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: Simultaneous measurements of soil temperature and moisture and related climate and vegetation variables at high altitudes are rare. Such knowledge is important to predict soil temperature and moisture across heterogeneous alpine landscapes and the impact of climate warming on alpine ecosystems. Based on the four-year observations in 12 plots across two contrasting timberline ecotones (north-facing Abies georgei var. smithii and south-facing Juniperus saltuaria timberlines of a valley) in the Sergyemla Mountains, we aimed to determine the role of altitude, aspect, climate, soil, and vegetation variables affecting the variability of soil temperature and moisture. The two timberlines had similar annual precipitation and seasonal mean air temperature, but the growing-season mean soil temperature differed by 0.8-1.0 K. The spring soil warming date was 20-30 days later on the north-facing slope than on the south-facing slope, which was associated with increased snow and vegetation covers on the north-facing slope. Slope aspect, canopy height, and leaf area index (LAI) rather than altitude were the major determining factors for spatial variability of seasonal mean soil temperatures across plots. A combination of aspect southness and canopy height/LAI explained 56-77% of the variations in the -20 cm mean soil temperatures for the year, growing season, and July across the 12 plots. In contrast, seasonal mean soil moistures did not correlate with altitude, aspect, and stand and soil variables. Furthermore, the -5 cm soil temperature amplitude in the growing season was much lower in the north-facing fir forest than in the south-facing juniper forest, suggesting an explanation for the distribution pattern of both species timberlines on opposite slopes of a valley in the Sergyemla Mountains. Content Type Journal Article Pages 229-238 DOI 10.1657/1938-4246-43.2.229 Authors Xinsheng Liu, Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China Tianxiang Luo, Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, 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: Arctic regions hold considerable reservoirs of soil organic carbon. However, most of this carbon is in a potential labile state, and expected changes in temperature and water availability could strongly affect the carbon balance of tundra ecosystems. Plant community composition and soil carbon are closely tied to microtopography and position relative to the water table. We evaluated CO 2 fluxes and moss contribution to ecosystem photosynthesis in response to fine-scale topography across a drained lake bed in Barrow, Alaska, during two contrasting growing seasons. CO 2 exchange was assessed through static chamber measurements in three vegetation classes distinguished by plant dominance and topographic position within lowcentered polygons. Gross primary production (GPP) and ecosystem respiration (ER) were the lowest under high soil moisture conditions in 2006. ER responded more strongly to wet conditions, resulting in a larger summer sink in 2006 than in 2005 (64 vs. 17g CO 2 m -2 , respectively). Microsites responded differently to contrasting weather conditions. Low elevation microsites presented a strong reduction in ER as a result of increased water availability. A maximum of 48% of daytime GPP and 33% of seasonal daytime GPP was contributed by moss on average across microtopographic positions. The interaction between fine-scale microtopography and variation in temperature and water availability can result in considerable differences in CO 2 sink activity of the polygonal tundra. Content Type Journal Article Pages 256-266 DOI 10.1657/1938-4246-43.2.256 Authors Paulo C. Olivas, Department of Biological Sciences, Florida International University, 11200 S.W. 8th Street, Miami, Florida 33199, U.S.A. Steven F. Oberbauer, Department of Biological Sciences, Florida International University, 11200 S.W. 8th Street, Miami, Florida 33199, U.S.A. Craig Tweedie, Department of Biological Sciences, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, U.S.A. Walter C. Oechel, Global Change Research Group, Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, California 92182, U.S.A. David Lin, Department of Biological Sciences, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, U.S.A. Andrea Kuchy, Department of Biological Sciences, Florida International University, 11200 S.W. 8th Street, Miami, Florida 33199, 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: Available soil N is a key factor limiting plant productivity in most low arctic terrestrial ecosystems. Atmospheric N 2 -fixation by cyanobacteria is often the primary source of newly fixed N in these nutrient-poor environments. We examined temporal and spatial variation in N 2 -fixation by the principal cyanobacterial associations (biological soil crusts, Sphagnum spp. associations, and Stereocaulon paschale ) in a wide range of ecosystems within a Canadian low arctic tundra landscape, and estimated N input via N 2 -fixation over the growing season using a microclimatically driven model. Moisture and temperature were the main environmental factors influencing N 2 -fixation. In general, N 2 -fixation rates were largest at the height of the growing season, although each N 2 -fixing association had distinct seasonal patterns due to ecosystem differences in microclimatic conditions. Ecosystem types differed strongly in N 2 -fixation rates with the highest N input (10.89 kg ha -1 yr -1 ) occurring in low-lying Wet Sedge Meadow and the lowest N input (0.73 kg ha -1 yr -1 ) in Xerophytic Herb Tundra on upper esker slopes. Total growing season (3 June-13 September) N 2 -fixation input from measured components across a carefully mapped landscape study area (26.7 km 2 ) was estimated at 0.68 kg ha -1 yr -1 , which is approximately twice the estimated average N input via wet deposition. Although biological N 2 -fixation input rates were small compared to internal soil N cycling rates, our data suggest that cyanobacterial associations may play an important role in determining patterns of plant productivity across low arctic tundra landscapes. Content Type Journal Article Pages 267-278 DOI 10.1657/1938-4246-43.2.267 Authors Katherine J. Stewart, Natural Resources and Environmental Studies, University of Northern British Columbia, Prince George, British Columbia, V2N 4Z9, Canada Darwyn Coxson, Natural Resources and Environmental Studies, University of Northern British Columbia, Prince George, British Columbia, V2N 4Z9, Canada Paul Grogan, Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6, 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: Increasing global annual temperature leads to massive loss of ice cover worldwide. Consequently, glaciers retreat and ice-covered areas become exposed. We report on a study from the Mittivakkat Gletscher forefield in Southeast Greenland with special focus on methanotrophy in relation to exposure time to the atmosphere. The Mittivakkat Gletscher has receded since the end of the Little Ice Age (LIA; about AD 1850) and has left behind a series of deposits of decreasing age concurrently with its recession. Soil samples from this chronosequence were examined in order to elucidate main soil variables, as well as the activity and community structure of methanotrophs, a group of microorganisms involved in regulation of atmospheric methane. Soil variables revealed poor soil development, and incubation experiments showed methane consumption rates of 2.14 nmol CH 4 day -1 g soil -1 at 22 °C and 1.24 nmol CH 4 day -1 g soil -1 at 10 °C in the LIA terminal moraine. Methane consumption was not detected in younger samples, despite the presence of high-affinity methanotrophs in all samples. This was indicated by successful amplification of partial pmoA genes, which code for a subunit of a key enzyme involved in methane oxidation. In addition, the results of the diversity study show that the diversity of the methanotrophic community at the younger, recently deglaciated site P5 is poorer than the diversity of the community retrieved from the LIA moraine. We put forward the hypothesis that aerobic methanotrophs were at very low abundance and diversity during glaciation probably due to anoxia at the ice-sediment interface and that colonization after deglaciation is not completed yet. More detailed studies are required to explain the causes of discrepancy between activity and presence of high-affinity methanotrophs and its relation to the transit from ice-covered probably anoxic to ice-free oxic conditions. Content Type Journal Article Pages 178-188 DOI 10.1657/1938-4246-43.2.178 Authors Teresa G. Bárcena, Center for Geomicrobiology, University of Aarhus, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark Kai W. Finster, Department of Biological Sciences, University of Aarhus, Ny Munkegade 114, DK-8000 Aarhus C, Denmark Jacob C. Yde, Center for Geomicrobiology, University of Aarhus, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark 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: Burrowing mammals often have considerable geomorphological impacts, and their tunneling activities may decrease the stability of landforms. We document the spatial distribution of Norwegian lemming burrows in a subarctic alpine meadow to determine the preferred locations for burrow entrances and to examine the potential for burrowing to decrease the stability of periglacial landforms at the site. Burrow entrances were disproportionately common into the base and sides of landforms (〉68% of burrows), probably reflecting the lower energetic cost of moving soil horizontally, rather than vertically, out of burrows. Most burrow entrances (〉60%) were also located under large rocks, which probably improve burrow stability by providing a firm ceiling to the entrance. Field observations show that these burrows are relatively stable, as only 3% were associated with any signs of increased erosion or landform instability. Therefore, in contrast to some previous studies, and despite burrowing being concentrated on landforms, we suggest that these rodents have little direct impact on landform integrity at this site. Content Type Journal Article Pages 223-228 DOI 10.1657/1938-4246-43.2.223 Authors Peter C. le Roux, Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7600, South Africa Jan Boelhouwers, Department of Social and Economic Geography, Uppsala University, Kyrkogårdsgatan 10, 75120 Uppsala, Sweden Jacqueline K. Davis, Department of Geography, Meteorology and Geoinformatics, Pretoria University, 0002, South Africa Natalie S. Haussmann, Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7600, South Africa Elin J. Jantze, Department of Physical Geography and Quaternary Geology, Stockholm University, 10691 Stockholm, Sweden K. Ian Meiklejohn, Geography Department, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa 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 the 2004-2006 growing seasons, we trapped a total of 6980 spiders (5066 adults, 1914 immatures) using pitfall traps at the Arctic Long Term Experimental Research (LTER) site in Toolik Lake, Alaska. We found 10 families and 51 putative species, with 45 completely identified, in two distinct habitats: Moist Acidic Tundra (MAT) and Dry Heath (DH) Tundra. We captured spiders belonging to the following families (number of species captured): Araneidae (1), Clubionidae (1), Dictynidae (1), Gnaphosidae (4), Linyphiidae (26), Lycosidae (11), Philodromidae (2), Salticidae (1), Theridiidae (1), and Thomisidae (3). Statistical comparisons of families captured at MAT and DH Tundra indicate that the habitats have significantly different spider communities (Chi Square Test: p 〈 0.0001, and Fisher's Exact Test: p = 0.0018). This finding is further supported by differences in similarity, diversity, evenness, and species richness between the two habitats. In this report, we present eight new state records and five extensions of previously described ranges for spider species. The following species are new state records for Alaska: Emblyna borealis (O.P.- Cambridge 1877), Horcotes strandi (Sytschevskaja 1935), Mecynargus monticola (Holm 1943), Mecynargus tungusicus (Eskov 1981), Metopobactrus prominulus (O.P.-Cambridge 1872), Poeciloneta theridiformis Emerton 1911, and Poeciloneta vakkhanka (Tanasevitch 1989). The following five species have been reported previously in Alaska, but not near Toolik Lake: Hypsosinga groenlandica Simon 1889, Gnaphosa borea Kulczyn'ski 1908, Gnaphosa microps Holm 1939, Haplodrassus hiemalis (Emerton 1909), and Islandiana cristata Eskov 1987. Pairwise similarity indices were calculated across 13 other arctic and subarctic spider communities and statistical tests show that all sites are dissimilar ( p = 0.25). These results fit the general pattern of both the patchiness and habitat specificity of arctic spider fauna. Content Type Journal Article Pages 301-312 DOI 10.1657/1938-4246-43.2.301 Authors Karl A. Wyant, School of Life Sciences, Arizona State University, Tempe, Arizona 85287, U.S.A. Michael L. Draney, Cofrin Center for Biodiversity and Department of Natural & Applied Sciences, University of Wisconsin-Green Bay, Green Bay, Wisconsin 54311-7001, U.S.A. John C. Moore, Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado 80523, 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: Surface fluxes are important boundary conditions for climatological modeling and the Asian monsoon system. The recent availability of high-resolution, multi-band imagery from the ASTER (Advanced Space-borne Thermal Emission and Reflection radiometer) sensor has enabled us to estimate surface fluxes to bridge the gap between local-scale flux measurements using micrometeorological instruments and regional scale land-atmosphere exchanges of water and heat fluxes that are fundamental for the understanding of the water cycle in the Asian monsoon system. A Surface Energy Balance System (SEBS) method based on ASTER data and field observations has been proposed and tested in this paper for deriving net radiation flux ( R n ), soil heat flux ( G 0 ), sensible heat flux ( H ), and latent heat flux (λ E ) over a heterogeneous land surface. As a case study, the methodology was applied to an experimental area at NamCo, located at the central Tibetan Plateau, China. The ASTER data of 11 June 2006, 29 October 2007, and 25 February 2008 was used in this paper for the NamCo area case. To validate the proposed methodology, the ground-measured land surface heat fluxes (net radiation flux ( R n ), soil heat flux ( G 0 ), sensible heat flux ( H ), and latent heat flux (λ E )) were compared to the ASTER derived values. The results show that the derived land surface heat fluxes in different months over the study area are in good accordance with the land surface status. The tendency is basically to maintain consistency. It is therefore concluded that the proposed methodology is successful for the retrieval of land surface heat fluxes using the ASTER data and filed observations over the study area. Content Type Journal Article Pages 239-245 DOI 10.1657/1938-4246-43.2.239 Authors Weiqiang Ma, Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China Yaoming Ma, Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China Bob Su, Faculty of Geo-Information Science and Earth Observation, University of Twente, Enschede P.O. Box 6, 7500 AA, Netherlands 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: Berg 2011. Edited by Walter Theil Content Type Journal Article Pages 491-491 Authors Miriam Dühnforth, Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, 450 UCB Boulder, CO 80309-0450 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 3 / August 2011

