Graduation Date

Summer 2019

Document Type

Thesis

Program

Master of Science degree with a major in Natural Resources, option Wildlife

Committee Chair Name

Daniel Barton

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Micaela Szykman Gunther

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Sharyn Marks

Third Committee Member Affiliation

HSU Faculty or Staff

Subject Categories

Wildlife

Abstract

The timescale of community response to disturbance varies drastically, and slow-recovering ecosystems such as coastal redwood forests may take hundreds of years to return to old-growth conditions post-logging. Few studies have quantified long-term (>50 years) impacts of disturbance on ecosystems, specifically aquatic ecosystems. This study provides evidence of the persistence of historical logging impacts 50 years post-logging through the comparison of headwater amphibian populations (occupancy and abundance) and stream characteristics using a control-treatment study with a logged watershed, Streelow Creek, as the treatment and a pristine old-growth watershed, Godwood Creek, as the control. The immediately adjacent old-growth watershed acts as a reference site because it is strikingly similar to the logged watershed including geology, orientation, topography, and forest species composition, differing only in logging history. I surveyed for the three obligate headwater amphibians in this system, which are often used as indicators for watershed quality: the coastal tailed frog (Ascaphus truei), coastal giant salamander (Dicamptodon tenebrosus), and southern torrent salamander (Rhyacotriton variegatus). Occupancy and abundance of headwater amphibians differed between the logged and unlogged watersheds, with greater estimates of occupancy for all three headwater amphibians and a greater relative abundance of D. tenebrosus in the unlogged watershed. These results provide restoration efforts with a clear target, which is often lacking in restoration designs. These data provide baseline information for a Redwood National and State Parks project aimed at ultimately restoring the logged watershed where natural recovery has been prevented due to a combination of highly-erodible geology, low-gradient streams, and excess woody-debris from logging slash disrupting fluvial processes.

Citation Style

JWM

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