• At the end of each trial, the correct category was revealed and the subjects recorded the accuracy of their category guess. Investigating the effects of a non-native salamander on the native salamander community at Mountain Lake Biological Station, Pembroke, Virginia. Alexander J. Novarro1 and August Blackman2 Background Results Literature Cited Methods 1. Rissler et al. 2000. Spatial and behavioral interactions between a native and introduced salamander species. Behavioral Ecology and Sociobiology, 48, 61-68. 2. Hairston, N.G. 1983. Alpha selection in competing salamanders: experimental veriﬁcation of an a priori hypothesis. The American Naturalist., 122, 105-113. 3. Fiske, I. and R. Chandler. 2011. An R package for ﬁtting hierarchical models of wildlife occurrence and abundance. Journal of Statistical Software, 43, 1-23. 1Department of Biology, University of Maryland, College Park, MD; 2Department of Biology, Oberlin College, Oberlin, OH Discussion @TheSalexmander Plethodon cinereus and Plethodon glutinosus naturally co-occur at Mountain Lake Biological Station. In the 1930s-40s, a third Plethodon species, P. montanus, was introduced1. Although these species coexist elsewhere, the introduction of novel salamander species is known to negatively impact the abundance of naïve species2. We hypothesized that the abundance of P. cinereus and P. glutinosus would be lower in the presence of P. montanus than in the absence of P. montanus. Has the introduction of Plethodon montanus affected the abundance of native Plethodon species at Mountain Lake Biological Station? Our study shows that a non-native Plethodon salamander may persist in a community of ecologically similar species without negatively impacting the abundance of the native species. However, an increase in the number of P. montanus is likely to have a negative impact on the dominant native species, P. cinereus. To our knowledge, this is the only human-introduced population of lungless salamanders. Our study provides insight to the community-level effects of human- and climate-induced range shifts in Plethodon salamanders. Anova1@umd.edu Our results suggest that the non-native P. montanus has not reached high enough densities to negatively impact the native salamander community at Mountain Lake Biological Station. We performed three nocturnal visual encounter surveys in 48 15x3m transects at sites where P. montanus was either absent, introduced, or native. We used N- mixture models in the R package unmarked to estimate abundance while accounting for imperfect detection3. Table 1. Beta estimates, standard error, conﬁdence intervals, and P-values for the best-supported abundance models. Fig. 3. Mean abundance of Plethodon salamanders in a 45m2 transect at sites where P. montanus is absent, introduced, and native. a b c Fig. 1. Photos of Plethodon species at Mountain Lake Biological Sta9on: (a) P. cinereus, (b) P. glu1nosus, and (c) P. montanus. Fig. 2. Predicted relationship between the abundance of P. montanus and the abundance of P. cinereus in a 45m2 transect. Fig. 2. Map showing the loca9on of study sites in Giles County, Virginia where surveys were conducted. Circles are color coded to represent the state of P. montanus. 0 20 40 60 80 100 Absent Introduced Native State of P.montanus Estimated Abundance Species P. cinereus P. glutinosus P. montanus 0 10 20 30 40 50 60 70 0 50 100 150 200 P. montanus P. cinereus Fitted Regression Line 95% Confidence Interval (SE) β SE 95% CI P-value P. cinereus Detection covariates: Precipitation 0.019 0.003 0.012 0.026 < 0.001 Time of survey -0.003 0.001 -0.004 -0.002 < 0.001 Understory cover 0.005 0.004 -0.004 0.013 0.275 Abundance covariates: Distance to stream -0.001 0.000 -0.002 < 0.001 0.118 Understory cover -0.007 0.005 -0.017 0.002 0.149 Estimated abundance of P. montanus -0.027 0.005 -0.036 -0.017 < 0.001 P. glutinosus Detection covariates: Precipitation -0.019 0.011 -0.041 0.002 0.088 Time of survey -0.003 0.001 -0.006 -0.001 0