Evaluating species-specific responses to camera-trap survey designs

Camera traps are widely used to collect information on the distribution and abundance of multiple species simultaneously. However, we still lack important guidance for designing camera-trap surveys monitor species, consequences species-specific responses survey design strategies often overlooked. Using data collected ten medium-to-large North-American carnivores in northern Minnesota, USA, between 2016 2018 (23 337 active trap-days), evaluated: 1) two different survey-design frameworks (random- versus road-based), 2) lure types (salmon oil fatty acid scent oil), 3) placement (completely random randomly-selected sites with feature-based placement), 4) timing (spring fall) 5) temporal trends daily encounter probabilities. generalized linear mixed models, found evidence differential all these strategies. For 9 out 10 strong frameworks: red foxes Vulpes vulpes, coyotes Canis latrans, bobcats, Lynx rufus, striped skunks Mephitis mephitis, wolves C. lupus gray Urocyon cinereoargenteus, had estimated frequencies that were 9- 106-fold higher at unlured along secondary roads; black bears Ursus americanus, martens Martes americana fishers Pekania pennanti 15- > 3600-fold lured, randomly selected sites. six salmon provided 2- 4-fold more encounters than oil, but feature-basedplacement only improved detections fishers. Daily probabilities differed spring fall usually decreased slightly within each sampling period Our study confirms even similar-sized or closely-related respond differently choices. To maximize frequencies, recommend multi-species studies use a mix include features during statistical analysis.