Measuring the effects of increasing loads of fine sediment from timber harvest and road building on aquatic populations of Dicamptodon tenebrosus (Pacific giant salamander) in California's redwoods

Seth Pogue

Graduation Date

2008

Document Type

Thesis

Program

Other

Program

Thesis (M.A.)--Humboldt State University, Science and Natural Resources: Biology, 2008

Committee Chair Name

John Reiss

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Road building, Dicamptodon tenebrosus, Humboldt State University -- Theses -- Biology, Timber harvesting, Pacific giant salamander

Abstract

Dicamptodon tenebrosus (Pacific giant salamander) was evaluated for suitability as an indicator of aquatic habitat quality relative to increasing loads of fine sediment from timber harvest and road building. I compared three surrogates of D. tenebrosus population success - biomass per unit area, density, and number of age classes (dependent variables) to two measures of stream sedimentation - RSI, which measures how much of the stream bed becomes mobilized at peak flow, and D50, the median bed particle diameter (independent variables) on 49 streams from three subjective disturbance categories: a control group, a moderate management group, and a high management group. Streams impacted by sediment exhibited fewer surviving age classes, and also significantly less biomass per square meter of pool bottom. These streams were from the moderate and high management categories. Unimpacted streams (control group) exhibited the greatest number of surviving age classes and the highest biomass. This study also presents the first quantitative analysis of D. tenebrosus age class structure. These animals live to be at least twelve years old.

https://scholarworks.calstate.edu/concern/theses/6682x632w

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