Description: Snowmelt is considered to affect growth of the boreal forest. So, we tested the hypothesis that late snowmelts delay the onset of xylogenesis and reduce xylem production in trees. Timings of xylem formation were compared to the dates of complete snowmelt combining a 7-year monitoring of cambial activity with meteorological records in four plots of Picea mariana in Quebec, Canada. The spatial and temporal variability in snowfall was analyzed separately, so taking into account both the long- and short-term effects. Snowfall occurred from October to May, with a snow cover lasting 173-199 days. Overall, xylogenesis lasted 99-117 days, with onsets ranging from late May to mid-June. The highest cell productions were observed in the warmest site, where the longest periods of growth were observed. Although at long-term the effects of snowmelt were significant for both onset and duration of xylogenesis and cell production, at short-term only the relationship between the onset of xylogenesis and the date of complete snowmelt was significant. The initial hypothesis could be confirmed only partially. The different responses to the long- and short-term analyses demonstrate the multi-scale influence of snowfall on tree growth and the determinant role of nutrient cycling in the productivity of boreal ecosystems. Content Type Journal Article Pages 457-464 DOI 10.1657/1938-4246-43.3.457 Authors Sergio Rossi, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 Boulevard de l'Université, Chicoutimi (QC), G7H2B1, Canada Hubert Morin, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 Boulevard de l'Université, Chicoutimi (QC), G7H2B1, Canada Annie Deslauriers, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 Boulevard de l'Université, Chicoutimi (QC), G7H2B1, Canada Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 3 / August 2011

Description: While there has been a general trend of climate warming in the Arctic causing early snowmelt and prolonged growing season, climate change models for some areas in the High Arctic suggest increased snow accumulation, delayed spring melt, and consequently shorter growing season. We tested the vegetative and reproductive responses of Cassiope tetragona , an arctic shrub, to increased snow depth and delayed snowmelt using a snow fence experiment in Adventdalen, Norway (78°54'N, 18°01'E). We recorded seasonal shoot length, number of leaves, and capsules per shoot for three summers (2005-2007): two prior and one after the treatment began. Phenological events were recorded in 2007. The number of seeds per capsule was counted and seed germination was tested. Phenological development was significantly delayed behind fences, with lower shoot length, number of leaves, capsules, and seeds per shoot segment (16, 20, 54 and 11%, respectively) compared to controls, but there was no difference in these parameters between plots prior to fence establishment. Seed viability was unaffected by treatment. A delay in start of growing season due to delayed snowmelt decreased vegetative and reproductive performance of C. tetragona; earlier melt may therefore improve performance. This may lead to floral composition change in some high arctic locations. Content Type Journal Article Pages 404-409 DOI 10.1657/1938-4246-43.3.404 Authors Azim U. Mallik, Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada Julia V. Wdowiak, Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada Elisabeth J. Cooper, Department of Arctic and Marine Biology, Faculty for Biosciences, Fisheries and Economics, University of Tromsø, N-9037 Tromsø, Norway Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 3 / August 2011

