Seven years of monitoring the demography and population density of jaguars (Panthera onca) in a human-modified landscape of eastern Amazonia

Abstract

The primary impacts of mining on wildlife are habitat loss and fragmentation, which reduce the availability of essential resources and disrupt ecological processes necessary for species persistence. Despite the growing expansion of mining activities in tropical regions, their effects on large mammals remain poorly understood. We used an open population, spatially explicit capture–recapture model to analyze jaguar ( Panthera onca ) population density and dynamics in a degraded landscape surrounding a bauxite mining area in eastern Brazilian Amazonia based on seven years (2014 to 2020) of continuous camera-trap monitoring data. We predict that the population declined or, at best, remained stable throughout the study, and that the area will harbor a relatively low jaguar density compared to nearby or similar areas due to active mining operations and the degraded state of most remaining forests. We identified individual jaguars by their unique spot patterns. We captured 24 individuals at least once across 125 detection events. The best model had encounter rate as a function of trap location (on-road/off-road), shifts in activity centers between sessions, and constant survival (φ) and recruitment (f). The population dynamics in the open-population model were characterized by high apparent survival (mean φ = 0.93) and low per capita recruitment (mean f = 0.07). The finite population growth rate was near zero (𝛌 = 1.007), and the population remained essentially stable across the study (mean 2.04 individuals/100 km 2 ). In the multisession, closed-population model, population density fluctuated from 1.24 to 3.27 (mean = 2.18) individuals/100 km 2 . The population density was low but stable, as predicted, but with very low recruitment. The study provides a rare and valuable long-term assessment of jaguar ecology in a mining landscape.