I used a long term collection database to compare 72 current populations of six species and three hybrids of Plethodon salamanders in the Great Smoky Mountains National Park (GRSM). I analyzed population abundance and adjusted for detection probabilities, over time for each species, with respect to null models. I also examined biotic and abiotic factors as potential causes for changes in population abundance. Population response varied among species, Plethodon glutinosus and P. teyahalee declined while P. jordani x metcalfi and P. ventralis increased at a greater rate than what was expected by historic variation in abundance. Declines of GRSM salamanders most likely began in the late 1960's to early 1970's and were associated with cooler and moister habitats. I conclude that species' biology may explain the variation in population responses and propose future research to determine the cause.