Description: Numerous small alpine glaciers occupy the high elevation regions of the central and southern Sierra Nevada, California. An inventory based on 1:24,000 topographic maps revealed 1719 glaciers and perennial snowfields for a total area of 39.15 ± 0.13 km 2 . The number of ‘true’ glaciers, versus non-moving ice, is estimated to be 122 covering 14.89 ± 0.08 km 2 or 38% of the ice-covered area. Historic photographs, geologic evidence, and field mapping were used to determine the magnitude of area change over the past century at 14 glaciers. The area change between 1903 and 2004 ranged from -31% to -78%, averaging -55%. Based on these values rough estimates of volume change suggest an ice volume loss from 1903 (1.09 km 3 ) to 2004 (0.43 km 3 ) of 0.66 km 3 (0.59 km 3 water). Rapid retreat occurred over the first half of the 20th century beginning in the 1920s and continued through the 1960s after which recession ceased by the early 1980s and some glaciers advanced. Since the late 1980s glaciers resumed retreat with a rapid acceleration starting in the early 2000s. The relatively uniform timing of area changes in the study glaciers is a response to regional climate whereas the magnitude of change is influenced by local topographic effects. Area changes correlate significantly with changes in summer and winter air temperatures. Warmer winter temperatures warm the snowpack lengthening the summer melt season. Spring air temperatures and precipitation may also play an important role. The occurrence of spring snowfall can delay the onset of melt due to the increased surface albedo. Examining the influence of topographic variables we only found headwall height at the top of the glacier to show an influence on glacier change. Higher headwalls shadow the glacier from solar radiation reducing melt and enhancing snow accumulation via avalanching. If the glaciers continue to shrink at current (1972-2004) rates, most will disappear in 50-250 years. Content Type Journal Article Pages 317-330 DOI 10.1657/1938-4246-43.3.317 Authors H. J. Basagic, Department of Geology, Portland State University, P.O. Box 751, Portland, Oregon 97207-0751, U.S.A. A. G. Fountain, Department of Geology, Portland State University, P.O. Box 751, Portland, Oregon 97207-0751, 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 3 / August 2011

Description: Subsurface flow pathways of groundwater-fed streams were characterized on a floodplain terrace of the Toklat River, Alaska, in summer 2008, to establish the influence of local physicochemical variability upon macroinvertebrate communities. Streams proximal to the valley side (A sites) and to the main meltwater channel (B sites) were studied. Chloride and natural isotopic tracers (δ 18 O and δ 2 H) were used to identify water sources and flow pathways. Results indicated that flow in B sites was dominated by seepage of glacial meltwater through the alluvial aquifer. Streamflow at sites situated at higher elevations was ephemeral, and commenced with the seasonal rise in the groundwater table. In contrast, the physicochemistry of A sites was characteristic of seepage from valley-side debris fans, which maintained perennial flow to streams at lower elevations. Macroinvertebrate diversity was lower in ephemeral streams, likely due to colonization constraints. In June macroinvertebrate abundance was significantly positively correlated with the percentage contribution to streamflow from debris-fan seepage ( p 〈 0.05) and with fine particulate organic matter concentration (FPOM) ( p 〈 0.05); FPOM was correlated with debris fan seepage ( p 〈 0.05). These relationships were not evident in July and August, when organic matter availability increased. Our study demonstrates that flow pathways and organic matter availability significantly influence macroinvertebrate communities in these groundwater-fed streams. Content Type Journal Article Pages 364-379 DOI 10.1657/1938-4246-43.3.364 Authors J. Crossman, School of Geography, Earth and Environmental Sciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, U.K. C. Bradley, School of Geography, Earth and Environmental Sciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, U.K. I. Boomer, School of Geography, Earth and Environmental Sciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, U.K. A. M. Milner, Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska 99775, 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 3 / August 2011

Description: Environmental conditions associated with climate change, such as earlier snowmelt, warmer spring temperatures, and increased soil mineralization, have resulted in shifts in the timing of plant phenological events. We assessed the effects of fertilizer and herbivory on the phenology of 7 plant species from a boreal forest understory using long-term experimental plots in the southwest Yukon. Fertilizer and fencing treatments were initiated in 1990, and discontinued in half of each plot in 2000. There were few effects on phenology of either fertilizer or fencing. In some species, fertilizer affected the final phenological stage reached, but the presence and direction of the effect was species-dependent. Epilobium angustifolium was the only species where the timing of phenological stages responded to fertilization; early phenological stages were advanced with fertilizer. First leaf expansion for Arctostaphylos uva-ursi occurred earlier in fenced plots, although this effect disappeared in plots where the fencing treatment had been discontinued. We conclude that previously observed changes in species abundance with fertilizer treatments are likely not caused by changes in the phenology of these species, and are more likely due to fertilization imposed changes in vegetative growth. Content Type Journal Article Pages 389-396 DOI 10.1657/1938-4246-43.3.389 Authors Kate M. Fremlin, Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada Jennie R. McLaren, Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada Lisa DeSandoli, Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada Roy Turkington, Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 3 / August 2011

Description: Arctic Discourses. Edited by Anka Ryall, Johan Schimanski, and Henning Howlid Wærp Content Type Journal Article Pages 661-662 DOI 10.1657/1938-4246-43.4.661 Authors Shelly Sommer, Institute of Arctic and Alpine Research, University of Colorado Boulder, Colorado 80309-0450 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 4 / November 2011

Description: Past debris-flow and snow avalanche activity was assessed for the Reiselehnrinne (Tyrol, Austria) using growth disturbances in growth-ring series of 372 Norway spruce ( Picea abies (L.) Karst.) trees. Determination of events was performed by analyzing (a) the number and (b) intensity of growth disturbances within tree-ring series and (c) the spatial distribution of affected trees. Differentiation of debris flow from snow avalanche events was based on the intra-annual position of scars, callus tissues or tangential rows of traumatic resin ducts, and on the spatial distribution of trees with simultaneous reactions in the tree-ring series. We introduce a weighting factor to substantiate the dating of past process activity in a comprehensive way and to compare individual events as to their intensity and total number of tree-ring responses. The accuracy of the dendrogeomorphic assessment was then evaluated by comparing the reconstructed event frequency with chronologies available for the Reiselehnrinne. Comparison of tree-ring with historical data demonstrated clearly that the reconstructed event frequency contains the majority of past debris flow and snow avalanche events in the Reiselehnrinne, but that dating of events is not always possible, especially if they are clustered in time or have a limited spread on the cone. Content Type Journal Article Pages 649-658 DOI 10.1657/1938-4246-43.4.649 Authors Barbara Kogelnig-Mayer, Institute of Mountain Risk Engineering, University of Natural Resources and Applied Life Sciences, Peter Jordanstrasse 82, A-1190 Vienna, Austria Markus Stoffel, Laboratory of Dendrogeomorphology, Institute of Geological Sciences, University of Berne, Baltzerstrasse 1+3, CH-3012 Berne, Switzerland Michelle Schneuwly-Bollschweiler, Climate Change and Climatic Impacts, Environmental Sciences, University of Geneva, 7 chemin de Drize, CH-1227 Carouge-Geneva, Switzerland Johannes Hübl, Institute of Mountain Risk Engineering, University of Natural Resources and Applied Life Sciences, Peter Jordanstrasse 82, A-1190 Vienna, Austria Florian Rudolf-Miklau, Federal Ministry for Agriculture, Forestry, Environment and Water Management, Marxergasse 2, A-1030 Vienna, Austria Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 4 / November 2011

