Jaguar (Panthera onca) density and population size across protected areas and indigenous lands in the Amazon biome, its largest stronghold

Protected areas, including Indigenous Lands, play a critical role in protecting natural habitats and wildlife. The Amazon has a remarkable network of protected areas and is home to the largest population of the Neotropics' largest felid, the jaguar ( Panthera onca ). Yet, knowledge of the population status of jaguars across the biome is scarce. In this article, we use camera trap data combined with multi-session spatial capture-recapture models to estimate site-independent jaguar densities in 22 protected areas. Additionally, we tested for density spatial variation based on anthropogenic and biological variables, predicting approximate jaguar population size for each protected area sampled. The estimated average density of jaguars across our sites was 3.08 ± 1.13 individuals per 100 km 2 but density estimates varied more than 20-fold from 0.60 ± 0.50 ind./100 km 2 in the Lower Negro River (Cuieiras Biological Reserve) to 9.97 ± 2.48 ind./100 km 2 in the várzea floodplains of the Amazon River (Sustainable Development Reserve Mamirauá). Our results revealed that the highest densities of jaguars occur in regions with higher primary productivity and that all 22 protected areas combined harbour an estimated jaguar population size of 6389 individuals (95 % CI: 4664-7986), highlighting the importance that protected areas have for the conservation of this emblematic species. We contend that implementing continuous monitoring programs across Amazonian protected areas and curbing escalating anthropogenic pressures is paramount to ensure these areas remain as a stronghold for the species.