Translocation of Boreal Toad (Anaxyrus boreas boreas) into two springs in the Grouse Creek Mountains, Utah, including demographic observations

摘要

The Boreal Toad (Anaxyrus boreas boreas) is widely distributed in western North America and has declined throughout portions of the Rocky Mountains. One mechanism to expand populations is to translocate toads into unoccupied habitats. Wild-captured juvenile (n = 229) and subadult/adult (n = 42) Boreal Toads were translocated into 2 unoccupied spring-fed ponds located near 10 known breeding populations in the Grouse Creek Mountains, northwestern Utah. Boreal Toad egg strands were observed at one pond in 8 of 9 years following the last translocation of toads (n = 1-5 egg strands deposited per year) and in 3 of 5 years in the second pond (n = 1-4 egg strands deposited per year). Both translocations were considered short-term successes. Between 1999 and 2017, 1964 Boreal Toads > 55 mm SVL were PIT-tagged in the Grouse Creek Mountains, and recaptures were used to develop a growth curve that explained 79% of the size-age variability in this population. The growth curve will allow managers to reasonably identify age-1 and age-2 toads based on SVL and better evaluate Boreal Toad recruitment during population monitoring. Eight Boreal Toads were documented to have lived 11-16 years, and movements up to 7.6 km were documented across a relatively arid sagebrush/juniper landscape.