Do long-term camera trap sampling designs matter to estimate diel activity?

Effective long-term ecological monitoring (LTEM) is critical for monitoring wildlife activity, yet the consequences of the study design choices on its results are not well established. This study examines how camera trap sampling design influences activity estimates of roe deer and wild boar in Belgium’s National Park Hoge Kempen. We compared two three-year designs: a systematic-random (SYS) and a stratified-random (STRAT) design, differing in camera trap (CT) number, deployment duration, and number of sampled locations. While activity levels were largely consistent across designs, diel activity patterns varied significantly, especially among years. This suggests that the use of different sampling designs in LTEM is not the main driver of differences in activity estimations. Hence, even when different camera trap study designs are applied over time within a long-term monitoring project, wildlife activity patterns can be analysed over the entire study period without loss of validity.