Mammalian defaunation across the Devonian kniferidges and meridional plateaus of the Brazilian Atlantic Forest

The vast majority of empirical studies on regional mammal defaunation across the Atlantic Forest biome of South America are concentrated in Southeastern and Northeastern regions. Thus, the lack of empirical information on the medium- to large-bodied mammal population declines across the subtropical region of this tropical biome and its major causes are paramount to conservation efforts. We investigate the influence of land use on mammal defaunation across the subtropical Atlantic Forest by sampling 91 points using 65 camera-traps installed for five consecutive years—totaling an effort of 30,189 camera-trap-days. We observed that the average defaunation across the Devonian Kniferidges Environmental Protection Area meta-region (spanning over subtropical Atlantic Forest plateaus) was 42% (D = 0.42; ± 0.17) when compared to presumed assemblages of historical times going back to the Pre-Columbian era (ca. 500 years ago). The main landscape predictors of regional defaunation were silviculture and agriculture, once the highest defaunation indexes were concentered in sites intensely human-modified by these features. Protected areas had significantly lower defaunation indexes in comparison with the unprotected areas. Although our results of defaunation were 29.2% lesser than the average for the entire biome, the negative consequences of regional defaunation on ecosystem services are already occurring, once two in each five local species presumably are locally extinct or present low abundances (i.e. functionally extinct). Given that habitat conversion is the primary cause of global biodiversity decline, our results reinforce that biodiversity conservation is still strongly dependent on natural protected areas networks.