Arp, C., Jones, B. M., Liljedahl, A. K., Lenters, J., Hinkel, K. M., and Welker, J. M. Ice regime and melt-out timing cause converging patterns of hydrologic response among Arctic lakes to a warming climate. JGR Water Resources Research (in press).

Puntsag, T., Mitchell, M., Campbell, J. L., Klein, E. S., Likens, G. E., and Welker, J. M. Arctic vortex changes alter the sources and the isotopic values of precipitation in the NE US. Nature Scientific Reports (in press).

Klein, E., Nolan, M., Cable, J., Cherry, J. and J M Welker. Northern Alaska precipitation and water vapor isotopic measurements applied to McCall Glacier ice core climate reconstructions. Quaternary Science Research 131: 274-284 .

Cahoon SMP, Sullivan PF, Post E. in press. Carbon and water relations of contrasting Arctic plants: implications for shrub expansion in West Greenland. Ecosphere

Cahoon SMP, Sullivan PF, Gamm C, Welker JM, Eissenstat D, Post E. in press. Limited variation in proportional contributions of auto- and heterotrophic soil respiration, despite large differences in vegetation structure and function in the Low Arctic. Biogeochemistry DOI: 10.1007/s10533-016-0184-x.

Brownlee AH, Sullivan PF, Csank AZ, Sveinbjörnsson B, Ellison SBZ. 2016. Drought-induced stomatal closure probably cannot explain divergent white spruce growth in the Brooks Range, Alaska, USA. Ecology 97: 145-159.

Csank, A., Miller, A., Sherriff, R. L., Berg, E. E., Welker, J. M. 2016. Environmental sensitivity of trees killed during insect outbreaks in south-central Alaska revealed by tree-ring isotope (δ¹³C & δ¹⁸O) chronologies. Ecological Monographs (in press).

Leffler, A. J., Klein, E., Oberbauer, S. and Welker, J. M. 2016. Coupled long-term summer warming and deeper snow alters species composition and stimulates gross primary productivity in tussock tundra. Oecologia (in press).

Yang, L., Rogers, M., and Welker, J. M. 2016. Wintering Monarch butterfly population identity in S California: Using precipitation and wing δ²H values across the western U. S. Ecograhy (in press)

Jasechko, S., McDonnell, J. J. and Welker, J. M. Young and old water in global rivers.  Nature Geoscience 9 DOI: 10.1038/NGEO 2636

• 2015 Publications

  Sullivan PF, Ellison SBZ, McNown RW, Brownlee AH, Sveinbjörnsson B. 2015. Evidence of soil nutrient availability as the proximate constraint on growth of treeline trees in northwest Alaska. Ecology 96: 716-727.

  Klein, E., Cherry, J., Cable, J., Noone, D., Leffler, J. and Welker, J. M. 2015. Arctic cyclone water vapor isotopes support past sea ice retreat recorded in Greenland ice. Nature Scientific Reports 5: 10295 DOI: 10:1038/srep10295

  Rogers, M. C., O’Dell, M. B., Peacock, E. L., Simac, K., and Welker, J. M. 2015. Isotopic (d¹³C, d¹⁵N) characteristics of Beaufort Sea polar bear tissues and diet: food web ecology of a top predator. Polar Biology DOI: 1007/s00300-015-1665-4

  Baltensperger, A. P., Hüttmann, F., and Welker, J. M. Quantifying trophic niche spaces of small mammals using stable isotopes (δ¹⁵N and δ¹³C) at two scales across Alaska. Canadian J of Zoology 93: 579-588.

  Vander Zanden, H. B., Wunder, M., Hobson, K., Van Wilgenburg, S., Wassenaar, L., Welker, J. M., and Bowen, G. J. Space-time tradeoffs in the development of precipitation isotope models for determining migratory origin. J of Avian Biology  DOI: 10.1111/jav.00656.

  Delavau, C., Sun, C., Stadnyk, T., McDonald, J., Birks, J., Welker, J. M. 2015. Time series modeling of precipitation isotopes (δ¹⁸0) across Canada and the northern United States. Water Resources Research- 51:1284–1299.

