Relationship between human pressure and activity patterns in marsh deer (Blastocerus dichotomus) populations

BERTO, D. O.; BRACK, I. V.; COELHO, I. P.; OLIVEIRA, L. F. B.; ROSA, A. O.; OLIVEIRA, R.; PERES, P. H. F. ; DUARTE, J. M. B.; FRAGA. A. R.; CONCONE, H. V. B.; ESTRELA, P. C.; IEZZI, M. E.; DI BITETTI, M. S.; KINDEL, A.

Virtual meeting

Congreso; 100th Annual Meeting of the American Society of Mammalogists; 2021

American Society of Mammalogists

Mammals can change their behavior as a response to human presence. Temporal segregation is an expected response to avoid humans, through an increase in nocturnal activity or a decrease in their activity level. The marsh deer inhabits wetlands in South America. Threatened by poaching and habitat loss, the remaining populations occur far from each other. We evaluated the relationship of two circadian activity metrics i) nocturnal activity and ii) activity level to four predictor variables (human influence index (HII), presence of predators, presence of poaching and latitude) of different populations of the marsh deer. Were used camera trap records from six populations in Brazil and Argentina. We estimated activity patterns of each population using kernel probability densities and calculated the two response variables. We performed beta-regressions to analyze the relationship of the response variables with the predictors. Nocturnal activity varied from 19% to 68% among populations and the activity level between 32% to 68%. We found a positive and significant relationship between HII and marsh deer nocturnal activity, but no relationship with the level of activity and predictors. Deer populations with greater human disturbance in their surroundings are more nocturnal, possibly as an adaptation to avoid risks and disturbances from human activities. Even so, these populations did not present shorter activity levels, which can enable them to perform vital functions such as foraging and reproduction.