ALBERT

Description: Recent studies have revealed positive and negative trends in the radial growth of treeline white spruce ( Picea glauca ) as temperatures have warmed in recent decades. Investigators have speculated that negative growth trends reflect the increasing importance of temperature-induced drought stress, yet direct observations of drought-induced stomatal closure have not been made in white spruce near the Arctic treeline. In this study, we measured needle gas exchange, a variety of needle traits, and branch growth in contrasting growing seasons on a riverside terrace near the Arctic treeline in Noatak National Preserve, northwest Alaska. Needle gas exchange was limited by cold soils (

Description: The hydrological and geomorphic functioning of high-mountain catchments is heavily influenced by snow accumulation and melt processes, which condition the timing and characteristics of discharges, solute outputs, and suspended sediment and bedload transport. We report here the transport of suspended sediment and solutes during the snowmelt period in a small experimental catchment in the subalpine belt of the Central Spanish Pyrenees. The seasonality of hydrological and sediment responses throughout the year was investigated using daily data of discharge, suspended sediment transport and solute outputs of the hydrological years 2003/2004 and 2005/2006. The study demonstrated the importance of the snowmelt period in terms of runoff p-roduction, and solute and suspended sediment yield: whereas precipitation during the snowmelt period (2-2.5 months) represented 10-13% of annual precipitation, discharge and suspended sediment transport accounted for up to 50% and 60%, respectively, and solute output approximately 40-50%. Solute transport dominated throughout the snowmelt period, whereas suspended sediment transport mostly occurred during the second phase of the snowmelt period (June), when an expanding area of the catchment was free from snow. The moderate daily increases in discharge, which were related to day-night temperature fluctuations, were insufficient to transport bedload material. Hourly data were used for preliminary assessment of the relationships among discharge, suspended sediment, and solute concentration, which provided insights into sediment sources and delivery mechanisms. Thus, during snowmelt-related events, the sediment mobilized was most probably derived from areas near or within the channel. In contrast, during events involving both snowmelt and rainfall, the gully system near the divide contributed to sediment load. The solute concentration was inversely related to water discharge, with higher concentrations during the first half of the snowmelt period (May) than during the second half (June). The results of this study demonstrate the key role of snow accumulation and melting processes in controlling the hydrological dynamics and patterns of particulate and solute mobilization in high-mountain environments. Future changes in snow volume and duration will affect the timing of snowmeltrelated spring high flows, as well as soil erosion and transport. Content Type Journal Article Pages 213-222 DOI 10.1657/1938-4246-43.2.213 Authors Noemí Lana-Renault, Department of Physical Geography, Faculty of Geosciences, Utrecht University, P.O. Box 80115, 3508 TC Utrecht, The Netherlands Bernardo Alvera, Instituto Pirenaico de Ecología, CSIC, Apdo. 64, 22700 Jaca, Spain José M. García-Ruiz, Instituto Pirenaico de Ecología, CSIC, Campus de Aula Dei, Apdo. 13034, 50080 Zaragoza, Spain Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 2 / May 2011