  Jasechko, S., Lechler, A., Welker, J. M. et al. 2015. Glacial-interglacial shifts in global precipitation δ¹⁸ Climates of the Past 11: 831-872.

  Blok, D., Weijers, S., Welker, J. M., Cooper, E., Michelsen, A., and Elberling, B. 2015. Differential shrub growth and physiological responses to deeper winter snow conditions in high-arctic tundra revealed with a multiple-isotope approach. Ecological Research Letters doi:10.1088/1748-9326/10/4/044008

• 2014 Publications

  Segal AD, Sullivan PF. 2014. Identifying the sources and uncertainties of ecosystem respiration in Arctic tussock tundra. Biogeochemistry 121: 498-503.

  Jasechko, S., Birks, J., Gleeson, T., Wada, Y, Fawceett, P. J., Sharpe, Z., McDonnell, J. J. and Welker, J. M. 2014. The pronounced seasonality of global groundwater recharge. Water Resources Research 50: 8845-8867.

  Winnick, M., Chamberlain, C. P., Cavers, J. K., Welker, J. M. Quantifying the isotopic “continential” effect.  Earth and Planetary Sciences Letters 406: 123-133.

  Vander Zanden, H, Hobson, K. A.,Wassenaar, L. I., Wunder, M. B., Welker, J. M. and  Bowen, G. 2014. Incorporating climate variability into precipitation isoscapes for interpreting animal migration. Methods in Ecology and Evolution DOI: 10.1111/2041-210X.12229.

  Liu, Z., Yoshimura, K., Bowen, G. J., Buenning, N. H., Risi, C., Welker, J. M. and Yuan, F. 2014. PNA-like climate teleconnections in continental North America during the mid- and late Holocene epoch. Nature Communications 5:3701 | DOI: 10.1038/ncomms4701

  Cable, J., Olge, K., Bolton, D., Bentley, L., Romonvsky, V., Iwata, H., Harazona, Y., and Welker, J. M. 2014. Permafrost thaw effects boreal deciduous plant transpiration through increased soil water, increased thaw and warmer temperatures. Ecohydrology 7: 982-987 DOI: 10.1002/eco.1423.

  Pattison, R., and Welker, J. M. 2014. Differential ecophysiological response of deciduous shrubs and a graminoid to long-term snow reductions and additions in moist acidic tundra, Northern Alaska. Oecologia 174: 339-350.

• 2013 Publications

  McNown RW, Sullivan PF. Low photosynthesis of treeline white spruce is associated with limited soil nitrogen availability in the Western Brooks Range, Alaska. Functional Ecology 27: 672-683.

  Ives SL, Sullivan PF, Dial R, Berg EE, Welker JM. 2013. CO₂ exchange along a hydrologic gradient in the Kenai Lowlands, AK: feedback implications of wetland drying and vegetation succession. Ecohydrology 6: 38-50.

  Sharp ED, Sullivan PF, Steltzer H, Czank AZ, Welker JM. 2013. Complex carbon cycle responses to multi-level warming and supplemental summer rain in the High Arctic. Global Change Biology 19: 1780-1792. 

  Liu, Z., Bowen, G., Yoshimura, K., and Welker, J. M. 2013. Pacific North American teleconnection controls on precipitation isotopes (δ¹⁸O) across the contiguous USA and adjacent regions. Climate doi:10.1175/JCLI-D-13-00334.1. 

  Leffler, J. and Welker, J. M. 2013. Long-term increases in snow elevate leaf N and photosynthesis in Salix arctica: response to a snow fence experiment in NW Greenland. Environmental Research Letters 8, 025023

  von Biela, V. R., Zimmerman, C. E., Cohn, B. R., and Welker, J. M. 2013. Evidence of multiple carbon sources and prey communities in young-of-the-year Arctic cisco (Coregonus autumnalis) using d¹³C, d¹⁵N and diet analyses. Polar Biology 36: 137-146

  Winnick, M., Welker, J. M., and Chamberlain, P. 2013. Stable Isotope evidence of El Nino like circulation in Pliocene western United States.  Climate of the Past 9: 903-912.