Description: In this study, we analyzed the effect of topography, particularly slope, on the expansion rates and population dynamics of Echinospartum horridum at small spatial and temporal scales in the grassland communities of Ordesa-Monte Perdido National Park (OMPNP) (NE Spain). E. horridum is a thorny cushion dwarf, endemic of Spain and south of France, forming dense mono-specific large patches difficult to be penetrated by other plants and large herbivores once it is established. Between 2005 and 2007, we collected demographic parameters from 300 marked plants of E. horridum that were distributed in the center and the edge of four patches. At the patch edge, two of the four patches had a high slope (≥10°) and two had a low slope (

Description: Directly measured growth rates of two lichens ( Pseudephebe minuscula and Rhizocarpon sections Rhizocarpon and Superficiale ) from Svalbard made over a two-decade interval (1984-2007) are presented. Growth rates were determined by measuring the change in area of the lichen thalli from digital images and converting area to diameter. Pseudephebe diameter growth rates ranged from 0.2 to 1.5 mm yr -1 and Rhizocarpon grew 0.05 to 0.30 mm yr -1 . Growth rates of both are a function of thalli size—growth rates increase with increasing thallus size up to 70 mm diameter for Pseudephebe and 30 mm diameter for Rhizocarpon . While these directly measured growth rate results are consistent with other recent directly measured lichen growth studies, they are not consistent with indirectly determined age-size curves that show a negative correlation between size and growth rate (i.e., rapid "great growth" followed by slower "linear growth"). We explore several reasons to explain the apparent discrepancy between directly measured and indirectly determined growth rates, including climate change, increased nutrient fluxes, and population sampling differences between the two methods. We argue that indirectly determined growth curves, which integrate the effects of changing growing conditions over time, remain the best basis for lichenometric dating. Content Type Journal Article Pages 621-631 DOI 10.1657/1938-4246-43.4.621 Authors Steven Roof, School of Natural Science, Hampshire College, Amherst, Massachusetts 01002, U.S.A. Al Werner, Department of Geology and Geography, Mount Holyoke College, South Hadley, Massachusetts 01075, 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 4 / November 2011

Description: About 5.6% of the drainage area of the Tanana River, Alaska, is covered by mountainous glacierized regions, and most of the other area by forests (51%) and wetlands (9%) with discontinuous permafrost. The water discharge and sediment load from glacierized and non-glacierized regions within the drainage area were represented by observed data of the proglacial Phelan Creek and the non-glacial Chena River, respectively, which are both the tributaries of the Tanana River and ultimately drain to the Yukon river basin. In the glacier-melt periods of 2007 and 2008, the runoff rate and suspended sediment concentration in Phelan Creek was 15 times and 36 times as high as those in the non-glacial Chena River, respectively. As a result, the mean sediment yield in the glacier-melt periods of 2007 and 2008 for Phelan Creek (24.8 t km -2 day -1 ) was estimated to be 640 times as high as that in the Chena River (0.039 t km -2 day -1 ). Hence, the glacierized regions were considered to be a major source of the fluvial sediment. In order to quantify the contribution of water discharge and sediment load from the glacierized regions to those of the Tanana River, the time series of water discharge, Q , and sediment load, L , in the glacier-melt periods were simulated by a tank model coupled with the L-Q equations (Nash-Sutcliffe efficiency coefficients, 0.41 to 0.82). The model indicates that the glacier-melt discharge accounted for 26-57% of the Tanana discharge, while the sediment load from the glacierized regions solely accounted for 76-94% of the Tanana sediment load. The remaining contribution (6-24%) of the sediment load was probably due to the fluvial resuspension of glacial sediment deposited previously in the river channels. Content Type Journal Article Pages 632-648 DOI 10.1657/1938-4246-43.4.632 Authors Tomoyuki Wada, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan K. A. Chikita, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan Y. Kim, The International Arctic Research Center, the University of Alaska Fairbanks, Fairbanks, Alaska, 99775-7340, U.S.A. I. Kudo, Faculty of Fisheries Sciences, Hokkaido University, Hakodate, 041-8611, Japan Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 4 / November 2011

Description: A review of published literature and satellite imagery from the late 1960s onwards has revealed 90 surge-type glaciers in the Karakoram mountains, of which 50 have not previously been described in detail. These glaciers were identified by a number of surface features indicative of surge-type behavior such as looped moraines, rapid terminus advance, strandlines and rapid changes in surface crevassing. These observations indicate that surge-type behavior is more common and widespread than previously believed on Karakoram glaciers. There is strong spatial clustering of the surge-type glaciers, and a doubling in the number of new surges in the 14 years after 1990 (26 surges) than in the 14 years before 1990 (13 surges). This is coincident with a period of increased precipitation and positive glacier mass balance in this region, and supports previous studies which have found that mass balance has an important control on the frequency of glacier surging. Content Type Journal Article Pages 503-516 DOI 10.1657/1938-4246-43.4.503 Authors Luke Copland, Department of Geography, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada Tyler Sylvestre, Department of Geography, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada Michael P. Bishop, Department of Geography and Geology, University of Nebraska at Omaha, Omaha, Nebraska 68182, U.S.A. John F. Shroder, Department of Geography and Geology, University of Nebraska at Omaha, Omaha, Nebraska 68182, U.S.A. Yeong Bae Seong, Department of Geography Education, Korea University, Seoul, 136-701, South Korea Lewis A. Owen, Department of Geology, University of Cincinnati, Cincinnati, Ohio 45221, U.S.A. Andrew Bush, Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Ulrich Kamp, Department of Geography, University of Montana, Missoula, Montana 59812, 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 4 / November 2011

Description: Flowering phenology is a key life history trait that strongly influences reproductive success. We investigated the relationship between flowering phenology and functional traits of 48 alpine herb species using the Leaf-Height-Seed (LHS) scheme developed by Westoby (1998) to quantify the ecological strategy of the plant species. Phenological data were obtained by weekly observation of fifty 0.5 × 0.5 m 2 quadrates. Specific leaf area (SLA), height, and seed size of 48 alpine herbs were measured. Comparative generalized estimating equations and generalized linear models suggested that flowering peak date was positively correlated with size of maternal plant (biomass and height) and negatively correlated with seed size. Species with a longer flowering period were smaller and produced bigger seeds than those with a short flowering season. Flowering peak date and duration were negatively correlated, although this correlation was mainly present in annuals, which are relatively rare in the alpine meadow. Relationships between flowering phenology and specific leaf area (SLA) were weak. There were only weak effects of phylogeny on the relationships between flowering phenology and functional traits. Wind-pollinated species flowered earlier than insect-pollinated species. Annuals flowered longer than perennials. Relationships between flowering phenology and functional traits indicate that there is a tradeoff between maternal and reproductive growth, and flowering time may underlie the correlation between plant height and seed size. Content Type Journal Article Pages 585-592 DOI 10.1657/1938-4246-43.4.585 Authors Peng Jia, Key Laboratory of Arid and Grassland Ecology of Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, P. R. China Twenke Bayaerta, Key Laboratory of Arid and Grassland Ecology of Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, P. R. China Xiangqian Li, Key Laboratory of Arid and Grassland Ecology of Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, P. R. China Guozhen Du, Key Laboratory of Arid and Grassland Ecology of Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, P. R. China Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 4 / November 2011

