Jefferey Welker

Jeffery Welker

Biological Sciences
ELB 117


  • Ph.D. Department of Rangeland Ecology and Management, Texas A&M, University, College Station, TX, 1985. Carbon and nitrogen cycling in native bunchgrass plants.
  • M.S. Range Science, Range and Animal Science Department, Montana State University, Bozeman, MT,1982. Climate change affects on prairie vegetation.
  • B.S. Agriculture-Range Science Major, Range and Animal Science Department, Montana State University, Bozeman, MT, 1980.

Research Interests

The Welker lab's research program centers on three main themes:

Precipitation & Water Cycle Isotope Geochemistry: Quantifying continental-scale processes and patterns in the isotope geochemistry of precipitation, river and lake water as a means to understand the ecohydrology of landscapes and the recording of climate records in proxies such as ice cores, tree rings and speleothems.

Wildlife, Food Web and Migration Ecology: Characterizing Arctic and Boreal carnivore and ungulate diets, landscape use and home ranges using isotope forensics and location information in the study of gray wolves, polar bears, caribou, white-fronted geese, tundraswans, seabirds and shore birds.

High and Low Arctic Ecosystems and Climate Change: Quantifying experimental and observational water, carbon and N cycling responses at the plant and ecosystem-scale of polar semi-deserts, tussock and dry tundra responses to long-term warming, deeper snow and increases in summer precipitation.


  • 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 (in press)
  • 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 (in press)
  • Pattison, R., R., Jorgenson, J. C., Raynolds, M. K., and Welker, J. M. (2015). Trends in NDVI and tundra community composition for in the Arctic National Wildlife Refuge, Alaska from 1988 to 2009. Ecosystems (in press).
  • Rogers, M. C., O'Dell, M. B., Peacock, E. L., Simac, K., and Welker, J. M. (2015). Isotopic (13C, 15N) characteristics of Beaufort Sea polar bear tissues and diet: food web ecology of a top predator. Polar Biology (in press)
  • 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-DOI: 10.1002/2014WR015687
  • Semenova, T. A., Morgado, L, N., Welker, J. M., Walker, M. D., Smets, E. and Geml, J. Long-term experimental warming alters community composition of ascomycetes in Alaskan moist and dry tundra. Journal in Molecular Ecology DOI: 10.1111/mec.13045
  • 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 ResourcesResearch 50: 8845-8867.
  • Healey, N. Oberbauer, S., Ahrends, H., Dierick, D., Leffler, J. and Welker, J. M., Holliser, R., and Tweedie, C. (2014). A Mobile Instrumented Sensor Platform for Long-term Terrestrial Ecosystem Observation: A Case Study in the Arctic. J of Environmental Informatics 24: 1-10
  • Winnick, M., Chamberlain, C. P., Cavers, J. K., Welker, J. M. (2014). Quantifying the isotopic "continential" effect. Earth and Planetary Sciences Letters 406: 123-133.
  • Morgado, L., Semenova, T., Welker, J. M.,Walker, M., Smets, E. and Geml. J. (2014). Summer temperature increases have distinct effects on ectomycorrhizal fungal communities of moist tussock and dry tundra in Arctic Alaska. Global Change BiologyDOI: 10.1111/gcb.12716.
  • 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
  • Herman, R. L., Cherry, J., Cable, J., Welker, J. M., Noone, D., Sodemann, H. and Worden, J. (2014). Aircraft Validation of Tropospheric Emission Spectrometer Retrievals of HDO and H2O. Atmospheric Measurement Techniques doi:10.5194/amtd-7-3801-2014.
  • Cable, J., Olge, K., Bolton, D., Bentley, L., Romonvsky, V., Iwata, H., Harazona, Y., andWelker, 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
  • Lupascu, M., Welker, J. M., Xu, X. and Czimczik, C. I. (2014). Rates and radiocarbon content of summer ecosystem respiration in response to long-term deeper snow in the High Arctic of NW Greenland  JGR Biogeoscience DOI: 10.1002/2013JG002494
  • Lupascu, M., Welker, J.M., Seibt, U., Xu, X., Velicogna, I., Lindsey, D. S. and Czimczik, C. I.  (2014). The amount and timing of precipitation control the magnitude,seasonality and sources (14C) of ecosystem respiration in a polar semi-desert, NW Greenland.Biogeoscience Discussion- 11, 2457–2496.
  • Lupascu, M., Welker, J. M., Seibt, U., Xu, X., Lindsey, D. S., Czimczik, C. I. (2013). The magnitude, seasonality and sources of CO2 emissions in a High Arctic polar semi-desert in NW Greenland are controlled by precipitation in puts and soil water conditions. Nature Climate Change 4, 51–55.
  • 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)
  • 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. J. Climate doi:10.1175/JCLI-D-13-00334.1.
  • Oberbauer, S. F., Elmendorf,, S. C., Troxler, T., Hollister, R. D., Welker, J. M., et al. (2013). Phenological responses of tundra plants to background climate variation tested using the International Tundra Experiment (ITEX) Proceedings of the Royal Academy 8025023.
  • 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 10.1002/hyp.9983.
  • 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
  • Schaeffer, S. M., Sharp, E., Schimel, J. and Welker, J. M. (2013). Soil N processes in the High Arctic: Responses to a long-term multi-level warming and added summer water experiment. Global Change Biology DOI: 10.1111/gcb.12318.
  • Sharp, E., Sullivan, P., Steltzer, H., Csank, A., and Welker, J. M. (2013). Complex carbon cycling responses to multi-level warming and supplemental summer rain in a High Arctic ecosystem. Global Change Biology DOI: 10.1111/gcb.12149, V 19: 1780-1792.
  • 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 δ13C, δ15N and diet analyses. Polar Biology 36: 137-146.
  • Tape, K. D., Hallinger, M., Welker, J. M., and Ruess, R. W. (2012). Landscape heterogeneity of shrub expansion in Arctic Alaska. Ecosystems doi:10.1007/s10021-012-9540-4.
  • Elmendorf, S., Henry, G. H. R., Hollister, R. D., Welker, J. M. et al. (2012a). Plot-scale evidence of tundra vegetation change to recent summer climate warming. Nature Climate Change. 2: 453-457. doi:10.1038/nclimate1465.
  • Elmendorf, S., Henry, G. H. R., Hollister, R. D., Welker, J. M., et al. (2012b). Global assessment of experimental climate warming on tundra vegetation: Heterogeneity over space and time. Ecology Letters. 15(2): 164-175. doi: 10.1111/j.1461-0248.2011.01716.x.
  • Welker, J. M. (2012). 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.
  • 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 (δD) analysis of feathers. Endangered Species Research. 16: 17-29. doi:10.3354/esr00383.
  • 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.
  • 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 (OnlineJournal).
  • Cahoon, S. M. P., Sullivan, P. F., Post, E., and Welker, J. M. (2012). Large herbivores limit CO2 uptakeand suppress carbon cycle responses to warming in West Greenland. Global Change Biology. 18(2): 469-479. doi:10.1111/j.1365-2486.2011.02528.x.
  • 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 10.1007/s00382-012-1548-0.
  • Cahoon, S., Sullivan, P. F., Shaver, G. R., Welker, J. M., and Post, E. (2012). Interactions among shrub cover and microclimate may determine future carbonbudgets. Ecology Letters 15: 1415-1422 doi: 10.1111/j.1461-0248.2012.01865.x.
  • Timling, L., Dahlbert, A., Walker, D. A., Gardes, M., Charcosset, J. Y., Welker, J. M. and Taylor, D. L. (2012). Distribution and drivers of ecotomychorrhizal fungal communities across the North American Arctic. Ecosphere 3: 1-25.

