The abundance of the remaining mammalian fauna and the impacts of hunting in a biodiversity hotspot´s hotspot in the Atlantic forest of north-eastern Brazil

Abstract

Abstract Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no studies to date have evaluated its impacts on the region´s mammalian fauna. For one year we carried out diurnal and nocturnal surveys using the Line Transect method in forest fragments varying from 7.32 ha to 469.76 ha, within a 4,000 ha forest island archipelago. We calculated species density, population size, biomass and synergetic biomass, and recorded direct and indirect human impacts along the study transects. We recorded 44 mammalian species, of which 45.5% (n = 20) went extinct. The smallest forest fragment had the lowest richness (n = 1), diversity (0.0001), population size (n = 10), and total biomass (38.91 kg/km2). It also had no synergetic biomass. The largest fragment had the highest richness (n = 7), total density (279.52 ind./km2), and population size (n = 1,298 individuals). There was a statistically significant relationship between fragment area and number of gunshots heard (r = 0.825, p = 0.022) and suspended hunting platforms found (r = 0.958, p = 0.001); between population size and gunshots heard (r = 0.871, p = 0.011), suspended hunting platforms (rho = 0.896, p = 0.006), free-roaming and feral dogs (r = 0.786, p = 0.036), and between total density and free-roaming and feral dogs (r = 0.783, p = 0.037). After more than 500 years of colonization hunting is still devastating, with larger fragments being linked to more hunters. Higher mammal abundances attracted more free-roaming and feral dogs, which have adapted to hunt wildlife on their own. Unless we protect every single forest fragment and create sustainable landscapes, we will not be able to save this hotspot´s hotspot.