Ecology and habitat utilization of leopard tortoise (stigmochelys pardalis) in Southern Kruger National Park

Abstract

This study investigated seasonal changes in habitat selection and movement patterns for Stigmochelys pardalis in the southern Kruger National Park. The aim of the study was to collect information on the ecology of S. pardalis in the KNP to facilitate conservation of this species by park authorities. Since no existing research is available for S. pardalis in KNP, this study also aims to provide baseline data on the ecology and habitat utilisation of S. pardalis. South Africa has the most diverse tortoise fauna of any country in the world, containing six genera and 13 species. This study focused only on S. pardalis, the largest and most abundant species of tortoise in the KNP. Seven S. pardalis were fitted with radio transmitters for monitoring their habitat selection and daily distances travelled over a 12- month period, covering both a warm wet and cold dry season. Data were used to estimate seasonal home range sizes, daily distances travelled and movement activity across three daily periods. Findings indicated seasonal shifts in home range utilization and daily distances travelled, with longer daily distances travelled and larger home range sizes in the warm wet months, compared to the cool dry months. Warm wet season daily distances travelled were typically between 20 and 120 m, and dry season distances were rarely further than 80 m, being mostly within the 20-80 m range. The effects that environmental variables (temperature, rainfall and photoperiod) had on daily distances travelled were also investigated and results show that the study tortoises travelled longer distances in the early morning and late afternoon periods when ambient temperatures are not too hot or too cold. Although the study tortoises moved around on warm nights, their distances travelled decreased during the cold period when temperatures were at their lowest. Daily distances travelled were further during the warm wet season for all daily periods and could be attributed to increases in daily temperatures and rainfall, which results in tortoises no longer bromating and becoming active after the cold, resource scarce dry season.