the Nagarahole National Park (Karanth 1995), marking the first time that camera traps were used to sample a wildlife population in a statistically rigorous manner. Since that time, camera traps have been employed for a wide variety of uses in behavioral and ecological studies. Camera trap studies can result in capture histories of species whose members are individually recognizable via distinct natural traits or artificial markings (e.g. radio collars, tags) as well as capture histories of species that are not reliably identified as individuals. In either case, dependent on study objectives, each type of data may be used to estimate population size, species richness, site occupancy or relative abundance indices. In addition, well-designed camera trap studies usually include data on covariates at the sites where the cameras are set. Ideally, covariates are chosen based on their purported influence on abundance or other parameters of interest, including detectability (White 2005). The challenge to biologists is to use these data to the greatest extent possible, to make unbiased inferences about the state of the target wildlife population under investigation.


Home Range Detection Probability Capture Probability Camera Trap Capture History 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



I thank K.U. Karanth, M.F. Kinnaird, J.D. Nichols, and A.F. O’Connell for many helpful comments that greatly improved the content and structure of the manuscript. I also thank The Wildlife Conservation Society and J. Ginsberg, E. McBean, A. Rabinowitz and J. Robinson for support during the preparation of this manuscript and, more importantly, for support of efforts to expand the application of camera trap methods in conservation biology.


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Copyright information

© Springer 2011

Authors and Affiliations

  1. 1.Wildlife Conservation SocietyBronxUSA
  2. 2.Mpala Research CentreNanyukiKenya

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