The Relationships of Season, Climate, Habitat, and Sex Variables With Fecal Cortisol, Progesterone, and Testosterone Metabolite Concentrations in Roe Deer

ABSTRACT Monitoring cortisol, progesterone, and testosterone metabolite levels is pivotal for wildlife management, as these hormones regulate how species respond to environmental changes and reproductive functions. Environmental and biological variables can markedly alter metabolite levels, affecting the health, survival, and reproductive success of wildlife populations. This study explored how season, climate, topography, habitat quality, and sex relate to fecal cortisol, progesterone, and testosterone metabolite concentrations in roe deer ( Capreolus capreolus ) within Kiasar National Park and Wildlife Refuge, Mazandaran Province, northern Iran. Between 2023 and 2024, we seasonally collected 50 fresh feces samples and quantified fecal metabolite concentrations using commercial enzyme immunoassays (EIAs). We assessed habitat quality using the Normalized Difference Vegetation Index (NDVI), topography via elevation, and climate through monthly temperature and precipitation data. We then analyzed these variables, alongside sex and season, to determine their relationships with fecal metabolite concentrations. Fecal cortisol metabolite concentrations varied significantly by season, reaching their lowest levels during the summer. Males exhibited higher fecal cortisol metabolite concentrations than females; these concentrations increased with NDVI but showed no relationship with elevation, temperature, or precipitation. Fecal progesterone and testosterone metabolite concentrations varied seasonally: testosterone concentrations declined significantly in summer and autumn, while progesterone concentrations peaked in summer. Elevated NDVI and altitude reduced fecal testosterone metabolite concentrations in males, but these variables showed no relationship with fecal progesterone metabolite concentrations in females. We found no correlations between steroid hormone metabolite concentrations. These insights are crucial for informing conservation strategies, population management, and animal welfare protocols, while also advancing our understanding of roe deer evolutionary adaptations under varying environmental pressures.