Study

Actions

This study is summarised as evidence for the following.

Action Category

Thin trees within forests

Action Link
Amphibian Conservation

Retain riparian buffer strips during timber harvest

Action Link
Amphibian Conservation
  1. Thin trees within forests

    A controlled, before-and-after site comparison study in 1998–2001 at two largely coniferous forest sites in western Oregon, USA (Rundio & Olson 2007) found that the amount of pre-existing downed wood affected the response of salamanders to forest thinning. At the site with high volumes of existing downed wood, there was no significant change in capture rates of the dominant species ensatina Ensatina eschscholtzii or Oregon slender salamander Batrachoseps wrighti following thinning. However, at the site with little downed wood, capture rates declined significantly for the two dominant species, ensatina (40%) and western red-backed salamanders Plethodon vehiculum (42%). Captures did not change in unharvested treatments. At the two sites, treatments were unharvested or thinned (80% thinned to 200–240 trees/ha; 10% harvested in groups; 10% patches retained; deadwood was retained) with riparian buffers (6 to ≥70 m). Monitoring was undertaken in May–June before and two years after thinning. Visual count surveys were along 64–142 m transects perpendicular to each stream bank (7–8/treatment).

     

  2. Retain riparian buffer strips during timber harvest

    A controlled, before-and-after, site comparison study in 1998–2001 at two forest sites in western Oregon, USA (Rundio & Olson 2007) found that the amount of pre-existing downed wood affected the response of salamanders to forest thinning with riparian buffers. At the site with high volumes of existing downed wood, there was no significant change in amphibian capture rates following thinning with three different buffer widths. However, at the site with little downed wood, capture rates declined following thinning with buffers of ≥6 m or ≥15 m, but not ≥70 m. At the two sites, treatments were unharvested or thinned (to 200 trees/ha; 10% cut in groups; 10% patches retained; deadwood retained) with riparian buffer widths of ≥6 m (streamside-retention), ≥15 m (variable-width) or ≥70 m. Monitoring was undertaken in May–June before and two years after thinning. Visual count surveys were along 102 m transects perpendicular to each stream bank (7–8/treatment).

     

Output references

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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