Effectiveness of camera traps for maximizing the detection of different species of large and medium-sized mammals: effect of the climatic, environmental, and seasonal conditions

Abstract

Although most mammals live in terrestrial environments, it is difficult to see them in the wild. However, there is a wide variety of techniques for their detection. Currently, camera trapping is the most widely used non-invasive detection technique for terrestrial mammals. Thus, we used this methodology to determine the optimal variables to carry out assessments of mammals by camera trapping in the wild. Therefore, we placed 20 camera traps in Os Montes do Invernadeiro Natural Park (Ourense, Galicia) between 2016 and 2020, resulting in 8044 records, including photographs and videos. We found significant differences in the frequency of records across categories of season, period, lunar cycle, location, habitat and sex. Atmospheric temperature, location, and period were the most influential variables in correlating detection events for different species. A generalized linear model (GLM) analysis revealed a higher number of records in deciduous and pine forests, during summer and autumn, and on nights of waxing and waning moon that holds for both predators, such as Iberian wolf, red fox, pine marten and European wildcat, and prey, such as red deer, wild boar, European roe deer and Iberian hare. Predators were observed more frequently at crossroads, whereas prey tended to avoid these areas. However, it can be stated that there are optimal climatic, such as the temperature, environmental, such as the habitat, and seasonal conditions to carry out camera trapping studies on mammal species. Altogether, understanding the optimal conditions for camera trapping of different mammal species could ultimately reduce the sampling effort.