Description: For over 100 years, mountain treelines have been the subject of varied research endeavors and remain a strong area of investigation. The purpose of this paper is to examine aspects of the epistemology of mountain treeline research—that is, to investigate how knowledge on treelines has been acquired and the changes in knowledge acquisition over time, through a review of fundamental questions and approaches. The questions treeline researchers have raised and continue to raise have undoubtedly directed the current state of knowledge. A continuing, fundamental emphasis has centered on seeking the general cause of mountain treelines, thus seeking an answer to the question, "What causes treeline?" with a primary emphasis on searching for ecophysiological mechanisms of low-temperature limitation for tree growth and regeneration. However, treeline research today also includes a rich literature that seeks local, landscape-scale causes of treelines and reasons why treelines vary so widely in three-dimensional patterns from one location to the next, and this approach and some of its consequences are elaborated here. In recent years, both lines of research have been motivated greatly by global climate change. Given the current state of knowledge, we propose that future research directions focused on a spatial approach should specifically address cross-scale hypotheses using statistics and simulations designed for nested hierarchies; these analyses will benefit from geographic extension of treeline research. Content Type Journal Article Pages 167-177 DOI 10.1657/1938-4246-43.2.167 Authors George P. Malanson, Department of Geography, University of Iowa, Iowa City, Iowa 52242, U.S.A. Lynn M. Resler, Department of Geography, Virginia Tech, Blacksburg, Virginia 24061, U.S.A. Maaike Y. Bader, Functional Ecology of Plants, Department of Biology and Environmental Sciences, University of Oldenburg, D-26111 Oldenburg, Germany Friedrich-Karl Holtmeier, Institute for Landscape Ecology, Westfälische Wilhelms-Universität, D-48149 Münster, Germany David R. Butler, Department of Geography, Texas State University-San Marcos, San Marcos, Texas 78666-4616, U.S.A. Daniel J. Weiss, Yellowstone Ecological Research Center, 2048 Analysis Drive, Bozeman, Montana 59718, U.S.A. Lori D. Daniels, Department of Geography, University of British Columbia, Vancouver, British Columbia V6T 1Z2, Canada Daniel B. Fagre, U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, Montana 59936, U.S.A. Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 2 / May 2011

Description: In exploring geographical distribution of mountain altitudinal belts (e.g., snowline, timber line, etc.), many unitary or dibasic fitting models have been developed to depict the relationship between altitudinal belts' elevation and longitude or latitude, or both. However, most of these models involve small scales and could not be applied to other regions, while those established for the northern hemisphere or the whole globe, are of very low precision. The reason is that these models neglect one of the most important factors controlling the distribution of altitudinal belts—mass elevation effect ( massenerhebungseffect , short as MEE in the following text). This concept (MEE) was introduced more than 100 years ago by A. de Quervain to account for the observed tendency for temperature-related parameters such as tree line and snowline to occur at higher elevations in the central Alps than on their outer margins. Although it has been widely observed and its effect on the elevation of mountain vegetation belts recognized, this phenomenon has not been quantitatively studied. We compiled 143 snowline descriptions from literature covering the Tibetan Plateau and its surrounding areas. Snowline elevation is related to longitude, latitude, and mountain base elevation (MBE), to construct a multivariate linear regression equation. These three factors could explain 83.5% of snowline elevation's variation in the Tibetan plateau and its surrounding areas. Longitude, latitude, and MBE (representing MEE to some extent) contribute 16.14%, 51.64%, and 32.22%, respectively, to the variability of snowline elevation. North of latitude 32°N, the three factors' contribution amounts to 18.72%, 44.27%, and 37.01%, respectively; to the south, their contribution is 28.12%, 15.37%, and 56.51%, respectively. A nonlinear model was also constructed, but it only enhances the ability slightly in fitting of snowline's distribution. Our analysis reveals that latitude and MBE are significant controlling factors of snowline elevation. Longitude, which stands for precipitation to a great extent, has limited impact on snowline's distribution. MEE should be further studied, or directly quantified so that it can be adequately incorporated into the development of spatial models for altitudinal belts, whereby the precision of such models could be greatly enhanced. Content Type Journal Article Pages 207-212 DOI 10.1657/1938-4246-43.2.207 Authors Han Fang, State Key Laboratory of Resource and Environment Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, No. A-11, Datun Road, Chaoyang District, Beijing, 100101, People's Republic of China Zhang Baiping, State Key Laboratory of Resource and Environment Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, No. A-11, Datun Road, Chaoyang District, Beijing, 100101, People's Republic of China Yao Yonghui, State Key Laboratory of Resource and Environment Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, No. A-11, Datun Road, Chaoyang District, Beijing, 100101, People's Republic of China Zhu Yunhai, Shandong Institute for Development Strategy of Science and Technology, No. 19, Keyuan Road, Jinan, Shandong Province, 250014, People's Republic of China Pang Yu, State Key Laboratory of Resource and Environment Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, No. A-11, Datun Road, Chaoyang District, Beijing, 100101, People's Republic of China Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 2 / May 2011

