气候变化领域集成服务门户(CCPortal): Stream temperature responses to experimental riparian canopy gaps along forested headwaters in western Oregon

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DOI	10.1016/j.foreco.2020.118354
	Stream temperature responses to experimental riparian canopy gaps along forested headwaters in western Oregon
	Swartz A.; Roon D.; Reiter M.; Warren D.
发表日期	2020
ISSN	0378-1127
卷号	474
英文摘要	Streamside (riparian) areas in the western United States and across much of North America are dominated by young, regenerating forests with closed canopies, which shade the understory and reduce light to streams. The addition of canopy gaps has been suggested as a management tool to accelerate development of riparian forest complexity, create stream light conditions that mimic those in late successional forests, and enhance in-stream productivity. Although gaps form naturally in late-successional forests, explicitly adding gaps is a concern because the increases in light that accompany a canopy gap may have the potential to increases stream temperature, which is an important ecological driver and regulatory metric in streams. The goal of this study was to determine whether and to what degree riparian forest canopy gaps that reflect localized disturbance events (mortality of one to a few dominant canopy trees) affect stream temperatures. We created experimental gaps in young regenerating riparian forests along six replicate headwater streams in western Oregon. Gaps increased light along 90 m study reaches by 3.91 (±1.63) moles of photons m−2 day−1, similar to that of a naturally occurring gap in a late-successional forest. Using a Before-After-Control-Impact study design, we assessed stream temperature by tracking multiple responses in each reach including: maximum seven day moving average of daily maximums (T7DayMax), maximum seven day moving average of daily means (T7DayMean), daily maximum, and mean summer temperatures, as well as within-reach (every 30 m) responses, and downstream recovery. Over a 40-day period in summer (July 22nd - August 30th), the mean response in T7DayMax across the six replicate streams was 0.21 °C ± 0.12, and the mean response in T7DayMean was 0.15 °C ± 0.14. Although the mean response in T7DayMax (a key regulatory metric) was small, changes varied across individual study streams, and the magnitude of the relative increase in stream T7DayMax as a result of the canopy gap was strongly negatively correlated with stream size. T7DayMax was not correlated with the size of the canopy opening or change in reach-scale light availability (within the range of gap sizes from 514 m2 to 1,374 m2 (0.05 to 0.14 ha)). Overall, riparian forest canopy gaps have the potential to increase stream temperatures, but in the western Cascade Mountain headwaters studied here, gap effects were small (all < 0.5 °C), and temperature responses declined as stream size increased. © 2020 Elsevier B.V.
关键词	Light Reforestation Before-after control impacts Light availability Multiple response Naturally occurring Stream temperatures Summer temperature Temperature response Western United States Rivers canopy gap disturbance forest canopy headwater light availability riparian forest spatiotemporal analysis streamwater understory water temperature Averages Forests Increments Light Reforestation Rivers Temperature North America Oregon United States
语种	英语
来源机构	Forest Ecology and Management
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/132624
推荐引用方式 GB/T 7714	Swartz A.,Roon D.,Reiter M.,et al. Stream temperature responses to experimental riparian canopy gaps along forested headwaters in western Oregon[J]. Forest Ecology and Management,2020,474.
APA	Swartz A.,Roon D.,Reiter M.,&Warren D..(2020).Stream temperature responses to experimental riparian canopy gaps along forested headwaters in western Oregon.,474.
MLA	Swartz A.,et al."Stream temperature responses to experimental riparian canopy gaps along forested headwaters in western Oregon".474(2020).