Career History/Work Experience


46 awards, exceeding $18,000,000)
(16 awards ~$9,000,000 since 2004, ~$6,000,000 to UAA) 

Selected Grants

1.        Oberbauer, S., Welker, J.M., Tweedie, C., and Hollister, R. (2014) Collaborative Research: Sustaining and amplifying the ITEX AON through automation and increased interdisciplinarity of observations. NSF Division of Polar Programs, Arctic Observing Network. $467,000.

2.   Beard, K., Welker, J. M. and Leffler, J. (2013) Collaborative Research: Tropic mismatch between geese and wet sedge tundra. National Science Foundation, Office of Polar Programs, $1,277,065.

3.         Welker, J. M. and Spalinger, D. (2012) Comparative ecology of caribou heards across Alaska: Collaborations between USFWS Land Conservation Consortiums. USGS Alaska Climate Science Center, $59,988.

4.         Welker, J M., Cable, J., and Cherry, J. (2012) EAGER-Collaborative Research: Quantifying changes in the Arctic hydrological cycle at the landscape scale using advances in water vapor isotope (d18O and dD) techniques and aircraft. National Science Foundation, Office of Polar Programs, $288,000.

5. Post, E., Sullivan, P. F., Welker, J. M., and Eissenstat, D. M. (2011) Collaborative Research: Linking belowground phenology and ecosystem function in a warming Arctic. National Science Foundation, Office of Polar Programs. $1,300,000.

6. Gonzalez-Meler, M., Sturchio, N., Welker, J. M., and Filley, T.R. (2011)  Collaborative Research: Permafrost thawing and vegetation change and effects on cryoturbation rates, CO2 and CH4 processes. Department of Energy, Terrestrial C cycle Research Program. $1,010,000.

7. Spalinger, D. E., Welker, J. M., Sullivan, P. F., and Collins, W. (2011) The Tundra in Transition: Unraveling the Dynamics of Western Alaska Caribou – Tundra Ecosystems. USFWS LCC program. $200,000.

