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Monitoring trends in the occurrence of species over time is important for informing conservation plans and concurrent management actions. Understanding the effectiveness of field methodologies for collecting accurate and precise data is crucial for optimizing allocation of sampling effort and resources. In this study, we compared mammalian species richness and detection probabilities between three field methodologies: line transects, ground camera traps and arboreal camera traps in Nyungwe National Park, Rwanda. Arboreal camera traps may be suitable for monitoring mammal communities with arboreal species, but their relative effectiveness compared to the more common field methods, line transects and ground camera traps, is relatively unknown. Using single‐season occupancy models with multi‐species data and single‐species multi‐method occupancy models, we estimated mammalian species richness and detection probability for each method and combination of methods. In addition, we estimated single‐species occupancy and detection probability by method for six diurnal primate species. And, we tested for the effect of height on a tree on estimated occupancy probability and detection probability for arboreal camera traps. Overall, for all species the combination of ground and arboreal cameras was the most effective methodology in terms of highest estimates of occupancy and detection coupled with highest precision. However, for the six primate species the most effective method differed between species. The height of the arboreal camera trap in the tree did not significantly affect estimates of occupancy or detection. We suggest using all three field methods concurrently to maximize detection of all species; however, if only two methods can be deployed combining arboreal and ground cameras provided the highest and most precise estimates of occupancy and detection. The addition of arboreal camera traps could improve detection of species and improve future species monitoring programs. [ABSTRACT FROM AUTHOR]

Exploring trends in species richness and the distribution of individual species over time as well as the factors affecting these trends informs conservation priorities in protecting species and ecosystems as a whole. We used data from 41 park‐wide line transect surveys in 2009 and 2014 and multi‐season occupancy models with multi‐species data to explore trends in species richness and distribution of individual species and factors affecting these trends in Nyungwe National Park (NNP), Rwanda. Mammalian species richness and the distributional range of 5 of the 7 species increased between 2009 and 2014 in NNP. The probability of colonization of a species into a new area in 2014, where it was not present in 2009, was highest in sites with a lower probability of poaching activity, close to tourist trails, and at lower elevations. The probability of colonization with no poaching activity was about 50% but dropped to about 10% with a 100% chance of poaching activity. Duiker species had the largest increase in distribution during the study, while there was a decrease in the distribution of the eastern chimpanzee and blue monkey. Our results suggest that increased patrols could be implemented in areas of the park with low species richness and areas with a low probability of occurrence for species of conservation concern to combat poaching activity and thus increase the probability of a species moving into a new area. Our use of a single multi‐season model for multiple species explicitly accounts for imperfect detection and species‐specific identities, while allowing for inferences to be made about rarely detected species by sharing covariates with common species. These results can be used to improve conservation planning in NNP for species management and ranger patrol protocols, and our modelling framework is broadly applicable to any protected area with presence/absence species field data. [ABSTRACT FROM AUTHOR]