Large-scale occupancy monitoring as a tool for Andean bear (Tremarctos ornatus) conservation in the northern Bolivian Andes

We estimated the occupancy of the Andean bear ( Tremarctos ornatus ) and identified factors influencing its occupancy using simple single-season models and spatial replicates across a 38,145 km 2 area in the northern Bolivian Andes, spanning elevations from 402 to 4,581 m above sea level from the Apolobamba Range to Lambate in the Cordillera Real. This region encompasses portions of two priority conservation areas for the Andean bear. Presence was determined through detection of signs such as tracks, scat, feeding sites, trails, and nests. Occupancy was assessed at two scales: the home range scale (16 km 2 cells with 12 visits in 57 cells) and the habitat use scale (1 km 2 cells with 3 visits in 226 cells). At the home range scale, occupancy probability (ψ) increased with distance from human settlements (β = 2.49), slope (β = 1.40), and elevation (β = 1.31). At the home range scale, overall occupancy for sampled cells was (ψ) was 0.60 (SE = 0.08) with detectability (p) of 0.39 (SE = 0.04). Model-averaged predictions estimated ψ as 0.69 (SE = 0.09) in the study area and 0.66 (SE = 0.12) when extrapolated to the broader Tropical Andes of central and northern Bolivia and southern Peru. Predicted occupancy was higher within priority Andean Bear Conservation Units (ψ = 0.77, SE = 0.08) and protected areas (ψ = 0.80, SE = 0.08) compared to areas outside these units (ψ = 0.54, SE = 0.18) and protected areas (ψ = 0.59, SE = 0.16). At the use scale, habitat use decreased near secondary roads (β = 2.33) and areas with human presence (β = −1.19) but increased near protected areas (β = −0.49). These findings highlight a significant positive relationship between Andean bear presence and protected areas while indicating negative impacts of human activity. The sign-based occupancy approach proved effective and cost-efficient for landscape-scale monitoring, providing valuable insights for conservation decision-making.