Dispersal of newly metamorphosed and juvenile western toads (Anaxyrus boreas) in northeastern Oregon, USA

Publication Type:

Journal Article

Authors:

Bull, Evelyn L.

Source:

Herpetological Conservation and Biology, Herpetological Conservation and Biology, Volume 4, Issue 2, p.236-247 (2009)

Call Number:

A09BUL01IDUS

URL:

http://www.herpconbio.org/Volume_4/Issue_2/Bull_2009.pdf

Keywords:

Anaxyrus boreas, Boreal Toad, Western Toad

Abstract:

The decline of Anaxyrus boreas, the western toad, in portions of its range has accentuated the need for additional information on all life stages of this species. The author’s objectives in this study were to identify patterns of dispersal, mortality factors, and conservation concerns for toadlets (i.e., newly metamorphosed toads) and juvenile (one-year-old) toads. Toadlets dispersed up to 2,720 m from the breeding site within eight weeks of transformation in one of three study areas in northeastern Oregon during 2006–2008. Toadlets traveled an average of 84 m/day and dispersed along drainages with intermittent or permanent water associated with streams, seeps, and marshy areas. Juveniles were detected 1,070–2,720 m from the breeding sites in all study areas. Desiccation, avian predation, vehicle and cattle movements, and chytridiomycosis were causes of mortality of toadlets. Conservation concerns identified in this study include 1) shoreline structure of reservoirs, 2) retention of water in reservoirs until after transformation, 3) protection from vehicle mortality, and 4) minimization of water loss in streams and pools along dispersal routes.