8. Campbell, R., Welker, J. M., Crusius, J., Gasso, S., Schroth, A., and Thomas, A. (2010) Collaborative Research: Melting ice, habitat change and nutrient flux: Hydrological, biogeochemical and biological linkages between the Copper River watershed and the coastal Gulf of Alaska. NASA. $1,388,000.

9. Welker, J. M. (2010). Grey wolf diet ecology in Lake Clark National Park. National Park Service, Anchorage, Alaska. $102,766.

10. Welker, J. M., Buck, C. L., van Tets, I. G., Burns, J. M., and Cable, J. (2009) MRI Acquisition: Detecting and monitoring changes in the arctic using stable isotope techniques: A facility that contributes to IPY, NEON and beyond. NSF Major Research Instrumentation. $588,000. 

11. Oberbauer, S., Welker, J. M., Sullivan, P. F., Tweedie, C., and Hollister, R. (2008)Collaborative Research: Sustaining and amplifying the ITEX AON through automation and increased interdisciplinarity of observations. NSF Office of Polar Programs, Arctic Observing Network. $1,233,000.

12. Czimczik, C. I., Welker, J. M., Sullivan, P. F., and Schimel, J. (2008) Collaborative Research: Processes governing the ages (14C) and magnitudes of ecosystem respiration in the High Arctic. NSF Office of Polar Programs. $1,250,000.

13. Cable, J., and Welker, J. M. (mentor). (2009) The consequences of permafrost degradation on plant-water use strategies. NSF Office of Polar Programs, Postdoctoral Fellowship. $208,000.

14. Hagedorn, B., Perry, M., Spalinger, D. E., and Welker, J. M. (2008) Enhancing Research and Education at the University of Alaska Anchorage with a state-of-the-art Liquid Chromatograph-Ion Trap Mass Spectrometer. NSF Major Research Instrumentation.  $411,000. 

15. Welker, J. M., Sveinbjörnsson, B., Sullivan, P. F. (2006) Mechanisms and feedback consequences of shrub expansion following long-term increases in winter snow depth in northern Alaska: a legacy for IPY.  National Science Foundation, Office of Polar Programs. $622,000.

16. Welker, J. M., Sveinbjörnsson, B., Sullivan, P. F., and Boggs, K. (2006) IPY: Collaborative Research: Study of arctic ecosystem changes in the IPY using the International Tundra Experiment.  NSF Office of Polar Programs. $257,000.

17. Welker, J. M., Sveinbjörnsson, B., Peterson, K., Olsson, P., Boggs, K, and Carlson, M. (2005) The UAA Boreal Forest Environmental Observatory (BFEO): A campus-based education and research platform that engages undergraduates and strengthens national funding competitivenessUAA Enhancement Fund.  $130,000. 

18. Welker, J. M., Wipfli, M., and Rinella, D. (2005) UAA & UAF Collaborative Research: Comparative marine-terrestrial nitrogen linkages in streams of the Kenai Peninsula. UAA’s Chancellor’s Fund. $24,500.

19. Welker, J. M., Hallet, B., Sletten. R., Schimel, J., and Fahnestock, J. T. (2002) Collaborative Research: Coupling of carbon and water cycles in a cold, dry ecosystem: Integrative physical, chemical and biological processes and their controls on CO2 exchange. National Science Foundation, Biocomplexity in the Environment. $1,700,000. 

20. Welker, J. M., and Fahnestock, J. T. (2001) Mixedgrass Prairie Responses to Simultaneous Increases in Winter Snow Depth and Changes in Summer Rainfall: C, N and H2O dynamics. National Institute of Global Climate Change, Great Plains Region, Department of Energy. $360,000.

21. Welker, J. M., Vance, G., Stahl, P. D., and Fahnestock, J. T. (2001) Controls of C sequestration on Northern Rocky Mountain Rangelands. USDA-NRI. $180,000. 

22. Welker, J. M. and White, J. (2000) Isotopic (d18O & dD) characteristics of precipitation across the U. S.: Temporal patterns and controlling processes. National Science Foundation, Earth System History Program.  $465,000.

23. Lockwood, J., Welker, J. M., and Kazmer, D. (2000) The Pied Piper IPM Strategy: Attracting rangeland grasshoppers with plant oils. USDA CSREES.  $200,000.

24. Welker, J. M., Fahnestock, J. T., and Bilbrough, C. J. (1999) Species responses to changes in climate across arctic gradients using the North American ITEX network (NATEX): influences on community and ecosystem processes. NSF Office of Polar Programs. $475,000. 

25. Molau, U., Henry, G., and Welker, J. M. (1998) Climatic impacts on annual growth and physiology in Cassiope tetragona. Swedish Royal Academy of Science, Polar Directorate, Tundra Northwest Expedition 1999.  $150,000.

26. Welker, J.M., Poulson, S. Smith, W.K., Drever, T., Jackson, S. (1998) A stable isotope facility to study terrestrial processes and their interactions with climate and the environment. National Science Foundation. Major Research Instrumentation. $335,000.