
Abstract: "Decision-makers in wildlife policy require reliable population size 
estimates to justify interventions, to build acceptance and support in 
their decisions and, ultimately, to build trust in managing authorities.
 Traditional capture-recapture approaches present two main shortcomings,
 namely, the uncertainty in defining the effective sampling area, and 
the spatially-induced heterogeneity in encounter probabilities. These 
limitations are overcome using spatially explicit capture-recapture 
approaches (SCR). Using wolves as case study, and non-invasive DNA 
monitoring (faeces), we implemented a SCR with a Poisson observation 
model in a single survey to estimate wolf density and population size, 
and identify the locations of individual activity centres, in NW Iberia 
over 4,378 km2. During the breeding period, posterior mean wolf density was 2.55 wolves/100 km2
 (95% BCI=1.87–3.51), and the posterior mean population size was 
111.6 ± 18.8 wolves (95% BCI=81.8–153.6). From simulation studies, 
addressing different scenarios of non-independence and spatial 
aggregation of individuals, we only found a slight underestimation in 
population size estimates, supporting the reliability of SCR for social 
species. The strategy used here (DNA monitoring combined with SCR) may 
be a cost-effective way to generate reliable population estimates for 
large carnivores at regional scales, especially for endangered species 
or populations under game management."
Read More: "https://www.nature.com/articles/s41598-018-20675-9"