DIET COMPOSITION EXPLAINS REDUCTIONS IN STREAM SALAMANDER OCCUPANCY AND ABUNDANCE ALONG A CONDUCTIVITY GRADIENT
OF THESIS DIET COMPOSITION EXPLAINS REDUCTIONS IN STREAM SALAMANDER OCCUPANCY AND ABUNDANCE ALONG A CONDUCTIVITY GRADIENT Changes in land use such as mountaintop removal mining with valley fills (MTR/VF) affect chemical, physical, and hydrological properties of headwater streams. Although numerous stream taxa have experienced significant declines from MTR/VF, stream salamanders appear to be particularly sensitive. Yet, the specific mechanism(s) responsible for the population declines has eluded researchers. We sampled salamander assemblages across a continuous specific conductivity (SC) gradient in southeastern Kentucky and estimated occupancy rates and abundance estimates along this gradient. We also examined the diet of larval and adult salamanders to determine if autochthony (A/T prey) total prey volume, and body condition is influenced by SC. As SC increased, occupancy and abundance declined consistently among all salamander species and life stages. Diet composition explained the declines; for example, larval salamanders experienced a 12 fold decline in autochthony, a 4.2 fold decline in total prey volume, and a rapid decline in body condition as SC increased. Our results indicate that SC indirectly affects stream salamander populations by eliminating an adequate availability of aquatic prey for salamanders, which in turn lead may lead to reduced population persistence in streams with elevated SC.