Elusive felids of lowland Amazonia: Assessing the effects of human disturbance across an unprotected landscape

Abstract

Rapid human population growth and land conversion in the Amazon rainforest have caused extensive habitat fragmentation and defaunation, affecting threatened mammals, yet their response remains understudied. To bridge this gap, I assessed the impact of human disturbances on terrestrial mammals in an unprotected area of Madre de Dios, Peru. Over eight years (2015-2022), I conducted a camera trap study on 17 terrestrial mammal species, including predators and prey, with 14,849 captures across 293 sites. Using occupancy models, I gauged the influence of ecological and anthropogenic factors on species occupancy and detection. Human disturbances notably affected mammal species, particularly persecuted ones such as jaguars (Panthera onca), tapirs (Tapirus terrestris), brocket deer (Mazama spp.), collared peccaries (Pecari tajacu), and agoutis (Dasyprocta variegata). These species displayed significant changes in occupancy probability based on proximity to settlements, agriculture, and land use type. Additionally, white-lipped peccaries (Tayassu pecari) remained undetected for seven years. I also studied the spatiotemporal overlap of five sympatric felid species: jaguars, pumas (Puma concolor), ocelots (Leopardus pardalis), jaguarundis (Herpailurus yagouaroundi), and margays (Leopardus wiedii). Temporal overlap was high due to nocturnal activity, except for the diurnal jaguarundi. Increased human activity led to reduced temporal overlap. Conditional occupancy models revealed that felid co-occurrence was influenced by dominant species, size differences, distance from settlements, rivers, and prey index/habitat quality. While intact Amazon rainforests support fine-scale niche differentiation among felid guilds, heightened disturbances could disrupt resource availability, affecting intraguild interactions, ecosystem structure, and function. Additionally, I explored the impact of human activity on ocelot density and temporal activity. Density remained unchanged across the mixed-use and protected areas, however, there was a significant difference in the overlap estimates of ocelot and human activity between the two areas. In conclusion, my findings underscore the vital importance of conserving intact forests in lowland Peruvian Amazonia. Targeted conservation measures like expanded protected forest buffers along rivers are essential to mitigate the negative effects of human activities in the Amazon rainforest. Given ongoing anthropogenic disturbance in the neotropics, further research is imperative to grasp the demographic dynamics of vulnerable mammals in human-modified areas.