The effect of season, topography, habitat quality, and gender on sexual and stress hormones in red deer (Cervus elaphus maral)

Abstract

Stress and sexual hormones play a crucial role in the survival of wildlife. Understanding how these hormone levels are influenced by environmental and biological factors is essential for effective wildlife management. This study aims to investigate the impact of season, topography, habitat quality, and gender on the levels of the stress hormone cortisol and the sexual hormones testosterone and progesterone in the red deer (Cervus elaphus maral), a key wildlife species in northern Iran. In summer 2022 and winter 2023, 80 fecal samples were collected from the summer and winter ranges of red deer habitats. The levels of cortisol, testosterone, and progesterone were measured in the laboratory using enzyme immunoassay with specific kits and an ELISA device. Among habitat parameters, total percentage of vegetation was selected, and among topographic parameters, elevation was chosen. The influence of these factors, along with gender and season (winter and summer), on stress and sexual hormones was determined. The results showed that season significantly affected cortisol, testosterone, and progesterone levels, with red deer experiencing greater stress and higher testosterone and progesterone levels in summer compared to winter. Total percentage of vegetation and elevation did not have significant effects on these hormones. There was no significant correlation between cortisol and testosterone or progesterone in red deer. These findings can inform conservation and management plans by considering seasonal variations in stress and sexual hormones for red deer and other deer species worldwide.