  Causey, D., Welker, J. M., Burnham, K., Padula, V. M., Bargmann, N. A. 2013. Fine-Scale Temporal and Spatial Patterns of a High Arctic Marine Bird Community. In: Responses of Arctic Marine Ecosystems to Climate Change Franz J. Mueter, Danielle M.S. Dickson, Henry P. Huntington, James R. Irvine, Elizabeth A. Logerwell, Stephen A. MacLean, Lori T. Quakenbush, and Cheryl Rosa (editors)

  Zeno, F., Siegel, D., Soumitri, S., Dasgupta, D, Glaser, P., Welker, J. M. 2013. Stable isotopes of peat pore water show seasonal recharge vertically penetrates both circumboreal bogs and fens. Hydrological Processes 1002/hyp.9983.

• 2012 Publications

  Welker, J. M. ENSO effects on the isotopic (δ¹⁸O, δ²H and d-excess) of precipitation across the US using a long-term network (USNIP). Rapid Communication in Mass Spectrometery 17: 1655-1660.

  Kikuchi, C., Ferre, T. P., and Welker, J. M. 2012. Groundwater-surface water interactions in an Alaskan freshwater stream. Journal of Hydrology.  doi:10.1016/j.jhydrol.2012.04.002.

  Van Wilgenburg, S. L., Hobson, K. A., Brewster, K. R., and Welker, J. M. 2012. Assessing dispersal in threatened migratory birds using stable hydrogen isotope (dD) analysis of feathers. Endangered Species Research. 16: 17-29. doi:10.3354/esr00383.

  Liu, Z., Bowen, G., Welker, J. M., and Yoshimura, K. 2012. Winter precipitation isotope gradients (δ¹⁸O) of the contiguous USA and their relationship to the Pacific/North American (PNA) pattern. 2012. Climate Dynamics 1007/s00382-012-1548-0.

  Werner, C., Welker, J. M., et al. 2012. Progress and challenges in using stable isotopes in trace plant carbon and water relations across scales. Biogeosciences Discussions. 9: 3083-3111 (Online Journal).

• 2011 Publications
   

  Sullivan PF, Sveinbjörnsson B. Environmental controls on needle gas exchange and growth of white spruce (Picea glauca) on a riverside terrace near the Arctic treeline. Arctic, Antarctic and Alpine Research 43: 279-288.

  Rogers MC, Sullivan PF, Welker JM. 2011. Evidence of nonlinearity in the response of net ecosystem CO₂ exchange to increasing levels of winter snow depth in the High Arctic of northwest Greenland. Arctic, Antarctic and Alpine Research 43: 95-106.

  Miles, G. R., Mitchell, M, J., Mayer, B., Likens, G., Welker, J. M. 2011. Long-term analysis of Hubbard Brook stable oxygen isotope ratios of stream water and precipitation sulfate. Biogeochemistry doi:10.1007/s10533-011-9670-3.

• 2010 Publications

  Sullivan PF, Arens SJT, Sveinbjörnsson B, Welker JM. 2010. Modeling the seasonality of belowground respiration along an elevation gradient in the western Chugach Mountains, Alaska. Biogeochemistry 101: 61-75.

  Sullivan PF, Sveinbjörnsson B. 2010. Microtopographic control of treeline advance in Noatak National Preserve, northwest Alaska. Ecosystems 11: 275-285.

  Sullivan PF. 2010. Snow distribution, soil temperature and late winter CO₂ efflux from soils near the Arctic treeline in northwest Alaska. Biogeochemistry 99: 65-77.

  Sullivan PF, Arens SJT, Chimner RA, Welker JM. 2008. Temperature and microtopography interact to control carbon cycling in a high arctic fen. Ecosystems 11: 61-76.

  Vachon, R. W., Welker, J. M., White, J. W. C., and Vaughn, B. H. 2010. Monthly precipitation isoscapes (δ¹⁸O) of the United States: Connections with surface temperatures, moisture source conditions, and air mass trajectories. JGR Atmospheres. 115: doi:10.1029/2010JD014105.

  Vachon, R. W., Welker, J. M., White, J. W. C., and Vaughn, B. H. 2010. Moisture source temperatures and precipitation d¹⁸O-temperature relationships across the US. Water Resources Research. 46: W07523. doi:10.1029/2009WR008558.