Description: Wind-blown mineral dust derived from the crustal surface is an important atmospheric component affecting the Earth's radiation budget. Deposition of dust particles was measured in snow on Glacier No. 72, Mount Tuomuer, in the western Tian Shan, China. The mean concentration of dust particles (measured as the number of particles) with 0.57 〈 d 〈 26 μm in the snow pack is 706 × 10 3 mL -1 , with a mean mass concentration of 3806 μg kg -1 . Dust number size distribution showed the dominant particles with d 〈 2 μm, while volume size distribution showed single-modal structures having volume median diameters from 3 to 25? μm. Results were compared with data from other sites in the Tian Shan and various Northern Hemisphere sites. A backward trajectory model was also employed to examine the transport process of dust particles in this region. Most of the air mass originated from southern China, e.g., the Taklimakan Deserts in springtime, during the Asian dust period. Transport of dust from southern Chinese deserts to adjacent mountains is in agreement with a growing body of evidence on the importance of dust inputs to alpine regions. Content Type Journal Article Pages 517-526 DOI 10.1657/1938-4246-43.4.517 Authors Dong Zhiwen, State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute/Tianshan Glaciological Station, Chinese Academy of Sciences, Lanzhou 730000, China Li Zhongqin, State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute/Tianshan Glaciological Station, Chinese Academy of Sciences, Lanzhou 730000, China Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 4 / November 2011

Description: Alpine plant communities are sensitive to global climate change, which has been predicted to cause increases in woody vegetation, possibly at the expense of herbs. We studied a community in western Maine, comparing the frequency and abundance of alpine plants in 2009 with frequency and abundance recorded in 1976. During the 33 years between surveys, the most common tree became more frequent, and as a result, the frequency of trees as a functional group increased. Shrubs did not become more frequent but did become more abundant, driven by the increasing abundance of two Vaccinium species. Several species provided evidence of strong affinities for the north or south slope of the mountain, but in most cases such evidence was apparent in a species' frequency or its abundance, not both, indicating that different forces regulate dispersal and vegetative growth of alpine plants, which could have implications for understanding responses to changing environmental conditions. Total species richness of the community increased, with the addition of several lower montane herbs. The changes are consistent with predictions and with observations made in tundra communities elsewhere. Content Type Journal Article Pages 495-502 DOI 10.1657/1938-4246-43.4.495 Authors R. S. Capers, George Safford Torrey Herbarium, Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut 06269-3043, U.S.A. A. D. Stone, Alton Engineering, Sterling Massachusetts 01564, 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 4 / November 2011

Description: Vegetation in primary succession is influenced by multiple stochastic and environmental factors at different spatial and temporal scales. In this study we analyze the effect of meso-topographic heterogeneity on vegetation development following the retreat of Glaciar Seco in the southern Patagonian Andes. Composition and cover of algae, lichens, mosses, and vascular plants were recorded in 580 plots located in different topographic positions within a chronosequence of eight consecutive moraines. Sample plots were characterized by topographical and surface features. Spatiotemporal patterns in vegetation composition and their relationships to environmental factors were assessed by classification and ordination. We recognized eight communities that correspond to four major successional stages. The successional sequence is characterized by a physiognomic development from pioneer saxicolous lichens (first stage) to secondary colonizer lichens (second stage), followed by shrub colonization (third stage) and the development of Nothofagus spp. forests (fourth stage). Alternative successional trajectories on different topographic positions vary in the sequence of these four major successional stages, with the trajectories on the moraine ridge-top and base not going through some of the stages. A variance partition procedure shows that time since deglaciation and topographic position on the moraines account for comparable amounts of vegetation variance, emphasizing the importance of spatiotemporal analysis of vegetation development on heterogeneous landscapes. Broad trends in vegetation development follow environmental gradients. However, emergence and persistence of vegetation patterns can also be attributed to dynamic geomorphic processes such as moraine slope degradation affecting boulder distribution along the moraine foreslope. At the landscape scale, successional trajectories converge to a Nothofagus -dominated state, but significant variability remains in the understory due to the differential distribution of cryptogams along the moraine topographic gradient. Convergence is mostly related to the expansion of communities from more favorable sites towards the harsher moraine crest, but it is not a process of gradual deterministic changes along the different successional pathways. Content Type Journal Article Pages 555-567 DOI 10.1657/1938-4246-43.4.555 Authors Irene A. Garibotti, Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, CCT-CONICET Mendoza, C.C. 330, (5500) Mendoza, Argentina Clara I. Pissolito, Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, CCT-CONICET Mendoza, C.C. 330, (5500) Mendoza, Argentina Ricardo Villalba, Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, CCT-CONICET Mendoza, C.C. 330, (5500) Mendoza, Argentina Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 4 / November 2011

Description: In a warming climate, sexual reproduction may play an important role in plant community composition in arctic tundra. As temperatures increase and currently immobilized soil nutrients become available, flowering, fruiting, and germination conditions will likely improve. We examined how experimentally adding soil nutrients for 13 and 20 years affected species composition, flower and fruit production, seed dispersal, composition of the seed bank, and seedling establishment in a dry heath plant community in northern Alaska. Fertilizer addition significantly shifted adult community composition by decreasing lichens and evergreen shrubs and increasing abundance of a bunchgrass, Hierochloe alpina , and dwarf birch, Betula nana . More seeds were dispersed adjacent to nutrient amended plots, particularly of B. nana , and soil seed banks differed significantly between control and fertilized soils reflecting the adult communities in the field. Few seedlings were observed in any field plots. However, seeds of H. alpina likely played a role in the community shift because this species has few, small individuals in control plots, yet is densely packed in fertilized plots. B. nana , on the other hand, appears to be increasing in relative abundance via vegetative growth of existing individuals. Therefore, although sexual reproduction leading to seedling establishment is rare currently, as nutrients become more available in a warming climate, individuals may recruit from seed more often as long as space is available. Content Type Journal Article Pages 612-620 DOI 10.1657/1938-4246-43.4.612 Authors Carol Ann Moulton, Biology Department, University of Texas at Arlington, Box 19498, Arlington, Texas 76019-0498, U.S.A. Laura Gough, Biology Department, University of Texas at Arlington, Box 19498, Arlington, Texas 76019-0498, 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 4 / November 2011

Description: We document the post-Last Glacial Maximum (LGM) deglaciation history of a small catchment in Colorado's Front Range and model the glacial history responsible. We combine cosmogenic exposure dating of moraine boulders and glacial polish from 10 sites down the valley axis with a set of 1-D and 2-D numerical glacier models in which climate is represented by prescribed winter and summer mass balance profiles. Moraine ages of 24-18 ka constrain the LGM maximum glacial extent at 15 km downvalley from the range crest. Glacial polish sites decline in age along the center portion of the valley, dropping to roughly 12 ka by 5 km from the crest. This supports a monotonic but non-steady decline in glacier length. Modeling of the deglaciation history reveals that the equilibrium line altitude (ELA) rise from ~18 ka to ~14 ka was between 250 and 350 m, and that from ~14 ka to ~12 ka was between 100 and 150 m. Complete deglaciation requires at least another 250-300 m of ELA rise. A transient model run employing this ELA history can both reproduce the spatio-temporal pattern of glacial polish ages, and honor the constraints on maximum glacial extent. The full deglaciation between 18 ka and 10 ka can be modeled successfully with a 4.5-6 °C temperature rise and little to no change in precipitation. Content Type Journal Article Pages 527-542 DOI 10.1657/1938-4246-43.4.527 Authors Miriam Dühnforth, Institute of Arctic and Alpine Research, University of Colorado, 450 UCB, Boulder, Colorado 80309-0450, U.S.A. Robert S. Anderson, Institute of Arctic and Alpine Research, University of Colorado, 450 UCB, Boulder, Colorado 80309-0450, 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 4 / November 2011

