Survey and assessment of amphibian populations in Rocky Mountain National Park

Northwestern Naturalist
By: , and 



We conducted surveys in Rocky Mountain National Park, Colorado for amphibians in 1987-1994. Four species, Ambystoma tigrinum, Bufo boreas, Pseudacris maculata, and Rana sylvatica, were recorded. Pseudacris maculata was the most widely distributed and abundant species in the Park. Two populations of E maculata were estimated to contain 161 and 136 breeding males in 1988. There was no evidence of a decline of A. tigrinum or R. sylvatica, but these species were found at relatively few locations. We did not detect Rana pipiens, which had been known previously from 3 locations in the Park. We found 7 breeding populations of B. boreas, which has declined recently elsewhere in the southern Rocky Mountains, but all but 2 of these populations were small and may not reproduce annually. At least one of these small populations is thought to have been extirpated. Estimated numbers of males in the 2 large populations, which are 6.4 km apart in the same drainage, were stable or increasing slightly from 1992 to 1995, averaging 189 and 239 individuals. Current and known locations of amphibians did not differ in elevation, size, lake type, presence of shallow water or emergent vegetation on the north shore, or presence of trout. Water chemistry at amphibian breeding sites was variable, but pH decreased significantly with increasing elevation. Causes of declines of B. boreas and R. pipiens are not known. Populations of B. boreas in the North Fork of the Big Thompson River are critically important to the conservation of this species in the Rocky Mountains.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Survey and assessment of amphibian populations in Rocky Mountain National Park
Series title Northwestern Naturalist
DOI 10.2307/3536856
Volume 78
Issue 1
Year Published 1997
Language English
Publisher Society for Northwestern Vertebrate Biology
Contributing office(s) Fort Collins Science Center
Description 22 p.
First page 34
Last page 55
Country United States
State Colorado
Other Geospatial Rocky Mountain National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N
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