Amphibian surveys at Klondike Gold Rush NHP: 2019 summary

Surdyk, Shelby; Furbish, Carolyn; Larsen, Jennifer; Hake, Mary

doi:10.36967/2293389

Amphibian monitoring has been conducted annually at Klondike Gold Rush National Historical Park (KLGO) since 2004 with the primary goal of monitoring long-term changes in amphibian distribution, abundance, reproduction, and survival at core breeding sites. The Park has two confirmed amphibian species, the Boreal Toad (Anaxyrus boreas, formerly Bufo boreas) and the Columbia Spotted Frog (Rana luteiventris); however, Boreal Toads are the primary focus of monitoring efforts due to their relative abundance in the Taiya River watershed. In 2018, a Focused Condition Assessment (FCA) of the KLGO Amphibian Monitoring Program was initiated, which resulted in a set of recommendations to maximize the efficiency and statistical value of data collected by the program. However, the FCA was not published until December 2019. Using a draft of the FCA and in consultation with an author, the 2019 season became a transitional year that partially implemented the FCA recommendations. Boreal Toad monitoring in 2019 started on 11 June and ended on 21 August. Data were collected through Visual Encounter Surveys (VES) that combined FCA and KLGO traditional methods and data. Monitoring adopted the FCA recommendation for multiple surveys during a single site visit, and for time windows targeted to larval (aquatic tadpole) and metamorph (tiny emergent terrestrial toadlet) detection. Monitoring methods also retained much of the detailed data traditionally collected by KLGO. A total of 51 routine Visual Encounter Surveys were conducted, of which 23 surveys detected toads. Breeding activity was found through larval and metamorph detection at four of the eight core sites. Larvae, but not metamorphs, were detected at one additional site. A small number of skin and buccal (mouth) swabs from eight toads, juvenile and adult, were collected and sent to Colorado State University in Fort Collins, CO to test for the presence of chytrid disease fungus. Chytrid was detected in five of the eight samples that were processed. Lastly, casual observations from interested staff, residents or visitors provided additional insight into general toad distribution and behavior, particularly migration corridors and the use of leaf piles as summer habitat and possible over-wintering hibernacula. Recommendations are presented for future Boreal Toad monitoring, including considerations for full implementation of the Focus Condition Assessment.