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PROTECTED AREAS AND NATIVE FORESTS BUFFER ENDANGERED MAMMALS FROM CHANGING THEIR PERIOD OF ACTIVITY IN DISTURBED LANDSCAPES OF THE BRAZILIAN CERRADO
Anthropogenic disturbances can cause behavioral changes in wild species, including spatial modifications in their habitat use and temporal displacement in their activity period. Recently, a growing number of studies report mammal species becoming more nocturnally active in response to the human footprint. The Brazilian Cerrado is a savannah hotspot that lost half of its original extent in the last 50 years. In the economically richest state of Brazil, São Paulo, where a third of the Brazilian ethanol is produced, this vegetation domain was reduced to 8.5%, of which only 6.5% is in protected areas. Notwithstanding this habitat transformation, how different land cover types, including native and man-made, influence the activity period of mammals remains little studied. We explored this information gap assessing if the proportion of nocturnal records varied in response to potential covariates. We used data from nine species of mammals recorded in 205 camera trap stations from three landscapes in the northeastern São Paulo state. We first categorize each record (filtered to 10-minute intervals) into nocturnal or diurnal (daytime plus twilight) for nine species having enough records: nine-banded armadillo (Dasypus novemcinctus), giant anteater (Myrmecophaga tridactyla), ocelot (Leopardus pardalis), maned wolf (Chrysocyon brachyurus), tayra (Eira barbara), puma (Puma concolor), collared peccary (Pecari tajacu), brocket deer (Mazama gouazoubira) and agouti (Dasyprocta agouti). We then performed binomial (logit link) Generalized Linear Models (GLMs) representing a fixed set of priori hypotheses. Our response variable was the proportion of nocturnal records and the tested predictors were: sampling station within protected areas (1, otherwise 0), % of native vegetation in a 200-ha buffer around the sampling station, distance to the nearest human household, and average monthly temperature. We ranked models with AICc and assessed the effect of covariates examining their estimated slope (betas) and corresponding 95% confidence intervals (hereafter CI). Six species either had the null model (intercept only model) as the best ranked (nine-banded armadillo, tayra, and agouti) or showed a weak effect of predictors, i.e., slope betas overlapping zero within their estimated CI (ocelot, maned wolf, and brocket deer). The remaining three species, all of conservation concern (giant anteater, puma, and collared peccary) were affected by the location of the sampling station (giant anteater and puma) or by the amount of native vegetation in the buffer (peccary). The proportion of nocturnal records is higher outside than inside protected areas for pumas (β= -0.70, IC= -1.403 to -0.0064) and giant anteaters (β= -1.63, IC= -2.32 to -0.94) and the peccary becomes less nocturnal the higher the percentage of native vegetation in the surroundings (β= -0.019, IC = -0.0389 to -0.0002). Our results show that three mammal species, all of which vulnerable to extinction regionally or nationally, are temporally changing their activity period, becoming more nocturnal in places with higher exposure to anthropogenic activity or less covered by native vegetation. We conclude that some species exhibit behavioral plasticity to avoid or minimize temporal overlap with humans and that protected areas and native vegetation are “reservoirs” of undisturbed behavior in biofuel producing zones.
puma, giant anteater, peccary, behavioral plasticity, Anthropocene
This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP 2011/22449-4). We would like to thank Dr. Aurelio Fontes for its support with Geographic Information Systems and mapping; the Instituto Geográfico Cartográfico do Estado de São Paulo (IGC) for providing orthophotomosaic images, and the University of São Paulo, the International Paper Co. of Brazil, the Instituto Florestal, and the Fundação Florestal for logistical support.
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