Description: Tree Rings and Natural Hazards: a State-of-The-Art, by Markus Stoffel, Michelle Bollschweiler, David R. Butler, and Brian H. Luckman (eds.) Content Type Journal Article Category Book Review Pages 161-162 DOI 10.1657/1938-4246-43.1.161b Authors Jeff Lukas, Western Water Assessment, Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado 80309, U.S.A. Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 1 / February 2011

Description: Wet sedge tundra communities in the High Arctic are valuable sources of forage for several resident and migratory herbivores; however, the effects of grazing on these systems have been rarely studied. We simulated grazing in two wet sedge meadows at a site on Ellesmere Island that has not been affected by grazing. Over two summers, we clipped plots at four different frequencies and removed litter to assess effects on aboveground net primary production, availability of soil nitrogen, shoot concentrations of carbon and nitrogen, and soil temperature and moisture regimes. Available soil nitrate and ammonium were highest in plots with intermediate clipping frequencies. Shoot nitrogen concentrations were also greater at intermediate clipping frequencies in two of the four species studied. Aboveground net primary production decreased after clipping, regardless of frequency. Litter removal resulted in slightly increased soil moisture, but had no effect on aboveground net primary production. Soil temperature was not affected by any of our treatments. These results suggest that nitrogen cycling is stimulated by intermediate frequencies of simulated grazing, but clipping decreased aboveground net primary production in ungrazed high arctic wet sedge tundra. Content Type Journal Article Pages 198-206 DOI 10.1657/1938-4246-43.2.198 Authors Tammy L. Elliott, Department of Geography, University of British Columbia, 1984 West Mall, Vancouver, British Columbia, V6T 1Z2, Canada Gregory H. R. Henry, Department of Geography, University of British Columbia, 1984 West Mall, Vancouver, British Columbia, V6T 1Z2, Canada Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 2 / May 2011

Description: Mosses are a major component of the tundra flora in the Canadian Arctic, yet their use in arctic contaminant research is lacking. Biomonitoring of atmospheric heavy metal deposition using mosses has been extensively employed in Europe, providing a higher sampling density than precipitation monitoring. Temporal, spatial, and habitat gradients of concentrations and enrichment factors of As, Cd, Cr, Cu, Ni, Zn, and Pb (and its stable isotopes) in mosses from Ellesmere Island are examined. Anthropogenically influenced concentrations of As, Cr, Cu, Ni, and Zn in samples collected in 2007 were observed. Concentrations of heavy metals in hydric taxa were larger than those observed in xeric or mesic taxa, though non-significant. Generally, heavy metal concentrations decreased from 1983 to 2007 in a single high arctic locality, though non-significant. Pb-isotope ratios were radiogenic and characteristic of the High Arctic Islands. Trends in high arctic moss data corresponded with environmental proxies such as glacial ice cores, lake sediments, and atmospheric aerosols illustrating the usefulness of bryophytes as biomonitors. This paper outlines the utility of using mosses as biomonitors of heavy metal depositions in the Canadian High Arctic. Content Type Journal Article Pages 289-300 DOI 10.1657/1938-4246-43.2.289 Authors David Wilkie, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada Catherine La Farge, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 2 / May 2011

