Stable population dynamics of the ocelot (Leopardus pardalis) in well-preserved Atlantic Forest areas

Abstract

Estimating demographic parameters is important for understanding species population trends and dynamics and requires long-term surveys. Estimating these parameters in forested areas for predator populations is a major challenge. The ocelot (Leopardus pardalis) is one of the Neotropical felids most sensitive to human impacts, and information on its population dynamics is scarce. We evaluated the population dynamics of ocelots in Argentina over 14years (2004 to 2018) at the southernmost extent of their range. We examined whether demographic parameters, survival, population growth, turnover, and density varied by sex or sampling year using data from 7 camera-trap surveys conducted in the Atlantic Forest of Argentina. We expected different survival and turnover rates for males and females due to their differential dispersal behavior. We did not expect temporal changes in population growth rate or density since this region has relatively low anthropogenic threats due to the large areal extent of protection. We studied ocelot population trends using spatially explicit open population capture–recapture models. The annual population growth rate was 1.01 (CI=0.98 to 1.03), and did not vary throughout the surveys. The annual adult survival rate was 0.80 (CI=0.75 to 0.84) for females and 0.78 (CI=0.72 to 0.83) for males. Two males survived for at least 12years, and 1 female was at least 19years old at the end of this study. Males showed greater intra- and inter-survey movements, and females showed greater detectability. Density did not vary over time, ranging from 7.85 indiv/100km2 (CI=5.59 to 11.00) in 2010 to 10.53 indiv/100km2 (CI=8.17 to 13.57) in 2016, with overlapping 95% CI for all surveys. These values suggest that the ocelot population in the study area has remained stable over the 14-year period, with low yearly population turnover and relatively high survival rate. Hence, wild ocelot populations inhabiting low human impact areas can be very stable over 2 generations. Our results established a reliable baseline for future comparisons in order to evaluate the effects of landscape fragmentation and other threats (e.g., poaching) on ocelot population dynamics.