Avoiding misleading messages: Population assessment using camera trapping is not a simple task

Abstract

Population assessment is indispensable for appropriate and socially acceptable conservation and management of wildlife populations. This article critiques the paper by Campos‐Candela et al. 2018 and highlights issues that could lead to inappropriate management and conservation policies.

Response to Abolaffio et al. (2019): Avoiding misleading messages

“…In the BRW model used, when the drift force equals 0, the movement reduces to a random walk diffusion model (Codling et al, ). Equalling the stochastic term to 0, as Abolaffio et al () discussed, will lead to a linear trajectory towards the HR centre, where the animal will remain forever, which is not biologically meaningful. In any case, a BRW with a Gaussian stochastic component is the simplest choice for simulating animal trajectories but any other movement model meeting the requirement of stationary criteria should be considered when addressing the particularities of a given species.…”

“…Evaluating absolute population density is an extremely complex task that requires strengthening the links between theorists and empiricists. Both, Campos‐Candela, Palmer, Balle, and Alós () and Abolaffio, Forcadi, and Santini (), contributed to this challenge from the theoretical side; the first one by demonstrating a theoretical postulate to estimate absolute densities from camera counts; the second one by exploring the proposed method for a specific species (the moose, Alces alces ). Note, however, that the undifferentiated use of model , method and simulation terms in Abolaffio et al (), when addressing concerns exclusively about our simulation procedure or the applicability of the method for a particular case, may be misleading.…”

“…Accordingly, our reported simulation results should be interpreted as a general guidance and not as species‐specific recommendations. Likewise, the work by Abolaffio et al () should be considered an improved simulation exercise that takes into account several species specificities but, even so, it may still leave behind some other hidden particularities of the system. Therefore, even after improving simulations, a pilot study is required to properly evaluate the applicability of the method when confronted with the real cases of study and decide whether the use of cameras is feasible or may complement other methods (e.g., mark‐and‐recapture, animal tracking, environmental DNA).…”

“…Instead, we proposed a specific protocol to evaluate the feasibility of our theoretical approach and its usefulness for any given case in the ‘real world’. Therefore, the statement in Abolaffio et al (): ‘Ideally, the method proposed by CC is perfect for wildlife managers: easy to use and cheap’ constitutes itself a deceiving message out of its original context. Their claim, quoted here: ‘[…] the proposed statistical method […] is not recommended for the use by wildlife managers and practitioners’, is exaggerated and misleading in itself.…”

“…Their claim, quoted here: ‘[…] the proposed statistical method […] is not recommended for the use by wildlife managers and practitioners’, is exaggerated and misleading in itself. In fact, the improved simulation work developed in Abolaffio et al (), which considers speed in a more mechanistic way and includes variability in the movement patterns, is framed in the explicit recommendations given in our previous work.…”