For more information on species & ecosystem science:

Wildlife Science

Fish Science

Habitat Science


Lead Scientist: Julie Tyson

Ecoregions: Puget Trough, Northwest Coast, East Cascades, West Cascades

Ecological Systems: North pacific Maritime Mesic-Wet Douglas-fir-Western Hemlock Forest, North Pacific Lowland Riparian Forest and Shrubland


Fig. 1 - WDFW Study Sites


Fig. 2 - 0% Shade Treatment


Fig. 3 - Instream enclosure for amphibians


Managed Lands in Coniferous Forests

Buffer Integrity-Shade Effectiveness Project

Project Description

Timber harvest along streams commonly reduces shade and increases inputs of fine sediments to the stream. The Buffer Integrity-Shade Effectiveness Project is an attempt to better understand how reductions in shade to headwater streams affect three species of stream-breeding amphibians (giant salamanders, torrent salamanders and tailed frogs).

The Shade Study provides an opportunity to study the effect of reducing shade (increasing sunlight), which is hypothesized to increase amphibian habitat quality without increased sedimentation, a condition thought to decrease habitat quality for these stream-breeding species.

The lead partner, Longview Timberlands began the study in 2004 and is responsible for monitoring 18 streams mostly on privately owned timberland in southwestern Washington and northwestern Oregon. WDFW expanded the study to include an additional 7 streams all on WDNR lands (Fig 1).

Each study stream has a control reach (no shade reduction) located upstream from a treatment reach where shade is reduced, both 50 meters long. Streamside vegetation in the treatment reach was removed to reduce shading over the stream from its original (unharvested) levels, of roughly 85-95%, down to either 67%, 33%, or 0% shade (Fig. 2). No vegetation was removed from control reaches and these served as a check that represented background conditions.

Evaluation of how five species of stream-breeding amphibians responded to these shading treatments is was done by measuring their body condition, growth rates, and numbers both in the stream and in enclosures placed in the stream (Fig. 3). Water temperature, instream production (as algae and invertebrates), light, litterfall, and sediment input were also measured to help properly interpret amphibian responses.

Sites were monitored 2-3 years before the treatments were applied, which took place in the fall of 2007 and spring of 2008. Post-treatment monitoring took place in 2008 and 2009. Data from this study are currently being processed and analyzed in preparation for the final report.

Key Findings

  • Different levels of shading result in different responses that vary with the species; preliminary analyses suggest that shade reduction has a positive response, but only up to a point; the final analyses of patterns by species are pending.

  • Data on torrent salamanders from this study suggest they have the potential to move much greater distances than previously thought.
  • The first female tailed frog ever found in the process of laying eggs was encountered during this study.
  • In choosing sites for this study, it was discovered that Cope’s giant salamanders range only partway up the east side of the Olympic Peninsula. It was previouisly thought that they were widespread throughout this area.


Funding for the above mentioned research was provided by the Cooperative Monitoring, Evaluation, and Research (CMER) Committee.


Publications and Posters

Examples of Amphibian Species Within Research Area
Click on photos to enlarge

Giant Salamander
Giant Salamander
Torrent Salamander
Torrent Salamander
Tailed Frog
Tailed Frog