Description: Fens and wet meadows are important mountain wetland types, but influences on assemblage structure of associated invertebrates are poorly understood compared with other aspects of the ecology of these habitats. We sought to determine the relative contributions of terrestrial and aquatic invertebrates to diversity and abundance in these wetlands, the extent to which terrestrial and aquatic invertebrate assemblages differ with wetland type, and to what degree the aquatic assemblages vary as a function of slow sheet flow. We compared assemblages in fens and wet meadows, with and without flow, at 80 backcountry sites dispersed across the 6200 km 2 landscape of Yosemite, Sequoia, and Kings Canyon National Parks in the Sierra Nevada mountains of California, U.S.A., using standard aquatic and terrestrial sweep netting. Cicadellid leafhoppers, aphids, and thomisid crab spiders were the most abundant terrestrial taxa. Cicadellids, Lepidoptera, anthomyiid, muscid, chloropid, and ephydrid flies, and thomisids were more abundant in fens than in wet meadows. Only mirid leaf bugs were significantly more abundant in wet meadows than fens. Sphaeriid clams and chironomid midges dominated aquatic assemblages both with and without flow. Chloroperlid stoneflies, mites, clams, and flatworms were all more abundant in flow, and Hemiptera and mosquitos were significantly more abundant in quiescent water. Mosquitos were more abundant in wet meadows, but there were few other population differences as a function of wetland type. Terrestrial diversity was 1.1 to 2.0 times that of aquatic diversity, depending on metric and habitat. Fens had greater terrestrial abundance, richness, evenness, and diversity than wet meadows; there were fewer differences as a function of wetland type for aquatic fauna. Presence or absence of slow sheet flow had more effect on these aquatic assemblages than did wetland type. Cluster analyses, ordination, and multi-response permutation procedures were generally consistent with the univariate results. Vegetation-based wetland classifications should be extrapolated to faunal assemblages with caution, particularly for aquatic invertebrates. Content Type Journal Article Pages 568-584 DOI 10.1657/1938-4246-43.4.568 Authors Jeffrey G. Holmquist, White Mountain Research Station, University of California San Diego, 3000 E. Line Street, Bishop, California 93514, U.S.A. Jennifer R. Jones, Department of Forest, Rangeland, and Watershed Stewardship, Colorado State University, Ft. Collins, Colorado 80523, U.S.A. Jutta Schmidt-Gengenbach, White Mountain Research Station, University of California San Diego, 3000 E. Line Street, Bishop, California 93514, U.S.A. Lyra F. Pierotti, White Mountain Research Station, University of California San Diego, 3000 E. Line Street, Bishop, California 93514, U.S.A. Jason P. Love, White Mountain Research Station, University of California San Diego, 3000 E. Line Street, Bishop, California 93514, 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 4 / November 2011

Description: Trees in the southern Siberian Mountains forest-tundra ecotone have considerably increased their radial and apical growth increments during the last few decades. This leads to the widespread vertical transformation of mat and prostrate krummholz forms of larch ( Larix sibirica Ledeb) and Siberian pine ( Pinus sibirica Du Tour). An analysis of the radial growth increments showed that these transformations began in the mid-1980s. Larch showed a greater resistance to the harsh alpine environment and attained a vertical growth form in areas where Siberian pine is still krummholz. Upper larch treeline is ≥10 m higher than Siberian pine treeline. Observed apical and radial growth increment increases were correlated with CO 2 concentration ( r 5 0.83-0.87), summer temperatures ( r = 0.55-0.64), and "cold period" (i.e. September-May) air temperatures ( r = 0.36-0.37). Positive correlation between growth increments and winter precipitation was attributed to snow cover protection for trees during wintertime. Content Type Journal Article Pages 593-600 DOI 10.1657/1938-4246-43.4.593 Authors V. I. Kharuk, V. N. Sukachev Institute of Forest, Krasnoyarsk, Russia M. L. Dvinskaya, V. N. Sukachev Institute of Forest, Krasnoyarsk, Russia S. T. Im, V. N. Sukachev Institute of Forest, Krasnoyarsk, Russia K. J. Ranson, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, 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 4 / November 2011

Description: Productivity of a managed grazing system is dependent upon both the grazing strategy of ungulates and decisions made by humans. Herds of domestic reindeer ( Rangifer tarandus tarandus ) graze on discrete ranges of the Seward Peninsula, Alaska with variable production rates. We show that the 15 N natural abundance of reindeer forages vary significantly and the δ 15 N value of collagen deposited in antler bone from spring until ossification was significantly correlated with the δ 15 N signature of the diet. Calf weight in June was related to isotopic signatures in antler and soft tissue of adult females, and was inversely correlated with the absolute differential between summer and winter serum δ 15 N values. This observation suggests that female reindeer with smaller calves had catabolized more body protein during winter than females in adjacent herds. Moreover, in herds with smaller calves, female reindeer consumed proportionately more shrubs in early spring resulting in a strong relationship between δ 15 N signatures of antler collagen deposited in May and calf weight. These data suggest female reindeer catabolizing relatively more body protein during winter may attempt to compensate by increasing consumption of high-protein catkins and leaf buds of shrubs during May. Herders with relatively smaller calves in their herds may be able to improve protein balance of reproductive females and thus increase calf productivity by increasing access to shrub habitats during spring. Content Type Journal Article Pages 543-554 DOI 10.1657/1938-4246-43.4.543 Authors Gregory L. Finstad, Reindeer Research Program, School of Natural Resources and Agricultural Sciences, University of Alaska Fairbanks, P.O. Box 757200, Fairbanks Alaska 99775-7200, U.S.A. Knut Kielland, Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska 99775, 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 4 / November 2011

Description: At a high mountain lake in catchments of mica schist and gneiss rock in the European Alps, substantial increases in solute concentrations of sulfate, magnesium, calcium, silica, manganese, and nickel were observed over the past two decades. We hypothesized that microbial interactions with rock in the catchment of the lake might play an important role. We studied the chemolithotrophic activities resulting in the production of metal mobilizing metabolites (mineral acids). The potential of nitrifying and sulfur-oxidizing cultures derived from rock to mobilize elements from this rock when augmented with ammonium and thiosulfate was investigated in a 35 day laboratory study. Bacterial species prevailing in the indigenous nitrifying and sulfur-oxidizing mixed cultures were determined by 16S rRNA gene sequence based analysis. The average mineralogical composition of the rock sample was quartz (50%), feldspar (27%), muscovite (15%), chlorite (6%), and dolomite (2%). The increase of each soluble element in the presence of cultures relative to the conditions without microbes was related to the total element in the rock sample (leaching efficiency in percent). After 35 days, leaching efficiency was 7% (Ca), 2.4% (Mg), and 6.3% (Mn) in the presence of the nitrifying culture. In the presence of the sulfur-oxidizing culture, leaching efficiency was 13% (Ca), 5.7% (Mg), 5.4% (Mn), 1.3% (Zn), 0.2% (Fe), and 0.1% (Al). The results suggest that under conditions of abundant substrate availability, chemolithotrophic activity on catchment rock can contribute to the increase in soluble Ca, Mg, and Mn in lake water. Content Type Journal Article Pages 465-473 DOI 10.1657/1938-4246-43.3.465 Authors Renate Sonnleitner, Institute of Microbiology, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria Bernhard Redl, Division of Molecular Biology, Biocenter-Medical University of Innsbruck, Fritz Pregl Strasse 3, A-6020 Innsbruck, Austria Franz Schinner, Institute of Microbiology, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 3 / August 2011

Description: Substantial climate warming is predicted for high latitude regions and may have large impacts on tundra communities. As part of the International Tundra Experiment, this study characterized plant responses to natural and experimental variations in temperature at a subarctic, alpine tundra site. Non-destructive measures of plant reproduction and growth were monitored annually for four target species (Dryas octopetala, Lupinus arcticus, Polygonum viviparum , and Salix arctica) from 1999 to 2008. Plants were exposed to 8 years of an experimental warming treatment using open-topped chambers (OTCs). Temperatures in OTCs tended to be warmer at midday but cooler at night, with little net daily warming. OTCs had relatively little effect on plant responses, except for positive effects on reproductive characteristics of D. octopetala and P. viviparum. All target species except L. arcticus showed significant annual variations in vegetative and reproductive characteristics. Nondestructive measures used to monitor plant performance were significantly related to actual growth and reproductive output in most cases. Plant community composition did not show experimental effects nor were there consistent trends in composition over the 10 years of the study. Results of the study highlight individualistic species responses and the resilience of the plant community to observed temperature variations at this site. Content Type Journal Article Pages 442-456 DOI 10.1657/1938-4246-43.3.442 Authors Sara J. Pieper, Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada Val Loewen, Environment Yukon, Box 2703, Whitehorse, Yukon, Y1A 2C6, Canada Mike Gill, Environment Canada, 91780 Alaska Highway, Whitehorse, Yukon, Y1A 5X7, Canada Jill F. Johnstone, Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 3 / August 2011