Description: We evaluated elevation changes at four sites on debris-covered ablation area of Khumbu Glacier, Nepal Himalaya, since 1978. In 2004, we carried out a ground survey by differential GPS in the upper- and lowermost areas of the ablation area. The amount of surface lowering was calculated by comparing digital elevation models (DEMs) with 30-m grid size, as generated from survey data corrected in 1978, 1995, and in the present study. Because we could not access the middle parts of the debris-covered area due to surface roughness, for this area we used an ASTER-DEM calibrated by the ground survey data. The amount of surface lowering during the period 1978-2004 was insignificant near the terminus. A remarkable acceleration of surface lowering was found in the middle part of the debris-covered ablation area, where the glacier surface is highly undulating. In the uppermost area, surface lowering has continued at a steady rate. Surface flow speeds have decreased since 1956, revealing that the recent decrease in ice flux from the upper accumulation area would have accelerated the rate of surface lowering of the debris-covered area of Khumbu Glacier during the period 1995-2004. Content Type Journal Article Pages 246-255 DOI 10.1657/1938-4246-43.2.246 Authors Takayuki Nuimura, Graduate School of Environmental Studies, Hydrospheric-Atmospheric Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan Koji Fujita, Graduate School of Environmental Studies, Hydrospheric-Atmospheric Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan Kotaro Fukui, Tateyama Caldera Sabo Museum, Toyama 930-1406, Japan Katsuhiko Asahi, Department of Geography, Ritsumeikan University, Kyoto 603-8577, Japan Raju Aryal, Department of Hydrology and Meteorology, Babar Mahal 406, Kathmandu 406, Nepal Yutaka Ageta, Graduate School of Environmental Studies, Hydrospheric-Atmospheric Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 2 / May 2011

Description: Soil moisture has both direct and indirect effects on carbon dioxide (CO 2 ) exchange in tundra vegetation. It directly affects vegetation distribution and functioning, thus CO 2 exchange at the leaf level, and it controls microbial decomposition influencing soil respiration. In this study we investigated CO 2 exchange on a heterogeneous tundra landscape in the Canadian low arctic with the primary purpose of exploring the relationship between moisture variability and community level fluxes. CO 2 exchange was measured with a portable chamber system, along with soil and air temperature. Biomass, leaf area, and foliar nitrogen were determined from harvested vegetation. Fluxes were compared in birch, tussock, heath, and sedge communities under different moisture regimes. Respiration and productivity were typically highest in wet or mesic groups, with fewer differences in net CO 2 exchange. Across the soil moisture gradient, productivity and net CO 2 exchange per unit leaf area and foliar nitrogen showed a significant negative linear trend. Respiration was limited in very dry and saturated soil, and soil temperature effects on respiration were seen only in mesic moisture conditions. These findings indicate that nutrient and temperature affects on fluxes can be at least partially explained within the framework of soil moisture availability. Content Type Journal Article Pages 189-197 DOI 10.1657/1938-4246-43.2.189 Authors Jennifer Dagg, Environmental and Life Sciences Program, Trent University, Peterborough, Ontario, K9J 7B8, Canada Peter Lafleur, Department of Geography, Trent University, Peterborough, Ontario, K9J 7B8, Canada Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 2 / May 2011

Description: Due to observed interactions between Svalbard reindeer ( Rangifer tarandus platyrhynchus ) and polar bears ( Ursus maritimus ) during field work on Edgeøya, Svalbard, we measured response distances for reindeer from a stalking polar bear and improvised five approaches from a person disguised as a polar bear for comparison with human encounters. The alert, flight initiation and escape distances were 1.6, 2.5 and 2.3 times longer, respectively, when Svalbard reindeer were encountered by a person disguised as a polar bear compared to a person in dark hiking gear. Population increase of polar bears on Svalbard and decrease in sea-ice cover in the Arctic region during summer probably results in more frequent interactions with reindeer on the archipelago. Similar reindeer response behavior from encounters with a polar bear and persons disguised as polar bears indicate a predator-prey relationship between the two species on Edgeøya. Content Type Journal Article Pages 483-489 DOI 10.1657/1938-4246-44.4.483 Authors Eigil Reimers, Department of Biology, University of Oslo, P.O. Box 1066 Blindern, 0316 Oslo, Norway Sindre Eftestøl, Department of Biology, University of Oslo, P.O. Box 1066 Blindern, 0316 Oslo, Norway Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 44 Journal Issue Volume 44, Number 4 / November 2012