Wetland occupancy of pond-breeding amphibians in Yosemite National Park, USA

Journal of North American Herpetology
By: , and 

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Abstract

We estimated wetland occupancy and population trends for three species of pond-breeding anurans in Yosemite National Park from 2007-2011. We used a double survey technique in which two observers independently surveyed each site on the same day. Double surveys allowed us to calculate detectability for the three most common anurans within the park: Rana sierrae, Anaxyrus canorus, and Pseudacris regilla. Annual estimates of detectability were generally high; mean detectability ranged from 73.7% + 0.6 (SE) for any life history stage of A. canorus to 86.7% + 0.7 for sites with P. regilla reproduction (eggs or larvae present). Detectability was most variable for Anaxyrus canorus, which ranged from 45.9% to 99.7%. The probability of occupancy for R. sierrae was highest in larger, low-elevation wetlands that lacked fish. Anaxyrus canorus were more common in shallow high-elevation ponds; their occurrence was minimally impacted by the presence of fish. Finally, occurrence of P. regilla was largely unrelated to wetland size and elevation, but like R. sierrae, they were less likely to occupy sites with fi sh. Occupancy showed no trend over the five years of our study for R. sierrae or A. canorus when considering either sites with any life stage or only sites with reproduction. However, P. regilla showed a modest downward trend for sites with any life stage and sites with reproduction. Our results for R. sierrae run counter to expectations given recent concern about the decline of this species, while our findings for P. regilla raise concerns for this widespread and generally common species.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Wetland occupancy of pond-breeding amphibians in Yosemite National Park, USA
Series title Journal of North American Herpetology
Volume 2015
Issue 1
Year Published 2015
Language English
Publisher The Center for North American Herpetology
Contributing office(s) Western Ecological Research Center
Description 12 p
First page 22
Last page 33
Time Range Start 2007-01-01
Time Range End 2011-12-31
Country United States
State California
Other Geospatial Yosemite National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N