Research overview: sampling effort and trap-nights in camera-trap studies

Trap-nights, the number of cameras multiplied by the days each is active, are the basic currency of camera-trap survey effort, and this overview examines how effort governs what a study can reveal. It explains species-accumulation curves showing that rare and elusive cats require far more trap-nights to detect than common species, how effort must be balanced between deploying more stations and running them longer, and how insufficient effort yields too few captures for reliable capture-recapture or occupancy estimates. It discusses standardizing effort for fair comparison across sites and seasons, and the demographic-closure tension between surveying long enough to gather data yet short enough that the population stays constant. Practical guidance helps researchers and photographers plan deployments that meet their detection and estimation goals efficiently.