Prey abundance drives habitat occupancy by jaguars in Amazonian floodplain river islands

Abstract

The jaguar (Panthera onca) is widely distributed across a broad range of habitat types, where its feeding habits and habitat use patterns vary significantly. The jaguar and its main arboreal preys -the brown-throated sloth (Bradypus variegatus) and the red howler monkey (Alouatta juara) -are widespread in the Amazonian floodplain forests Mamirauaó Reserve. These forest-dwelling species are the most common mammal species both in the continuous forest and the forest patches surrounded by a river matrix -the fluvial islands -at Solimoã es and Japuraó rivers. We used sign surveys along line-transects to assess the pattern of habitat occupancy by jaguars in Amazonian floodplain forests. Specifically, we (i) tested whether habitat occupancy by jaguars differs between river islands and continuous forest;and (ii) evaluated whether and how the local abundance of sloths and howler monkeys influence the probability of site occupancy by jaguars. We built an occupancy model and used Bayesian inference to reach these goals. The proportion of sites estimated to be used by jaguars was ψ = 0.75 (HPD95: 0.36-1.00), and it did not differ between islands and continuous forest. The abundance of both prey species had a direct influence on jaguar's habitat use, whereas the aquatic matrix seems to have a negligible effect on the use of islands by jaguars. We conclude that prey search modulates jaguars' habitat occupancy patterns with both prey species having a similar effect. This finding reinforces the importance of sloths to the diet of jaguars in the study region despite its lower abundance than howlers. Finally, we suggest that sign surveys are an alternative method to assess the pattern of jaguar habitat occupancy in floodplain forests.

Total mercury in wild felids occurring in protected areas in the central Brazilian Amazon

“…The species P. onca and L. pardalis presented the highest Hg concentrations. The main diet components of P. onca are caimans (Caiman crocodilus Linnaeus, 1758 and Melanosuchus niger Spix, 1825), which are associated with várzea-lake environments (Ramalho and Magnusson 2008;Rabelo et al 2019). There is no study concerning dietary habits of L. pardalis in the study areas.…”

Artificial refuges to combat habitat loss for an endangered marsupial predator: How do they measure up?

“…The lack of potential mammal prey at artificial dens is important, as small marsupials and rodents can make up a large portion of northern quoll diet (Dunlop et al, 2017), and predators often use habitat based on the availability of prey (Gallant et al, 2014; Khalatbari, Yusefi, Martínez‐Freiría, Jowkar, & Brito, 2018; Rabelo, Aragon, & Bicca‐Marques, 2019). The most commonly recorded mammal prey in this study was the common rock‐rat ( Z .…”

Wildfires Disproportionately Affected Jaguars in the Pantanal

“…2, 3). Jaguars are apex predators, often considered as a keystone [50][51][52][53] and umbrella species 40,54 , highly dependent on large habitat areas 55 , dense native vegetation cover 32,56,57 , and abundance of prey 58,59 . Considering that jaguars often select areas with high environmental integrity, the higher impact of recent fires on HRs corroborates reports showing that 43% of the 2020 burned area (≈13% of the Pantanal) had not been burnt since 2000 16 .…”