Abstract 277 – Demography of a poorly-known large carnivore population at the range edge: Andean bears in the equatorial dry forest of north-western Peru.

Robyn Appleton, Alexander More, Mathias Tobler

We report for the first time estimated survival, reproduction, and population growth rates for
individually-identified Andean bears (Tremarctus ornatus) in equatorial dry forests of northern
Peru, an area recorgnized as a global biodiversity hotspot. We used 15 years of re-sighting data
to parameterize spatial capture-recapture (SCR) models and population viability analyses (PVA)
to identify the demographic rates most influential of population growth and extinction risk. To
do so, we collated 8,262 observations of 73 bears from 2008 to 2022 within our 350 km2 study
area, using camera trap grid to estimate density (SCR), and repreated observations at focal
waterholes and dens to estimate age-specific survival and fecundity. We estimated bear density
at 7.1 (± 1.3) / 100 km-2, and annual survival probabilities for cubs (<12 months) (0.40 ±),
juveniles (1-2 years) (0.72 ±) and subadults (2-3 years) (0.82 ± ), and adult (4 years) females
(0.88 ±), and adult males (0.90 ± ). Model estimates of lambda (0.88 ± ) and mean time ot
extinction (18.6 yrs ± ) therefore suggest an urgent need to enhance demographic performance
and/or facilitate continued immigration into this range-edge population. Sensitivity analyses
indicated that female survival had the largest influence on estimated population growth.
Because female and cub survival and reproductive success were low relative to other bear
populations globally, our results suggest population growth may be limited by the effects of
food quality or quantify on maternal condition and exacerbated by anthropogenic factors
limiting access to food resources in the dry season. Our findings underscore an urgent need for
landscape-level planning aimed at conserving and restoring habitats essential to the persistence
and movement of large carnivores in this global biodiversity hotspot.