Search

Wildlife monitoring is of fundamental importance to establish baseline information, measure population changes, and extinction risk. Motion‐triggered camera traps are an increasingly popular tool for monitoring terrestrial species over large landscapes. Over the years, occupancy has become a robust and unbiased state variable to monitor species worldwide. However, the optimal sampling design required for robust estimations of occupancy is lacking for many species. Here, we estimated the optimum sampling design by varying the number of sites (50–400) and sampling days (10–25) for a range of mammal species using camera‐trap survey data from central India. We used power analysis and mean‐squared error and evaluated the hypothesis of how various species‐specific traits influence occupancy and detectability of the species. We found that mean‐squared error changed significantly with the number of sampling sites for rare species, whereas for species with moderate and high detection probability, the mean‐squared error changed significantly with the number of sampling occasions. Power increased with an increase in the number of sampling sites and occasions for all species, although the change was not significant for species with higher occupancies or detection probabilities. We found that body size was positively related to occupancy but did not influence detection probability significantly. No relationship was detected with social status or diet on occupancy or detection probability. Our results suggest a minimum of 50 sites for 15–20 d for common species and 100 sites for 20–30 d for rare, elusive species. Our results provide guidelines to managers and practitioners for effective allocation of cost and sampling effort for a wide variety of terrestrial mammals in camera‐trap surveys. [ABSTRACT FROM AUTHOR]

The Lao People's Democratic Republic (PDR) may have the largest Asian elephant population in Indochina. However, elephants on Lao PDR's Nakai Plateau are potentially threatened by the construction of a hydropower dam that will flood important habitat. We conducted a non-invasive genetic study of elephants in this region to provide baseline data on genetic diversity and social structure prior to dam construction. For the 102 elephants we detected, values of observed heterozygosity (0.711) and allelic diversity (8.0 alleles/locus) at microsatellite loci were higher than those found in elephant populations in India and Vietnam, while mitochondrial diversity (haplotype diversity 0.741; nucleotide diversity 0.011) was similar to that reported for the Lao/Vietnam region. Six mitochondrial haplotypes were detected, representing both major clades previously reported in this species. Relatedness estimates between females and young detected near each other are consistent with familial relationships, and relatedness estimates between adult males and females suggest male locational dispersal. Since family group structure appears to be intact in the Nakai region, these elephants will likely move as relatively large family groups in response to habitat disturbance. These results have positive implications for the viability of the elephant population in this region, demonstrate its conservation significance, and will be valuable for predicting and monitoring the effects of the hydropower dam over time. [ABSTRACT FROM AUTHOR]