Description: The diversity and distribution of aquatic benthic invertebrate communities of 17 lakes and 3 shallow ponds near Iqaluit and Rankin Inlet, Nunavut, Canada, were examined to assess patterns with respect to environmental gradients. Macroinvertebrates were collected using 500 μ mesh D-nets, and collected specimens were identified and enumerated; a total of 40 taxa were identified. Multivariate analyses (Redundancy Analysis) of relative abundance (%) data identified habitat (dominant substrate type), water chemistry, nutrients, and food/productivity (total phosphorus, total nitrogen, sulfate, dissolved oxygen, chlorophyll a ), physical characteristics (maximum depth), catchment-related properties (lake elevation), and climate-related properties as significant environmental gradients influencing community composition. Ecosystem-scale lake characteristics had the greatest influence on benthic communities, followed by substrate type; however, there were substantive amounts of community variation influenced by the interaction between lake characteristics, substrate type, and regional differences. A number of environmental variables may have been significant due to differences in their values when comparing Rankin Inlet region sites versus Iqaluit region sites. The results agree with other studies indicating that benthic invertebrate communities are influenced by environmental gradients acting at different scales ranging from local, within-lake scales to large, regional scales. Content Type Journal Article Pages 417-428 DOI 10.1657/1938-4246-43.3.417 Authors Armin Namayandeh, Department of Environmental Science, Trent University, 1600 West Bank Drive, Peterborough, Ontario, K9J 7B8, Canada Roberto Quinlan, Department of Environmental Science, Trent University, 1600 West Bank Drive, 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 3 / August 2011

Description: Previous research has indicated that modeling evapotranspiration (ET) in the Arctic Coastal Plain is challenging due to unique ecosystem conditions which include mosses, permafrost, and standing dead vegetation. A new version of the commonly used Biome-BGC (Biogeochemical Cycles) model (Arctic Biome-BGC) was developed that included: (1) a water storage and vertical drainage/infiltration routine that accounts for permafrost and mosses, (2) a modified representation of energy available at the surface which includes ground heat flux and simulates interception of incoming radiation by standing dead vegetation, and (3) a background evaporation routine that allows for moss and open water evaporation. In this study we investigated the sensitivity of model predictions to variations in parameter values, and to provide a conceptual validation of Arctic Biome-BGC. Using the generalized sensitivity analysis methodology, 13 parameters were evaluated. Results indicate that the model was sensitive to 8 of the 13 parameters. Seven of these parameters were introduced in the development of Arctic Biome-BGC and related to both energy reaching the ground surface and the amount of water stored within the soil and moss layers. The remaining sensitive parameter modulates the rate of snowmelt. These results validate the conceptual modifications included in the Arctic Biome-BGC model for estimating ET. Content Type Journal Article Pages 380-388 DOI 10.1657/1938-4246-43.3.380 Authors Ryan Engstrom, Department of Geography, George Washington University, 922 F Street, NW, Washington, DC 20052, U.S.A. Allen Hope, Department of Geography, San Diego State University, San Diego, California 92182-4493, 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 3 / August 2011

Description: Coastal erosion rates locally exceeding 30 m y -1 have been documented along Alaska's Beaufort Sea coastline, and a number of studies suggest that these erosion rates have accelerated as a result of climate change. However, a lack of direct observational evidence has limited our progress in quantifying the specific processes that connect climate change to coastal erosion rates in the Arctic. In particular, while longer ice-free periods are likely to lead to both warmer surface waters and longer fetch, the relative roles of thermal and mechanical (wave) erosion in driving coastal retreat have not been comprehensively quantified. We focus on a permafrost coastline in the northern National Petroleum Reserve-Alaska (NPR-A), where coastal erosion rates have averaged 10-15 m y -1 over two years of direct monitoring. We take advantage of these extraordinary rates of coastal erosion to observe and quantify coastal erosion directly via time-lapse photography in combination with meteorological observations. Our observations indicate that the erosion of these bluffs is largely thermally driven, but that surface winds play a crucial role in exposing the frozen bluffs to the radiatively warmed seawater that drives melting of interstitial ice. To first order, erosion in this setting can be modeled using formulations developed to describe iceberg deterioration in the open ocean. These simple models provide a conceptual framework for evaluating how climate-induced changes in thermal and wave energy might influence future erosion rates in this setting. Content Type Journal Article Pages 474-484 DOI 10.1657/1938-4246-43.3.474 Authors Cameron Wobus, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, U.S.A. Robert Anderson, Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado 80309, U.S.A. Irina Overeem, Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado 80309, U.S.A. Nora Matell, Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309, U.S.A. Gary Clow, U.S. Geological Survey, Box 25046, Federal Center, Denver, Colorado 80225, U.S.A. Frank Urban, U.S. Geological Survey, Box 25046, Federal Center, Denver, Colorado 80225, 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 3 / August 2011

Description: The melting of glaciers in the European Alps has exposed new terrain in the last decades. Ground beetles (Carabidae, Coleoptera) are among the first colonizers of this new alpine land. Since 1999, we have studied the ground beetle assemblages of the recently deglaciated areas in the Hornkees glacier foreland (Zillertal Alps, Austria). Data were collected in July 1999, 2001, 2007, and 2009. Two species of Carabidae, Nebria jockischii and Nebria germari , were dominant in the areas immediately below the glacier in all sampling periods. The occurrence of Nebria jockischii larvae very close to the edge of the glacier strongly suggests that reproduction occurred in the area which had been ice-free for only one year. Comparison of the carabid beetle assemblages from the recently deglaciated areas with those from neighboring and longer exposed areas indicates that the first colonizers continuously expanded their range following the path of the glacial retreat. We hypothesize that Nebria jockischii populated the new alpine terrain by initial migration from the banks of the glacial stream, whereas Nebria germari probably colonized the recently deglaciated area by migration from the lateral moraines. These carabid beetles represent the first predatory insects in the initial phase of colonization of the Hornkees foreland. Content Type Journal Article Pages 397-403 DOI 10.1657/1938-4246-43.3.397 Authors Barbara-Amina Gereben-Krenn, Faculty of Life Sciences, Department of Evolutionary Biology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria Harald W. Krenn, Faculty of Life Sciences, Department of Evolutionary Biology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria Markus A. Strodl, Vienna Institute of Plant Protection, University of Natural Resources and Applied Life Sciences, Peter Jordan-Strasse 82, A-1190 Vienna, Austria Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 3 / August 2011

Description: We used a regionally modified global vegetation model (BIOME4-Tibet) to simulate biome distribution on the Tibetan Plateau under current climate conditions derived from regional meteorological observations. The bioclimatic limits (mean temperatures of the coldest and warmest months, minimum temperature, growing degreedays on 5 °C and 0 °C bases) for some key alpine plant functional types (temperate deciduous and conifer trees, boreal deciduous and conifer trees, desert woody plants, tundra shrubs, cold herbaceous plants, and lichens/forbs) were redefined based on regional vegetation-climate relationships. Modern vegetation maps confirmed that the BIOME4-Tibet model does a better job of simulating biome patterns on the plateau (gridcell agreement 52%) than the original BIOME4 model (35%). This improved model enhanced our ability to simulate temperate conifer forest, cool conifer and mixed forest, evergreen taiga, temperate xerophytic shrubland, temperate grassland and desert, and steppe and shrub tundra biomes, but made a negligible or reduced difference to the prediction of temperate deciduous forest, warm-temperate mixed forest, and three tundra biomes (erect dwarf-shrub tundra, prostrate dwarfshrub tundra, and cushion forb, lichen, and moss tundra). Future modification of the vegetation model, by increasing the number of shrub and herb plant functional types, re-parameterization of more precise bioclimatic constraints, and improved representation of soil, permafrost, and snow processes, will be needed to better characterize the distribution of alpine vegetation on the Tibetan Plateau. Content Type Journal Article Pages 429-441 DOI 10.1657/1938-4246-43.3.429 Authors Jian Ni, Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, D-14473 Potsdam, Germany Ulrike Herzschuh, Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, D-14473 Potsdam, Germany Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 3 / August 2011

