Downed Wood Microclimates and Their Potential Impact on Plethodontid Salamander Habitat in the Oregon Coast Range
Downed Wood Microclimates and Their Potential Impact on Plethodontid Salamander Habitat in the Oregon Coast Range
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倒下的木材小气候及其对俄勒冈海岸地区无齿蝾螈栖息地的潜在影响
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发表时间：
2009
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影响因子：
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通讯作者：
K. Puettmann
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作者：
Matthew R. Kluber;D. Olson;K. Puettmann
倒下的木材为许多无脊椎动物、小型哺乳动物和两栖动物提供了重要的动物微栖息地。在受管理的太平洋西北森林中，被砍伐木材作为避难所的生境适宜性日益受到关注，在那里，被砍伐木材的减少可能导致被砍伐木材补充减少和原木内温度升高。我们研究了俄勒冈州西部的温度剖面，以评估相对于夏季极端气温，原木和土壤的热状态差异及其对多齿蝾螈栖息地适宜性的影响。在三个案例研究中，在距离溪流边缘0-5 m和35-40 m的两个不同位置（距离溪流边缘0-5 m和35-40 m）测量了60年林分的小直径（0.3-0.45 m）和大直径（0.7-1.0 m）原木的温度分布，以及环境土壤和空气温度：1)沿着具有狭窄河岸缓冲带（~ 6 m）和适度上坡减薄的源头溪流；2)沿上游有较宽的河岸缓冲带（~ 15 m）和适度的上坡变薄；3)沿着上游未变薄的上游河流。2006年7月，这三条河流的河面和上坡最高气温均接近或超过30°C，这是西部多齿蝾螈的临界耐热阈值。小原木、大原木和土壤的河滨和上坡温度保持在临界温度以下。我们的研究结果表明，在未砍伐的森林和覆盖层有限的稀疏林分中，宽尺寸范围的原木和土壤可能提供足够的保护，以抵御极端温度。
Abstract Downed wood provides important faunal microhabitat in forests for numerous invertebrate taxa, small mammals and amphibians. Habitat suitability of downed wood as refugia is an increasing concern in managed Pacific Northwest forests, where overstory reduction may result in both reduced downed wood recruitment and increased temperatures within logs. We examined temperature profiles in western Oregon to assess differences in thermal regimes of logs and soil relative to summer air temperature extremes and their implications with respect to habitat suitability for plethodontid salamanders. Temperature profiles of small- (0.3–0.45 m) and large- (0.7–1.0 m) diameter logs, as well as ambient soil and air temperatures, were measured in a 60-year-old forest stand at two different positions (0–5 m and 35–40 m from stream edge) in three case studies: 1) along a headwater stream with a narrow riparian buffer (∼6 m) and moderate upslope thinning; 2) along a headwater stream with a wider riparian buffer (∼15 m) and moderate upslope thinning; and 3) along a headwater stream with an unthinned upslope. Streamside and upslope maximum air temperatures measured during July 2006 along all three streams were near or exceeded 30°C, the critical thermal tolerance threshold for western plethodontid salamanders. Streamside and upslope temperatures inside small logs, large logs and soils stayed below critical temperatures. Our results suggest that logs of a wide size range, as well as soils, may provide sufficient protection against thermal extremes in uncut forests and thinned stands with limited overstory.