Treesearch

Diel fluctuations in streamflow during base flow have been observed in many streams and are typically attributed to water losses from evapotranspiration (ET). However, there is no widely transferable conceptual model that explains how ET results in diel fluctuations in streamflow at the watershed outlet. For fluctuations to occur, two factors must be present: (1) some process must generate the fluctuations and transfer them to the stream channel, and (2) fluctuations must be accumulated and transported down the stream network in such a way that they arrive at a stream gauge as a coherent...

We have learned that although urban and rural communities in interior Alaska face similar increased exposure to wildfire as a result of climate change, important differences exist in their sensitivity to these biophysical, climate-induced changes. In particular, reliance on wild foods, delayed suppression response, financial resources, and institutional connections vary between urban and rural communities. These differences depend largely on social, economic, and institutional factors, and are not necessarily related to biophysical climate impacts per se. Fire management and suppression...

The movements of salmon carcasses over time were studied in two forest streams in the context of a large-scale salmon carcass supplementation program. The objectives were to assess both the level of treatment after stream flows had displaced carcasses and to evaluate whether the magnitude of carcass movements outside of a given reach could be predicted. The movements of hand-placed, radio-tagged salmon carcasses were studied and compared with those of flagged carcasses dropped by helicopter. Repeated surveys showed that in both streams radio-tagged carcasses moved only a short distance,...

The Northern Circumpolar Soil Carbon Database was developed to determine carbon pools in soils of the northern circumpolar permafrost region. Here we report a new estimate of the carbon pools in soils of the northern permafrost region, including deeper layers and pools not accounted for in previous analyses.

We reconstruct the infrageneric phylogeny of Pinus from 37 nearly-complete chloroplast genomes (average 109 kilobases each of an approximately 120 kilobase genome) generated using multiplexed massively parallel sequencing. We found that 30/33 ingroup nodes resolved wlth > 95-percent bootstrap support; this is a substantial improvement relative to prior studies, and shows massively parallel sequencing-based strategies can produce sufficient high-quality sequence to reach support levels originally proposed for the phylogenetic bootstrap. Resampling simulations show that at least the entire...

Nonclimate variables shape vulnerability and adaptive capacity to climate change. Here, we describe how recent environmental and socioeconomic developments have transformed reindeer herding and perceptions of weather on the Seward Peninsula, Alaska. The reindeer industry has shrunk considerably since the early 1990s, when the winter range of the Western Arctic Caribou Herd expanded, and over 17,000 reindeer mixed with migrating caribou and left the region. Socioeconomic and environmental repercussions make the continuation of herding tenuous, and erode the ability of herders to cope with...

The seasonal diel behaviour of age 1+ steelhead from Coast and Cascade Range streams in Oregon was examined in the field and in laboratory streams. During the summer, fish from both areas were active during the day in natural streams: they held position in the water column in moderate velocities and depths. At night, fish were in slower water, closer to the bottom above smaller substrates. In winter, diel behaviour differed between the two groups. Coastal fish exhibited behaviour similar to that observed in the summer. Cascade Range fish were not observed during the day, but were found at...

Tensions between amenity- and timber-based economies in the U.S. and Canadian Pacific Northwest motivated a study of scenic beauty inside mature forests and timber harvests. A diverse sample of regional forests, measures of forest structure, and large, representative samples of photographs and public judges were employed to measure scenic beauty inside unharvested mature and old-growth forests, and timber harvests. The latter varied systematically in down wood levels and retention level and pattern. Scenic beauty tended to be optimized at a basal area of 110 to 155 m3/ha and/or 700 to 900...

Atmospheric nitrogen (N) fixation by Alnus tenuifolia can account for up to 70 percent of the N accumulated during vegetation development along river flood plains in interior Alaska. We assessed disease incidence and related mortality of a recent outbreak or fungal stem cankers on A. tenuifolia across three regions in Alaska during the 2005 growing season, and determined the impacts on N-fixation rates, nodule biomass, and stand-level N-fixarion inputs. The highest percentage of ramets colonized or dead with canker was found on Tanana River plots, suggesting the epidemic is most severe in...

We describe the process by which the Long-Term Ecological Research (LTER) Network standardized their metadata through the adoption of the Ecological Metadata Language (EML). We describe the strategies developed to improve motivation and to complement the information technology resources available at the LTER sites. EML implementation is presented as a mapping process that was accomplished per site in stages, with metadata quality ranging from "discovery level" to rich-content level over time. As of publication, over 6,000 rich-content standardized records have been published using EML,...