Description: In situ observations show increases in shrub cover in different arctic regions in recent decades and have been cited to explain the increases in arctic vegetation productivity revealed by satellite remote sensing. A widespread increase in shrub cover, particularly tall shrub cover, is likely to profoundly alter the tundra biome because of its influence on biogeochemical cycling and feedbacks to climate. To monitor changes in shrub cover, aid field studies, and inform ecosystem models, we mapped shrub cover across the North Slope of Alaska. First, images from the IKONOS and SPOT satellite sensors were used to detect tall (〉1 m) and short shrub presence at high resolution (〉5 m grid cells) in different parts of the domain. The resulting maps were then used to train a Random Forest regression algorithm that mapped total and tall shrub cover, expressed as a percent of the total surface area, at 30 m resolution from a mosaic of Landsat scenes. The final shrub cover maps correspond well with field measurements ( r 2 = 0.7, root mean square error = 17%, N = 24) and compared well with the existing vegetation type maps of the study area and a gridded temperature data set not used in the map generation. Content Type Journal Article Pages 355-363 DOI 10.1657/1938-4246-43.3.355 Authors Pieter S. A. Beck, Woods Hole Research Center, 149 Woods Hole Road, Falmouth, Massachusetts 02540, U.S.A. Ned Horning, Center for Biodiversity and Conservation, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, U.S.A. Scott J. Goetz, Woods Hole Research Center, 149 Woods Hole Road, Falmouth, Massachusetts 02540, U.S.A. Michael M. Loranty, Woods Hole Research Center, 149 Woods Hole Road, Falmouth, Massachusetts 02540, U.S.A. Ken D. Tape, Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska Fairbanks, P.O. Box 80425, Fairbanks, Alaska 99708, 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 3 / August 2011

Description: Melilotus albus (white sweetclover) has invaded Alaskan glacial river floodplains. We measured cover and density of plant species and environmental variables along transects perpendicular to the Nenana, Matanuska, and Stikine Rivers to study interactions between M. albus and other plant species and to characterize the environment where it establishes. Melilotus albus was a pioneer species on recently disturbed sites and did not persist into closed canopy forests. The relationships between M. albus cover and density and other species were site-specific. Melilotus albus was negatively correlated with native species Elaeagnus commutata at the Nenana River, but not at the Matanuska River. Melilotus albus was positively correlated with the exotic species Crepis tectorum and Taraxacum officinale at the Matanuska River and T. officinale on the upper Stikine River. However, the high density of M. albus at a lower Stikine River site was negatively correlated with T. officinale and several native species including Lathyrus japonicus var. maritimus and Salix alaxensis . Glacial river floodplains in Alaska are highly disturbed and are corridors for exotic plant species movement. Melilotus albus at moderate to low densities may facilitate establishment of exotic species, but at high densities can reduce the cover and density of both exotic and native species. Content Type Journal Article Pages 343-354 DOI 10.1657/1938-4246-43.3.343 Authors Jeffery S. Conn, U.S. Department of Agriculture, Agricultural Research Service, University of Alaska Fairbanks, Subarctic Agricultural Research Unit, 360 O'Neill Building, Fairbanks, Alaska 99775, U.S.A. Nancy R. Werdin-Pfisterer, U.S. Department of Agriculture, Agricultural Research Service, University of Alaska Fairbanks, Subarctic Agricultural Research Unit, 360 O'Neill Building, Fairbanks, Alaska 99775, U.S.A. Katherine L. Beattie, U.S. Department of Agriculture, Agricultural Research Service, University of Alaska Fairbanks, Subarctic Agricultural Research Unit, 360 O'Neill Building, Fairbanks, Alaska 99775, U.S.A. Roseann V. Densmore, U.S. Geological Survey, Alaska Science Center, 1011 Tudor Road, Anchorage, Alaska 99503, 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 3 / August 2011

Description: James Bell Benedict Content Type Journal Article Pages 485-489 DOI 10.1657/1938-4246-43-3.485 Authors Peter W. Birkeland, Department of Geological Sciences, 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 3 / August 2011

Description: The blue-white gentian, Gentiana leucomelaena (Gentianaceae), bears two colors of flowers (blue and white) within populations and on individual plants. We tested the hypothesis that these flower morphs have different mating systems associated with differences in pollinator species and visitation rates. This hypothesis was driven by the fact that colorful flowers are often more likely to be pollinated by diverse animal pollinators, and by the observation that white G. leucomelaena flowers always blossom earlier than blue ones in early spring, when few pollinators are available. This hypothesis was investigated by determining the pollination success, daily duration of flower opening, flower life span, the number of pollen grains and ovules per flower, pollinator visitation rates, and seed output for both color morphs during the flowering season of 2009. Hand-pollination and pollinator-exclusion experiments were also conducted to determine whether the two color morphs differed in their ability to self-pollinate. In general, blue flowers were found to have a trait combination that favors a significantly higher degree of pollinator specificity and cross fertilization, whereas white flowers were characterized as pollinator generalists and self-fertilizing. We speculate that the difference in the floral structure and function between blue and white flowers and their coexistence are likely adaptive in unpredictable and often pollinator-limited environments such as those found in the alpine meadows of the Qinghai-Tibet Plateau. Content Type Journal Article Pages 410-416 DOI 10.1657/1938-4246-43.3.410 Authors Junpeng Mu, ECORES Lab, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China Guoyong Li, ECORES Lab, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China Karl J. Niklas, Department of Plant Biology, Cornell University, Ithaca, New York 14850, U.S.A. Shucun Sun, ECORES Lab, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China Journal Arctic, Antarctic, and Alpine Research Online ISSN 1938-4246 Print ISSN 1523-0430 Journal Volume Volume 43 Journal Issue Volume 43, Number 3 / August 2011

Description: The distribution of alpine tundra in the Adirondack Mountains of New York was investigated through a combination of field mapping and GIS analysis. Alpine tundra vegetation covers 26.3 ha (65 acres). Tundra patches are rare below an elevation of 1350 m although significant differences exist in mean tundra elevation between summits reflecting overall summit morphology. Tundra is generally more abundant, and extends to lower elevations on windward slopes with northerly and northwesterly aspects. Tundra patches on leeward slopes are found at higher elevations and are considerably larger, reflecting increased fragmentation on windward slopes and development of snowbank communities on leeward slopes. At a regional scale, the percentage of high-elevation land covered by tundra decreases from the northwest to southeast across the study area, suggesting that mountains upwind along the prevailing winter wind vector shield downwind summits, underscoring the role of exposure in limiting the upward growth of trees. Because exposure exerts a fundamental control over patch boundaries, shifts in the balance between arboreal and non-arboreal vegetation over time could be expected if changes occur in the frequency of icing events, the severity of winter storms, temperature, cloudiness, or prevailing wind directions. Content Type Journal Article Pages 331-342 DOI 10.1657/1938-4246-43.3.331 Authors Bradley Z. Carlson, Department of Geography, Middlebury College, Middlebury, Vermont 05753, U.S.A. Jeffrey S. Munroe, Department of Geology, Middlebury College, Middlebury, Vermont 05753, U.S.A. Bill Hegman, Department of Geography, Middlebury College, Middlebury, Vermont 05753, 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 3 / August 2011