Infodoc : Sciences, Techniques et Culture

Introduction : The elusive behaviour of rainforest large vertebrates combined with the inaccessibility of their habitat makes their study challenging (Sollman et al., 2011). Estimations of population size only based on direct observations are therefore infeasible and alternative methods must be used. Since the 1990’s, the use of camera-traps as observer substitute has greatly increased and concerns studies on a wide range of rainforest species or communities (Trolliet et al.,2014) such as the tiger (Karanth, 1995), the puma (Bauer et al., 2005), the ocelot (Trolle and Kéry, 2013), the tapir (Tobler et al., 2013), mammals, (Griffiths and van Schaik, 1993), birds and mammals (Campo et al., 2012), rodents (Nyiramana, 2011). The space which these animals use is also difficult to evaluate [...]

Introduction : The elusive behaviour of rainforest large vertebrates combined with the inaccessibility of their habitat makes their study challenging (Sollman et al., 2011). Estimations of population size only based on direct observations are therefore infeasible and alternative methods must be used. Since the 1990’s, the use of camera-traps as observer substitute has greatly increased and concerns studies on a wide range of rainforest species or communities (Trolliet et al.,2014) such as the tiger (Karanth, 1995), the puma (Bauer et al., 2005), the ocelot (Trolle and Kéry, 2013), the tapir (Tobler et al., 2013), mammals, (Griffiths and van Schaik, 1993), birds and mammals (Campo et al., 2012), rodents (Nyiramana, 2011). The space which these animals use is also difficult to evaluate as they generally range widely. Consequently, it is hard to estimate population density. Accurate and precise estimates of density are of paramount importance for the identification of wildlife reservoirs on which conservation efforts must focus, as well as the long-term monitoring of these populations to assess conservation action efficiency. This study assesses the current camera-trapping methodology employed by conservationists to estimate density of these populations by studying the impact of study period and choice of statistical method.The largest mammal predator of the Americas, the jaguar (Panthera onca, Linnaeus, 1758), is an excellent case study to illustrate this issue. Typically, this predator inhabits dense second-ary rainforest (Caso et al., 2008). In addition to being elusive, the jaguar is solitary and mostly nocturnal (Harmsen et al., 2010b). Because direct observations in rainforest are scarce, current knowledge on jaguar ecology and ranging behaviour is very limited.
[…] In summary, we focus our study on density estimations for elusive populations through a jaguar camera-trapping dataset, and the possible influence of time and SECR model parameterisation on these estimations. It completes the study of Harmsen et al. (in press.) on temporal variations in abundance estimates, which used the same dataset on the CBWS jaguar population. We finally explore the relation between the size and overlap of jaguar HRs with the population density, which is of paramount importance to understand temporal variations indensity.