Survival and Growth of Larval Coastal Giant Salamanders (Dicamptodon tenebrosus) in Streams in the Oregon Coast Range
Conditions that affect amphibian larval growth and survival can affect population structure through both larval and adult stages of their life history. We conducted a two-year, mark-recapture study of larval, Coastal Giant Salamanders, Dicamptodon tenebrosus, in 14 small streams in the Oregon Coast Range to assess spatial and temporal variation in growth and apparent survival. We modeled larval survival and growth by season and age class and examined these demographic rates in the presence of road crossing culverts. Cormack-Jolly-Seber models indicated that apparent survival was lower for first-year larvae than second/third-year larvae (13%, SE = 0.03; 28%, SE = 0.08) and apparent survival varied by time/season. The >5% difference in the effect of age on survival is potentially biologically significant (effect size = −0.10; confidence interval = −0.05, −0.16). Effects of culverts on larval survival were inconclusive, while no effects on growth were detected.Abstract
Map of southwestern Oregon showing the location of study area and the 14 study sites within the Coquille, Coos, and Umpqua River basins.
Snout–vent length of larval D. tenebrosus at onset of metamorphosis from 14 study streams in the Oregon Coast Range.
Contributor Notes
(JPS, RAS) Department of Fisheries and Wildlife, 104 Nash Hall, Oregon State University, Corvallis, Oregon 97331; and (DHO) USDA Forest Service Pacific Northwest Research Station, 3200 Southwest Jefferson Way, Corvallis, Oregon 97331. E-mail: (JPS) jpsagar@hotmail.com. Send reprint requests to JP.