  Liu, Z., Bowen, G., and Welker, J. M. 2010. Atmospheric circulation is reflected in precipitation isotope gradients over the conterminous United States. JGR Atmospheres. 115: D22120. doi:10.1029/2010JD014175.

• 2009 Publications

  Sjostrom, D. and Welker, J. M. 2009. The influence of air mass source on the seasonal isotopic composition of precipitation, eastern USA. Journal of Geochemical Exploration-Isoscapes Special Issue. 102(3):103-112. doi:10.1016/j.gexplo.2009.03.001.

  Still, C. J., Riley, W.J., Biraud, S.C., Noone, D.C., Buenning, N.H., Randerson J.T., Torn, M.S., Welker, J. M., White, J.W.C., Vachon, R., Farquhar, G.D., and Berry, J.A. 2009. The influence of clouds and diffuse radiation on ecosystem-atmosphere CO₂ and CO¹⁸O exchanges. Biogeosciences. 7: 210-217. doi:10.1029/2007JG000675.

• 2008 Publications

  Arens SJT, Sullivan PF, Welker JM. Nonlinear responses to nitrogen and strong interactions with nitrogen and phosphorus additions drastically alter the structure and function of a high arctic ecosystem. Journal of Geophysical Research 113: G03S09.

  Steltzer H, Hufbauer RA, Welker JM, Casalis M, Sullivan PF, Chimner RA. 2008. Frequent sexual reproduction and high intraspecific variation in Salix arctica: implications for a terrestrial feedback to climate change in the High Arctic. Journal of Geophysical Research 113: G03S10.

• 2007 Publications

  Sullivan PF, Sommerkorn M, Rueth HM, Nadelhoffer KJ, Shaver GR, Welker JM. 2007. Climate and species affect fine root production with long-term fertilization in acidic tussock tundra near Toolik Lake, Alaska. Oecologia 153: 643-652.

  Sullivan PF, Welker JM. Variation in leaf physiology of Salix arctica within and across ecosystems in the High Arctic: test of a dual isotope conceptual model. Oecologia 151: 372-386.

• Thesis

  Ellison SBZ. 2015. Can divergent white spruce growth in the eastern Brooks Range be explained by low soil nutrient availability? MS Thesis. University of Alaska Anchorage

  Gamm CM. 2015. Declining growth of Arctic shrubs in a warming climate: species-specific effects of drought and herbivory in West Greenland. MS Thesis. University of Alaska Anchorage

  Brownlee AH. 2014. Carbon isotope discrimination in tree ring alpha-cellulose indicates that drought stress cannot explain white spruce growth declines in the eastern Brooks Range, Alaska. MS Thesis. University of Alaska Anchorage

  MacNeille, M. 2014. Seasonal accumulation of anthocyanin pigmentation is too late to protect photosynthesis or nitrogen resorption in three widespread high-latitude plants. MS Thesis. University of Alaska Anchorage

  Stanek, A. 2014. Dietary ecology of Alaskan gray wolves: Variation in seasonal foraging strategies in a salmon subsidized ecosystem. MS Thesis. University of Alaska Anchorage

  Templin, JP. 2014. Using the doubly labeled water method to measure field metabolic rate in northern red-backed voles, Myodes rutilus. MS Thesis. University of Alaska Anchorage

  Carney, B. 2013. Diet patterns of black oystercatchers (Haematopus bachmani) in the northern Gulf of Alaska. MS Thesis. University of Alaska Anchorage

  Mazzacavallo, M. 2012. Rooting out the difference: A quantitative test of the two-layer hypothesis in a sub-tropical African savanna. MS Thesis. University of Alaska Anchorage

  McNown RW. 2012. Low photosynthetic rates of treeline white spruce are associated with limited soil nitrogen availability in northwest Alaska. MS Thesis. University of Alaska Anchorage

  Segal AD. 2012. Root and microbial respiration dominate CO₂ efflux in an arctic ecosystem. MS Thesis. University of Alaska Anchorage

  Ives S. 2010. CO₂ exchange along a hydrologic gradient in the Kenai Lowlands, AK: feedback implications of wetland drying and vegetation succession. MS Thesis. Alaska Pacific University