Swine Flu or 1918 Pandemic? Upper Respiratory Tract Disease and the Sudden Mortality of Gopher Tortoises (Gopherus polyphemus) on a Protected Habitat in Florida

Abstract

Although Upper Respiratory Tract Disease (URTD) has been recognized as a potentially serious problem threatening the viability of gopher tortoises, little is known about the impact of this disease on tortoise populations in the wild, and some researchers regard the disease as relatively benign. We monitored the impact of URTD on gopher tortoises at the Kennedy Space Center, Florida, and found a striking increase in the proportion of tortoises showing signs of URTD between 1995–2000. We also documented a sudden increase in the number of tortoises found dead at the site, starting in 1998 and continuing through 2001. Based on condition and position of dead tortoises, we strongly suspect that URTD was the cause of death. Sex ratios and body sizes of tortoises found dead were not distinguishable from samples of living tortoises, indicating that mortality was not confined to a single gender or age class. Combined with recent reports of large-scale mortality of tortoises from other sites in Florida, we suggest that URTD is not benign but may instead have a substantial impact on tortoise populations. If so, the “protected lands paradigm” that many resource managers rely on to conserve tortoise populations may be violated, suggesting that more active management measures are needed.