Preliminary study of the effects of headwater riparian reserves with upslope thinning on stream habitats and amphibians in western Oregon

  • Published source details Olson D.H. & Rugger C. (2007) Preliminary study of the effects of headwater riparian reserves with upslope thinning on stream habitats and amphibians in western Oregon. Forest Science, 53, 331-342.


This study is summarised as evidence for the following.

Action Category

Retain riparian buffer strips during timber harvest

Action Link
Amphibian Conservation
  1. Retain riparian buffer strips during timber harvest

    A replicated, controlled, before-and-after study in 1995–2002 of amphibians in managed forest stands at 11 sites in Oregon, USA (Olson & Rugger 2007) found that retaining riparian buffers maintained amphibian abundance in the first two years after tree thinning. There was no significant decrease in four species within buffers following thinning (change: −0.1 to 0.1 animals/m2). Rough-skinned newts Taricha granulosa and coastal giant salamander Dicamptodon tenebrosus numbers increased within buffers following thinning (0.007–0.034/m2) and declined at unthinned control sites (−0.043 to 0.008/m2). Forty-five streams were assigned riparian buffers of 6, 15, 70 or 145 m on each side within tree thinning areas (from 600 to 200 trees/ha). Thinning took place in 1997–2000. Monitoring was undertaken in spring and summer, before treatment, in 1995–1999 and for two years after treatment, in 1998–2002. Amphibians were sampled in 10 units/stream using hand sampling, electrofishing and visual counts of bank sides (2 m wide). Twenty-three streams within unharvested areas were also monitored.


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