Entity

Time filter

Source Type

Longview, WA, United States

Kroll A.J.,Weyerhaeuser Company | MacCracken J.G.,Longview Timberlands LLC | Bakke J.,Forest Capital Partners LLC | Peterson P.,Forest and Channel Metrics | Bach J.,Weyerhaeuser Company
Journal of Wildlife Management | Year: 2010

Conservation and management of native species on landscapes managed for intensive wood production represents an ongoing challenge to forest managers. Previous research suggests that impacts of forest practices on stream-associated amphibians (SAA; giant Dicamptodon spp., torrent Rhyacotriton spp., and plethodontid Plethodon spp. salamanders and coastal tailed frogs Ascaphus truei) in Oregon and Washington, USA, vary spatially and temporally as a result of biotic and abiotic factors, some of which can be influenced by management treatments. Although individual harvest units can encompass multiple stream reaches and entire second-order basins, nearly all published research studies used stream reaches of various lengths as sample units. To address this discrepancy between research and operational scales, we sampled first-, second-, and third-order streams in 70 randomly selected third-order basins in Oregon and Washington in 2007 and 2008 to estimate detection and occupancy parameters for SAA and to develop basin-level density estimates for different species and genera. We estimated occupancy probabilities of 0.99 (95 CL 0.961.00) for torrent and giant salamanders, 0.93 (95 CL 0.760.92) for Dunn's salamanders (Plethodon dunni), and 0.60 (95 CL 0.460.72) for tailed frogs. Our estimates can be compared with estimates for unmanaged third-order basins in Oregon and Washington to provide a relative measure of potential impacts of forest management on these taxa. In addition, our estimates provide baseline information with which to assess potential effects of future environmental changes on the 4 genera. © 2010 The Wildlife Society. Source


Pollett K.L.,Utah State University | MacCracken J.G.,Longview Timberlands LLC | MacMahon J.A.,Utah State University
Forest Ecology and Management | Year: 2010

We addressed the efficacy of stream-side buffers in ameliorating the effects of clearcut timber harvest on Cascade torrent salamanders (Rhyacotriton cascadae), coastal/Cope's giant salamanders (Dicamptodon tenebrosus/. D. copei), coastal tailed frogs (Ascaphus truei), and water temperature regimes in the Cascade Range in southern Washington. Forty-one streams in 4 categories were sampled; streams in clearcuts with and without buffers, streams in 35+ year old second-growth forest, and streams in unharvested forest (150+ years old). Tailed frog and Cascade torrent salamander densities were 2-7-fold lower (P<0.05), respectively, in streams in managed forests than in streams in unharvested forest. In addition, both these species were less abundant (P<0.05) in unbuffered streams than streams with buffers or in second-growth forest. In contrast, giant salamander densities were 5-50% greater (P>0.05) in managed streams than unharvested, being greatest in unbuffered and second-growth streams. We used the differences in density estimates of unbuffered streams and unharvested streams to define an ecologically important effect size for each species and then compared the mean effect size and 95% confidence intervals of contrasts between managed stream categories to assess buffer effectiveness. Buffers had a positive ecologically important effect on the density of torrent salamanders and tailed frogs, but had an ecologically negative effect on giant salamanders. Water temperatures were similar among stream categories. However, Cascade torrent salamanders were nearly absent from streams where temperatures were ≥14. °C for ≥35 consecutive hours. Issues that need further study include effective buffer width and longitudinal extent, and confirmation of the water temperature threshold we identified. © 2010 Elsevier B.V. Source


MacCracken J.G.,Longview Timberlands LLC | Stebbings J.L.,Longview Timberlands LLC
Journal of Herpetology | Year: 2012

We conducted experimental feeding trials with larval and juvenile Bullfrogs (Lithobates catesbeianus) and Rough-skinned Newts (Taricha granulosa) to assess the accuracy of the scaled mass index (SMI). A control group was fed and a treatment group was starved within a randomized block design. After each of three trials, amphibian tissues were analyzed for lipid, protein, and water content. Mean pretreatment wet weight and SMI of individuals of each species and body form, representing two populations of equal body condition, were similar between control and treatment groups. Starved animals, representing a population in poor condition, had a 1732 lower SMI than fed animals. Scaled fat and protein or lean mass were strongly correlated (r 0.850.99) with SMI compared with percentages of fat, protein, or lean mass (r 0.080.60). The SMI accurately reflected amphibian energy stores, but the depletion of energy stores differed by species and body form, with tadpoles retaining fat and the other species and body forms depleting fat stores. In addition, factors that we controlled in the laboratory (e.g., hydration, gut fill, reproductive state) may alter mass-length relationships in the field, so we advise collecting some specimens for body composition analyses to ensure the accuracy of the SMI when used in other applications. Source

Discover hidden collaborations