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Number of populations of each species present in 42 Yellowstone ponds during at least 1 year during 1992–1993 or 2006–2008. AT, Ambystoma tigrinum; BB, Bufo boreas; PT, Pseudacris triseriata; RL, Rana luteiventris. Asterisks denote statistical significance, determined by McNemar's Test (P <0.01).
