Fire-associated reptile mortality in Tembe Elephant Park, South Africa

Abstract

Background: Even though fire has been used extensively as part of conservation management in South Africa, its impact on the life history and mortality of fossorial reptiles is poorly documented. We conducted post-fire transects after three controlled burns during different seasons in Tembe Elephant Park, recorded 14 reptile species, and found fewer mortalities in winter compared to spring. Results: Histopathological examinations of species were conducted from different microhabitats to elucidate the possible cause of death. The unburned condition of most mortality specimens prompted suspicion of particulate smoke inhalation as a possible cause of death. However, the relative absence of carbon-rich particulate matter and the occasional presence of pulmonary oedema suggested asphyxiation, heat-induced cardiac arrest, or gas intoxication as the most likely cause of death. The association of most specimens with microhabitats rich in leaf litter may indicate higher reptile densities in this habitat or increased mortalities due to smoldering detrital material, or both. Detrital combustion and smoldering may result in advective transportation of heated gasses into underlying soil layers, with subsequent increased mortalities. Conclusion: Even though burrowing could potentially offer protection from fire to fossorial vertebrates through vertical movements into deeper substrate, our results indicated that they are not necessarily protected from fire effects. We speculate that seasonal reproductive behavior may contribute to fire mortality. These observations may contribute to improved understanding and management of fire in areas where fossorial reptiles occur.